Follow-up of normal individuals with a positive antiglobulin test

Over a period of 20 yr (1962-1982), 67 apparently fit donors at a Regional Blood Transfusion Service were found to have an unexplained positive direct antiglobulin test (DAT). During 1983, 26 were traced and re-tested. 9 still had a positive DAT only 1 of whom had developed autoimmune haemolytic anaemia. 17 had become negative though in 7 of these an autoantibody could still be detected by an enzyme technique. Unlike patients with established autoimmune disorders, the positive DAT individuals were found to have normal T cell subsets though B cells were significantly increased.