Case Report: Favorable outcome of allogeneic hematopoietic stem cell transplantation in SARSCoV2 positive recipient, risk-benefit balance between infection and leukemia.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) in SARS-CoV-2 positive candidates is usually delayed until the clinical resolution of the infection's symptoms and a negative nasopharyngeal molecular test. However, prolonged SARS-CoV-2 positivity has been frequently observed in haematological malignancies, thus representing a challenge for the timing of transplant procedures. Here, we report on the case of a 34-year-old patient with recent pauci-symptomatic COVID-19 undergoing transplant for high-risk acute B-lymphoblastic leukemia before achieving viral clearance. Shortly before their scheduled allogeneic HSCT from a matched unrelated donor, the patient developed mild Omicron BA.5 infection receiving nirmatrelvir/ritonavir with fever resolution within 72 hours. Twenty-three days after COVID-19 diagnosis, because of increasing minimal residual disease values in the context of high-risk refractory leukemia and clinical resolution of SARS-2-CoV infection with reduction of viral load at surveillance nasopharyngeal swabs, it was decided not to delay further allo-HSCT. During myelo-ablative conditioning, the nasopharyngeal SARS-CoV-2 viral load increased while the patient remained asymptomatic. Consequently, two days before the transplant, intra-muscular tixagevimab/cilgavimab 300/300 mg and a 3-day course of intravenous remdesivir were administered. During the pre-engraftment phase, veno-occlusive disease (VOD) occurred at day +13, requiring defibrotide treatment to obtain a slow but complete recovery. The post-engraftment phase was characterized by mild COVID-19 at day +23 (cough, rhino-conjunctivitis, fever) that spontaneously resolved, achieving viral clearance at day +28. At day +32, she experienced grade I acute graft-versus host disease (a-GVHD, skin grade II) treated with steroids and photo-apheresis, without further complications during follow-up until day +180. Addressing the issue of allo-HSCT timing in patients recovering from SARS-CoV-2 infection with high-risk malignant diseases is challenging because of 1] the high risk of COVID-19 clinical progression, 2] the impact of transplant delay on leukemia prognosis and 3] the occurrence of endothelial complications such as VOD, a-GVHD, and transplant associated thrombotic micro-angiopathy. Our report describes the favourable outcome of allo-HSCT in a recipient with active SARS-CoV2 infection and high-risk leukemia thanks to timely anti-SARS-CoV-2 preventive therapies and prompt management of transplant-related complications.

The Immunological Profile of SARS-CoV-2 Infection in Children Is Linked to Clinical Severity and Age.

Coronavirus disease 19 (COVID-19) is clinically less severe in children, even if the wide variety and degree of severity of symptoms reported in children pose a still-unresolved challenge for clinicians. We performed an in-depth analysis of the immunological profiles of 18 hospitalized SARS-CoV-2-infected children, whose results were compared to those obtained from 13 age- and sex-matched healthy controls (HC). The patients were categorized as paucisymptomatic/moderate (55.6%) or severe/critical (44.5%) according to established diagnostic criteria and further stratified into the categories of infants (1-12 months), children (1-12 years), and adolescents (>12 years). We assessed SARS-CoV-2-specific RBD antibodies (Ab), neutralizing antibodies (nAb), and circulating cytokines/chemokines in the plasma, and the SARS-CoV-2-specific immune response was measured in PBMCs by gene expression and secretome analyses. Our results showed peculiar circulating cytokine/chemokine profiles among patients sharing a similar clinical phenotype. A cluster of patients consisting of infants with severe symptoms presented hyperinflammatory profiles, together with extremely polarized antibody profiles. In a second cluster consisting of paucisymptomatic patients, a less pronounced increase in the level of inflammatory cytokines, together with an association between the selected cytokines and humoral responses, was observed. A third cluster, again consisting of paucisymptomatic patients, showed a circulating cytokine/chemokine profile which overlapped with that of the HC. The SARS-CoV-2-stimulated production of pro-inflammatory proteins, T lymphocyte activation, and migration-specific proteins, were significantly increased in SARS-CoV-2-infected children compared to the HC. Our findings suggest that immune response activation in the course of SARS-CoV-2 infection in children is directly correlated with clinical severity and, to a lesser extent, age.

A Case Study to Dissect Immunity to SARS-CoV-2 in a Neonate Nonhuman Primate Model.

