Three months after birth, the patient had recurrent mycotic stomatitis, tinea capitis and onychomycosis. He had a poor physique throughout childhood and often went to the hospital because of Candida dermatitis (Figure 1D). Because of long-term malnutrition, he was thin with a body mass index of 16.52. Knowing the medical history, it was found that he had no other obvious infection except Candida dermatitis. At the age of 20, he was admitted to the hospital with severe pneumonia. His body temperature reached a peak of 39.3 C. He had chills, cough and white sticky sputum but no night sweats, no chest tightness, no headache, and no abdominal pain or diarrhea. Pulmonary CT revealed bilateral pulmonary infection with bilateral pleural effusion, a patchy high-density shadow near the right lung hilum, a paraspinal mass in the right lower mediastinum, and pericardial effusion (Figures 1A, B). Fiberoptic bronchoscopy showed that the mucosal surface of each segment of the right bronchus was covered with a large amount of white caseous necrotic tissue. Acid-fast bacilli staining and testing for Mycobacterium tuberculosis DNA in bronchoalveolar lavage fluid were both negative. Sputum acid-fast staining was performed repeatedly during hospitalization, and all of the results were negative. During this hospitalization, routine bone marrow smears showed poor megakaryocyte function and macrophage phagocytosis of red blood cells, white blood cells and platelets. He was positive with IgG antibodies of Rubella virus, Herpes virus, and Epstein-Barr virus (Table 1). Upon physical examination, the patient was awake, thin, and had normal secondary sexual characteristics, chapped and brittle nails on his hands and feet, a thick white membrane on his tongue, no ulcers, and no obvious swelling of bilateral tonsils. No bleeding was observed on the skin or mucosa, and no rashes, no enlargement of the liver or spleen, no tenderness of the abdomen, no rebound pain in the abdomen, no palpation of superficial lymph nodes and normal auscultation of the heart and lungs were observed. After admission, empirical anti-infective treatment was performed with meropenem and voriconazole due to his unidentified pathogenic infection.