Thymic B cells promote germinal center-like structures and the expansion of follicular helper T cells in lupus-prone mice

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibody production and immune complex deposition. Previous evidence showed abnormal accumulation of B cells in the thymus of lupus-prone mice, but the role of this population remains undefined. We analyzed the distribution, function, and properties of thymic B cells in the BWF1 murine model of SLE. We found that B cells proliferate and cluster in germinal center-like structures along with autoantibody-secreting cells in the thymus of diseased-BWF1 mice. These thymic B cells induced the differentiation of follicular helper T cells (TFH). Our data suggest that the accumulation of B cells in the thymus of BWF1 mice results in the formation of germinal center-like structures and the expansion of TFH cells, which may favor the differentiation of autoreactive plasma cells. Therefore, the thymus emerges as a niche supporting the maintenance of the pathogenic humoral response in the development of murine SLE. Overall design: Thymic B cells mRNA profiles of lupus-diseased-BWF1 mice (BWF1 mice) and non-lupus-susceptible mice (control mice) were generated by deep sequencing, in triplicate, using MiSeq Reagent Kit v3 150-cycle PE