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J Am Soc Nephrol ; 2021 Oct 19.
Article in English | MEDLINE | ID: covidwho-1566580


Background: Accumulating evidence suggests that solid organ transplant recipients, as opposed to the general population, show strongly impaired responsiveness towards standard SARS-CoV-2 mRNA-based vaccination, demanding alternative strategies for protection of this vulnerable group. Methods: In line with recent recommendations, a third dose of either heterologous ChAdOx1 (AstraZeneca) or homologous BNT162b2 (BioNTech) was administered to 25 kidney transplant recipients (KTR) without humoral response after 2 doses of BNT162b2, followed by analysis of serological responses and vaccine-specific B- and T-cell immunity. Results: 9/25 (36%) KTR under standard immunosuppressive treatment seroconverted until day 27 after the third vaccination, while one patient developed severe COVID-19 infection immediately after vaccination. Cellular analysis seven days after the third dose showed significantly elevated frequencies of viral spike protein receptor binding domain specific B cells in humoral responders as compared to non-responders. Likewise, portions of spike-reactive CD4+ T helper cells were significantly elevated in seroconverting patients. Furthermore, overall frequencies of IL-2+, IL-4+ and polyfunctional CD4+ T cells significantly increased after the third dose, whereas memory/effector differentiation remained unaffected. Conclusions: Our data suggest that a fraction of transplant recipients benefits from triple vaccination, where seroconversion is associated with quantitative and qualitative changes of cellular immunity. At the same time, the study highlights that modified vaccination approaches for immunosuppressed patients still remain an urgent medical need.

Sci Immunol ; 6(60)2021 06 15.
Article in English | MEDLINE | ID: covidwho-1369380


Patients with kidney failure are at increased risk for SARS-CoV-2 infection making effective vaccinations a critical need. It is not known how well mRNA vaccines induce B and plasma cell responses in dialysis patients (DP) or kidney transplant recipients (KTR) compared to healthy controls (HC). We studied humoral and B cell responses of 35 HC, 44 DP and 40 KTR. Markedly impaired anti-BNT162b2 responses were identified among KTR and DP compared to HC. In DP, the response was delayed (3-4 weeks after boost) and reduced with anti-S1 IgG and IgA positivity in 70.5% and 68.2%, respectively. In contrast, KTR did not develop IgG responses except one patient who had a prior unrecognized infection and developed anti-S1 IgG. The majority of antigen-specific B cells (RBD+) were identified in the plasmablast or post-switch memory B cell compartments in HC, whereas RBD+ B cells were enriched among pre-switch and naïve B cells from DP and KTR. The frequency and absolute number of antigen-specific circulating plasmablasts in the cohort correlated with the Ig response, a characteristic not reported for other vaccinations. In conclusion, these data indicated that immunosuppression resulted in impaired protective immunity after mRNA vaccination, including Ig induction with corresponding generation of plasmablasts and memory B cells. Thus, there is an urgent need to improve vaccination protocols in patients after kidney transplantation or on chronic dialysis.

Antibodies, Viral/blood , COVID-19 Vaccines/immunology , COVID-19/prevention & control , Immunocompromised Host , Kidney Transplantation , Adult , Aged , Aged, 80 and over , Antibodies, Viral/immunology , COVID-19/immunology , Female , Humans , Immunity, Humoral/drug effects , Immunity, Humoral/immunology , Male , Middle Aged , Renal Dialysis , SARS-CoV-2 , Transplant Recipients
Front Immunol ; 12: 690698, 2021.
Article in English | MEDLINE | ID: covidwho-1317227


Patients with kidney failure have notoriously weak responses to common vaccines. Thus, immunogenicity of novel SARS-CoV-2 vaccines might be impaired in this group. To determine immunogenicity of SARS-CoV-2 vaccination in patients with chronic dialysis, we analyzed the humoral and T-cell response after two doses of mRNA vaccine Tozinameran (BNT162b2 BioNTech/Pfizer). This observational study included 43 patients on dialysis before vaccination with two doses of Tozinameran 21 days apart. Overall, 36 patients completed the observation period until three weeks after the second dose and 32 patients were further analyzed at week 10. Serum samples were analyzed by SARS-CoV-2 specific IgG and IgA antibodies ~1, ~3-4 and ~10 weeks after the second vaccination. In addition, SARS-CoV-2-specific T-cell responses were assessed at ~3-4 weeks by an interferon-gamma release assay (IGRA). Antibody and T cell outcomes at this timepoint were compared to a group of 44 elderly patients not on dialysis, after immunization with Tozinameran. Median age of patients on chronic dialysis was 74.0 years (IQR 66.0, 82.0). The proportion of males was higher (69.4%) than females. Only 20/36 patients (55.6%, 95%CI: 38.29-71.67) developed SARS-CoV-2-IgG antibodies at the first sampling, whereas 32/36 patients (88.9%, 95%CI: 73.00-96.38) demonstrated IgG detection at the second sampling. In a longitudinal follow-up at ~10 weeks after the second dose, the proportion of dialysis patients reactive for anti-SARS-CoV-2-IgG decreased to 27/32 (84.37%, 95%CI: 66.46-94.10) The proportion of anti-SARS-CoV-2 S1 IgA decreased from 33/36 (91.67%; 95%CI: 76.41-97.82) at weeks 3-4 down to 19/32 (59.38; 95%CI: 40.79-75.78). Compared to a cohort of vaccinees with similar age but not on chronic dialysis seroconversion rates and antibody titers were significantly lower. SARS-CoV-2-specific T-cell responses 3 weeks after second vaccination were detected in 21/31 vaccinated dialysis patients (67.7%, 95%CI: 48.53-82.68) compared to 42/44 (93.3%, 95%CI: 76.49-98.84) in controls of similar age. Patients on dialysis demonstrate a delayed, but robust immune response three to four weeks after the second dose, which indicates effective vaccination of this vulnerable group. However, the lower immunogenicity of Tozinameran in these patients needs further attention to develop potential countermeasures such as an additional booster vaccination.

COVID-19 Vaccines/immunology , COVID-19/prevention & control , Immunogenicity, Vaccine , Renal Dialysis , SARS-CoV-2/immunology , Vaccination/methods , Aged , Aged, 80 and over , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/blood , COVID-19/virology , Female , Follow-Up Studies , Humans , Immunity , Immunoglobulin A/blood , Immunoglobulin G/blood , Longitudinal Studies , Male , Middle Aged , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/immunology , T-Lymphocytes/immunology