CLINICAL SIGNIFICANCE OF ANTI-H IN AN INDIVIDUAL WITH THE OH (BOMBAY) PHENOTYPE

To evaluate the clinical significance of anti‐H present in individuals with the Oh (Bombay) phenotype, red blood cell 51chromium survival studies and related serological tests were undertaken in an Oh (Bombay) individual. A small sample of group O donor red blood cells was labeled with 51chromium and infused into the patient. The T ½ of the infused cells was six minutes, with two per cent of the cells surviving at 24 hours. A similar study using the patient's own labeled red blood cells demonstrated 100 per cent survival at 24 hours. Initial laboratory studies indicated that the anti‐H was active in saline at 4, 22 and 37 C and by the indirect antiglobulin test. Analysis of the antibody in both pre‐and posttransfusion specimens showed it to have both IgM and IgG components. The anti‐H titer at 37 C rose from 1:4 prior to the infusion of the O cells to 1:32 one week postinfusion, and a partial hemolysin appeared. Saliva inhibition studies demonstrated that the antibody was neutralizable prior to the group O exposure but was not neutralizable one week post exposure. We conclude that the anti‐H present in this individual rapidly destroyed infused group O red blood cells. Individuals with the Oh (Bombay) phenotype should be transfused only with Oh (Bombay) blood. 1978 AABB