SARS-CoV-2 N-Antigen Quantification in Respiratory Tract, Plasma and Urine: Kinetics and Association with RT-qPCR Results.

Qualitative SARS-CoV-2 antigen assays based on immunochromatography are useful for mass diagnosis of COVID-19, even though their sensitivity is poor in comparison with RT-PCR assays. In addition, quantitative assays could improve antigenic test performance and allow testing with different specimens. Using quantitative assays, we tested 26 patients for viral RNA and N-antigen in respiratory samples, plasma and urine. This allowed us to compare the kinetics between the three compartments and to compare RNA and antigen concentrations in each. Our results showed the presence of N-antigen in respiratory (15/15, 100%), plasma (26/59, 44%) and urine (14/54, 28.9%) samples, whereas RNA was only detected in respiratory (15/15, 100%) and plasma (12/60, 20%) samples. We detected N-antigen in urine and plasma samples until the day 9 and day 13 post-inclusion, respectively. The antigen concentration was found to correlate with RNA levels in respiratory (p < 0.001) and plasma samples (p < 0.001). Finally, urinary antigen levels correlated with plasma levels (p < 0.001). Urine N-antigen detection could be part of the strategy for the late diagnosis and prognostic evaluation of COVID-19, given the ease and painlessness of sampling and the duration of antigen excretion in this biological compartment.

Coronavirus spike protein-specific antibodies indicate frequent infections and reinfections in infancy and among BNT162b2-vaccinated healthcare workers.

The prevalence of seasonal human coronavirus (HCoV) infections in early childhood and adults has not been well analyzed in longitudinal serological studies. Here we analyzed the changes in HCoV (229E, HKU1, NL63, OC43, MERS, and SARS-CoV-2) spike-specific antibody levels in follow-up serum specimens of 140 children at the age of 1, 2, and 3 years, and of 113 healthcare workers vaccinated for Covid-19 with BNT162b2-vaccine. IgG antibody levels against six recombinant HCoV spike subunit 1 (S1) proteins were measured by enzyme immunoassay. We show that by the age of three years the cumulative seropositivity for seasonal HCoVs increased to 38-81% depending on virus type. BNT162b2 vaccinations increased anti-SARS-CoV-2 S1 antibodies, but no increase in seasonal coronavirus antibodies associated with vaccinations. In healthcare workers (HCWs), during a 1-year follow-up, diagnostic antibody rises were seen in 5, 4 and 14% of the cases against 229E, NL63 and OC43 viruses, respectively, correlating well with the circulating HCoVs. In 6% of the HCWs, a diagnostic antibody rise was seen against S1 of HKU1, however, these rises coincided with anti-OC43 S1 antibody rises. Rabbit and guinea pig immune sera against HCoV S1 proteins indicated immunological cross-reactivity within alpha-CoV (229E and NL63) and beta-CoV (HKU1 and OC43) genera.

Overview of autoantibodies in COVID-19 convalescents.

Accumulating evidence shows that SARS-CoV-2 can potentially trigger autoimmune processes, which can be responsible for the long-term consequences of COVID-19. Therefore, this paper aims to review the autoantibodies reported in COVID-19 convalescents. Six main groups were distinguished: (i) autoantibodies against components of the immune system, (ii) autoantibodies against components of the cardiovascular system, (iii) thyroid autoantibodies, (iv) autoantibodies specific for rheumatoid diseases, (v) antibodies against G-protein coupled receptors, and (vi) other autoantibodies. The evidence reviewed here clearly highlights that SARS-CoV-2 infection may induce humoral autoimmune responses. However, the available studies share number of limitations, such as: (1) the sole presence of autoantibodies does not necessarily implicate the clinically-relevant risks, (2) functional investigations were rarely performed and it is often unknown whether observed autoantibodies are pathogenic, (3) the control seroprevalence, in healthy, noninfected individuals was often not reported; thus it is sometimes unknown whether the detected autoantibodies are the result of SARS-CoV-2 infection or the accidental post-COVID-19 detection, (4) the presence of autoantibodies was rarely correlated with symptoms of the post-COVID-19 syndrome, (5) the size of the studied groups were often small, (6) the studies focused predominantly on adult populations, (7) age- and sex-related differences in seroprevalence of autoantibodies were rarely explored, (8) genetic predispositions that may be involved in generation of autoantibodies during SARS-CoV-2 infections were not investigated, and (9) the autoimmune reactions following infection with SARS-CoV-2 variants that vary in the clinical course of infection remain unexplored. Further longitudinal studies are advocated to assess the link between identified autoantibodies and particular clinical outcomes in COVID-19 convalescents.

