文摘
Objective We investigated associations between treatment with methotrexate (MTX) or biological disease-modifying antirheumatic drugs (DMARDs) and elevation of serum Krebs von den Lungen-6 (KL-6) levels in Japanese patients with rheumatoid arthritis (RA). Methods Using a standardized form, data were collected retrospectively from medical records and analyzed descriptively. Results Of a total of 198 RA patients with KL-6 serum levels measured at initiation of treatment (month?0) and two or more times by month?12, 27 (17.9?%) of 151 RA patients treated with biological DMARDs, including infliximab, etanercept, adalimumab, and tocilizumab (the biological DMARDs group), and 5 (10.6?%) of 47 patients treated without biological DMARDs but with MTX (MTX group), met criterion?B (max. KL-6 ?00?U/ml and >1.5-fold from baseline) by 12?months. The majority of patients (n?=?28) meeting criterion?B had no apparent interstitial lung disease or malignancy. Of these 28 patients, 21 had serum KL-6 levels available after reaching their maximum level, and 13 (61.9?%) of the 21 then met criterion?R [decrease to less than 500?U/ml or to less than (baseline?+?0.5?×?(maximum???baseline))] by month?12. Conclusion Serum KL-6 levels may increase during treatment with MTX or these biological DMARDs without significant clinical events.