Rituximab therapy leads to impaired response to SARS-CoV2 vaccination in the majority of vaccinated patients with autoimmune rheumatic diseases.
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Immunoglobulin levels are a major predictor of immunization response to SARS-CoV2 vaccination in rituximab treated patients.
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Older individuals treated with Rituximab may be less likely to respond to SARS-CoV2 vaccination.
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Responses to the SARS-CoV2 vaccination did not improve even after following published guidelines on timing vaccination post RTX infusion.
Abstract
Rituximab (RTX), an important therapeutic option for patients with rheumatic diseases, has been shown to reduce immune responses to various vaccines. We asked whether following SARS-CoV-2 vaccination, response rates in RTX treated patients are reduced and whether specific patient characteristics influence the responses. We recruited patients on chronic RTX therapy undergoing anti-SARS-CoV2 vaccination and measured the post-vaccination anti-spike IgG antibody levels. The median time from pre-vaccination RTX infusion to vaccination and from vaccination to the post-vaccination RTX infusion was 20.5 weeks and 7.2 weeks respectively. Only 36.5% of patients developed measurable titers of IgG anti-SARS-CoV-2 spike antibody after vaccination. Hypogammaglobulinemia (IgG and/or IgM) but not timing of vaccination, B cell numbers, or concomitant immune suppressive medications, correlated with sero-negativity (p = 0.004). Our results underscore the fact that even after B cell reconstitution, RTX induced chronic hypogammaglobulinemia significantly impairs the ability of the immune system to respond to SARS-CoV-2 vaccination.