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Introduction To prevent and treat thrombotic complications in patients hospitalized with severe COVID-19 infection, anticoagulation treatments primarily with heparin and low molecular weight heparin have been recommended. Heparin-induced thrombocytopenia (HIT) is a rare but conceivably fatal reaction to heparin that is characterized by a sudden drop in platelet count accompanied by new onset of thrombosis 4-10 days after heparin exposure. The purpose of this retrospective study was to investigate the prevalence of thrombocytopenia and HIT in hospitalized COVID-19 patients, as well as their association with mortality. Methods 3,672 plasma samples were collected from patients admitted to the first wave of COVID-19 in our institution at New York City (March to May 2020). All patients admitted with a platelet count of less than 150 k/ul were assigned to the thrombocytopenic group. In addition, two groups with similar demographics and normal platelet counts were randomly selected based on discharge outcome: alive vs. deceased (n= 88 per group). PF4 IgG Elisa and heparin neutralization were carried out in accordance with the manufacturer's instructions. A positive HIT result required an optical density (OD) greater than 0.4 and heparin neutralization greater than 50%. Statistical analysis was done in R studio (V.1.4.1717) to analyze demographics (age, gender, ethnicity), initial laboratory data, anticoagulation on admission, and thrombosis. Results Only 86 of the 3,672 (2.3%) patients admitted had thrombocytopenia. Only 1 of the 86 patients tested positive for HIT (1.1%). 4 cases of the non-survivors (4.5%) tested positive for HIT compared to none of the survivors in the two groups with normal platelet counts. One of these 4 cases had a history of thrombosis (DVT). Interestingly, the PF4 Elisa ODs in non-survivors were significantly higher than in survivors (0.09 vs. 0.06, p-value< 0.001). Although the platelet count did not differ significantly between the two groups, the mean platelet volume (MPV) on admission and its maximum peak during hospitalization were significantly higher in non-survivors than in survivors. Conclusions We only found HIT positive cases among non-survivors, implying that HIT is associated with COVID severity. The incidence of HIT in severe COVID-19 patients appears to be higher than the pre-COVID-19 historical rates of HIT in hospitalized patients (<1%). Although thrombocytopenia is relatively uncommon in COVID-19 patients, the MPV was significantly higher in non-survivors, suggesting that platelet activation and destruction may explain the higher rate of HIT in COVID-19.
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Introduction Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare, but severe side effect after vaccination with adenovirus vector-based vaccines (ChAdOx1 nCoV-19, AstraZeneca and Ad26.COV2.S, Johnson & Johnson/ Janssen) in which platelet activating anti-platelet factor 4 (PF4) antibodies cause thrombocytopenia and thrombosis at unusual sites. Patients and treating physicians are concerned about whether other vaccinations can also trigger thrombosis in patients with a history of VITT. We showed that VITT patients can safely receive their second and third vaccination against Covid-19 with an mRNA-based vaccine. [1] However, there is limited information on whether other vaccines than against Covid-19 could booster platelet activating anti-PF4 antibodies. Uncertainty increased after a report of VITT caused by human papilloma vaccination. [2] Method In our follow-up study of patients with laboratory confirmed VITT (EUPAS45098), an anti-PF4/heparin IgG enzyme immune assay (EIA) and a PF4-dependent platelet activation assay (PIPA) were performed at regular intervals and after each vaccination reported to us. Results Seventy-one VITT patients (43 female, median age at VITT diagnosis 48, range 18-80) were followed for a median of 56 weeks (range: 13-77 weeks). During the follow-up period, eight vaccinations other than against Covid-19 were reported: Six vaccinations against influenza (three Influvac, two Vaxigrip Tetra, one Influsplit Tetra) and two consecutive vaccinations against tick-borne encephalitis (TBE) in one patient. In six patients who received vaccination against influenza, all patients showed decreasing or stable EIA optical density (OD) levels. None of them showed a reactivation of platelet-activating anti- PF4-antibodies in the PIPA. The patient who was vaccinated against TBE twice showed stable EIA OD levels and remained negative in the PIPA throughout. No new thrombosis or recurrent thrombocytopenia were observed after any vac- cination. Five out of six patients still received therapeutic anticoagulation, one patient did not receive any anticoagulative drug (Fig. 1). Conclusion Similar to observations after consecutive mRNA-vaccinations against Covid-19 in VITT patients, vaccinations against influenza and TBE very unlikely reactivate platelet-activating anti-PF4-antibodies. Further follow up of the VITT patient cohort is performed to detect any new safety signal related to recurrence of VITT. (Table Presented).