The safety and immunogenicity of a two-dose schedule of CoronaVac, and the immune persistence of vaccination for six months, in people living with HIV: A multicenter prospective cohort study.

Background: People living with HIV (PLWH) are more vulnerable to SARS-CoV-2. However, evidence on the immunogenicity of coronavirus disease 2019 (COVID-19) vaccines in this population is insufficient. The objective of this study is to assess the immunogenicity and safety of the two-dose schedule of Sinovac CoronaVac for 6 months postvaccination in PLWH. Methods: We conducted a multicenter prospective cohort study among PLWH and HIV-negative adults in China. Participants who received two doses of CoronaVac prior to the recruitment were allocated into two groups and followed up for 6 months. The neutralizing antibodies (nAbs), immunoglobulin G against the receptor-binding domain of the spike protein (S-IgG), and gamma-interferon (IFN-γ) were measured to assess the associations among CoronaVac immunogenicity and related factors. Adverse reactions were collected to evaluate the safety profile of vaccination. Results: A total of 203 PLWH and 100 HIV-negative individuals were enrolled. A small portion of participants reported mild or moderate adverse reactions without serious adverse events. Median nAbs level in PLWH (31.96 IU/mL, IQR: 12.34-76.40) was lower than that in the control group (46.52 IU/mL, IQR: 29.08-77.30) at the 2-4 weeks postvaccination (P=0.002), and the same trend was presented for median S-IgG titer (37.09 vs. 60.02 IU/ml) (both P <0.05). The nAbs seroconversion rate in the PLWH group was also lower than in the control group (75.86% vs. 89.00%). After then, the immune responses reduced over time in term of only 23.04% of PLWH and 36.00% of HIV-negative individuals had a positive seroconversion for nAbs at 6-month. The multivariable generalized estimating equation analysis showed that PLWH with CD4+T count≥350 cells/µL presented higher immune response than PLWH with CD4+T count <350 cells/µL in terms of antibody seroconversion and titers. The immunogenicity did not differ in participants with low or high HIV viral load. The S-antigen specific IFN-γ immunity was generally stable and had a slow attenuation in both two groups for 6 months postvaccination. Conclusion: The Sinovac CoronaVac was generally safe and immunogenic in PLWH, but the immunity response was inferior and the antibodies vanished faster compared to HIV-negative individuals. This study suggested a shorter than 6-month interval of prime-boost vaccination for PLWH to ensure a better protection.

Antibody response to different COVID-19 vaccines among the migrant workers of Bangladesh.

Background: Due to the ongoing COVID-19 pandemic, various host countries such as Singapore, imposed entry requirements for migrant workers including pre-departure COVID-19 seroconversion proof. To combat COVID-19 worldwide, several vaccines have acquired conditional approval. This study sought to assess antibody levels after immunization with different COVID-19 vaccines among the migrant workers of Bangladesh. Methods: Venous blood samples were collected from migrant workers who were vaccinated with different COVID-19 vaccines (n=675). Antibodies to SARS-CoV-2 spike protein (S) and nucleocapsid protein (N) were determined using Roche Elecsys® Anti-SARS-CoV-2 S and N immunoassay, respectively. Results: All participants receiving COVID-19 vaccines showed antibodies to S-protein, while 91.36% were positive for N-specific antibodies. The highest anti-S antibody titers were found among the workers who completed booster doses (13327 U/mL), received mRNA vaccines Moderna/Spikevax (9459 U/mL) or Pfizer-BioNTech/Comirnaty (9181 U/mL), and reported SARS-CoV-2 infection in the last six months (8849 U/mL). The median anti-S antibody titers in the first month since the last vaccination was 8184 U/mL, which declined to 5094 U/mL at the end of six months. A strong correlation of anti-S antibodies was found with past SARS-CoV-2 infection (p < 0.001) and the type of vaccines received (p <0.001) in the workers.Conclusion: Bangladeshi migrant workers receiving booster doses of vaccine, vaccinated with mRNA vaccines, and having past SARS-CoV-2 infection, mounted higher antibody responses. However, antibody levels waned with time. These findings suggest a need for further booster doses, preferably with mRNA vaccines for migrant workers before reaching host countries.

SARS-CoV-2 infection and COVID19 vaccination across eight immune-mediated inflammatory disorders: A prospective, real-life Belgian cohort study - the BELCOMID study.

