Alpha-1-antitrypsin levels and prevalence of Pi variant phenotypes in adult Nigerian asthmatics.

Alpha-1-antitrypsin (A1AT) phenotypes and serum levels were determined in 99 asthmatic patients and 100 control subjects. The phenotypes encountered were PiMM 74% in asthmatics, 98% in controls; PiMZ 19% in asthmatics, 1% in controls; PiMW 3% in asthmatics, 0% in controls; and PiLM 2% in asthmatics, 1% in controls. There was one asthmatic patient with the homozygous deficient phenotype ZZ. The result revealed that there were more deficient heterozygous phenotypes in the asthmatic group than the control group. There was also a positive correlation between the number of patients with deficient phenotypes and the severity of asthma (P less than 0.02). Analysis of the serum A1AT levels revealed that as a group the asthmatic patients had significantly lower A1AT levels (1.97 +/- 0.18 g/l) than the control group (2.21 +/- 0.15 g/l) (P less than 0.01). However, there was no statistically significant difference in the A1AT serum levels of patients with P1MM phenotype and the control of the same phenotype. Statistical analysis could not be done for the other phenotypes because of the small number of subjects. Apart from the patient with PiZZ the A1AT serum levels encountered in the study were not low enough to justify replacement therapy with alpha-1-proteinase inhibitor in our asthmatic patients.