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Background: Adapted anti-SARS- CoV- 2 vaccination schedules have been recommended for patients with IMID due to a higher risk of reduced vaccine response. Nonetheless, there is little data on how different vaccine schedules influence immune responses and on the long-term persistence of vaccination responses in this subset. Purpose(s): The aim of this study is to assess the long-term course of humoral responses to SARS-CoV- 2 vaccines in a large prospective cohort of IMID patients and non-IMID controls with up to 10 months of follow-up following the first vaccine dose. Method(s): In February 2020, we started a prospective cohort of IMID patients and healthy controls (HC) to evaluate immune responses to SARS-CoV- 2 vaccines and infection (1). Individuals who provided data starting 4 weeks before their first vaccination and forward were included. Serum anti-SARS- CoV- 2 spike protein IgG were measured by ELISA (EUROIMMUN, Lubeck, Germany) in units of Optical density (OD) at 450 nm. An OD <1.1 was considered as poor response. We used time splines to fit linear mixed-effect models for log-transformed antibody levels and logistic mixed-effects models, adjusting for age and sex to estimate marginal mean antibody levels and adjusted risk of poor response with 95 percent confidence intervals. Antibody levels of twice-vaccinated patients were also compared to those who received 3 vaccinations. Result(s): Between December 2020 and December 2021, 3733 IMID patients and HC contributed 5564 samples, with a median (IQR) follow-up of 23.3 (13.9-0.9) weeks following first immunization (Table 1). By the date of their most recent sampling, 3280 (88%) participants had received two vaccines and 241 (6%) received three. Age and sex-adjusted estimated marginal mean IgG in IMID patients declined after week 10 and were significantly lower at all timepoints compared to controls (Figure 1A, Table 1). Adjusted risk of poor response at week 40 was 2.9% (1.4%-6.1%) in HC whereas 26.1% (15.8-40.0) in IMID (Figure 1B). After a median 20 (10-26). weeks from the second dose, 147 (6%) IMID patients had received a third dose. Adjusted mean antibody levels at 40 weeks in IMID patients who received three vaccine doses were higher than in HC who received two doses (Figure 1C). Conclusion(s): IMID patients had a weaker humoral response to SARS-CoV- 2 vaccination than controls at all time points following the first dose with a high risk of poor response at 40 weeks. Nonetheless, a third dose in IMID patients could provide higher antibody levels compared to unboosted healthy individuals.
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Background: As COVID-19 is associated with a prothrombotic condition and some critically ill patients may even undergo extracorporeal oxygenation treatment, heparin is the essential for treatment in these situations. The prevalence of anti-platelet factor 4 (PF4)/heparin antibodies associated with thrombotic tendency may be present in patients hospitalized for COVID-19 without heparin therapy. Lupus anticoagulant (LA) included in the diagnostic criteria for antiphospholipid syndrome, which is one of the common causes of thrombophilia, is also commonly detected during SARS-CoV- 2 infection. Most patients hospitalized for COVID-19 showed elevated D-dimer and prolonged activated partial thromboplastin time (aPTT), However, there were no studies on the association of SARS-CoV- 2 infection with LA and anti-PF4/ heparin antibodies. Aim(s): The purpose of this study was to analyze the expression of LA and anti-PF4/ heparin antibodies associated with thrombotic tendency in COVID-19 patients. Method(s): We performed LA test (Instrumentation Laboratory, Bedford, MA) and LIFECODES PF4 IgG assay (Immucor, Norcross, GA) on 46 COVID-19 patients admitted to Asan Medical Center and analyzed their frequency. Result(s): Of a total of 46 COVID-19 patients, 26 patients (56.5%) were positive for LA test, 3 patients (6.5%) for anti-PF4/ heparin antibodies. In particular, anti-PF4/ heparin antibodies was detected only in LA-negative patients and showed low optical density values (3 out of 20 LA-negative patients, 15.0%). All three patients positive for anti-PF4/ heparin antibodies had no history of heparin treatment. Conclusion(s): In COVID-19- patients, anti-PF4/ heparin antibody test does not predict clinically relevant HIT antibodies. Anti-PF4/ heparin antibodies appear in LA-negative COVID-19 patients, so they are carefully expected to serve as LA-independent indicators. (Table Presented).
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Purpose: To evaluate post-vaccination cellular and antibody (Ab) immunity after COVID-19 vaccination in single blood samples from 17 kidney transplant (KT) recipients who had received COVID-19 vaccination Methods: We measured frequencies of peripheral blood T- and B-cells which expressed the inflammatory marker CD154 after overnight stimulation with peptide mixtures representing the spike protein S, its S2 component which is conserved between SARS-CoV-2 and human coronaviruses, and the S1 component, which is specific to SARS-CoV-2 and also contains its receptor binding domain (RBD). Serum from each sample was assayed for anti-RBD and anti-S IgG Abs with ELISA. Optical density at 450nm (OD450) of 0.45 or greater implied presence of either Ab. Frequencies of monocytic and polymorphonuclear (PMN) myeloid-derived suppressor cell were also measured with flow cytometry. Result(s): Median age was 40 yrs (range 25 to 83), male:female gender distribution was 7:8. All recipients received mRNA vaccination. Anti-S-IgG and anti-RBD-IgG were detected in 11 (Ab+) and were absent in four (Ab-). Compared with Ab+ KT recipients, those who were Ab- had lower frequencies of S2-reactive and S-reactive B-cells (p<0.05), CD4+ and CD8+ T-cells (Table 1, Fig 1). S1-reactive T-cell and B-cells were non-detectable. Frequencies of PMN-MDSC were numerically higher in Ab- compared with Ab+ KT recipients (Mean +/- SEM 38.9+/-8.1 vs 19.4+/-1.8, p-value 0.1, NS). Significant negative correlation was observed between PMN-MDSC frequencies and strength of anti-RBD IgG and anti-SPIKE IgG (Fig 1). Conclusion(s): COVID-19 vaccination results in spike antigen reactive T- and B-cells in KT recipients who develop Abs after vaccination. Failure of an Ab response is associated with impaired B-cell responses to the spike antigen and an increase in circulating polymorphonuclear myeloid derived suppressor cells. (Table Presented).
