Abstract: | During the GVH reaction produced in adult (C57B1 ☿×CBA ♂) F1 hybrid mice by injection of C57B1 cells a profound drop in serum immunoglobulin levels was observed. The fall in IgG and IgA values was not reversed by antigenic stimulation with BSA, but the IgM level rose somewhat after BSA though never to the level seen in immunized controls. The antibody response to BSA, as measured by passive haemagglutination, was grossly depressed in experimental animals. Animals undergoing the GVH reaction showed less local inflammatory response at the site of Freund''s adjuvant injection than did controls. The possible importance of this immunoglobulin deficiency in the clinical presentation of the GVH syndrome is considered. |