Background: The risks and impact of COVID19 disease and vaccination in patients with Immune Mediated Inflammatory Diseases (IMID) remain incompletely understood. IMID patients and particularly patients receiving immunosuppressive treatment were excluded from the original, registrational phase-3 COVID19 vaccination efficacy and safety trials. Real-world observational data can help to fill this gap in knowledge. The BELCOMID study aims to explore the interaction between IMIDs, immune-modulating treatment modalities and SARS-CoV-2 infection and vaccination in a real-life patient cohort. Methods: A multidisciplinary, prospective, observational cohort study was set up. Consecutive patients with IMIDs of the gut, joints and skin followed at two high-volume referral centers were invited. Both patients under conventional treatment or targeted immune modulating therapies were included. Patient data and serological samples were collected at 3 predefined periods (before COVID19 vaccination, before booster vaccination, after booster vaccination). Primary endpoints were positive PCR-test and SARS-CoV-2 serology reflecting previous SARS-CoV-2 infection or vaccination. Associations with IMID treatment modality and IMID disease activity were assessed. Results of the first two inclusion periods (before booster vaccination) are reported. Results: At the first inclusion period data was assessed of 2165 IMID-patients before COVID19 vaccination. At the second inclusion period, data of 2065 patients was collected of whom 1547 had received complete baseline COVID19 vaccination and 222 were partially vaccinated. SARS-CoV-2 infection rate remained low in both groups. No significant increase in IMID flare-up rate was noted in patients with prior SARS-CoV-2 infection. Multiple logistic regression analyses did not show a significant influence of IMID-treatment modality or IMID activity on SARS-CoV-2 infection risk (based on PCR positivity or N-serology). Patients treated with conventional immunomodulators, systemic steroids, and patients on advanced therapies such as biologics or small molecules, had reduced S-antibody seroconversion. S-antibody response was also lower in patients without prior SARS-CoV-2 infection and in active smokers. A subset of patients (4.1%) had no S- nor N-antibody seroconversion following complete baseline vaccination. Conclusion: The BELCOMID study results confirm the benign course of COVID19 infection and vaccination in a large real-life IMID-population. However, our results underscore the need for repeated vaccination and smoking cessation in patients with IMIDs treated with immune-modulating therapies or systemic steroids during the pandemic.

Antibody response in children with multisystem inflammatory syndrome related to COVID-19 (MIS-C) compared to children with uncomplicated COVID-19.

Objectives: To comprehensively analyze the quality of the antibody response between children with Multisystem inflammatory syndrome (MIS-C) and age-matched controls at one month after SARS-CoV-2 exposure, and infected in the same time-period. Methods: Serum from 20 MIS-C children at admission, and 14 control children were analyzed. Antigen specific antibody isotypes and subclasses directed against various antigens of SARS-CoV-2 as well as against human common coronavirus (HCoVs) and commensal or pathogenic microorganisms were assessed by a bead-based multiplexed serological assay and by ELISA. The functionality of these antibodies was also assessed using a plaque reduction neutralization test, a RBD-specific avidity assay, a complement deposition assay and an antibody-dependent neutrophil phagocytosis (ADNP) assay. Results: Children with MIS-C developed a stronger IgA antibody response in comparison to children with uncomplicated COVID-19, while IgG and IgM responses are largely similar in both groups. We found a typical class-switched antibody profile with high level of IgG and IgA titers and a measurable low IgM due to relatively recent SARS-CoV-2 infection (one month). SARS-CoV-2-specific IgG antibodies of MIS-C children had higher functional properties (higher neutralization activity, avidity and complement binding) as compared to children with uncomplicated COVID-19. There was no difference in the response to common endemic coronaviruses between both groups. However, MIS-C children had a moderate increase against mucosal commensal and pathogenic strains, reflecting a potential association between a disruption of the mucosal barrier with the disease. Conclusion: Even if it is still unclear why some children develop a MIS-C, we show here that MIS-C children produce higher titers of IgA antibodies, and IgG antibodies with higher functionality, which could reflect the local gastro-intestinal mucosal inflammation potentially induced by a sustained SARS-CoV-2 gut infection leading to continuous release of SARS-CoV-2 antigens.

Methodological approaches to optimize multiplex oral fluid SARS-CoV-2 IgG assay performance and correlation with serologic and neutralizing antibody responses.

