Treatment of refractory anti-melanoma differentiation-associated gene 5 anbibody-positive dermatomyositis complicated by rapidly progressing interstitial pulmonary disease: Two case reports

BACKGROUND: Anti-melanoma differentiation-associated gene 5 antibody-positive (anti-MDA5 Ab(+)) dermatomyositis complicated with rapidly progressive interstitial lung disease (anti-MDA5 Ab(+) DM-RP-ILD) has an unclear underlying mechanism with no recommended unified treatment plan. Herein, one of the cases that we report (Case 2) was successfully treated with tocilizumab despite having lung infection. CASE SUMMARY: Case 1 was a 30-year-old woman who was admitted due to recurrent rash for 5 mo, fever and cough for 1 mo, and chest tightness for 3 d. She was diagnosed with non-myopathic dermatomyositis (anti-MDA5 Ab(+)) and interstitial pneumonia, and was treated with the combination of hormone therapy and cyclophosphamide followed by oral tacrolimus. Case 2 was a 31-year-old man admitted due to systemic rash accompanied by muscle weakness of limbs for more than 1 mo, and chest tightness and dry cough for 4 d. He was diagnosed with dermatomyositis (anti-MDA5 Ab(+)) and acute interstitial pneumonia with Pneumocystis jirovecii and Aspergillus fumigatus infections and was treated with hormone therapy (without cyclophosphamide) and the combination of tocilizumab and tacrolimus. The condition of both patients eventually improved and they were discharged and showed clinically stable condition at the latest follow-up. CONCLUSION: Tocilizumab could be a salvage treatment for patients with anti-MDA5 Ab(+) DM-RP-ILD who are refractory to intensive immunosuppression.