Model Immunization with Coronavirus-2 Vaccines Induce Potent Antibody Responses but Does Not Aggravate Lymphocyte Abnormalities in Primary Sjogren's Syndrome Patients

ABSTRACT

Objectives. The peripheral lymphocyte compartment of patients with primary Sjogren's syndrome (pSS) differs strongly from healthy individuals. Whether this altered lymphocyte composition also abnormally changes during immune reactions, especially in the context of novel mRNA-vaccines, is unknown. Methods. Peripheral blood samples from 26 pSS patients were compared to 6 healthy controls before Coronavirus-2 (CoV-2) vaccination (BNT162b2, ChAdOx1, mRNA-1273) and 7 days after secondary vaccination. Spike. 1 (S1)-receptor binding domain (RBD)-neutralizing IgG antibodies were measured in serum samples. Within peripheral blood mononuclear cells (PBMC), lymphocytes were characterized using spectral flow cytometry and B and T cell subpopulations were phenotypically analyzed. Results. Immunization induced CoV-2 specific serum antibodies in all pSS and healthy participants. When analyzing pSS and healthy individuals together, frequencies of circulating IgG+ RBD-binding antibody-secreting cells (ASC) and anti-CoV-2 serum titers correlated (r=0.42, p=0.022). Previously described alterations of peripheral B cells in pSS patients (like reduced memory B cells, increased naive and transitional B cells and higher maturity of ASCs) remained stable during vaccination. Also the subset distribution of CD4+ and CD8+ T cells mainly stayed unchanged. However, CD4+CXCR5-PD-1+ T cells phenotypically mimicking peripheral helper TPH cells increased in pSS patients comparing pre- and post-vaccination (p=0.020), while circulating CD4+CXCR5+PD-1+ follicular helper TFH cells declined (p=0.024). Conclusions. An immune reaction induced by vaccination with the novel mRNA technology yields adequate antibody production and vaccine specific lymphocytes in pSS patients and controls. However, no major changes within the typical composition of lymphocyte subpopulations of pSS patients were observed despite small changes in TPH and TFH subsets.