Role of IL-10-Producing Regulatory B Cells in Chronic Hepatitis B Virus Infection.

A subset of interleukin (IL)-10-producing regulatory B (Breg) cells that suppress T-cell-mediated immunity was recently identified; however, their role in chronic hepatitis B (CHB) remains elusive. To explore the possible role of Breg in the interaction with Th cells and consequent pathogenesis of CHB. The prevalence of Breg as well as 3 major effector T-cell subsets--CD4(+)CD25(high)Foxp3(+) regulatory T (Treg) cells, T helper 1 cells (Th1), and T helper 2 cells (Th2)--was assessed in the peripheral blood of 31 patients with CHB, 28 patients with acute hepatitis B (AHB), and 25 healthy controls (HC). Compared to patients with AHB and HC, the prevalence of Breg and Treg cells and the concentration of IL-10 in the supernatant of cultured peripheral blood mononuclear cells (PBMCs) were greatly increased in patients with CHB. A significantly decreased proportion of Th1 cells was also observed in patients with CHB and was demonstrated to have a negative correlation with the prevalence of Breg. Furthermore, depletion of Treg cells in the PBMCs of patients with CHB did not alter the frequency of Breg cells or their ability to produce IL-10, indicating little, if any, impact of Treg cells on the generation and maintenance of Breg cells. Our data indicate that increased Breg cells might be a major source of elevated IL-10 in CHB and represent a critical and independent regulatory force in the development of impaired anti-HBV immunity, consequently contributing to the pathogenesis of CHB.