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Background: The frst vaccine against SARS-CoV-2 was approved in December 2020. Immunogenicity of SARS-CoV2 vaccines in patients with immune-mediated infammatory disease (IMID) have so far been evaluated in the 2-6 weeks following complete vaccination and risk groups for poor early vaccine response have been identifed leading to specifc vaccination recommendations. However, data on the long-term course and persistence of vaccine response in IMID patients, as well as the outcomes of the specifc recommendations are lacking. Objectives: To evaluate the long-term course of humoral response to SARS-CoV-2 vaccination in a large prospective cohort of IMID patients and non-IMID controls with a follow-up duration of up-to to 10 months after the frst vaccine dose. Methods: We have initiated a prospective dynamic cohort of IMID patients and healthy controls in February 2020 to monitor immune response to SARS-CoV-2 and respiratory infections including COVID-19 (1). Participants who contributed data starting from the 4 weeks before their frst vaccination onwards were included in this analysis. Antibodies against SARS-CoV-2 spike protein were quantifed with an ELISA from Euroimmun (Lübeck, Germany) with an optical density cutoff of 0.8. We ftted linear mixed-effect models for log-transformed antibody levels using time splines with adjustment for age and sex. Marginal mean antibody levels with 95% confdence intervals (CI) were estimated at selected time points for IMID patients and controls with double vaccination. We descriptively analyzed the observed antibody levels over time in cohort participants receiving two vaccinations vs. three vaccinations. Results: Among 5076 cohort participants, 3147 IMID patients and healthy controls (mean (SD) age 49 (16)) provided 4756 samples for this analysis between December 2020 and 2021, with a median (IQR) 28 (14-31) weeks of follow-up after the frst vaccination (Table 1). 2965 (94%) participants had received at least 2 and 223 (7%) participants had received three vaccine doses by the date of their latest sampling. In IMID patients, age and sex-adjusted estimated marginal mean antibody levels waned after week 16 and were substantially reduced at all time points compared to the controls, fnally dropping to the borderline range (1.01, 95%CI 0.86 to 1.19) at week 40 (Figure 1A, Table 1). A third dose was given to 128 (7%) of IMID patients with a poor response to 2 vaccine doses after a median 20 weeks of the second dose (IQR 10 to 26 weeks). After the third dose, antibody levels in IMID patients were comparable to those of healthy controls at 40 weeks who had three vaccine doses. These were also higher than that of IMID patients and controls who did not receive a third dose (Figure 1B). Conclusion: Humoral response to vaccination against SARS-CoV-2 was weaker in IMID patients compared to controls at all time points after the frst vaccine dose and practically disappeared after 1 year. IMID patients can still achieve a good antibody response with a third dose even after a weak response with two doses.
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Background: Patients with immune-mediated infammatory diseases (IMID), particularly if treated with B-cell depleting therapies, show reduced humoral responses to SARS-CoV-2 vaccines and increased risk of severe COVID-19 (1,2). Since pre-exposure prophylaxis (PrEP) with monoclonal antibodies against SARS-CoV-2 proved effective in preventing infection and COVID-19 (3) in the general population, PrEP could be used for passive immunization of vaccine-refractory patients with IMIDs. Objectives: To evaluate the persistence of serum and salivary anti-SARS-CoV-2 IgG antibodies in vaccine-refractory patients with IMID after PrEP with casiriv-imab/imdevimab. Secondary outcomes were safety, SARS-CoV-2 infection, and adverse COVID-19 outcomes. Methods: We performed a longitudinal analysis on anti-SARS-CoV-2 IgG titers in IMID patients who received a PrEP with 1200 mg of subcutaneous casirivimab/imdevimab due to high infection risk, as they had not developed an adequate humoral response at least 21 days after three COVID-19 vaccinations (Table 1). Serum and salivary anti-SARS-CoV-2 Spike IgG were quantifed by ELISA (EUROIMMUN, Lübeck, Germany) before PrEP and after 1, 14, and 30 days. IgG levels are given as antibody ratios by dividing the optical density of the sample by that of the calibrator. A cutoff of ≥1.1 was considered positive. Safety as well as polymerase chain reaction (PCR)-confrmed SARS-CoV-2 infection and adverse COVID-19 outcomes (hospitalization, mechanical ventilation, death) after PrEP were recorded. Results: We obtained 92 serum and 75 saliva samples from 26 participants at four consecutive timepoints (Figure 1). Anti-SARS-CoV-2 IgG titers were observed in serum and saliva samples of all participants from day 1 and throughout 30 days after PrEP independently of diagnosis, therapy, total IgG, and peripheral CD19+ B-cells. Serum IgG increased rapidly at day 1 and plateaued from day 14 to 30 (Figure 1A), reaching similar levels as seen in healthy subjects after full vaccination (1), while saliva IgG increased steadily from administration up to day 14 and plateaued at day 30 (Figure 1B). No side effects were reported. Five patients (19.2%) had a close contact with a SARS-CoV-2-infected person, after which all but one remained asymptomatic and with a negative PCR test. The patient who tested positive developed mild COVID-19 with fever and cough. Conclusion: SARS-CoV-2 PrEP induces stable serum and salivary antibody levels in IMID patients who did not respond to COVID-19 vaccination, regardless of pre-existing clinical and serological features. In IMID, PrEP with casiriv-imab/imdevimab is safe and has the potential to prevent infection and severe COVID-19.
