TY - JOUR T1 - Cerebral toxoplasmosis in a middle-aged man as first presentation of primary immunodeficiency due to a hypomorphic mutation in the CD40 ligand gene JF - Journal of Clinical Pathology JO - J Clin Pathol SP - 1220 LP - 1222 DO - 10.1136/jcp.2008.058362 VL - 61 IS - 11 AU - P F K Yong AU - F A Post AU - K C Gilmour AU - D Grosse-Kreul AU - A King AU - P Easterbrook AU - M A A Ibrahim Y1 - 2008/11/01 UR - http://jcp.bmj.com/content/61/11/1220.abstract N2 - Cerebral toxoplasmosis can occur outside the setting of advanced HIV immunodeficiency or drug-induced immunosuppression. A case of cerebral toxoplasmosis is reported in a previously healthy 41-year-old man who was found to have a genetic defect in CD40 ligand, resulting in the X linked hyper-IgM syndrome despite normal surface protein expression on flow cytometry. This highlights the fact that primary immunodeficiencies can first present late in life with a relatively mild phenotype and should be considered in the differential diagnosis of opportunistic infections in non-HIV infected patients; in addition, normal protein expression does not necessarily rule out hypomorphic mutations. ER -