AB0912 RP-ILD IN PATIENTS WITH ANTI-MDA5 POSITIVE ANTIBODIES: CLINICAL EVALUATION AND PROGNOSIS. RETROSPECTIVE DATA FROM A SINGLE CENTER COHORT

Abstract

BackgroundPatients with anti-melanoma differentiation-associated gene 5 antibody-positive (anti-MDA5+) dermatomyositis (DM) often develop a rapidly progressive interstitial lung disease (RP-ILD) associated with high mortality[1].Objectivesto evaluate clinical features and prognosis of patients with anti-MDA5+ DM who developed RP-ILD.MethodsAnti-MDA5+ patients were selected from a single center cohort of 198 idiopathic inflammatory myopathies (IIM) patients. Data were collected retrospectively. Onset clinical manifestations considered were muscle, joint, skin and lung involvement. All patients underwent chest high resolution computed tomography (HRCT). RP-ILD was defined by hypoxemia and dyspnea associated with radiological worsening within 3 months from pulmonary symptoms onset[2]. The dosage of ferritin during the follow up was also evaluated. Muscle involvement was assessed by myocytolysis indexes and Manual Muscle Test 8 (MMT-8). Joint and skin involvement was defined by clinical judgment. The therapeutic approach and the clinical outcome were also considered for each patient.Resultsbased on inclusion criteria 11 patients were identified, 7 males and 4 females, aged between 30 and 67 years (mean age 55.54±9.58 years). The duration of the follow-up was 19.9±24.25 months. Cutaneous, pulmonary, joint and muscle involvement at onset were 63%, 36%, 36% and 9% respectively. Complete clinical and serological data are shown in Table 1.Ten patients (91%) develop ILD and the most frequently observed radiological pattern was organizing pneumonia (OP) found in 60% of cases, followed by OP/Nonspecific interstitial pneumonia (NSIP) (30%), NSIP (10%). During the disease course, 60% of patients with ILD developed RP-ILD with a mean time of 7.8±7.13 months from onset. RP-ILD patients showed a higher mean ferritin level than in those without (mean 13506±2219.05 vs 473±538.33 ug/L). Immunosuppressive therapy in all RP-ILD patients was based on cyclophosphamide plus tacrolimus and/or plasmapheresis. Two patients underwent extracorporeal membrane oxygenation. Four patients with RP-ILD died (66%), one from SARS-CoV-2 infection and three from respiratory failure. None of the patients with non-RP-ILD died.Conclusionin our cohort RP-ILD occurred in 60% of patients with MDA5+ ILD and was characterized by elevated ferritin levels. An intense immunosuppressive combination therapeutic scheme was always required. Nevertheless, mortality rate remained high.