Timing is essential: Humoral and cellular responses to SARS-CoV-2 vaccination in a cohort of patients with auto-immune diseases treated with rituximab

Abstract

Rituximab (RTX), an anti CD20 monoclonal antibody, is now a gold standard treatment for several auto-immune and chronic inflammatory diseases. Receiving RTX exposes patients to more severe infections as vaccinations become virtually inefficient in terms of B cell responses. During the COVID-19 crisis, RTX-exposed patients exhibited more severe forms of the disease, and in some cases, the introduction of RTX was delayed or avoided to protect patients as much as possible against SARS-CoV-2 infections. We retrospectively collected cellular and humoral responses from thirteen patients with dermatological and rheumatological autoimmune diseases who had been vaccinated after receiving RTX. Memory T cells subsets from patients that exposed to RTX showed few differences when compared to a cohort of healthy donors. The IFNᵧ ELISpot assay using SARS-CoV-Prot_S1 showed that eight patients exhibited a positive response that was neither correlated to the time between RTX infusion and the sampling nor to the time between RTX and the vaccination. Conversely, analysis of the SARS-CoV-2 serology showed a clearly lower binding antibody units per mL in case of recent RTX infusion. The safe threshold forconsistently positive serology was to vaccinate at least 300 days after RTX infusion (p = 0.02). Our data illustrate the difficulty in obtaining a satisfactory response to vaccination after RTX treatment within almost a year after the latest infusion, and emphasize the need to better evaluate the risk of relapses in auto-immune diseases before administering RTX in order to maintain RTX only in patients whose medical situation requires it.

Fig. 1

Influence of the time between vaccination and RTX infusion on the humoral and cellular responses to SARS-CoV-2 vaccination A) Schematization of the patients included, the icons represent from left to right: RTX infusion, SARS-CoV-2 vaccination, and blood sampling with the corresponding number of days between each event written in the bars. The±icons refer to the positivity or negativity of the serology using the 50 AU/mL threshold. The ELISPOT images shows the IFNᵧ ELISPOT response to SARS-CoV-2 Spike S1 protein. Controls for the Elispot are shown in Supplementary Fig. 1. Diagnosis are written on the far right: Rheumatoid arthritis, Pemphigus vulgaris, superficial Pemphigus, Evans syndrome (auto-immune hemolytic anemia and thrombocytemia), Systemic Lupus Erythematosus, Polymyositis, Sjögren syndrome, ANCA vasculitis, Devic syndrome (neuromyelitis). B) Memory CD4 and CD8 T cells subsets were analyzed in PBMC of healthy controls (gray, n = 13) and patients (black, n = 12). C-D) Correlation between C) SARS-CoV-Prot_S1 specific immune responses (IFNᵧ spots/3.10⁵ cells, positivity shown as dotted line); or D) SARS-CoV-2 serology level (AU/mL, positivity shown as dashed line), according to the days between the infusion of Rituximab and the vaccination. E) Dot plots of the number of days between the infusion of Rituximab and the vaccination according to the serological responses in patients (negative if the serology was inferior to 50AU/mL). Mann-Whitney test, where ∗p < 0.05 and ∗∗p < 0.01. Abbreviations: RTX: Rituximab, HC: healthy controls, Tn: Naive T cells, Tscm: stem cell-like memory T cells, Tcm: central memory T cells, Teff: effector memory T cells and Temra: Terminally differentiated effector memory T cells. ∗ identifies the patient who had a positive response to protein M in the ELISpot, suggesting a previous infection by SARS-CoV-2. Male and female icons show the gender of patients. Fig. 1C and D: statistical testing with pearson correlations are non-significant.