Immune Responses to Mrna Vaccines against Sars-Cov2 in Patients with Immune-Mediated Inflammatory Rheumatic Diseases

ABSTRACT

Background/Aims Patients with immune-mediated rheumatic diseases (IMRD) are commonly treated with immunosuppressors and are prone to infections. Recently introduced mRNA SARS-Cov2 vaccines have demonstrated extraordinary efficacy across all ages. Immunosuppressed patients were excluded from phase III trials with SARS-We aim to fully characterize B and T cell immune responses elicited by mRNA SARS-Cov2 vaccines in patients with rheumatic diseases under immunotherapies, and to identify which drugs reduce vaccine's immunogenicity. Methods Humoral, CD4 and CD8 immune responses were investigated in 147 SARS-Cov2-naive patients with selected rheumatic diseases under immunosuppression after a two-dose regimen of SARS-Cov2 mRNA vaccine. Responses were compared with age, gender, and diseasematched IMRD patients not receiving immunosuppressors and with healthy controls Results IMRD patients showed decreased seroconversion rates (63% vs 100%, p=0.04) and cellular immune responses (59% vs 100%, p=0.007). Patients on methotrexate achieved seroconversion in 62% of cases and cellular responses in 80% of cases. Abatacept deeply affected humoral and cellular responses. Rituximab (31% responders) and belimumab (50% responders) showed severely impaired humoral responses but cellular responses were often preserved. Antibody titers were reduced with mycophenolate and azathioprine but preserved with leflunomide. Conclusion IMRD patients exhibit impaired SARS-CoV-2 vaccine-immunogenicity, variably reduced with immunosuppressors. Among commonly used therapies, abatacept and B-cell depleting therapies show the most deleterious effects, while anticytokines preserved immunogenicity. The effects of cumulative methotrexate and glucocorticoid doses on immunogenicity should be considered. Humoral and cellular responses are weakly correlated, but CD4 and CD8 tightly correlate. Seroconversion alone might not reflect the vaccine's immunogenicity.