B35-27 Early Recognition and Treatment in Isolated Anti-EJ Antisynthetase Syndrome With Interstitial Lung Disease and Mechanic’s Hands

Introduction Antisynthetase syndrome (ASSD) is a rare autoimmune disorder marked by anti–aminoacyl tRNA synthetase (anti-ARS) antibodies and multi-system involvement, including interstitial lung disease (ILD), myositis, and characteristic skin findings such as mechanic’s hands. Among these antibodies, the anti-EJ subtype is particularly uncommon, found in less than 2% of myositis cases, and often presents with ILD as the main or only feature. Early recognition of subtle cutaneous signs can guide timely antibody testing and treatment, which is crucial to prevent irreversible lung fibrosis. We report a rare case of isolated anti-EJ ASSD with ILD and mechanic’s hands that showed marked improvement after early immunosuppression. Case Presentation A 51-year-old man presented with progressive shortness of breath and hyperkeratotic, fissured hands previously treated as eczema. High-resolution CT of the chest revealed peripheral ground glass opacities in lower lobes with pleural sparing. Serologic testing demonstrated isolated anti-EJ antibody positivity, while anti-Jo-1, PL-7, and PL-12 antibodies were negative. Examination of both hands was consistent with mchanics hands. The patient started treatment with mycophenolate mofetil (MMF). Over the next 12 months, he achieved significant clinical and radiologic improvement: forced vital capacity increased from 67% to 97%, diffusion capacity for carbon monoxide rose from 70% to 86%, and both respiratory symptoms and cutaneous signs improved markedly. This case emphasizes the impact of early recognition and timely immunosuppressive therapy in reversing disease progression. Discussion Anti-EJ antisynthetase syndrome (ASSD) is rare and often overlooked, particularly when myositis is absent and interstitial lung disease (ILD) is the main feature. ILD occurs in nearly 90% of patients with anti-EJ antibodies. Mechanic’s hands, though sometimes subtle, can be an early visible clue that should raise suspicion for ASSD and prompt antibody testing. Reports show that delayed diagnosis, especially in non–Jo-1 subtypes, is linked to poorer survival and irreversible lung fibrosis. Early and adequate immunosuppressive therapy is therefore essential to prevent fibrotic remodeling. In this patient, timely initiation of corticosteroids and mycophenolate mofetil led to marked improvement in both symptoms and imaging findings. This case highlights how recognizing minor cutaneous signs in patients with ILD can enable early treatment and prevent permanent fibrosis. This abstract is funded by: None