Abrupt Breathlessness: Pneumocystis jirovecii Pneumonia Associated with Inebilizumab in Neuromyelitis Optica Spectrum Disorder: A Case Report and Literature Review.

Opportunistic infections pose significant challenges in patients undergoing immunosuppressive treatment for autoimmune disorders. Neuromyelitis optica spectrum disorder (NMOSD) is a rare disabling autoimmune condition requiring both acute attack management and long-term relapse prevention. B-cell depleting therapies, such as inebilizumab have demonstrated efficacy in reducing relapse rates and disability progression in NMOSD. Here, we present the first known NMOSD case who developed Pneumocystis jirovecii pneumonia following maintenance therapy with inebilizumab, showing a probable association (Naranjo score=6). We explored the underlying mechanisms linking B-cell depletion to Pneumocystis jirovecii, including antibody-dependent and immunomodulatory pathways. Furthermore, we provided an overview of Pneumocystis jirovecii pneumonia in autoimmune central nervous system disorders and summarized its clinical features, previous medication use, and prognostic factors. We advocate for risk-adapted prophylaxis to reduce morbidity and mortality associated with opportunistic infections in NMOSD.