一名 16 岁男孩在急性髓性白血病第二次缓解期间接受了无关的骨髓移植。他患有严重的口腔粘膜并发症，并且难以服用磺胺甲恶唑/甲氧苄啶（ST）等口服药物。移植第 35 天获得植入，移植第 60 天左右出现视力模糊和头痛。眼底镜检查显示视网膜出血和黄斑水肿，头部 MRI 扫描显示左侧壳核有结节性病变。脑脊液PCR检测出弓形虫，诊断为脑弓形体病。在接受 ST 和克林霉素治疗后，患者服用乙胺嘧啶、磺胺嘧啶和亚叶酸。症状迅速改善，治疗开始 45 天后 CSF PCR 呈阴性。由于弓形虫抗体的患病率随着年龄的增长而增加，因此在青春期后患者的造血细胞移植后通过 ST 避免弓形虫重新激活至关重要。

A 16-year-old boy received an unrelated bone marrow transplant while in second remission of acute myeloid leukemia. He suffered from severe oral mucosal complications and had difficulty taking oral drugs such as sulfamethoxazole/trimethoprim (ST). Engraftment was obtained on transplant day 35, and blurred vision and headache appeared around transplant day 60. Funduscopy revealed retinal hemorrhage and macular edema, and an MRI scan of the head revealed a nodular lesion in the left putamen. Toxoplasma gondii was detected by CSF PCR, and cerebral toxoplasmosis was diagnosed. Following therapy with ST and clindamycin, the patient was administered pyrimethamine, sulfadiazine, and leucovorin. Symptoms improved promptly, and CSF PCR was negative 45 days after the start of treatment. Since the prevalence of toxoplasma antibodies increases with age, it is crucial to avoid toxoplasma reactivation by ST after hematopoietic cell transplantation in postpubescent patients.