9-Month observational Dia-Vacc study of vaccine type influence on SARS-CoV-2 immunity in dialysis and kidney transplant patients.

BACKGROUND: SARS-CoV-2mRNA vaccination related seroconversion rates are reduced in dialysis and kidney transplant patients. METHODS: We evaluated nine months follow up data in our observational Dia-Vacc study exploring specific cellular (interferon-γ release assay) or/and humoral immune responses after 2x SARS-CoV-2mRNA vaccination in 880 participants including healthy medical personnel (125-MP), dialysis patients (595-DP), kidney transplant recipients (111-KTR), and apheresis patients (49-AP) with positive seroconversion (de novo IgA or IgG antibody positivity by ELISA) after eight weeks. FINDINGS: Nine months after first vaccination, receptor binding domain (RBD) antibodies were still positive in 90 % of MP, 86 % of AP, but only 55 %/48 % of DP/KTR, respectively. Seroconversion remained positive in 100 % of AP and 99·2 % of MP, but 86 %/81 % of DP/KTR, respectively. Compared to MP, DP but not KTR or AP were at risk for a strong RBD decline, while KTR kept lowest RBD values over time. By multivariate analysis, BNT162b2mRNA versus 1273-mRNA vaccine type was an independent risk factor for a strong decline of RBD antibodies. Within the DP group, only time on dialysis was another (inverse) risk factor for the DP group. Compared to humoral immunity, T-cell immunity decline was less prominent. INTERPRETATION: While seroconverted KTR reach lowest RBD values over time, DP are at specific risk for a strong decline of RBD antibodies after successful SARS-CoV-2mRNA vaccination, which also depends on the vaccine type being used. Therefore, booster vaccinations for DP should be considered earlier compared to normal population.

Severity of neurological Long-COVID symptoms correlates with increased level of autoantibodies targeting vasoregulatory and autonomic nervous system receptors.

BACKGROUND: The Long-COVID syndrome constitutes a plethora of persisting symptoms with neurological disorders being the most disabling ones. The pathogenesis of Long-COVID is currently under heavy scrutiny and existing data on the role of auto-immune reaction to G-protein coupled receptors (GPCR) are conflicting. METHODS: This monocentric, cross-sectional study included patients who suffered a mild to moderate SARS-CoV-2 infection up to 12 months prior to enrollment with (n = 72) or without (n = 58) Long-COVID diagnosis according to the German S1 guideline or with no known history of SARS-CoV-2 infection (n = 70). While autoantibodies specific for the vasoregulation associated Adrenergic Receptor (ADR) B1 and B2 and the CNS and vasoregulation associated muscarinic acetylcholine receptor (CHR) M3 and M4 were measured by ELISA, neurological disorders were quantified by internationally standardized questionnaires. RESULTS: The prevalence and concentrations of evaluated autoantibodes were significantly higher in Long-COVID compared to the 2 other groups (p = 2.1*10-9) with a significantly higher number of patients with simultaneous detection of more than one autoantibody in the Long-COVID group (p = 0.0419). Importantly, the overall inflammatory state was low in all 3 groups. ARB1 and ARB2 correlated negatively CERAD Trail Marking A and B (R ≤ -0.26, p ≤ 0.043), while CHRM3 correlated positively with Chadler Fatigue Scale (R = 0.37, p = 0.0087). CONCLUSIONS: Concentrations of autoantibodies correlates to the intensity of neurological disorders including psychomotor speed, visual search, attention, and fatigue.

Predictors of impaired SARS-CoV-2 immunity in healthcare workers after vaccination with BNT162b2.

