Severe finger necrosis in antisynthetase syndrome with positive anti-OJ antibodies

INTRODUCTIONAminoacyl tRNA synthetases (ARSs) are a group of cytoplasmic enzymes that bind to transcribed RNA during protein synthesis, esterify amino acids to transcribed RNA, and function as catalysts for aminoacyl-transcribed RNA.1 Patients who test positive for anti-ARS antibodies present with various extramuscular symptoms, such as interstitial pneumonia, mechanic’s hands, Raynaud phenomenon, polyarthritis, fever, and myositis. These symptoms share common clinical features, which led Targoff in 1992 to term them ”antisynthetase antibody syndrome.”2 Since Jo-1 (histidyl-tRNA synthetase: HisRS) antibody was discovered in 19803, eight ARS antibodies have been identified: histidyl-tRNA synthetase-1 (Jo-1), anti-threonyl (PL-7), anti-alanyl (PL-12), anti-glycyl (EJ), anti-isoleucyl (OJ) anti-asparaginyl (KS), anti-phenylalanyl (Zo) and anti-tyrosyl (Ha) tRNA synthetase4.5, 6 Among these antibodies, anti-OJ is the least prevalent (3.1%).7 Anti-OJ- positive anti-ARS syndrome is extremely rare, and is usually accompanied by interstitial pneumonia.8 Anti-OJ and anti-Sjögren’s-syndrome-related antigen A (Ro-52) antibodies are occasionally detected in patients with dermatomyositis and are a poor prognostic factor when associated with interstitial pneumonia.9 However, we encountered a patient with OJ-and Ro-52 positive anti-ARS syndrome without interstitial pneumonia and with severe phalanx necrosis due to Raynaud phenomenon. The activity of disease could be suppressed with steroid pulse therapy. We believe that this is an atypical clinical presentation that deserves acknowledgement by means of this case report. We also report it here with a review of the literature.