Characteristics of Regulatory T Cell Function in Patients with Chronic Hepatitis B and C Coinfection.

Regulatory T cells (Tregs) affect the pathogenesis and disease progression of chronic viral hepatitis. This study evaluated the frequency and function of Tregsin patients with chronic HBV/HCV co-infection. Seventy-four untreated HBV/HCV co-infected patientswere enrolled in this study. These subjects were divided into four subgroups:HBV-active/HCV-active (BACA), HBV-inactive/HCV-active (BICA), HBV-active/HCV-inactive (BACI), andHBV-inactive/HCV-inactive (BICI).Treg frequency was calculated as the fraction of CD4(+) Foxp3(+) T cells among CD4(+) T cells. Treg-mediated inhibition was measured as percent of inhibition of T cell proliferation. The expression of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-10 with/without Treg inhibition was also studied.Among the patients, there were 8 cases of BACA (10.8%), 38 of BICA (51.4%), 14 of BACI (18.9%), and 14 of BICI (18.9%).The frequency of CD4(+) Foxp3(+) T cells were comparable between the four groups. The inhibitory function of Tregs among the patients in the BACA and BICA was higher than that in the BICI(BACA vs.BICI, P=0.0210; BICA vs.BICI, P=0.0301).Patients in theBACA and BICA had higher fibrosis-4 (FIB-4)scores and serum ALTlevels and lower serum albumin levels than those of the other groups. ALT abnormalitywas significantly and independently associated with a higher Treg immunosuppressive ability.The IFN-gamma expression of the effector T cells in theBACA was higherthan that of the other groups. In conclusion, the inhibitory function of Tregs is higher among the HBV/HCV co-infected patients with active HCV infection. ALT abnormality plays a dominant role in Treg function.