A study of the Ag factors in a British (West Midland) population.

168 sera from a British (West Midlands) population of normal blood donors were typed for the factors Ag (x, y, a1, d, t, c, g and h). The results were compared with the published data from other populations. The 8 factors were found in 27 different phenotypic combinations including a single instance of the combination Ag (y-h+) not previously reported. The occurrence of this phenotype is discussed in relation to the theoretical models of the genetic control of the Ag system.