Reported instances of sensitization to the U factor are extremely rare; in fact, we could find only three cases reported in the literature. In 1953 Wiener and co-workers1 reported a fatal hemolytic transfusion reaction caused by sensitization to a previously unreported blood factor which they designated as U. Greenwalt and co-workers,2 in 1954, and Wiener and Unger,3 in 1958, reported the second and third cases respectively. All of these cases occurred in Negroes. We believe that the case presented here represents the fourth reported instance of isosensitization to the U factor.
Report of a Case
A 58-year-old Negro man was admitted to Freedmen's Hospital on March 19, 1959, for treatment of a malignancy of the prostate gland. On admission, a blood count showed 8.3 Gm. of hemoglobin per 100 cc., 27% hematocrit, and 11,000 white blood cells per cubic millimeter, with 66% neutrophils, 27% lymphocytes, and 5%