Clinical features and immunological parameters, including neutrophil CD64 (nCD64), myeloid-derived suppressor cells (MDSCs), activated T cells, and serum cytokine profiles, were compared between patients with and without fungal infections.<h4>Results</h4>Compared to non-infected AOSD patients, those with fungal infections had a higher frequency of splenomegaly (60.0% vs. 33.5%, p = 0.0024), pulmonary infiltrates (57.1% vs. 20.2%, p < 0.001), and pericarditis (42.9% vs. 20.7%, p = 0.0038). Here, FCGR1A is linked to Splenomegaly.