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Reliable and scalable seroepidemiology methods are needed to estimate SARS-CoV-2 incidence and monitor the dynamics of population-level immunity as the pandemic evolves. We aimed to evaluate the reliability of SARS-CoV-2 normalized ELISA optical density (nOD) at a single dilution compared to titers derived from serial dilutions. We conducted serial serosurveys within a community-based cohort in Salvador, Brazil. Anti-S IgG ELISA (Euroimmun AG) was performed with 5 serial 3-fold dilutions of paired sera from 54 participants. Changes in nOD reliably predicted increases and decreases in titers (98.1% agreement, κ = 95.8%). Fitting the relationship between nOD and interpolated titers to a log-log curve yields highly accurate predictions of titers (r2 = 0.995) and changes in titers (r2 = 0.975), using only 1 to 2 dilutions. This approach can significantly reduce the time, labor and resources needed for large-scale serosurveys to ascertain population-level changes in exposure and immunity.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Reproducibility of Results , Seroepidemiologic Studies , Antibodies, Viral , COVID-19/diagnosis , Immunoglobulin GABSTRACT
Background. Measuring SARS-CoV-2 antibody prevalence in spent samples at serial time points can determine seropositivity in a diverse pool of individuals to inform understanding of trends as vaccinations are implemented. Methods. Blood samples collected for clinical testing and then discarded ("spent samples") were obtained from the clinical laboratory of a medical center in Atlanta. A convenience sample of spent samples from both inpatients (medical/surgical floors, intensive care, obstetrics) and outpatients (clinics and ambulatory surgery) were collected one day per week from January-March 2021. Samples were matched to clinical data from the electronic medical record. In-house single dilution serological assays for SARSCoV-2 receptor binding domain (RBD) and nucleocapsid (N) antibodies were developed and validated using pre-pandemic and PCR-confirmed COVID-19 patient serum and plasma samples (Figure 1). ELISA optical density (OD) cutoffs for seroconversion were chosen using receiver operating characteristic analysis with areas under the curve for all four assays greater than 0.95 after 14 days post symptom onset. IgG profiles were defined as natural infection (RBD and N positive) or vaccinated (RBD positive, N negative). Single dilution serological assays for SARS-CoV-2 nucleocapsid antibodies were validated using pre-pandemic and PCR-confirmed COVID-19 patient serum and plasma samples. ELISA optical density (OD) cutoffs for seroconversion were chosen using receiver operating characteristic (ROC) analysis with areas under the curve (AUC) for all four assays greater than 0.95 after 14 days post symptom onset. Results. A total of 2406 samples were collected from 2132 unique patients. Median age was 58 years (IQR 40-70), with 766 (36%) ≥ 65 years. The majority were female (1173, 55%), and 1341 (63%) were Black. Median Elixhauser comorbidity index was 5 (IQR 2-9). 210 (9.9%) patients ever had SARS-CoV-2 detected by PCR, and 191 (9.0%) received a COVID-19 vaccine within the health system. Nearly half (1186/2406, 49.3%) of samples were collected from inpatient units, 586 (24.4%) from outpatient labs, 403 (16.8%) from the emergency department, and 231 (9.6%) from infusion centers. Overall, 17.0% had the IgG natural infection profile, while 16.2% had a vaccination profile. Prevalence estimates for IgG due to natural infection ranged from 24.0% in week 2 to 9.7% in week 5, and for IgG due to vaccine from 4.4% in week 2 to 32.0% in week 6 (Table, Figure 2). Conclusion. Estimated SARS-CoV-2 IgG seroprevalence among patients at a medical center from January-March 2021 was 17% by natural infection, and 16% by vaccination. Weekly trends likely reflect community spread and vaccine uptake.
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Background:Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV2), spreads mainly through respiratory drop- lets, aerosols and indirectly through contaminated fomites. Healthcare workers (HCWs) are particularly at risk of infec- tion when caring for such patients. Demonstration of antibodies especially IgG helps to identify the prevalence of SARS - CoV2 infection. Methods:The study was conducted in a 212 bed hospital in Mumbai with a 52 bed isolation facility for COVID 19 pa- tients which included 16 intensive care monitoring beds. The study was conducted between the 3rd and 4th week of July 2020. SARS-CoV2 Total (IgA, IgM & IgG) and IgG antibodies were performed from serum samples using the chemilu- minescence on the VITROS 3600 (Orth clinical diagnostics, USA). The target antigen was the spike protein. Past history of SARS-CoV2 infection by way of PCR was also noted. The cut off optical density (OD) value used for both antibodies was greater than 1. Results:A total of 473 HCWs were tested for total and IgG antibodies. Of these, 294 (62.15%) had been previously tested for SARS-CoV2 PCR either as symptomatic HCWs or as those in high risk contact with positive cases.179 (37.85%) HCWs never went through a PCR. Of these, 28/179(15.64%) HCWs seroconverted indicating asymptomatic past infection. Among the 294 HCWs who were tested by PCR, 88(29.93%) were positive. 22.72% (20/88) PCR positive HCWs did not seroconvert and produce either antibodies. Of the 207 HCWs who were PCR negative, 52(25.12%) seroconverted with either one of the antibodies. Conclusions:The study observed high rates of seroconversion among those who had never tested (15.64%) and those who were PCR negative (25.12%) indicating a high prevalence of infection among HCWs. Another concern observed was that 22.72% of the PCR positive HCWs did not produce antibodies even after 4 weeks.
