IgG production in 'autoimmune' chronic active hepatitis. Effect of prednisolone on T and B lymphocyte function.

In vitro IgG production was measured using peripheral blood mononuclear cells from patients with autoimmune chronic active hepatitis (CAH) to determine whether the increased serum IgG levels were related to abnormalities of T or B lymphocyte function. A marked increase in spontaneous and pokeweed mitogen-induced proliferation of IgG producing cells was observed in 30 patients with untreated autoimmune CAH when compared with 25 normal subjects and 21 patients with autoimmune disease in whom a remission had been induced and maintained by prednisolone (P less than 0.01). Co-culture experiments clearly demonstrated that abnormalities of T lymphocyte function in untreated autoimmune CAH were responsible for the heightened IgG production in vitro. Pre-incubation of T lymphocytes from untreated patients with 5 X 10(-8)M prednisolone significantly reduced the number of cells producing IgG (P less than 0.05), suggesting that the modulation of the immune response following corticosteroid therapy is likely to be due to an alteration in T lymphocyte function.