Most children are less severely affected by coronavirus-induced disease 2019 (COVID-19) than adults, and thus more difficult to study progressively. Here, we provide a neonatal nonhuman primate (NHP) deep analysis of early immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in blood and mucosal tissues. In addition, we provide a comparison with SARS-CoV-2-infected adult NHP. Infection of the neonate resulted in a mild disease compared with adult NHPs that develop, in most cases, moderate lung lesions. In concomitance with the viral RNA load increase, we observed the development of an early innate response in the blood, as demonstrated by RNA sequencing, flow cytometry, and cytokine longitudinal data analyses. This response included the presence of an antiviral type-I IFN gene signature, a persistent and lasting NKT cell population, a balanced peripheral and mucosal IFN-γ/IL-10 cytokine response, and an increase in B cells that was accompanied with anti-SARS-CoV-2 antibody response. Viral kinetics and immune responses coincided with changes in the microbiota profile composition in the pharyngeal and rectal mucosae. In the mother, viral RNA loads were close to the quantification limit, despite the very close contact with SARS-CoV-2-exposed neonate. This pilot study demonstrates that neonatal NHPs are a relevant model for pediatric SARS-CoV-2 infection, permitting insights into the early steps of anti-SARS-CoV-2 immune responses in infants.

Seasonal Betacoronavirus Antibodies' Expansion Post-BNT161b2 Vaccination Associates with Reduced SARS-CoV-2 VoC Neutralization.

SARS-CoV-2 vaccination is known to induce antibodies that recognize also variants of concerns (VoCs) of the virus. However, epidemiological and laboratory evidences indicate that these antibodies have a reduced neutralization ability against VoCs. We studied binding and neutralizing antibodies against the Spike protein domains and subunits of the Wuhan-Hu-1 virus and its alpha, beta, delta VoCs and of seasonal betacoronaviruses (HKU1 and OC43) in a cohort of 31 health care workers prospectively followed post-vaccination with BNT162b2-Comirnaty. The study of sequential samples collected up to 64 days post-vaccination showed that serological assays measuring IgG against Wuhan-Hu-1 antigens were a poor proxy for VoC neutralization. In addition, in subjects who had asymptomatic or mild COVID-19 prior to vaccination, the loss of nAbs following disease could be rapid and accompanied by post-vaccination antibody levels similar to those of naïve vaccinees. Interestingly, in health care workers naïve for SARS-CoV-2 infection, vaccination induced a rapid and transient reactivation of pre-existing seasonal coronaviruses IgG responses that was associated with a subsequent reduced ability to neutralize alpha and beta VoCs.

COVID-19 in Solid Organ Transplant Recipient: Exploring Cumulative Incidence, Seroprevalence and Risk Factors for Disease Severity.

BACKGROUND: Solid organ transplant (SOT) recipients may be at increased risk for severe disease and mortality from COVID-19 because of immunosuppression and prolonged end-stage organ disease. As a transplant center serving a diverse patient population, we report the cumulative incidence and outcomes of SARS-CoV-2 infection in our cohort of SOT recipients. METHODS: We prospectively included in this observational study SOT recipients with a functioning kidney (n = 201), pancreas ± kidney (n = 66) or islet transplant (n = 24), attending outpatient regular follow-up at the San Raffaele Hospital from February 2020 to April 2021. Antibodies to SARS-CoV-2 were tested in all patients by a luciferase immunoprecipitation system assay. RESULTS: Of the 291 SOT recipients, 30 (10.3%) tested positive for SARS-CoV-2 during the study period and prevalence was not different among different transplants. The SARS-CoV-2 antibody frequency was around 2.6-fold higher than the incidence of cases who tested positive for SARS-CoV-2 RT-PCR. As for the WHO COVID-19 severity classification, 19 (63.3%) SOT recipients were mild, nine (30%) were moderate, and two were critical and died yielding a crude mortality rate in our patient population of 6.7%. Kidney transplant (OR 12.9 (1.1-150) p = 0.041) was associated with an increased risk for moderate/critical disease, while statin therapy (OR 0.116 (0.015-0.926) p = 0.042) and pancreas/islet transplant (OR 0.077 (0.007-0.906) p = 0.041) were protective. CONCLUSIONS: The incidence of SARS-CoV-2 infection in SOT recipients may be higher than previously described. Due to the relative high crude mortality, symptomatic SOT recipients must be considered at high risk in case of SARS-CoV-2 infection.

Pre-Existing Diabetes and COVID-Associated Hyperglycaemia in Patients with COVID-19 Pneumonia.