BACKGROUND: Oral fluid (hereafter, saliva) is a non-invasive and attractive alternative to blood for SARS-CoV-2 IgG testing; however, the heterogeneity of saliva as a matrix poses challenges for immunoassay performance. OBJECTIVES: To optimize performance of a magnetic microparticle-based multiplex immunoassay (MIA) for SARS-CoV-2 IgG measurement in saliva, with consideration of: i) threshold setting and validation across different MIA bead batches; ii) sample qualification based on salivary total IgG concentration; iii) calibration to U.S. SARS-CoV-2 serological standard binding antibody units (BAU); and iv) correlations with blood-based SARS-CoV-2 serological and neutralizing antibody (nAb) assays. METHODS: The salivary SARS-CoV-2 IgG MIA included 2 nucleocapsid (N), 3 receptor-binding domain (RBD), and 2 spike protein (S) antigens. Gingival crevicular fluid (GCF) swab saliva samples were collected before December 2019 (n = 555) and after molecular test-confirmed SARS-CoV-2 infection from 113 individuals (providing up to 5 repeated-measures; n = 398) and used to optimize and validate MIA performance (total n = 953). Combinations of IgG responses to N, RBD and S and total salivary IgG concentration (µg/mL) as a qualifier of nonreactive samples were optimized and validated, calibrated to the U.S. SARS-CoV-2 serological standard, and correlated with blood-based SARS-CoV-2 IgG ELISA and nAb assays. RESULTS: The sum of signal to cutoff (S/Co) to all seven MIA SARS-CoV-2 antigens and disqualification of nonreactive saliva samples with ≤15 µg/mL total IgG led to correct classification of 62/62 positives (sensitivity [Se] = 100.0%; 95% confidence interval [CI] = 94.8%, 100.0%) and 108/109 negatives (specificity [Sp] = 99.1%; 95% CI = 97.3%, 100.0%) at 8-million beads coupling scale and 80/81 positives (Se = 98.8%; 95% CI = 93.3%, 100.0%] and 127/127 negatives (Sp = 100%; 95% CI = 97.1%, 100.0%) at 20-million beads coupling scale. Salivary SARS-CoV-2 IgG crossed the MIA cutoff of 0.1 BAU/mL on average 9 days post-COVID-19 symptom onset and peaked around day 30. Among n = 30 matched saliva and plasma samples, salivary SARS-CoV-2 MIA IgG levels correlated with corresponding-antigen plasma ELISA IgG (N: ρ = 0.76, RBD: ρ = 0.83, S: ρ = 0.82; all p < 0.001). Correlations of plasma SARS-CoV-2 nAb assay area under the curve (AUC) with salivary MIA IgG (N: ρ = 0.68, RBD: ρ = 0.78, S: ρ = 0.79; all p < 0.001) and with plasma ELISA IgG (N: ρ = 0.76, RBD: ρ = 0.79, S: ρ = 0.76; p < 0.001) were similar. CONCLUSIONS: A salivary SARS-CoV-2 IgG MIA produced consistently high Se (> 98.8%) and Sp (> 99.1%) across two bead coupling scales and correlations with nAb responses that were similar to blood-based SARS-CoV-2 IgG ELISA data. This non-invasive salivary SARS-CoV-2 IgG MIA could increase engagement of vulnerable populations and improve broad understanding of humoral immunity (kinetics and gaps) within the evolving context of booster vaccination, viral variants and waning immunity.

Cross-Reactive Profile Against Two Conserved Coronavirus Antigens in Sera from SARS-CoV-2 Hybrid and Vaccinated Immune Donors.

Since the beginning of the pandemic, the pre-existing immunity against SARS-CoV-2 has been postulated as one possible cause of asymptomatic infections. Later, various works reported that pre-existing immune response against the two structural conserved antigens: S2 subunit and the nucleocapsid protein, were associated to some level of asymptomatic profile in infected individuals. To explore the Ab background against these two antigens, in the context of vaccine-elicited and hybrid (natural infection plus vaccination induced) immunity of SARS-CoV-2, in this work, we tested sera from inactivated vaccine-immunized donors and from vaccinated and subsequent natural infected donors upon the Omicron variant wave in Guangdong province, China. Serum samples were collected from 27 COVID-19 convalescent, 25 SARS-CoV-2 vaccinated, and 10 negative donors. The IgG cross-reactivity response against these two antigens from another relevant human coronavirus (HCoV) was also evaluated. The findings indicate that IgG response against S2 and N protein was particularly higher in sera with hybrid immunity. The cross-reactive Abs were more significant against SARS-CoV-1, while a wide cross-reactivity was detected for N antigen for one human Alpha coronavirus HCoV-229E even in the negative control samples. The presence of cross-reactive Abs against the two conserved antigens N and S2, particularly in the context of hybrid immunity, could pave the way for future boosted vaccines carrying these conserved regions.

