CD19+CD24hiCD38hi B Cells Exhibit Regulatory Capacity in Healthy Individuals but Are Functionally Impaired in Systemic Lupus Erythematosus Patients

SummaryThe immunosuppressive function of regulatory B cells has been shown in several murine models of chronic inflammation, including collagen-induced arthritis, inflammatory bowel disease, and experimental autoimmune encephalomyelitis. Despite interest in these cells, their relevance to the maintenance of peripheral tolerance in humans remains elusive. Here, we demonstrate that human CD19+CD24hiCD38hi B cells possessed regulatory capacity. After CD40 stimulation, CD19+CD24hiCD38hi B cells suppressed the differentiation of T helper 1 cells, partially via the provision of interleukin-10 (IL-10), but not transforming growth factor-β (TGF-β), and their suppressive capacity was reversed by the addition of CD80 and CD86 mAbs. In addition, CD19+CD24hiCD38hi SLE B cells isolated from the peripheral blood of systemic lupus erythematosus (SLE) patients were refractory to further CD40 stimulation, produced less IL-10, and lacked the suppressive capacity of their healthy counterparts. Altered cellular function within this compartment may impact effector immune responses in SLE and other autoimmune disorders.

► Human regulatory B (Breg) cells are enriched within a CD19+CD24hiCD38hi subset
► Human CD19+CD24hiCD38hi Breg cells suppress T helper 1 cell differentiation in vitro
► Human Breg cell-suppressive function depends on expression of IL-10, CD80, and CD86
► Breg cells from systemic lupus erythematosus subjects lack suppressive capacity