Humoral and cellular responses to mRNA vaccines against SARS-CoV2 in patients with a history of CD20-B-cell depleting therapy

Background B-cell depleting therapies increase COVID19 morbidity and mortality. For this specific population, evidence-based vaccination strategies are lacking. Here, we investigated humoral and cell mediated immune responses to SARS-CoV2 mRNA-based vaccines in patients receiving CD20-B-cell depleting agents for autoimmune disease, malignancy, or transplantation. Methods Patients at the Bern University Hospital with a treatment history of anti-CD20 depleting agents (rituximab or ocrelizumab) were enrolled for analysis of humoral and cell-mediated immune responses (by IFN-g release assay) after completing vaccination against SARS-CoV2. Primary outcome was the the anti-spike antibody response in anti-CD20-treated patients (n=96) in comparison to immunocompetent controls (n=29). Results Anti-spike IgG antibodies were detected in 49% of patients 1.79 months after the second vaccine dose (interquartile range, IQR: 1.16-2.48) compared to 100% of controls (p<0.001). SARS-CoV2 specific interferon-g; release was detected in 17% of patients and 86% of healthy controls (p<0.001). Only 5% of patients, but 86% of healthy controls showed positive reactions in both assays, respectively (p<0.001). Time since last anti-CD20 therapy (7.6 months), peripheral CD19+ (>27/ul), and CD4+ lymphocyte count (>653/ul) predicted humoral vaccine response (area under the curve [AUC]: 62% [CI 56-78], 67% [CI 58-80] and 67% [CI 54-79], (positive predictive value [PPV]: 0.76, 0.7 and 0.71). Conclusion This study provides evidence for blunted humoral and cell-mediated immune responses elicited by SARS-CoV2 mRNA vaccines in patients with CD20-depleting treatment history. Lymphocyte subpopulation counts are associated with vaccine response in this highly vulnerable population. (Funded by Bern University Hospital, ClinicalTrials.gov number, NCT04877496)