C68-18 Disseminated Non-tuberculous Mycobacterial Infection and Secondary Hlh Revealing a Germline Gata2 Deficiency: A Multidisciplinary Diagnostic Challenge

Abstract Introduction Germline GATA2 deficiency is a rare immunodeficiency predisposing to recurrent infections, bone marrow failure, and life-threatening hyperinflammatory complications. The disease often presents with nonspecific pulmonary manifestations, leading to delayed diagnosis. We report a complex case of GATA2 deficiency initially masquerading as refractory pneumonia and adult-onset Still’s disease. Case Description A 43-year-old man presented with 10 months of recurrent fever, cough, and bilateral pulmonary infiltrates unresponsive to broad-spectrum antimicrobials and corticosteroids. PET-CT revealed multiple hypermetabolic nodules. Serial bronchoscopic and transthoracic biopsies showed organizing pneumonia without malignancy or pathogens. Due to persistent fever and progressive cytopenias, video-assisted thoracoscopic right upper and middle lobectomy was performed for diagnostic clarification. Histopathology demonstrated necrotizing inflammation with acid-fast bacilli. Bone-marrow next-generation sequencing identified Mycobacterium kansasii and EBV co-infection. The patient developed pancytopenia, splenomegaly, hyperferritinemia, hypertriglyceridemia, elevated soluble CD25, and decreased NK activity, fulfilling HLH-2004 criteria. Germline testing confirmed a pathogenic GATA2 mutation (primary lymphedema with myelodysplasia and immunodeficiency type 21). Despite immunoglobulin, corticosteroids, and plasma exchange, he remained febrile but stabilized with targeted antimycobacterial therapy. Hematopoietic stem-cell transplantation was planned once infection control was achieved. Discussion This case illustrates the diagnostic complexity of GATA2 deficiency with overlapping infectious and hyperinflammatory phenotypes. The combination of disseminated NTM infection, EBV reactivation, and HLH should prompt evaluation for underlying immunodeficiency. Thoracic surgical biopsy provided the tissue necessary for molecular diagnosis. Early recognition and multidisciplinary management—integrating infectious disease, pulmonary, hematology, and surgical teams—are essential for optimizing outcomes. Clinicians should lower the threshold for GATA2 testing in adults with refractory or disseminated pulmonary infections and cytopenias. This abstract is funded by: None