A new red cell phenotype I-i-: red cells lacking both I and i antigens.

When blood samples from 5,864 healthy Indian blood donors were tested with anti-I, seven samples failed to react or reacted only weakly. Further studies with a number of anti-I and anti-i sera suggested that these samples had the phenotype I-i- and reacted weakly with anti-IT. In one family, the I-i- phenotype was present in three generations.