PI SZ PHENOTYPE IN CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

Background - A study was undertaken to clarify whether the Pi SZ pheno type of the protease inhibitor system predisposes to chronic obstructi ve pulmonary disease (COPD). Methods - The prevalence of PI Z and PI S Z deficient phenotypes was investigated in a population of 702 patient s with COPD followed up at the Chest Unit of a tertiary hospital and i n 15 400 newborn infants from the same geographical area. Individuals with deficiency were detected by screening of dried blood spots on fil ter paper using a comparative electroimmunodiffusion technique for alp ha(1)-antitrypsin and transferrin. The serum phenotype was confirmed b y means of isoelectrofocusing on polyacrylamide gel. Results - Of the 702 blood samples from patients with COPD, six PI Z subjects (0.85%) a nd one PI SZ (0.14%) were detected. Of the 15 400 samples from neonate s, the number of PI Z subjects was eight (0.052%) and that of PI SZ wa s 24 (0.156%). The difference between the two groups was significant f or PI Z but not for PI SZ. Conclusions - The data do not indicate an i ncreased risk for development of COPD associated with the PI SZ phenot ype but confirm the predisposition of PI Z individuals for the develop ment of COPD.