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COVID-19, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has become a global pandemic. Patients with hematological disorders are known to be at high risk of morbidity and mortality from COVID-19, and vaccines against SARS-CoV-2 have been rapidly developed. Although mRNA vaccines against SARS-CoV-2 are reported to be effective, efficacy in patients with hematological malignancies who have received anti-CD20 antibody treatment remains unclear. Here, we prospectively evaluated the efficacy of BNT162b2 mRNA COVID-19 vaccine in patients with B-cell malignancies treated with anti-CD20 antibody. We first evaluated antibody titers in 12 healthy volunteers (median age 75.5 years, range 57-82) and three lymphoma patients undergoing R-CHOP therapy (73, 81, and 81 years old) who had received 2 vaccine doses of BNT162b2 at pre-vaccination, 21 days after the first dose and 14 days after the second dose of vaccination. IgG antibody titers for S1 protein were measured in serum samples by ELISA. In healthy control subjects, titers were clearly increased. In contrast, no patient treated with R-CHOP developed antibodies even after the second vaccination (Figure A). To determine the SARS-CoV-2-specific T-cell reactivity in these three patients, we evaluated interferon (IFN)-γ response to the SARS-CoV-2 spike peptide before and after the second vaccination dose, and detected IFN-γ responses after vaccination in all three patients (Figure B). Next, to investigate the duration of the effect of anti-CD20 antibody on antibody production to BNT162b2, we enrolled 36 patients (median age 74 years, range 50-87) who had received the final dose of anti-CD20 antibody 48-1320 (median 571) days before vaccination. S1 antibody titers were measured 14 days after the second dose of vaccination. Diagnoses included diffuse large B-cell lymphoma (n = 21), follicular lymphoma (n = 9), lymphoplasmacytic lymphoma/Waldenström's macroglobulinemia (n = 3), and mantle cell lymphoma (n = 3). Thirty-four patients had received rituximab-based and 2 had received obinutuzumab-based therapy, with a median of 6 (range 3-20) courses. No patient had received any chemotherapy after the last anti-CD20 antibody dose. No patient vaccinated within close to one year or sooner after the last anti-CD20 antibody administration showed an increase in titers. Furthermore, titers in most patients were lower than in healthy volunteers even among those vaccinated more than three years after the last administration (Figure C). Finally, we investigated surrogate markers of antibody production ability. We found no relationship between the percent of B-cells (CD19-positive cells) and S1 antibody titers (Figure D), whereas all patients (n = 9) with total IgG level below lower normal limit (< 870 mg/dl) had low S1 antibody titers (< 0.16), below the lowest optical density (O.D.) value in healthy donors (Figure E). These findings indicate that the antibody-mediated response to vaccination in patients following treatment with anti-CD20 antibody was considerably impaired for an extended time. Alternative protection strategies for these patients are therefore warranted. Although T-cell responses were detected, we recommend that these patients continue to wear a face mask and wash their hands to prevent COVID-19 even after vaccination. [Formula presented] Disclosures: Yakushijin: Chugai pharmaceutical Co. Ltd.: Research Funding;Jazz pharmaceuticals: Research Funding;Nippon Shinyaku: Honoraria. Kiyota: Bristol-Myers Squibb: Honoraria, Research Funding;Ono Pharmaceutical: Honoraria, Research Funding;Astra-Zeneca: Honoraria, Research Funding;Roche Phamaceuticals: Research Funding;Merck Biopharma: Honoraria;Merck Sharp & Dohme: Honoraria;Eisai: Honoraria;Bayer: Honoraria. Matsuoka: Takeda Pharmaceutical Company: Research Funding;Sysmex: Research Funding. Minami: Behring: Research Funding;CSL: Research Funding;Yakult Honsha: Research Funding;Nippon Shinyaku: Research Funding;Astellas Pharma: Research Funding;Asahi-Kasei Pharma: Research Funding;Eli Lilly: H noraria, Research Funding;Taiho Pharmaceutical: Honoraria, Research Funding;Takeda Pharmaceutical: Honoraria, Research Funding;Sanofi: Honoraria, Research Funding;Pfizer: Honoraria, Research Funding;Ono Pharmaceutical: Honoraria, Research Funding;Novartis: Honoraria, Research Funding;MSD: Honoraria, Research Funding;Merck Serono: Honoraria, Research Funding;Kyowa-Kirin: Honoraria, Research Funding;Eisai: Honoraria, Research Funding;DaiichiSankyo: Honoraria, Research Funding;Chugai Pharmaceutical: Honoraria, Research Funding;Bristol-Myers Squibb: Honoraria, Research Funding;Boehringer Ingelheim: Honoraria, Research Funding;Bayer Yakuhin: Honoraria, Research Funding;Nippon Kayaku: Research Funding;Celgene: Honoraria;Ohtsuka Pharmaceutical: Honoraria;Shire Japan: Honoraria;Genomic Health: Honoraria;Abbvie: Honoraria.
