K-lymphocytes (killer-cells) in Crohn's disease and acute virus B-hepatitis.

Total lymphocyte counts, B-, T-, C'3 receptor-bearing lymphocytes, and K-cell activity were studied in peripheral blood in patients with Crohn's disease and inflammatory liver disease. Patients with active untreated Crohn's disease and acute virus B hepatitis exhibited a markedly increased K-cell activity measured in a plaque assay when compared with normal controls (P less than 0.01). Patients with immunosuppressive treated Crohn's disease, HBsAg-positive chronic active hepatitis, and cirrhosis of the liver showed only a slight increase of K-cell activity (P less than 0.01). In the postacute phase of hepatitis (four to 12 weeks from onset) K-cell activity fell to normal levels. The number of B-lymphocytes showed a relative and absolute decrease in all groups of patients. With the exception of patients with acute HBsAg-positive hepatitis and the post-acute phase of hepatitis all the other groups showed statistically decreased absolute numbers for C'3 receptor-bearing lymphocytes. The significant decrease in K-cell activity and the number of T-lymphocytes in Crohn's disease treated with immunosuppressive drugs was interpreted as an effect of azathioprine and prednisone on these lymphocyte subpopulations.