Association of Airway Disease and Single-Nucleotide Variants in PTPN14 and IL9RP3 in Japanese Cases of Rheumatoid Arthritis

Objectives: Airway disease, commonly related to rheumatoid arthritis (RA), confers an inferior prognosis. Few genetic analyses in RA have investigated patient susceptibility to airway disease. We examined if single-nucleotide variants related to idiopathic pulmonary fibrosis susceptibility were related to airway disease in Japanese cases of RA. Methods: Genotyping for rs4233306 [C/T] in PTPN14 and rs3930589 [T/C] in IL9RP3 in 246 patients with RA and airway disease, and 425 with RA but without chronic lung disease was performed. Results:PTPN14 rs4233306C and IL9RP3 rs3930589T were significantly related to airway disease in RA under a dominant model for minor alleles (p = 0.0398; odds ratio [OR] 1.41; 95% confidence interval [CI] 1.02–1.96; p = 0.0462; OR 3.19; 95% CI 1.06–9.63, respectively). Stratification by male sex resulted in the remaining significant association of PTPN14 rs4233306 with airway disease in RA cases (p = 0.0028; OR 3.70; 95% CI 1.55–8.84). A significant relationship between IL9RP3 rs3930589 and airway disease in RA patients aged > 65 years was noted (p = 0.0135; OR 9.79; 95% CI 1.21–79.20). Conclusions: This is the first study to report associations of rs4233306 and rs3930589 with airway disease in Japanese RA cases.