Favorable Response to Adjuvant Tofacitinib in a Case of Anti-Melanoma Differentiation-Associated Gene-5 Antibody Positive Clinically Amyopathic Dermatomyositis

Anti-melanoma differentiation-associated gene-5 antibody (anti-MDA-5 Ab) associated with clinically amyopathic dermatomyositis (CADM) is characterized by vasculopathic ulcers, mechanic's hands, and progressive interstitial lung disease (ILD). We present a case of 38-year-old female who presented with all these classical clinical features. Her investigations revealed normal serum muscle enzyme levels and the presence of anti-Mi2 and anti-MDA-5 antibodies by immunoblot. Imaging study revealed changes suggestive of ILD. She was treated with rituximab along with oral glucocorticoid and other supportive treatment to which she didn't respond adequately. Recently, it has been postulated that plasmacytoid dendritic cells produce interferon which is responsible for tissue injury in dermatomyositis (DM). Tofacitinib, by inhibiting JAK-STAT pathway, inhibits downstream cytokines, mainly type 1 interferon. So, we added tofacitinib as adjuvant therapy in our patient. Post-six months of commencement of adjuvant tofacitinib, patient experienced remarkable improvement in cutaneous features as well as in pulmonary fibrosis.