Performance evaluation of the Ortho VITROS SARS-CoV-2 Spike-Specific Quantitative IgG test by comparison with the surrogate virus neutralizing antibody test and clinical assessment.

BACKGROUND: Despite the worldwide campaigns of COVID-19 vaccinations, the pandemic is still a major medical and social problem. The Ortho VITROS SARS-CoV-2 spike-specific quantitative IgG (VITROS S-IgG) assay has been developed to assess neutralizing antibody (NT antibody) against SARS-CoV-2 spike (S) antibodies. However, it has not been evaluated in Japan, where the total cases and death toll are lower than the rest of the world. METHODS: The clinical performance of VITROS S-IgG was evaluated by comparing with the NT antibody levels measured by the surrogate virus neutralizing antibody test (sVNT). A total of 332 serum samples from 188 individuals were used. Of these, 219 samples were from 75 COVID-19 patients: 96 samples from 20 severe/critical cases (Group S), and 123 samples from 55 mild/moderate cases (Group M). The remaining 113 samples were from 113 healthcare workers who had received 2 doses of the BNT162b2 vaccine. RESULTS: VITROS S-IgG showed good correlation with the cPass sVNT assay (Spearman rho = 0.91). Both VITROS S-IgG and cPass sVNT showed significantly higher plateau levels of antibodies in Group S compared to Group M. Regarding the humoral immune responses after BNT162b2 vaccination, individuals who were negative for SARS-CoV-2 nucleocapsid (N)-specific antibodies had statistically lower titers of both S-IgG and sVNT compared to individuals with a history of COVID-19 and individuals who were positive for N-specific antibodies without history of COVID-19. In individuals who were positive for N-specific antibodies, S-IgG and sVNT titers were similar to individuals with a history of COVID-19. CONCLUSIONS: Although the automated quantitative immunoassay VITROS S-IgG showed a reasonable correlation with sVNT antibodies, there is some discrepancy between Vitros S-IgG and cPass sVNT in milder cases. Thus, VITROS S-IgG can be a useful diagnostic tool in assessing the immune responses to vaccination and herd immunity. However, careful analysis is necessary to interpret the results.

Neutralization activity of IgG antibody in COVID­19­convalescent plasma against SARS-CoV-2 variants.

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We evaluated the anti-SARS-CoV-2 antibody levels, anti-spike (S)-immunoglobulin G (IgG) and anti-nucleocapsid (N)-IgG, and the neutralization activity of IgG antibody in COVID­19­convalescent plasma against variants of SARS-CoV-2, alpha, beta, gamma, delta, kappa, omicron and R.1 strains. The study included 30 patients with clinically diagnosed COVID-19. The anti-S-IgG and anti-N-IgG levels ranged from 30.0 to 555.1 and from 10.1 to 752.6, respectively. The neutralization activity (50% inhibition concentration: IC50) for the wild-type Wuhan strain ranged from < 6.3 to 81.5 µg/ml. IgG antibodies were > 100 µg/ml in 18 of 30 (60%) subjects infected with the beta variant. The IC50 values for wild-type and beta variants correlated inversely with anti-S-IgG levels (p < 0.05), but no such correlation was noted with anti-N-IgG. IgG antibodies prevented infectivity and cytopathic effects of six different variants of concern in the cell-based assays of wild-type, alpha, gamma, delta, kappa and R.1 strains, but not that of the beta and omicron strains. IgG is considered the main neutralizing activity in the blood, although other factors may be important in other body tissues.

Lessons learned from the COVID-19 pandemic: Improving initial investigations with the implementation of a COVID-19 blood request panel.

BACKGROUND: During the COVID-19 pandemic, the Hillingdon Hospitals NHS Foundation Trust produced trust guidelines for the initial blood investigation of COVID-19 inpatients. However, insufficient education meant inconsistent adherence to this guidance. OBJECTIVE: To examine whether the implementation of a COVID-19 blood request panel improves adherence to local trust guidelines. METHOD: Between March and April 2020, initial blood investigations performed for positive COVID-19 cases were compared to guidelines. Results were presented locally and a COVID-19 panel was added to the electronic system that provided prompts for appropriate investigations. A re-audit between May and June 2020 was conducted to assess adherence post-intervention. RESULTS: 383 patients were identified in the initial audit cohort and a sample of 20 patients were re-audited. Adherence to Full Blood Count, Urea and Electrolytes, C-reactive Protein and Liver Function Tests increased to 100% from 99.7% (p = 0.8), 99.2% (p = 0.69), 98.7% (p = 0.61), and 96.6% (p = 0.4) respectively. Coagulation screen adherence increased to 90% from 72.8% (p = 0.09). Appropriate requesting of D dimers increased to 50% from 19.9% (p = 0.001). Inappropriate troponin requesting decreased to 26.3% from 38.9% (p = 0.23). CONCLUSION: A user-friendly COVID-19 panel of investigations resulted in improved adherence to guidelines. Clear communication and education are essential to help alleviate uncertainty during a pandemic.

