T cell subpopulations defined by monoclonal antibodies in autoimmune hemolytic anemia.

T cell subsets were studied using monoclonal anti-T cell antibodies in 10 patients with IgM cold agglutinins and 30 patients with IgG warm autoantibodies. Two of the 10 patients with cold agglutinin disease had abnormally low helper/suppressor T cell ratio. In the 30 patients with IgG warm autoantibodies this ratio was abnormally low in 7 and abnormally high in 7 other patients. Treatment by steroids or immunosuppressive agents tended to decrease OKT4/OKT8 ratio since high ratios were essentially found in untreated patients. This report documents the high incidence of T cell imbalance in autoimmune hemolytic anemia due to IgG warm autoantibodies and comments on its significance in the light of the great heterogeneity of this syndrome.