B70-06 Clinical Characteristics and Outcomes in Adults With Anti-ifn-γ Autoantibody-associated Immunodeficiency and Skeletal Involvement: A 10-year Retrospective Cohort Study

Background Anti-interferon-γ autoantibodies (AIGAs)-associated immunodeficiency is a rare, adult-onset disease with multi-system involvement, typically presenting as disseminated infections whose affected sites exhibit geographic variations. However, the clinical features and prognosis of its association with bone involvement remain unclear. Methods This retrospective study was conducted at the First Affiliated Hospital of Guangxi Medical University from May 2015 to May 2025. Patients who were AIGAs-positive with skeletal involvement and HIV-negative were enrolled. Results A total of 103 patients were enrolled, with a median age of onset of 55 years and a median follow-up time of 28.4 months, during which 13 patients died due to severe infections. Common underlying diseases included hypertension (29.13%) and hepatitis B virus carriage (10.68%). The most frequent initial symptoms were cough/sputum (66.99%), while bone pain accounted for only 21.36%. Among patients with bone involvement, common manifestations included peripheral lymphadenopathy (86.41%) and cough/sputum (85.44%), whereas bone/joint pain and myalgia were observed in 37.86% and 14.56% of cases, respectively. Laboratory tests revealed that most patients had elevated levels of white blood cells (92.23%), neutrophils (91.26%), C-reactive protein (95.15%), procalcitonin (100.00%), erythrocyte sedimentation rate (100.00%), globulin (72.82%), immunoglobulin (Ig) G (77.67%), and IgE (66.02%). The predominant types of infection were disseminated non-tuberculous mycobacteria (NTM) (55.34%) and Talaromyces marneffei (TM) (63.11%), with an increasing trend of co-infection observed. Chest CT findings indicated pulmonary involvement in all patients, with 63.11% showing evidence of bone involvement. Bone emission computed tomography (ECT) scans demonstrated abnormal foci of increased radiotracer uptake, such as in the thoracic vertebrae (75.73%), lumbar vertebrae (56.31%), and ribs (49.51%). Bone destruction was present in 63.11% of patients, including osteolytic destruction in 13.59%. All patients received full-course anti-infective therapy, some received individualized immunotherapy, and 19.41% required surgical intervention. Conclusion Skeletal involvement in AIGAs syndrome is common but clinically subtle, indicating systemic dissemination. Infection with either TM or NTM is common, and co-infection presents a greater clinical challenge. The axial skeleton is frequently involved, with early detection by bone ECT enabling comprehensive treatment and precise management to improve prognosis.Key words: AIGAs, skeletal involvement, clinical characteristics, infection This abstract is funded by: the Guangxi Key Technologies R&D Program (Grant No. 2023AB22055), the Central Leading Local Science and Technology Development Fund Project (Grant No. 2023ZYZX1021).