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Background The ChAdOx1 nCoV-19 vaccine has been shown to induce Vaccine-induced Immune Thrombotic Thrombocytopenia (VITT), a syndrome that shares clinical features with heparin-induced thrombocytopenia (HIT). The mechanism of thrombocytopenia and thrombosis in these disorders appears to be related to the development of pathologic anti-PF4/heparin antibodies, some of which could activate complement. Interestingly, we and others have found that complement activation is vital when both pediatric and adult patients have severe respiratory illness from SARS-CoV-2 virus (COVID-19) or in the post-infectious multisystem inflammatory syndrome in children (MIS-C). We hypothesized that patients with severe COVID-19 or MIS-C develop similar anti-PF4/heparin antibodies, which lead to endothelial complement activation that drive the inflammatory responses seen in these diseases. Methods Our cohort included 30 pediatric patients with positive SARS-CoV-2 RT-PCRs: 10 each of severe COVID-19 (“Severe”, MIS-C, and mild/asymptomatic (“Mild”) infection. Using ELISA, we evaluated the levels of antibodies to various platelet-related proteins including PF4, PF4-heparin, and NAP2;in addition, we examined the ability of plasma from each patient to activate complement. The antibody levels were compared to control samples including samples from adult patients with VITT and HIT. Statistical analyses with ANOVA were performed to evaluate differences. Results Patients with MIS-C have a significantly higher anti-PF4 antibody concentration (as measured by mean optical density [OD]) than patients with either mild/asymptomatic disease, or severe COVID-19: Severe 0.5 +/- 0.14;Mild 0.3 +/- 0.12;MIS-C 0.77 +/- 0.35, p=0.003 MIS-C vs. Mild);Similar results were seen for anti-PF4/heparin antibodies: Severe 0.4 +/- 0.14;Mild 0.35 +/- 0.12;MIS-C 0.64 +/- 0.3, p=0.003 MIS-C vs. Mild;p=0.034 MIS-C vs. Severe). These were similar to values obtained for the HIT sample (Figure). Conclusion Patients with MIS-C and severe COVID19 have significant detectable anti-PF4 and PF4/heparin antibodies in contrast to those patients with mild/asymptomatic disease. Our previous studies have shown that patients with MIS-C and COVID-19 have evidence of endovascular complement activation in the form of elevated soluble membrane attack complex (sC5-b9). We have also previously demonstrated that VITT anti-PF4 and anti-PF4/heparin antibodies activate complement and result in endothelial cell activation. These antibodies in pediatric SARS-CoV-2 infection may be involved in the development of more severe disease manifestations. Ongoing investigations will identify if this is due to endothelial complement activation and inflammatory responses that accompany severe disease. This is the first demonstration of the role of anti-PF4 and PF4/heparin antibodies in pediatric SARS-CoV-2. [Formula presented] Disclosures: Bassiri: Guidepoint Global: Consultancy;Kriya Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company. Teachey: Janssen: Consultancy;NeoImmune Tech: Research Funding;Sobi: Consultancy;BEAM Therapeutics: Consultancy, Research Funding. Lambert: ClinGen, ISTH, ASH, GW University: Honoraria;Rigel: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Bayer: Consultancy;Dova: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Shionogi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees;Argenx: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Principia: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Astra Zeneca: Research Funding;Novartis: Consultancy, Honoraria, Research Funding;Sysmex: Research Funding;PDSA: Research Funding;Octapharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Fundi g.
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Introduction: Vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) were rapidly developed during the COVID-19 pandemic. There is emerging evidence of adverse hematologic effects including thrombocytopenia, for recipients of both mRNA and adenovirus-vector vaccines. We report findings in 9 patients diagnosed with thrombocytopenia following administration of an approved COVID-19 vaccine and managed according to the ASH COVID-19 Thrombosis with Thrombocytopenia Syndrome (TTS) recommendations [https://www.hematology.org/covid-19/vaccine-induced-immune-thrombotic-thrombocytopenia]. Methods: The study population included adults >18 years of age presenting to a large Canadian tertiary care centre, between April 1 st, 2021 and May 31 st, 2021, with new-onset thrombocytopenia within 31 days of receiving COVID-19 vaccination. Vaccines approved during this time period in Canada included BNT162b2 (Pfizer-BioNTech, mRNA) vaccine, mRNA-1273 (Moderna, mRNA) vaccine, and ChAdOx1-S (AstraZeneca (AZ), adenovirus vector-based) vaccine. We report on the initial presentation, management and 90-day outcomes. Results: Among 9 patients with thrombocytopenia included in this cohort, the median age was 55 years (range 24 to 73), and 5 patients (56%) were female. Seven patients received AZ and 2 had Pfizer vaccines. All events occurred after the first dose of COVID-19 vaccine with a median of 11 days between vaccination and presentation to hospital (range 2 to 31). All patients admitted to hospital tested negative for COVID-19 by PCR. Four patients developed TTS, as confirmed on both HIT ELISA and serotonin release assay, following AZ vaccination. Two patients presented with headaches and were diagnosed with cerebral vein thrombosis (CVT);and 2 presented with dyspnea and were diagnosed with venous thromboembolism (VTE). Platelet counts at presentation ranged 14-136 and D-dimer ranged 4000 to >44,000. HIT ELISA optical densities were persistently elevated. Three patients were admitted to hospital and received non-heparin parenteral anticoagulation, IVIG, and steroids. One patient had refractory thrombocytopenia with extension of CVT prompting use of therapeutic plasma exchange. Two patients had recurrent thrombocytopenia within 30 days of discharge and responded to repeat IVIG treatment. Five patients developed immune thrombocytopenic purpura (ITP), four without associated thrombosis and one patient with history of ITP and splenectomy, maintained on Revolade, presented with ITP flare and deep vein thrombosis. Presenting complaints included petechial rash and minor bleeding such as epistaxis. Platelet counts ranged from undetectable to 67;D-dimer levels were normal in all at presentation. Four patients were admitted to hospital and received IVIG +/- steroids. Two patients had recurrent severe thrombocytopenia within 14 days of discharge, requiring repeat steroid pulse. See Table for summary of all patients. Conclusion: In summary, application of the ASH TTS guidance to patients presenting with thrombocytopenia, with and without thrombosis, following COVID-19 vaccination was instrumental in the early identification and successful management of these complications. [Formula presented] Disclosures: Carrier: Sanofi: Honoraria;Pfizer: Honoraria, Research Funding;Servier: Honoraria;Bayer: Honoraria;Leo Pharma: Honoraria, Research Funding;BMS: Honoraria, Research Funding. Le Gal: BMS: Honoraria;Aspen: Honoraria;Bayer: Honoraria;LEO Pharma: Honoraria;Pfizer: Honoraria;Sanofi: Honoraria. Castellucci: BMS: Honoraria;Pfizer: Honoraria;Amag Pharmaceuticals: Honoraria;The Academy: Honoraria.
