Latent autoimmune hemolytic syndrome.

The direct anti-globulin test was performed at random on 310 hospitalized patients with various diseases. Thirty-three patients were positive to anti-globulin test without any evidence of manifest autoimmune hemolytic anemia. Hematologic and erythrokinetic studies on these patients with latent autoim mune hemolytic syndrome revealed that their slight anemia was secondary anemia due to their basic diseases with a slightly increased hemolysis. The basic diseases of these patients were autoimmune diseases, mesenchymal disease, chronic infections, hypersensitivity disease, pulmonary silicosis associated with tuberculosis, leukemia, Hodgkin's disease and others. Anti-erythrocyte autoantibodies were of warm type and intermediate type except for one case of y-globulin type. The immunoglobulin class of anti-erythro cyte autoantibodies was IgG. Their light chain type was as follows: K type, 2; A type 5; and K+A type, 1. The coexistence of other various autoantibodies was demonstrated in most of the patients A marked increase of peripheral large lymphocytes, hyperplasia of germinal centers associated with proliferations of reticulum cells and lymphogonias (immunoblasts) and a marked infiltration of plasma cells were demonstrated in biopsied lymph nodes. The mechanism of the association of latent au toimmune hemolytic syndrome with basic diseases was discussed.