Liver distribution of γδ-T-cells in patients with chronic hepatitis of different etiology

The gamma delta T cells represent a minor unique T-cell subpopulation long been considered as innate-like immune cells. They are found in increased numbers in tissues from various inflammatory conditions. Their role in chronic hepatitis, however, is still discussed controversially. Fresh frozen tissues from 50 patients (18 cases hepatitis B infection, 25 hepatitis C, three cases with co-infection of hepatitis B and C and four patients with autoimmune hepatitis) were investigated. Immunohistochemistry with primary antibodies detecting alpha beta and gamma delta TCR was used to evaluate their incidence and distribution in the different histological structures of the liver. The inflammatory infiltrate in all cases of chronic hepatitis was dominated by alpha beta T cells and was mainly localized in the portal tracts with formation of an interface hepatitis (95.3%alpha beta T cells; 4.7%gamma delta T cells). There were neither significant differences between inflammatory infiltrate nor the amount or percentage of gamma delta T cells between hepatitis B, C or autoimmune hepatitis. No accumulation of gamma delta T cells could be observed in cases of chronic hepatitis of different etiologies. The immune-mediated phenomena in chronic hepatitis are dominated by alpha beta T cells. Thus, the adapted immune system is responsible for the inflammatory processes in chronic hepatitis.