Gene polymorphisms in fibrosing alvelolitis in rheumatoid arthritis amd idiopathic pulmonary fibrosis

Background: Fibrosing alveolitis in rheumatoid arthritis (FA) histologically and clinically shares characteristics with idiopathic pulmonary fibrosis (IFF). The primary pathogenic mechanism is thought to involve an imbalance between pro and antifibrotic cytokines and growth factors in the lung, which are influenced by gene polymorphisms determining their level of expression. Method: A case-control study was undertaken recruiting patients with FA as cases compared to three separate sets of controls: random anonymous healthy blood donors, patients with rheumatoid arthritis (RA) without lung fibrosis and patients with histologically/ clinically evident IFF. Medical records, chest radiographs and respiratory function were reviewed. Genotyping was performed on DNA extracted from peripheral blood lymphocytes using PCRRFLP. Polymorphisms for the following genes were determined according to published techniques: IL-6; TGF; TNFcc and ILRal .Statistical analysis was performed using x- squared test, t-test and ANOVA. A p-value of 0.05 (two-tailed) was considered significant. Results: All cases were Caucasian. Mean age for 140 healthy blood donors was 42+/-I3 years. Characteristic FA (n=5) IFF (n=22) RA(n=22) Male sex % 60 73 50 Age, yr 63+7-7.5 60+/-14 62+/-10 Current/ex-smoker% 60 82 45 VC%pred 78+/-S 65+/-18 85+/-16 KCO% pred 74+/-23 67+7-27 8S+/-24