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Background: COVID-19 pandemic created an unprecedented demand for reagents and diagnostic tools to confirm COVID-19 cases. Thus, the development of a robust in-house diagnostic test is considered of high importance. Within a few days after exposure, the human body produces specific antibodies that recognize the surface proteins of the invading SARS-CoV-2 virus1. Therefore, virus specific immunoglobulins are neutralizing antibodies and their appearance in the blood is a good sign of immunity2. The aim of this study was to develop an in-house COVID-19 serology ELISA test to quantify induced antibody responses. This test can help identify convalescent plasma donors with high antibody titers that can be used to treat other patients. Methods: Spike protein antigen is highly expressed in SARS-CoV-23. Recombinant protein corresponding to the spike receptor-binding domain (RBD), which binds to specific antibodies circulating in COVID-19 patients' blood was used as the antigen in this colorimetric ELISA test. Briefly, a 96-microtiter well plate was coated with RBD protein, where serum dilutions were added. Antibody titers were detected using an anti-human IgG- peroxidase labelled antibody and the substrate o-phenylenediamine dihydrochloride;measured at optical density (OD) of 450 nm (Figure 1). Results: The in-house quantitative serology test was validated using serum samples collected from severe COVID-19 patients (n=282) admitted to the intensive care unit at Hamad General Hospital. Serum samples from non-COVID-19 (n=10) were used as a negative control. We detected high antibody titers in ∼90% of COVID-19 sera. In contrast, no SARS-CoV-2 specific antibodies were detected in the serum of non-infected subjects (n=6), pooled human serum collected before 2019, or Middle East Respiratory Syndrome (MERS) infected subjects (n=3) confirming the specificity and the sensitivity of this in-house serology test. Conclusion: This in-house quantitative serology test is sensitive, specific, and inexpensive. The test can address the rising issue of COVID-19 supply chain globally and foster the capacity-building efforts envisioned by Qatar University.
ABSTRACT
Introduction: Coagulopathy plays a significant role in COVID-19 pathogenesis. Benefit from anticoagulation is well established in hospitalized patients. But since there is a lack of data on coagulopathy resolution: there is no consensus in guidelines if extended anticoagulation is required. Purpose: The purpose of our work was to analyze coagulation abnormalities at 2 to 5 months after moderate to severe COVID-19. Methods: COVID-19 reconvalescents (CR), discharged from our hospital, were called for follow-up at 2-3 (CR1 group, 21 patients) or 5-6 (CR2 group, 26 patients) months after discharge. All CR were not on the anticoagulation therapy by that time. In addition to clinical examination and standard lab tests, we performed an FMD-test to analyze endothelial function, impedance aggregometry to analyze platelet aggregation, and a thrombodynamics test to assess thrombogenesis and fibrinolysis. The control group was recruited before the pandemic started. Results: All CR were free from thrombotic complications after discharge from the hospital. Endothelial function was not significantly impaired in CR compared with control, and was still in the normal range (7,07, IQR (3,36;11,56) vs. 7,87 (5,42;13,45)). Platelet aggregation was significantly lower in CR1 than in the control group in ADP-induced mode (37, IQR (19;47) vs. 46, IQR (41;50), p=0,02) and didn't differ in other groups and other modes (Asa, TRAP-induced). Thrombodynamics tests revealed suppression of the clot formation process in both CR1 and CR2 compared with control. There were decreased clot growth rates (μm/min) (CR1/CR2: 27,1, IQR (26,1;29,2)/27,6, IQR (26,4;30,0) vs. 32,2, IQR (30,0;35,1), both p<0,001);decreased clot size (μm) (CR1/CR2: 1099, IQR (1069;1194)/1199, IQR (1058;1221) vs. 1304, IQR (1164;1380), both p<0,001), and decreased optical density (arb units) (CR1/CR2: 21'607, IQR (20'363;24'545)/22'741, IQR (21'344;25'961) vs. 26'556, IQR (24'672;29'387, p<0,001 and p=0,09 respectively. Fibrinolysis was enhanced in CR groups compared with control (lysis progression was significantly higher for CR2 only, CR1/CR2: 2,9, IQR (2,5;3,8)/3,8, IQR (2,6;5,4) vs. 2,5, IQR (1,1;3,4) %/min, p=0,087 and p=0,007 respectively;expected clot lysis time was shorter in both CR1 and CR2: 36,5, IQR (29,8;44,2)/31,7, IQR (24,3;42,7) vs. 65,9. IQR (36,3;95,5) min, p=0,019 and p=0,016 respectively). There was no statistical difference in clot formation and in fibrinolysis between CR1 and CR2. Conclusion: In the deferred period (2-5 months) of COVID-19 the fibrinolysis process remains still active whereas the process of clot formation is mostly suppressed. Endothelial function assessed via the FMD test is within the normal range in the post COVID period.
