Activities of lymphocytes mediating antibody-dependent cell-mediated cytotoxicity in patients with chronic active...

Antibody-dependent cell-mediated cytotoxicity (ADCC) of peripheral blood lymphocytes against sheep erythrocytes, cultured rat hepatocytes (BRL-3A) and Chang cells in the presence of specific anti-serum was evaluated in patients with chronic active hepatitis (CAH) and healthy subjects. ADCC activities against these cells were significantly decreased in patients with CAH when compared with healthy subjects. Significant correlations were observed between degrees of ADCC against BRL-3A, Chang cells and sheep erythrocytes. In patients with CAH, percentage and absolute number of E-rosette forming cells in the peripheral blood lymphocytes were decreased but Fc-receptor bearing (EA gamma) lymphocyte concentration was normal. There was no clear-cut relationship between the concentration of EA gamma-lymphocytes and the degree of ADCC. Preincubation of lymphocytes from healthy subjects with CAH sera significantly reduced ADCC against sheep erythrocytes. Furthermore, analysis of effector lymphocytes mediating ADCC (K-cell) against BRL-3A indicated that T lymphocytes bearing Fc-receptors with lower affinity for sheep erythrocytes are active in ADCC, though a population of K-cell is heterogeneous. It seems likely that decreased T cells in the peripheral blood and possibly the presence of serum factors in patients with CAH may partly participate in impairment of ADCC.