Decreased interleukin-2 receptor β chain expression by peripheral blood lymphocytes in chronic liver disease

To investigate the decrease in natural killer (NK) activity in chronic liver disease, interleukin-2 receptor beta chain (IL-2R beta) expression was assessed by peripheral blood lymphocytes (PBL) using flow cytometry and an IL-2R beta chain-specific mouse monoclonal antibody. The percentage of IL-2R beta chain-positive PBL was significantly decreased in patients with chronic viral hepatitis, liver cirrhosis and hepatocellular carcinoma in comparison with normal controls (P less than 0.01). Among chronic viral hepatitis patients, it was significantly less in those with chronic active hepatitis than in those with chronic persistent hepatitis (P less than 0.05). Two-colour flow cytometry revealed that the IL-2R beta chain was mainly expressed by CD8+ or CD16+ cells in both the controls and the liver disease patients. CD8dull+ cells (NK cells) constituted more than 60% of the CD8+ cells expressing the IL-2R beta chain. Expression of the IL-2R beta chain with CD8 or CD16 was also significantly decreased in chronic liver disease patients compared with controls. In chronic viral hepatitis, there was a significant correlation between NK activity and the percentage of IL-2R beta+ PBL (P less than 0.001, r = 0.916), as well as between NK activity and the percentage of PBL co-expressing both the IL-2R beta chain and CD16 (P less than 0.001, r = 0.850). These findings suggest that decreased expression of the IL-2R beta chain by PBL may result in diminished NK activity in chronic liver disease.