Alpha-1-antitrypsin and chronic bronchitis in adult Nigerians

Alpha-1-antitrypsin (A1AT) serum levels and phenotypes were determined in 49 Nigerians with chronic bronchitis and 100 normal controls. The A1AT phenotypes encountered were PiMM, 69% in chronic bronchitics, 98% in controls; PiMZ, 23% in chronic bronchitics, 1% in controls; PiLM, 2% in chronic bronchitics, 1% in controls. There were three patients (6%) with the homozygous-deficient phenotype PiZZ. Spirometry confirmed obstructive ventilatory pattern in the patients with chronic bronchitis, and the difference in the values obtained between the patients and controls was statistically significant (P less than 0.01). Serum A1AT levels were within the normal range of 1.4-2.7 g/l in all except the three patients with PiZZ. There was no significant difference in the A1AT serum levels between patients with chronic bronchitis and control subjects with the PiMM phenotype; tests of significance were not possible for the other phenotypes because of the small number of subjects. The observation of PiZZ in 6% of our patients with chronic bronchitis is in support of screening of this category of patients. Replacement therapy with alpha-1-antitrypsin inhibitor is currently under investigation and may be worthwhile in these patients if detected early.