Lack of association of the alpha-1-antitrypsin PIZ allele with rheumatoid arthritis or with its extra articular complications

PIZ allele frequencies were defined by PCR amplification and hybridization using a PIZ SSO (sequence specific oligonucleotide) probe. The groups studied included 64 normal controls, 104 subjects with rheumatoid arthritis (RA) without any extra-articular features, 29 of whom had severe arthritis and 31 of whom had mild RA. The extra-articular subsets include 41 with RA-bronchiectasis (RA-BR), 21 with bronchiectasis without RA (BR), and 23 with RA and pulmonary fibrosis (RA-PF). Fifteen RA subjects with obstructive airways disease (RA-OAD) were compared to 25 RA patients with normal lung function tests. Using Fishers' exact test and chi-squared statistical analysis with Yates correction, no statistically significant associations were found between PIZ and any of the groups studied. Thus in this population there is no evidence that PIZ either increases susceptibility to rheumatoid arthritis or affects the risk of pulmonary complications or the severity of arthritis in subjects with rheumatoid arthritis.