What Decides Your Athletic Career?-Reflection from Our Study of GP.Mur-Associated Sports Talents during the COVID-19 Pandemic Era.

This opinion article discusses the factors that attract children and teens to athletic careers. The most important attribute for the making of athletes is polished sports talent, followed by psychological, environmental, and incentive factors. Our laboratory studies a red blood cell (RBC) type called GP.Mur, which is rare in most parts of the world besides Southeast Asia. Intriguingly, the prevalence of the GP.Mur blood type is relatively high among Taiwanese elite athletes. The highest frequency of the GP.Mur blood type worldwide is found among Taiwan's Ami people (88-95% from hospital blood bank surveys in the 1980s). Though the Ami constitute only 0.6-0.8% of the Taiwanese population, from records of national track-and-field games in the past century, 10-60% of the medalists were Ami. Biologically, GP.Mur expression supports blood CO2 metabolism, which may have implications for athleticism. As many of our study subjects are elite college athletes with the GP.Mur blood type, we contemplated their upbringings and career dilemmas, especially during the difficult COVID-19 pandemic. Beyond individual sports talent, the pandemic particularly tests personal characteristics and socioeconomic support for becoming an athlete.

International Society of Blood Transfusion Working Party on Red Cell Immunogenetics and Blood Group Terminology Report of Basel and three virtual business meetings: Update on blood group systems.

BACKGROUND AND OBJECTIVES: Under the ISBT, the Working Party (WP) for Red Cell Immunogenetics and Blood Group Terminology is charged with ratifying blood group systems, antigens and alleles. This report presents the outcomes from four WP business meetings, one located in Basel in 2019 and three held as virtual meetings during the COVID-19 pandemic in 2020 and 2021. MATERIALS AND METHODS: As in previous meetings, matters pertaining to blood group antigen nomenclature were discussed. New blood group systems and antigens were approved and named according to the serologic, genetic, biochemical and cell biological evidence presented. RESULTS: Seven new blood group systems, KANNO (defined numerically as ISBT 037), SID (038), CTL2 (039), PEL (040), MAM (041), EMM (042) and ABCC1 (043) were ratified. Two (039 and 043) were de novo discoveries, and the remainder comprised reported antigens where the causal genes were previously unknown. A further 15 blood group antigens were added to the existing blood group systems: MNS (002), RH (004), LU (005), DI (010), SC (013), GE (020), KN (022), JMH (026) and RHAG (030). CONCLUSION: The ISBT now recognizes 378 antigens, of which 345 are clustered within 43 blood group systems while 33 still have an unknown genetic basis. The ongoing discovery of new blood group systems and antigens underscores the diverse and complex biology of the red cell membrane. The WP continues to update the blood group antigen tables and the allele nomenclature tables. These can be found on the ISBT website (http://www.isbtweb.org/working-parties/red-cell-immunogenetics-and-blood-group-terminology/).

De novo natural anti-M alloantibody emergence in severe Coronavirus Disease 2019.

The immune response is a key player in the course of SARS-CoV-2 infection, and is often seriously dysfunctional in severe Coronavirus Disease 2019. The hyperinflammatory status has been described to be accompanied by the appearance of autoantibodies. In a lethal COVID-19 infection, we observed the emergence of a de novo natural alloantibody which targeted the M antigen from the MNS blood group on red blood cells (RBC) without evidence of any cross-reaction with SARS-CoV-2 antigens. This IgM lambda alloantibody was unmutated and unswitched. Here, we describe for the first time the emergence of a bystander de novo natural alloantibody against RBCs in a severe COVID-19 patient, highlighting the extra-follicular humoral response reported in these cases.

Association of blood group A with hospital comorbidity in patients infected by SARS-CoV-2. / Asociación del grupo sanguíneo A con mayor comorbilidad hospitalaria en pacientes infectados por SARS-CoV-2.

