Positive Coombs' test associated with ulcerative colitis. A prevalence study.

Among 112 patients with ulcerative colitis (UC), a positive Coombs' test was detected in two cases. The immunoglobulins were IgG and no complement could be detected on the red cells. None of the two patients showed laboratory evidence of hemolysis, although reduced red cell survival was suspected in one patient with a 6-year history of UC, previous autoimmune hemolytic anemia and a positive in vitro monocyte-macrophage phagocytosis test. The HLA-antigens in the two patients were different except for the common antigen HLA-A1.