患儿，男，2岁，因咳嗽、发热第6次入院。患儿2月龄时发现腋下淋巴结结核，多次因发热、咳嗽住院，并发现嗜酸性粒细胞增多，以及多次免疫全套提示IgG、IgA、IgM降低。入院后予以抗结核、抗细菌、抗真菌治疗，仍反复发热、肝脾进行性增大，入院第35天出现果酱样大便、B超提示左侧腹局部肠管横断面呈“同心圆征”，于全麻下行剖腹探查、肠套叠复位+回盲部成形术以及肠壁结节、肠系膜淋巴结活检、肝活检术，术后患儿出现肝功能衰竭、DIC、电解质紊乱，救治无效死亡。入院后血培养及肝活检均发现马尔尼菲青霉菌；并进一步对患儿、患儿父母及弟弟进行免疫缺陷病相关基因检测，提示患儿存在CD40L基因半合突变 （IVS1-3T→G），确诊为高IgM综合征。患儿母亲为此拼接点错误基因的携带者、父亲正常，患儿弟弟与患儿有相同的CD40L基因突变。

A 2-year-old boy was admitted into the hospital because of cough and fever. Lymph node tuberculosis was noted when he was 2 months old and he was subsequently hospitalized several times because of cough and fever. After hospitalization the laboratory examination showed an increased eosinophia level in blood. The immune function tests shows decreased levels of IgG, IgA, and IgM. The patient had no response to anti-tuberculosis, anti-bacterial, and anti-fungal treatment, resulting in recurrent fever and progressive enlargement of the liver and spleen. Jam-like stools were noted 35 days after admission. B ultrasonography showed suspected intussusception. Laparotomy, reduction of intussusception and ileocecum angioplasty, biopsies of intestinal wall nodules and lymphoglandulae mesentericae, and hepatic biopsy were then performed under general anesthesia. The patient eventually died because of postoperative severe liver damage, disseminated intravascular coagulation and electrolyte disorder. Both the blood culture and hepatic biopsy tests showed Penicillium marneffei infecton. Immunodeficiency gene test was performed on the patient, his bother and their parents. T→G base substitution mutation (IVS1-3 T→G) in the CD40L gene was found in the patient. X-linked hyper-IgM syndrome was thus diagnosed in the patient. His mother was a carrier of the mutated CD40L gene, but his father was normal in the gene test. Hemizygous mutation in the CD40L gene was found in both the patient and his bother.