Healthcare workers are at substantially increased risk for infection with SARS-CoV-2. Successful vaccination constitutes a crucial prerequisite to protect this group during the pandemic. Since post vaccination antibody monitoring is not standard of care in all healthcare institutions, data on risk factors of impaired vaccine induced immune response are urgently required. Moreover, there are no data on cellular immune responses in humoral low responders so far. Anti-SARS-CoV-2 spike IgG was assessed after vaccination with BNT162b2 in 1386 employees of three hospitals of a German healthcare provider. Concentrations were compared to those of 45 convalescent employees. Vaccine-induced cellular immunity was measured in employees with reduced humoral response by assessment of frequencies of SARS-CoV-2-reactive CD4+ and CD8+ T cell. Anti-SARS-CoV-2 spike IgG were detected in 99.9% of 1386 healthcare workers after completed vaccination. The median antibody concentration was significantly higher after vaccination than after infection with SARS-CoV-2 (p = 0.0001). 10 subjects (0.7%) generated an IgG concentration < 100 IU/ml, and only two persons (0.1%, solid organ recipients) did not produce detectable antibodies at all. T cell responses of those subjects with submaximal or lacking humoral response were comparable to employees with maximal antibody titers. 50% of those individuals with impaired or lacking humoral immune response were on immunosuppression. Vaccination to SARS-CoV-2 with BNT162b2 is very effective in healthcare workers yielding a seroconversion rate of 99.9%. Immunosuppression is the most important risk factor of an impaired immune response. There was no case of vaccination failure without immunosuppression. Thus, post vaccination antibody monitoring is highly recommendable in those employees with immunosuppression.

Severe Acute Respiratory Syndrome Coronavirus 2 Cross-Reactive B and T Cell Responses in Kidney Transplant Patients.

BACKGROUND: Immune responses to seasonal endemic coronaviruses might have a pivotal role in protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Those SARS-CoV-2-crossreactive T cells were recently described in immunocompetent individuals. Still, data on cross-reactive humoral and cellular immunity in kidney transplant recipients is currently lacking. METHODS: The pre-existing, cross-reactive antibody B and T cell immune responses against SARS-CoV-2 in unexposed adults with kidney transplantation (Tx, n = 14) and without (non-Tx, n = 12) sampled before the pandemic were compared with 22 convalescent patients with COVID-19 (Cp) applying enzyme-linked immunosorbent assay and flow cytometry. RESULTS: In both unexposed groups, SARS-CoV-2 IgG antibodies were not detectable. Memory B cells binding spike (S) protein SARS-CoV-2 were detected in unexposed individuals (64% among Tx; 50% among non-Tx) and higher frequencies after infection (80% Cp). The numbers of SARS-CoV-2-reactive T cells were comparable between patients who had undergone Tx and those who had not. SARS-CoV-2-reactive follicular T helper cells were present in 61% of the unexposed cohort in both patients who had undergone Tx and those who had not. CONCLUSIONS: Cross-reactive memory B and T cells against SARS-CoV-2 exist also in transplanted adults, suggesting a primed adaptive immunity. The effect on the disease course may depend on the concomitant immunosuppressive drugs.

Immune Response in Moderate to Critical Breakthrough COVID-19 Infection After mRNA Vaccination.

SARS-CoV-2 variants of concern (VOCs) can trigger severe endemic waves and vaccine breakthrough infections (VBI). We analyzed the cellular and humoral immune response in 8 patients infected with the alpha variant, resulting in moderate to fatal COVID-19 disease manifestation, after double mRNA-based anti-SARS-CoV-2 vaccination. In contrast to the uninfected vaccinated control cohort, the diseased individuals had no detectable high-avidity spike (S)-reactive CD4+ and CD8+ T cells against the alpha variant and wild type (WT) at disease onset, whereas a robust CD4+ T-cell response against the N- and M-proteins was generated. Furthermore, a delayed alpha S-reactive high-avidity CD4+ T-cell response was mounted during disease progression. Compared to the vaccinated control donors, these patients also had lower neutralizing antibody titers against the alpha variant at disease onset. The delayed development of alpha S-specific cellular and humoral immunity upon VBI indicates reduced immunogenicity against the S-protein of the alpha VOC, while there was a higher and earlier N- and M-reactive T-cell response. Our findings do not undermine the current vaccination strategies but underline a potential need for the inclusion of VBI patients in alternative vaccination strategies and additional antigenic targets in next-generation SARS-CoV-2 vaccines.

Detection of pre-existing SARS-CoV-2-reactive T cells in unexposed renal transplant patients.