ABSTRACT
Serological testing is a tool to predict protection against later infection. This potential heavily relies on antibody levels showing acceptable agreement with gold standard virus neutralization tests. The aim of our study was to investigate diagnostic value of the available serological tests in terms of predicting virus neutralizing activity of serum samples drawn 5-7 weeks after onset of symptoms from 101 donors with a history of COVID-19. Immune responses against Receptor Binding Domain (RBD), Spike1 and 2 proteins and Nucleocapsid antigens were measured by various ELISA tests. Neutralizing antibody activity in serum samples was assessed by a cell-based virus neutralization test. Spearman correlation coefficients between serological and neutralization results ranged from 0.41 to 0.91 indicating moderate to strong correlation between ELISA test results and virus neutralization. The sensitivity and specificity of ELISA tests in the prediction of neutralization were 35-100% and 35-90% respectively. No clear cut off levels can be established that would reliably indicate neutralization activity. For some tests, however, a value below which the sample is not expected to neutralize can be established. Our data suggests that several of the ELISA kits tested may be suitable for epidemiological surveys 1-2 months after the infection, estimating whether a person may have recently exposed to the virus. Sensitivities considerably superseding specificity at the cut-off values proposed by the manufacturers suggest greater potential in the identification of insufficient antibody responses than in confirming protection. Nevertheless, the former might be important in assessing response to vaccination and characterizing therapeutic plasma preparations.
ABSTRACT
By the end of year 2019, the new virus SARS-CoV-2 appeared, causing the Coronavirus Disease 2019 (COVID-19), and spread very fast globally. A continuing need for diagnostic tools is a must to contain its spread. Till now, the gold standard method, the reverse transcription polymerase chain reaction (RT-PCR), is the precise procedure to detect the virus. However, SARS-CoV-2 may escape RT-PCR detection for several reasons. The development of well-designed, specific and sensitive serological test like enzyme immunoassay (EIA) is needed. This EIA can stand alone or work side by side with RT-PCR. In this study, we developed several EIAs including plates that are coated with either specially designed SARS-CoV-2 nucleocapsid or surface recombinant proteins. Each protein type can separately detect anti-SARS-CoV-2 IgM or IgG antibodies. For each EIAs, the cut-off value, specificity and sensitivity were determined utilizing RT-PCR confirmed Covid-19 and pre-pandemic healthy and other viruses-infected sera. Also, the receiver operator characteristic (ROC) analysis was performed to define the specificities and sensitivities of the optimized assay. The in-house EIAs were validated by comparing against commercial EIA kits. All in-house EIAs showed high specificity (98-99%) and sensitivity (97.8-98.9%) for the detection of IgG/IgM against RBD and N proteins of SARS-CoV-2. From these results, the developed Anti-RBD and anti-N IgG and IgM antibodies EIAs can be used as a specific and sensitive tool to detect SARS-CoV-2 infection, calculate the burden of disease and case fatality rates.
ABSTRACT
OBJECTIVE: The new coronavirus disease 2019 (COVID-19) is a major health problem worldwide. The surveillance of seropositive individuals serves as an indicator to the extent of infection spread and provides an estimation of herd immunity status among population. Reports from different countries investigated this issue among healthcare workers (HCWs) who are "at risk" and "sources of risk" for COVID-19. This study aims to investigate the seroprevalence of COVID-19 among HCWs in one of the COVID-19 referral centers in Makkah, Saudi Arabia using three different serological methods. METHODS: In-house developed enzyme-linked immunoassay (ELISA), commercially available electro-chemiluminescence immunoassay (ECLIA), and microneutralization (MN) assay were utilized to determine the seroprevalence rate among the study population. 204 HCWs participated in the study. Both physicians and nurses working in the COVID-19 and non COVID-19 areas were included. Twelve out of 204 were confirmed cases of COVID-19 with variable disease severity. Samples from recovered HCWs were collected four weeks post diagnosis. RESULTS: The overall seroprevalence rate was 6.3% (13 out of 204) using the in-house ELISA and MN assay and it was 5.8% (12 out of 204) using the commercial ECLIA. Among HCWs undiagnosed with COVID-19, the seroprevalence was 2% (4 out 192). Notably, neutralizing antibodies were not detected in 3 (25%) out 12 confirmed cases of COVID-19. CONCLUSIONS: Our study, similar to the recent national multi-center study, showed a low seroprevalence of SARS-Cov-2 antibodies among HCWs. Concordance of results between the commercial electro-chemiluminescence immunoassay (ECLIA), in-house ELISA and MN assay was observed. The in-house ELISA is a promising tool for the serological diagnosis of SARS-CoV-2 infection. However, seroprevalence studies may underestimate the extent of COVID-19 infection as some cases with mild disease did not have detectable antibody responses.