BACKGROUND AND OBJECTIVES: In the pandemic caused by SARS-CoV-2, identifying which risk factors are associated with the most serious forms of the disease is important. Blood group A has been presented in various studies as a poor prognostic factor. The objective of this study was to evaluate whether patients with blood group A were associated with more important comorbidities, measured by the Charlson Index, which may explain their worse clinical evolution. PATIENTS AND METHODS: A prospective and consecutive study examined 100 patients diagnosed with COVID-19 and admitted in March 2020. A multivariate linear regression model was used to evaluate the association of blood group A with the Charlson Index. RESULTS: Patients in group A had a higher Charlson Index (P=.037), rate of lymphopenia (P=.039) and thrombopenia (P=.014), and hospital mortality (P=.044). Blood group A was an independent factor associated with the Charlson Index (B 0.582, 95% CI 0.02-1.14, P=0.041). CONCLUSIONS: Group A was independently associated with greater comorbidity, associated with an increase of 0.582 points in the Charlson Index compared to other blood groups. It was also associated with lower hospital mortality.

Immune response after COVID-19 vaccination among patients with chronic kidney disease and kidney transplant.

BACKGROUND: Vaccination of patients with chronic kidney disease (CKD) and kidney transplants (KTs) may achieve a less robust immune response. Understanding such immune responses is crucial for guiding current and future vaccine dosing strategies. METHODS: This prospective, observational study estimated the immunogenicity of humoral and cellular responses of two SARS-CoV-2 vaccines in different patient groups with CKD compared with controls. Secondary outcomes included adverse events after vaccination and the incidence of COVID-19 breakthrough infection, including illness severity. RESULTS: In total, 212 patients received ChAdOx1 nCoV-19 (89.62 %) or inactivated vaccines (10.38 %).The antibody response against the S protein was analyzed at T0 (before the first injection), T1 (before the second injection), and T2 (12 weeks after the second injection). Seroconversion occurred in 92.31 % of controls at T2 and in 100 % of patients with CKD, 42.86 % undergoing KT, 80.18 % of hemodialysis (HD), and 0 % of patients undergoing continuous ambulatory peritoneal dialysis (CAPD) at T2 of the ChAdOx1 nCoV-19 vaccine. Neutralizing antibody levels by surrogate virus neutralization test were above the protective level at T2 in each group. The KT group exhibited the lowest neutralizing antibody and T cell response. Blood groups O and vaccine type were associated with good immunological responses. After the first dose, 14 individuals (6.6 out of the total population experienced COVID-19 breakthrough infection. CONCLUSION: Immunity among patients with CKD and HD after vaccination was strong and comparable with that of healthy controls. Our study suggested that a single dose of the vaccine is not efficacious and delays may result in breakthrough infection. Some blood groups and types of vaccine can affect the immune response.

Genome Reporting for Healthy Populations-Pipeline for Genomic Screening from the GENCOV COVID-19 Study.

Genome sequencing holds the promise for great public health benefits. It is currently being used in the context of rare disease diagnosis and novel gene identification, but also has the potential to identify genetic disease risk factors in healthy individuals. Genome sequencing technologies are currently being used to identify genetic factors that may influence variability in symptom severity and immune response among patients infected by SARS-CoV-2. The GENCOV study aims to look at the relationship between genetic, serological, and biochemical factors and variability of SARS-CoV-2 symptom severity, and to evaluate the utility of returning genome screening results to study participants. Study participants select which results they wish to receive with a decision aid. Medically actionable information for diagnosis, disease risk estimation, disease prevention, and patient management are provided in a comprehensive genome report. Using a combination of bioinformatics software and custom tools, this article describes a pipeline for the analysis and reporting of genetic results to individuals with COVID-19, including HLA genotyping, large-scale continental ancestry estimation, and pharmacogenomic analysis to determine metabolizer status and drug response. In addition, this pipeline includes reporting of medically actionable conditions from comprehensive gene panels for Cardiology, Neurology, Metabolism, Hereditary Cancer, and Hereditary Kidney, and carrier screening for reproductive planning. Incorporated into the genome report are polygenic risk scores for six diseases-coronary artery disease; atrial fibrillation; type-2 diabetes; and breast, prostate, and colon cancer-as well as blood group genotyping analysis for ABO and Rh blood types and genotyping for other antigens of clinical relevance. The genome report summarizes the findings of these analyses in a way that extensively communicates clinically relevant results to patients and their physicians. © 2022 Wiley Periodicals LLC. Basic Protocol 1: HLA genotyping and disease association Basic Protocol 2: Large-scale continental ancestry estimation Basic Protocol 3: Dosage recommendations for pharmacogenomic gene variants associated with drug response Support Protocol: System setup.

