B Cell Migration Into Skin Limits Local Inflammation

Abstract Regulatory B cells (Bregs) limit inflammatory responses in various organs. While most studies suggest that Bregs exert their anti-inflammatory functions by virtue of IL-10 production in lymphoid tissues such as spleen and lymph nodes, we found that IL-10 producing B cells reside constitutively in skin and are preferentially recruited in inflammation in an α4β1 integrin-dependent manner. To address whether Bregs suppress inflammation at the effector site (i.e. inflamed skin), we employed mice with an inducible B-cell specific deletion of α4-integrin. Selectively blocking migration of B cells into the inflamed skin led to increased localized inflammation in mouse models of psoriasis and cutaneous hypersensitivity. The data support a model in which Bregs suppress inflammation not only in lymphoid tissues but also at effector sites.