AIM: The aim of the current study was to compare clinical characteristics, laboratory findings, and major outcomes of patients hospitalized for COVID-19 pneumonia with COVID-associated hyperglycaemia or pre-existing diabetes. METHODS: A cohort of 176 adult patients with a diagnosis of pre-existing diabetes (n = 112) or COVID-associated hyperglycaemia (n = 55) was studied. RESULTS: Patients with COVID-associated hyperglycaemia had lower BMI, significantly less comorbidities, and higher levels of inflammatory markers and indicators of multi-organ injury than those with pre-existing diabetes. No differences between pre-existing diabetes and COVID-associated hyperglycaemia were evident for symptoms at admission, the humoral response against SARS-CoV-2, or autoantibodies to glutamic acid decarboxylase or interferon alpha-4. COVID-associated hyperglycaemia was independently associated with the risk of adverse clinical outcome, which was defined as ICU admission or death (HR 2.11, 95% CI 1.34-3.31; p = 0.001), even after adjustment for age, sex, and other selected variables associated with COVID-19 severity. Furthermore, at the same time, we documented a negative association (HR 0.661, 95% CI 0.43-1.02; p = 0.063) between COVID-associated hyperglycaemia to swab negativization. CONCLUSIONS: Recognizing hyperglycaemia as a specific clinical entity associated with COVID-19 pneumonia is relevant for early and appropriate patient management and close monitoring for the progression of disease severity.

Neutralizing antibody responses to SARS-CoV-2 in symptomatic COVID-19 is persistent and critical for survival.

Understanding how antibody responses to SARS-CoV-2 evolve during infection may provide important insight into therapeutic approaches and vaccination for COVID-19. Here we profile the antibody responses of 162 COVID-19 symptomatic patients in the COVID-BioB cohort followed longitudinally for up to eight months from symptom onset to find SARS-CoV-2 neutralization, as well as antibodies either recognizing SARS-CoV-2 spike antigens and nucleoprotein, or specific for S2 antigen of seasonal beta-coronaviruses and hemagglutinin of the H1N1 flu virus. The presence of neutralizing antibodies within the first weeks from symptoms onset correlates with time to a negative swab result (p = 0.002), while the lack of neutralizing capacity correlates with an increased risk of a fatal outcome (p = 0.008). Neutralizing antibody titers progressively drop after 5-8 weeks but are still detectable up to 8 months in the majority of recovered patients regardless of age or co-morbidities, with IgG to spike antigens providing the best correlate of neutralization. Antibody responses to seasonal coronaviruses are temporarily boosted, and parallel those to SARS-CoV-2 without dampening the specific response or worsening disease progression. Our results thus suggest compromised immune responses to the SARS-CoV-2 spike to be a major trait of COVID-19 patients with critical conditions, and thereby inform on the planning of COVID-19 patient care and therapy prioritization.

COVID-19 survival associates with the immunoglobulin response to the SARS-CoV-2 spike receptor binding domain.

BACKGROUNDSerological assays are of critical importance to investigate correlates of response and protection in coronavirus disease 2019 (COVID-19), to define previous exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in populations, and to verify the development of an adaptive immune response in infected individuals.METHODSWe studied 509 patients confirmed to have COVID-19 from the San Raffaele Hospital of Milan and 480 samples of prepandemic organ donor sera collected in 2010-2012. Using fluid-phase luciferase immune precipitation (LIPS) assays, we characterized IgG, IgM, and IgA antibodies to the spike receptor binding domain (RBD), S1+S2, nucleocapsid, and ORF6 to ORF10 of SARS-CoV-2, to the HCoV-OC43 and HCoV-HKU1 betacoronaviruses spike S2, and the H1N1Ca2009 flu virus hemagglutinin. Sequential samples at 1 and 3 months after hospital discharge were also tested for SARS-CoV-2 RBD antibodies in 95 patients.RESULTSAntibodies developed rapidly against multiple SARS-CoV-2 antigens in 95% of patients by 4 weeks after symptom onset and IgG to the RBD increased until the third month of follow-up. We observed a major synchronous expansion of antibodies to the HCoV-OC43 and HCoV-HKU1 spike S2. A likely coinfection with influenza was neither linked to a more severe presentation of the disease nor to a worse outcome. Of the measured antibody responses, positivity for IgG against the SARS-CoV-2 spike RBD was predictive of survival.CONCLUSIONThe measurement of antibodies to selected epitopes of SARS-CoV-2 antigens can offer a more accurate assessment of the humoral response in patients and its impact on survival. The presence of partially cross-reactive antibodies with other betacoronaviruses is likely to impact on serological assay specificity and interpretation.TRIAL REGISTRATIONCOVID-19 Patients Characterization, Biobank, Treatment Response and Outcome Predictor (COVID-BioB). ClinicalTrials.gov identifier: NCT04318366.FUNDINGIRCCS Ospedale San Raffaele and Università Vita Salute San Raffaele.

