Peripheral T regulatory cells and cytokines in hepatitis E infection.

This study addresses the involvement of regulatory T cells in hepatitis E (HE) infection. The study population comprised 77 acute viral HE patients, 52 recovered individuals (overall, 129 individuals with HE) and 53 healthy controls. Peripheral CD4(+)CD25(+)Foxp3(+) and CD4(+)CD25(-)Foxp3(+) frequencies by flow cytometry and HE-specific cytokines/chemokines quantitation were carried out. The median percentage of CD4(+)CD25(+)Foxp3(+) and CD4(+)CD25(-)Foxp3(+) T cells in acute patients were significantly higher compared to controls and recovered individuals. Both of the T regulatory (Treg) subset populations in overall HE were significantly elevated compared to controls. Comparisons of cytokines/chemokines revealed that the levels of IL-10 were elevated in: (a) acute viral hepatitis E (AVH-E) versus recovered individuals and controls, and (b) HE versus controls. Overall, the elevation of CD4(+)CD25(+)Foxp3(+) and CD4(+)CD25(-)Foxp3(+) frequencies and the rise in IL-10 suggest that Treg cells might be playing a pivotal role in hepatitis E virus (HEV) infection.