Significant differences in the prevalence of alpha 1 antitrypsin phenotypes have been reported among various ethnic groups. The possibility of such differences among newborn infants in the U.S. has not been investigated. In a prospective study, the authors have examined umbilical cord blood sera of 1010 healthy full term infants of black (B), white (W) or Hispanic (H) background over a 2 year interval using the crossed immunoelectrophoresis technique of Fagerhol and Laurell. Alpha 1 antitrypsin and alpha 2 macroglobulin were measured by radial immunodiffusion and trypsin inhibitory capacity was measured by the method of Erlanger using BAPNA as substrate. Among the B group, MM prevalence (97%) was higher than the H group (88%) (p < 0.05). MS prevalence in the H group (6.7%) was higher than among B (1.5%) or W (3.9%), p < 0.001 and < 0.005, respectively. Among those with an MM pattern, a 'step' variant, representing more cathodal migration of MM was found in 96% of neonates (926 of 956), but only among 9.8% of infants aged 1 month to 2 years (7 of 71) and 18% (8 of 45) among children aged 2-10 years regardless of race. Significantly elevated levels of both alpha 1 antitrypsin and trypsin inhibitory capacity were found in MM compared with non MM groups only among the H but not the B or W groups. Alpha 2 macroglobulin was significantly lower among the MM than non MM in all 3 groups. Our results show that ethnicity is a major determinant of alpha 1 antitrypsin Pi types among neonates in the U.S., and that the MM pattern seen in umbilical cord serum differs from that observed later in life. Quantitative levels of enzyme inhibitor do not correlate in neonates with phenotype except for an inverse relationship of MM with alpha 2 macroglobulin levels. A controlled, prospective study of the effect of non MM phenotypes on lung disease in infancy is presently being undertaken by our group.
|Original language||English (US)|
|Number of pages||1|
|Journal||American Review of Respiratory Disease|
|Issue number||4 II|
|Publication status||Published - Jan 1 1976|
All Science Journal Classification (ASJC) codes
- Pulmonary and Respiratory Medicine