ABSTRACT
Background. Interstitial lung disease (ILD) is the common internal organ manifestation of idiopathic inflammatory myopathies (IIM) that can severely affect the course and prognosis of the disease. Rituximab (RTX) has been used to treat IIM, including variants with ILD. Objectives. To describe the course of disease in IIM patients with ILD, treated with RTX in long-term follow-up. Methods. Our prospective study included 35 pts with IIM fulfilling Bohan and Peter criteria and having ILD. The mean age was 51.8+/-11.9 years, female-26 pts (74%);24 (68.5%) with antisynthetase syndrome, 5 (14.3%) dermatomyositis (DM), 5 (14.3%) with a-Pm/Scl overlap myositis and 1 (2,9%) with a-SRP necrotizing myopathy were included. 25 (71,4% ) patients had nonspecific interstitial pneumonia, 9 (25,7%) organizing pneumonia (OP) and 1 (2,9%) OP, transformed to diffuse alveolar damage. All pts had the standard examination including manual muscle testing (MMT), creatinkinase (CK) anti-Jo-1 antibodies (anti-Jo-1) assay;forced vital capacity (FVC) and carbon monoxide diffusion capacity (DLCO) evaluation as well as high-resolution computed tomography (HRCT) scanning of the chest were performed at baseline, and 36 and more months. The median disease duration was 3.2 [0.16-18] years, 21 (60%) of pts were positive for a-Jo-1 antibody. All pts received prednisolone at a mean dose of 24.3+/-13 mg/day, immunosupressants at inclusion received 25 (71%) pts: cyclophosphamide 18 , mycophenolate mofetil 6 and comdination 1;Rituximab (RTX) was administered in case of severe course of disease and intolerance or inadequate response to GC and other immunosuppressive drugs. Results. The mean follow-up period after the first infusion of RTX was 47.2+/-11.9 months. Pts received 1-11 courses of RTX . The cumulative mean dose of RTX was 4.6 +/-2.5g. MMT 8 increased from 135.8+/-13.5 to 148.75+/-3.5 (p=0.000001). CK level decreased DELTACK - 762 u/l(median 340;25th% 9;75th% 821). anti-Jo-1 decreased from 173.4+/-37 to 96.5+/-79 u/ml (p=0.00002), FVC increased from 82+/-22.6 to 96,9+/-22% (p=0.00011). DLCO increased from 51.4+/-15.2 to 60+/-77.8% (p=0.0001). The mean prednisone dose was reduced from 24.3+/-13 to 5.7+/-2.4 mg/day. 3 pts died: ILD progression was the cause of death in 1 case, 1 bacterial pneumonia and COVID19 pneumonia. Conclusions. The results of this study confirm the positive effect of RTX in IIM patients with ILD (increase of muscle strength and improve lung function, decrease in anti-Jo-1 levels) and also its good steroid-sparing effect. RTX could be considered as an effective drug for the complex therapy of IIM patients with ILD when standard therapy is ineffective or impossible.