Postnatal development of red cell Le(a) and Le(b) antigens in Chinese infants.

Lewis phenotyping of 487 blood samples from Chinese newborn infants and young children, revealed that 50% of cord cells were Le(a-b+) and 50% Le(a-b-). The weak Leb antigen of Le(a-b+) cord cells is most likely produced by the newborn infant rather than of maternal origin and it appears that these infants eventually develop by way of an intermediate Le(a+b+) stage into the adult Le(a-b+) phenotype. Most infants with Le(a-b-) cord cells, but not all, appear to develop through a transitional Le(a+b-) stage, into Le (a+b+) by about 1 month of age, most likely continuing as such into adulthood. This development of Le(a-b-) cord cells into the adult Le(a+b+) phenotype is postulated to be the result of the weak secretor gene Se omega. Those infants with Le(a-b-) cord cells that do not convert to Le(a+b+) during the first month of life, most likely remain as such into adulthood. The blood of 120 adult voluntary blood donors, used as controls, reconfirmed adult Chinese phenotypic frequencies of approximately 70% Le(a-b+), 22% Le(a+b+) and 8% Le(a-b-).