Robust Neutralizing Antibodies to SARS-CoV-2 Develop and Persist in Subjects with Diabetes and COVID-19 Pneumonia.

CONTEXT: Demonstrating the ability to mount a neutralizing antibody response to SARS-CoV-2 in the presence of diabetes is crucial to understand COVID-19 pathogenesis, reinfection potential, and vaccine development. OBJECTIVE: The aim of this study was to characterize the kinetics and durability of neutralizing antibody (Nab) response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the presence of hyperglycemia. METHODS: Using a lentiviral vector-based SARS-CoV-2 neutralization assay to measure Nabs, we characterized 150 patients randomly selected from a cohort of 509 patients with confirmed COVID-19 pneumonia. We analyzed Nab response according to the presence of diabetes or hyperglycemia, at the time of hospitalization and during the postdischarge follow-up: 1-, 3-, and 6-month outpatient visits. RESULTS: Among 150 randomly selected patients 40 (26.6%) had diabetes. Diabetes (hazard ratio [HR] 8.9, P < .001), glucose levels (HR 1.25 × 1.1 mmol/L, P < .001), and glucose variability (HR 1.17 × 0.6 mmol/L, P < .001) were independently associated with an increased risk of mortality. The neutralizing activity of SARS-CoV-2 antibodies in patients with diabetes was superimposable, as for kinetics and extent, to that of patients without diabetes. It was similar across glucose levels and correlated with the humoral response against the SARS-CoV-2 spike protein. Positivity for Nabs at the time of hospital admission conferred protection on mortality, both in the presence (HR 0.28, P = .046) or absence of diabetes (HR 0.26, P = .030). The longevity of the Nab response was not affected by diabetes. CONCLUSION: Diabetes and hyperglycemia do not affect the kinetics and durability of the neutralizing antibody response to SARS-CoV-2. These findings provide the rational to include patients with diabetes in the early phase of the vaccination campaign against SARS-CoV-2.

Antibody response to multiple antigens of SARS-CoV-2 in patients with diabetes: an observational cohort study.

AIMS/HYPOTHESIS: The aim of the study was to characterise the humoral response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients with diabetes. Demonstrating the ability to mount an appropriate antibody response in the presence of hyperglycaemia is relevant for the comprehension of mechanisms related to the observed worse clinical outcome of coronavirus disease 2019 (COVID-19) pneumonia in patients with diabetes and for the development of any future vaccination campaign to prevent SARS-CoV-2 infection. METHODS: Using a highly specific and sensitive measurement of antibodies by fluid-phase luciferase immunoprecipitation assays, we characterised the IgG, IgM and IgA response against multiple antigens of SARS-CoV-2 in a cohort of 509 patients with documented diagnosis of COVID-19, prospectively followed at our institution. We analysed clinical outcomes and antibody titres according to the presence of hyperglycaemia, i.e., either diagnosed or undiagnosed diabetes, at the time of, or during, hospitalisation. RESULTS: Among patients with confirmed COVID-19, 139 (27.3%) had diabetes: 90 (17.7%) had diabetes diagnosed prior to the hospital admission (comorbid diabetes) while 49 (9.6%) had diabetes diagnosed at the time of admission (newly diagnosed). Diabetes was associated with increased levels of inflammatory biomarkers and hypercoagulopathy, as well as leucocytosis and neutrophilia. Diabetes was independently associated with risk of death (HR 2.32 [95% CI 1.44, 3.75], p = 0.001), even after adjustment for age, sex and other relevant comorbidities. Moreover, a strong association between higher glucose levels and risk of death was documented irrespective of diabetes diagnosis (HR 1.14 × 1.1 mmol/l [95% CI 1.08, 1.21], p < 0.001). The humoral response against SARS-CoV-2 in patients with diabetes was present and superimposable, as for timing and antibody titres, to that of non-diabetic patients, with marginal differences, and was not influenced by glucose levels. Of the measured antibody responses, positivity for IgG against the SARS-CoV-2 spike receptor-binding domain (RBD) was predictive of survival rate, both in the presence or absence of diabetes. CONCLUSIONS/INTERPRETATION: The observed increased severity and mortality risk of COVID-19 pneumonia in patients with hyperglycaemia was not the result of an impaired humoral response against SARS-CoV-2. RBD IgG positivity was associated with a remarkable protective effect, allowing for a cautious optimism about the efficacy of future vaccines against SARs-COV-2 in people with diabetes. Graphical abstract.