Rotavirus C Replication in Porcine Intestinal Enteroids Reveals Roles for Cellular Cholesterol and Sialic Acids.

Rotaviruses (RVs) are a significant cause of severe diarrheal illness in infants and young animals, including pigs. Group C rotavirus (RVC) is an emerging pathogen increasingly reported in pigs and humans worldwide, and is currently recognized as the major cause of gastroenteritis in neonatal piglets that results in substantial economic losses to the pork industry. However, little is known about RVC pathogenesis due to the lack of a robust cell culture system, with the exception of the RVC Cowden strain. Here, we evaluated the permissiveness of porcine crypt-derived 3D and 2D intestinal enteroid (PIE) culture systems for RVC infection. Differentiated 3D and 2D PIEs were infected with porcine RVC (PRVC) Cowden G1P[1], PRVC104 G3P[18], and PRVC143 G6P[5] virulent strains, and the virus replication was measured by qRT-PCR. Our results demonstrated that all RVC strains replicated in 2D-PIEs poorly, while 3D-PIEs supported a higher level of replication, suggesting that RVC selectively infects terminally differentiated enterocytes, which were less abundant in the 2D vs. 3D PIE cultures. While cellular receptors for RVC are unknown, target cell surface carbohydrates, including histo-blood-group antigens (HBGAs) and sialic acids (SAs), are believed to play a role in cell attachment/entry. The evaluation of the selective binding of RVCs to different HBGAs revealed that PRVC Cowden G1P[1] replicated to the highest titers in the HBGA-A PIEs, while PRVC104 or PRVC143 achieved the highest titers in the HBGA-H PIEs. Further, contrasting outcomes were observed following sialidase treatment (resulting in terminal SA removal), which significantly enhanced Cowden and RVC143 replication, but inhibited the growth of PRVC104. These observations suggest that different RVC strains may recognize terminal (PRVC104) as well as internal (Cowden and RVC143) SAs on gangliosides. Finally, several cell culture additives, such as diethylaminoethyl (DEAE)-dextran, cholesterol, and bile extract, were tested to establish if they could enhance RVC replication. We observed that only DEAE-dextran significantly enhanced RVC attachment, but it had no effect on RVC replication. Additionally, the depletion of cellular cholesterol by MßCD inhibited Cowden replication, while the restoration of the cellular cholesterol partially reversed the MßCD effects. These results suggest that cellular cholesterol plays an important role in the replication of the PRVC strain tested. Overall, our study has established a novel robust and physiologically relevant system to investigate RVC pathogenesis. We also generated novel, experimentally derived evidence regarding the role of host glycans, DEAE, and cholesterol in RVC replication, which is critical for the development of control strategies.

IgG antibodies to SARS-CoV-2 in asymptomatic blood donors at two time points in Karachi.

INTRODUCTION: An estimated 1.5 million cases were reported in Pakistan until 23 March, 2022. However, SARS-CoV-2 PCR testing capacity has been limited and the incidence of COVID-19 infections is unknown. Volunteer healthy blood donors can be a control population for assessment of SARS-CoV-2 exposure in the population. We determined COVID-19 seroprevalence during the second pandemic wave in Karachi in donors without known infections or symptoms in 4 weeks prior to enrollment. MATERIALS AND METHODS: We enrolled 558 healthy blood donors at the Aga Khan University Hospital between December 2020 and February 2021. ABO blood groups were determined. Serum IgG reactivity were measured to spike and receptor binding domain (RBD) proteins. RESULTS: Study subjects were predominantly males (99.1%) with a mean age of 29.0±7.4 years. Blood groups were represented by; B (35.8%), O (33.3%), A (23.8%) and AB (7%). Positive IgG responses to spike were detected in 53.4% (95% CI, 49.3-37.5) of blood donors. Positive IgG antibodies to RBD were present in 16.7% (95% CI; 13.6-19.8) of individuals. No significant difference was found between the frequency of IgG antibodies to spike or RBD across age groups. Frequencies of IgG to Spike and RBD antibodies between December 2020 and February 2021 were found to be similar. Seropositivity to either antigen between individuals of different blood groups did not differ. Notably, 31.2% of individuals with IgG antibodies to spike also had IgG antibodies to RBD. Amongst donors who had previously confirmed COVID-19 and were seropositive to spike, 40% had IgG to RBD. CONCLUSIONS: Our study provides insights into the seroprevalence of antibodies to COVID-19 in a healthy cohort in Karachi. The differential dynamics of IgG to spike and RBD likely represent both exposure to SARS-CoV-2 and associate with protective immunity in the population.