[Cerebral toxoplasmosis after umbilical cord blood transplantation diagnosed by the detection of anti-toxoplasma specific IgM antibody in cerebrospinal fluid].

Cerebral toxoplasmosis is a rare, potentially fatal, complication of hematopoietic cell transplantation. Early definitive diagnosis is very difficult and it may be associated with a poor prognosis. Herein, we describe a 60-year-old woman who developed cerebral toxoplasmosis after cord blood transplantation for myelodysplastic syndrome. During treatment with tacrolimus and methylprednisolone for relapsed grade 2 acute gut GVHD, fever and disturbance of consciousness occurred on day 210. Brain MRI showed multiple ring-enhancing nodular lesions in the thalamus, basal ganglia, brainstem, and subcortical white matter. Cerebrospinal fluid (CSF) assessment revealed elevations of both anti-to-xoplasma IgM and IgG, which were also elevated in serum, but no evidence of other infections or malignancies. Notably, the IgM level was higher in the CSF than in serum. Thus, cerebral toxoplasmosis was diagnosed. Soon after administration of oral sulfamethoxazole/trimethoprim and intravenous clindamycin in combination with short-term dexamethasone for the cerebral edema, her symptoms and signs began to improve. On day 229, both IgM and IgG titers in CSF had clearly decreased but remained essentially constant in serum. She was discharged without clinically significant neurological disorders. This case suggests that CSF specific anti-toxoplasma IgM titers might be useful for early diagnosis of cerebral toxoplasmosis after transplantation.