A new complication of stem cell transplantation: measles inclusion body encephalitis.

Measles inclusion body encephalitis (MIBE) is a disease of the immunocompromised host and typically occurs within 1 year of acute measles infection or vaccination. We report a 13-year-old boy who had chronic granulomatous disease and presented 38 days after stem cell transplantation with afebrile focal seizures that progressed despite multiple anticonvulsants. After an extensive diagnostic evaluation, brain biopsy was performed, revealing numerous intranuclear inclusion bodies consistent with paramyxovirus nucleocapsids. Measles studies including reverse transcriptase-polymerase chain reaction and viral growth confirmed measles virus, genotype D3. Immunohistochemistry was positive for measles nucleoprotein. Despite intravenous ribavirin therapy, the patient died. MIBE has not been described in stem cell recipients but is a disease of immunocompromised hosts and typically occurs within 1 year of measles infection, exposure, or vaccination. Our case is unusual as neither the patient nor the stem cell donor had apparent recent measles exposure or vaccination, and neither had recent travel to measles-endemic regions. The patient had an erythematous rash several weeks before the neurologic symptoms; however, skin biopsy was consistent with graft-versus-host disease, and immunohistochemistry studies for measles nucleoprotein were negative. As measles genotype D3 has not been seen in areas where the child lived since his early childhood, the possibility of an unusually long latency period between initial measles infection and MIBE is raised. In addition, this case demonstrates the utility of brain biopsy in the diagnosis of encephalitis of unknown cause in the immunocompromised host.