The prevalence of pulmonary airway lesions is high in HTLV-1–positive rheumatoid arthritis: a cross-sectional observational study

Objective To investigate whether human T cell leukaemia virus type 1 (HTLV-1) infection increases the risk of respiratory complications in patients with rheumatoid arthritis (RA), focusing on high-resolution computed tomography (HRCT) findings and clinical features. Methods We retrospectively analyzed 30 HTLV-1-positive patients with RA enrolled in the HTLV-1 RA Miyazaki Registry who had undergone chest HRCT. For each patient, three age- and sex-matched HTLV-1-negative RA patients (n = 90) were recruited as controls. We compared pulmonary abnormalities on HRCT, RA disease activity, medication use, and systemic complications between the groups. In the HTLV-1-positive group, we also assessed the relationship between HTLV-1 proviral load (PVL) and pulmonary findings. Results Although age and disease duration were similar between groups at the time of HRCT, HTLV-1-positive patients had significantly higher disease activity (CDAI: 6.4 vs.s 3.3, p = 0.01; SDAI: 7.28 vs.s 3.46, p = 0.01), greater glucocorticoid use (70% vs.s 36%), and lower biologic use (33% vs.s 61%). Abnormal pulmonary findings were observed in about 50% of both groups; however, bronchiolitis was more frequent in HTLV-1-positive patients, while interstitial lung disease patterns were comparable. HTLV-1 PVL did not differ significantly based on the presence or absence of pulmonary lesions. Conclusion HTLV-1 infection may link to an increased prevalence of airway lesions, such as bronchiolitis and bronchiectasis, in RA patients. These findings suggest that screening for HTLV-1 should be considered in RA patients, especially those with respiratory symptoms or complications.