Decreased level of interleukin-10-producing B cells in patients with pemphigus but not in patients with pemphigoid.

Background: While the frequency of interleukin (IL)-10-producing B (B10) cells is reported to have an inverse correlation with disease activity in some human autoimmune diseases, the association between B10 cells and autoimmune blistering diseases (AIBD) has not been well evaluated. Although several phenotypes of human regulatory B cells have been proposed, the most appropriate one in AIBD has not been established.
Objective: To evaluate B10 cells in AIBD including their phenotypes.
Methods: Peripheral blood mononuclear cells were isolated from 39 patients with AIBD, including 14 with pemphigus and 25 with pemphigoid, and 10 healthy controls. We investigated the frequencies of B10 cells and CD19 ⁺ CD24 ^hi CD38 ^hi B cells using flow cytometry.
Results: The frequencies of B10 cells and CD19 ⁺ CD24 ^hi CD38 ^hi B cells were significantly lower and higher, respectively, in patients with pemphigus compared with healthy controls. Comparing patients with pemphigoid and healthy controls, no significant difference in the frequencies of B10 cells and CD19 ⁺ CD24 ^hi CD38 ^hi B cells was observed. B10-cell level in pemphigus was not associated with disease severity but inversely correlated with the required dose of steroid for treatment. While no significant difference in the frequency of IL-10-producing cells among CD19 ⁺ CD24 ^hi CD38 ^hi B cells was observed, in CD9 ⁺ and CD27 ^- B-cell subsets it was significantly decreased in patients with pemphigus compared with healthy controls.
Conclusions: Our results suggest the association of B10 cells with pemphigus but not with pemphigoid. The decrease in B10-cell level in pemphigus is partly caused by the lower production of IL-10 in CD9 ⁺ and CD27 ^- B-cell subsets.
(© 2016 British Association of Dermatologists.)