BACKGROUND: Recent data demonstrate potentially protective pre-existing T cells reactive against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in samples of healthy blood donors, collected before the SARS-CoV-2 pandemic. Whether pre-existing immunity is also detectable in immunosuppressed patients is currently not known. METHODS: Fifty-seven patients were included in this case-control study. We compared the frequency of SARS-CoV-2-reactive T cells in the samples of 20 renal transplant (RTx) patients to 20 age/gender matched non-immunosuppressed/immune competent healthy individuals collected before the onset of the SARS-CoV-2 pandemic. Seventeen coronavirus disease 2019 (COVID-19) patients were used as positive controls. T cell reactivity against Spike-, Nucleocapsid-, and Membrane- SARS-CoV-2 proteins were analyzed by multi-parameter flow cytometry. Antibodies were analyzed by neutralization assay. RESULTS: Pre-existing SARS-CoV-2-reactive T cells were detected in the majority of unexposed patients and healthy individuals. In RTx patients, 13/20 showed CD4+ T cells reactive against at least one SARS-CoV-2 protein. CD8+ T cells reactive against at least one SARS-CoV-2 protein were demonstrated in 12/20 of RTx patients. The frequency and Th1 cytokine expression pattern of pre-formed SARS-CoV-2 reactive T cells did not differ between RTx and non-immunosuppressed healthy individuals. CONCLUSIONS: This study shows that the magnitude and functionality of pre-existing SARS-CoV-2 reactive T cell in transplant patients is non-inferior compared to the immune competent cohort. Although several pro-inflammatory cytokines were produced by the detected T cells, further studies are required to prove their antiviral protection.

ACE2 polymorphism and susceptibility for SARS-CoV-2 infection and severity of COVID-19.

OBJECTIVES: The RNA virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for coronavirus disease 2019 (COVID-19). Cell entry is mediated by the human angiotensin-converting enzyme II (ACE2). ACE2 and its close homolog angiotensin-converting enzyme I (ACE) are currently discussed candidate genes, in which single-nucleotide polymorphisms (SNPs) could alter binding or entry of SARS-CoV-2 and enhance tissue damage in the lung or other organs. This could increase the susceptibility for SARS-CoV-2 infection and the severity of COVID-19. PATIENTS AND METHODS: We performed genotyping of SNPs in the genes ACE2 and ACE in 297 SARS-CoV-2-positive and 253 SARS-CoV-2-negative tested patients. We analyzed the association of the SNPs with susceptibility for SARS-CoV-2 infection and the severity of COVID-19. RESULTS: SARS-CoV-2-positive and SARS-CoV-2-negative patients did not differ regarding demographics and clinical characteristics. For ACE2 rs2285666, the GG genotype or G-allele was significantly associated with an almost two-fold increased SARS-CoV-2 infection risk and a three-fold increased risk to develop serious disease or COVID-19 fatality. In contrast, the ACE polymorphism was not related to infection risk or severity of disease. In a multivariable analysis, the ACE2 rs2285666 G-allele remained as an independent risk factor for serious disease besides the known risk factors male gender and cardiovascular disease. CONCLUSIONS: In summary, our report appears to be the first showing that a common ACE2 polymorphism impacts the risk for SARS-CoV-2 infection and the course of COVID-19 independently from previously described risk factors.

COVID-19-Induced ARDS Is Associated with Decreased Frequency of Activated Memory/Effector T Cells Expressing CD11a+.

Preventing the progression to acute respiratory distress syndrome (ARDS) in COVID-19 is an unsolved challenge. The involvement of T cell immunity in this exacerbation remains unclear. To identify predictive markers of COVID-19 progress and outcome, we analyzed peripheral blood of 10 COVID-19-associated ARDS patients and 35 mild/moderate COVID-19 patients, not requiring intensive care. Using multi-parametric flow cytometry, we compared quantitative, phenotypic, and functional characteristics of circulating bulk immune cells, as well as SARS-CoV-2 S-protein-reactive T cells between the two groups. ARDS patients demonstrated significantly higher S-protein-reactive CD4+ and CD8+ T cells compared to non-ARDS patients. Of interest, comparison of circulating bulk T cells in ARDS patients to non-ARDS patients demonstrated decreased frequencies of CD4+ and CD8+ T cell subsets, with activated memory/effector T cells expressing tissue migration molecule CD11a++. Importantly, survival from ARDS (4/10) was accompanied by a recovery of the CD11a++ T cell subsets in peripheral blood. Conclusively, data on S-protein-reactive polyfunctional T cells indicate the ability of ARDS patients to generate antiviral protection. Furthermore, decreased frequencies of activated memory/effector T cells expressing tissue migratory molecule CD11a++ observed in circulation of ARDS patients might suggest their involvement in ARDS development and propose the CD11a-based immune signature as a possible prognostic marker.