Anti-Eukaryotic Initiation Factor 2B-Positive Systemic Sclerosis-Associated Interstitial Lung Disease With Progressive Fibrosis: A Case Report.

Anti-eukaryotic initiation factor 2B (anti-eIF2B) is a rare systemic sclerosis (SSc)-related autoantibody. Longitudinal treatment data for anti-eIF2B-positive SSc-associated interstitial lung disease (ILD) remain limited. We herein describe the case of a 46-year-old man with limited cutaneous SSc who developed lower-lobe-predominant fibrotic ILD. Major SSc autoantibodies were negative, and an antigen-specific panel identified anti-eIF2B. Mycophenolate mofetil was initiated; however, serial high-resolution computed tomography showed incremental fibrotic progression, and the diffusing capacity declined, consistent with progressive SSc-ILD, prompting the addition of nintedanib to the ongoing therapy. This case supports testing for minor specificities when SSc-ILD is suspected despite negative results for major autoantibodies and adds new information on the post-treatment disease course and therapeutic selection in this serological subset. Further case accumulation with standardised longitudinal outcomes is needed to define the prognosis and treatment response.