# X-linked Inhibitor of Apoptosis (XIAP) Deficiency Complicated by Hemophagocytic Lymphohistiocytosis on Immunotherapy Leading to Acute Respiratory Distress Syndrome and Multiorgan Failure Secondary to Opportunistic Infections

## TL;DR

A man with a rare immune disorder developed severe lung and organ failure from infections after complications from immunotherapy.

## Contribution

This case highlights the complex clinical course and management challenges of XIAP deficiency.

## Key findings

- XIAP deficiency can lead to ARDS from PJP and multiorgan failure from MAI.
- Immunotherapy in XIAP deficiency may worsen susceptibility to opportunistic infections.
- Early recognition is critical for managing XIAP deficiency and its complications.

## Abstract

X-linked inhibitor of apoptosis (XIAP) deficiency is a rare primary immunodeficiency with a broad spectrum of clinical manifestations, including susceptibility to hemophagocytic lymphohistiocytosis (HLH), inflammatory bowel disease (IBD), hypogammaglobulinemia, and severe infections. We present a case of a 39-year-old male with a past medical history of XIAP deficiency complicated by HLH, Crohn’s disease, and hypogammaglobulinemia, who developed acute respiratory distress syndrome (ARDS) due to Pneumocystis jiroveci pneumonia (PJP) and concurrent multiorgan failure due to disseminated Mycobacterium avium intracellulare (MAI) infection. This case highlights the challenges in managing XIAP deficiency, emphasizing the importance of early recognition, and the need for further research to improve outcomes in this population.