The development of ABO isohemagglutinins in Taiwanese.

To evaluate the developmental pattern of ABO isohemagglutinins in Taiwanese, 644 blood samples (349 males, 295 females), including cord blood, were collected from individuals with ages ranging from newborn to 83 years. Synthesis of anti-A and anti-B could be demonstrated in most Taiwanese infants by 2-4 months of age, increasing progressively to reach adult levels (titers of 1:32-1:256) at around 1 year of age. Peak levels were reached at between 3-10 years of age and then declined with advancing years, with individuals of 80 years of age and over showing reduced levels similar to those seen in 6- to 12-month-old infants. Sex and parity did not appear to influence ABO isohemagglutinin development.