B43-45 A Rare Antibody Culprit: Anti-OJ Mediated Anti-Synthetase Syndrome Presenting as a Rapidly Progressive Interstitial Lung Disease

Abstract Introduction Anti-synthetase syndrome (ASyS) is a group of systemic rheumatic diseases characterized by antibodies attacking aminoacyl-transfer RNA (tRNA) synthetases and represents approximately 11-39% of idiopathic inflammatory myopathies. (IIMs) ASyS has a variety of manifestations including interstitial lung disease, myositis, Raynaud’s, fever, or mechanic’s hands. Most cases are associated with Anti-Jo Antibody, and ASyS arising from anti-OJ antibodies is exceedingly rare, representing less than 2% of ASyS cases. Case Presentation A 60-year-old male with history of hypertension, hyperlipidemia, depression and daily vaping presented to the emergency department with 1 week of shortness of breath and cough. He was tachypneic and hypoxic to requiring BIPAP support. Physical exam revealed diffuse crackles, increased work of breathing, and euvolemia. Labs were notable for leukocytosis and elevated inflammatory markers. CT imaging was negative for pulmonary embolism but showed diffuse ground glass air space opacities and mediastinal lymphadenopathy. Dexamethasone was started for suspected E-cigarette-Vaping Product Use-Associated Lung Injury and antibiotics were empirically added for pneumonia. When extensive infectious workup returned negative, subsequently autoimmune workup was sent. The patient’s respiratory status decompensated on high flow nasal cannula requiring intubation. Repeat CT chest revealed worsening opacities with near complete consolidations of the bilateral lower lobes and crazy paving concerning for progression to ARDS. Inflammatory workup returned notable for a myositis panel positive for anti-OJ antibody concerning ASyS. The patient was initiated on mycophenolate and plasma exchange therapy (PLEX). Unfortunately, the patient’s course was further complicated by difficult ventilation and pneumothorax. Unfortunately, due to the lack of improvement after 4 of 5 sessions of PLEX and patient goals, life sustaining treatment was discontinued and the patient passed. Discussion of Novelty and Importance Literature on anti-OJ antibodies is limited as clinical significance was not described until 1993 and its role in ASyS was not heavily investigated until 2012-2014. Despite emerging lab techniques allowing for better detection, clinical presentations of anti-OJ antibodies in ASyS are limited to a handful of case reports and represent a gap in medical literature and practice. While rare, patients with anti-OJ antibodies can present with ASyS manifesting as isolated, rapidly progressive interstitial pulmonary fibrosis. Treatment approaches include high dose steroids and immunosuppressants, and in severe cases, PLEX. The diagnostic difficulty, aggressive course, and limited efficacy of treatment in our case highlights why IIM associated with Anti-OJ antibodies have a poor prognosis, and the importance of early diagnosis and considering IIMs when approaching pulmonary symptoms. This abstract is funded by: None