Recent advances have demonstrated the existence of a B cell subset with regulatory function named (Bregs). Bregs have been shown to restrain the severity of several autoimmune disease and contribute to the development of infection and cancer. In human CD19+CD24hiCD38hiCD1dhiregulatory B cells inhibit the activation of T helper (Th)1 and Th17 responses whilst supporting the differentiation of FoxP3+ Tregs. We have shown that in addition to regulate CD4+T cells differentiation, Breg are essential for iNKT cell homeostasis in healthy individuals but fail to exert the same effect in SLE patients. CD1d-restricted invariant natural killer T (iNKT) cells play an immune-regulatory role functioning in both innate and adaptive immunity. Defective B cell-mediated stimulation of iNKT cells in SLE, was associated with rapid internalization and reduced surface expression of CD1d on immature B cells from SLE patients compared with B cells from healthy individuals. iNKT cell number and function were restored in SLE patients responding to B cell depletion therapy, upon normalization of CD1d levels in repopulated CD19+CD24hiCD38hiCD1dhiregulatory B cells.
Disclosure of Interest None Declared