Up-regulation of CD11a (LFA-1) expression on peripheral CD4⁺ T cells in primary biliary cirrhosis

Up-regulation of CD11a expression on CD4⁺ T lymphocytes is considered to be one of the mechanisms involved in the initiation of the Th-1-mediated immune response. In this study, peripheral blood mononuclear cells from patients with primary biliary cirrhosis (PBC) were evaluated for CD11a^highCD2^low T cells and populations of type 1 (Th-1) and type 2 (Th-2) helper T cells. CD11a^highCD2^low T cells were found in PBC (7/15) and in active rheumatoid arthritis (4/4), but not in chronic hepatitis C (0/5) or in healthy subjects (0/6). The population of Th-1 had a positive correlation with that of CD4⁺CD11a^highCD2⁺ cells in patients with PBC (P = 0.034). The serum levels of interferon-γ also had a weak correlation with the population of CD4⁺CD11a^highCD2^low cells (P = 0.050). There was no statistically significant correlation of Th-2 population (P = 0.295) or serum interleukin-4 level (P = 0.685) with the population of CD4⁺CD11a^highCD2^low cells. These results suggest that CD4⁺CD11a^high cells play a role in Th-1-predominance and in the autoimmune process of PBC.