Subacute measles encephalitis in a young man immunosuppressed for ankylosing spondylitis.

Subacute measles encephalitis occurred 1 month after measles onset in a 26-year-old HIV-negative man undergoing immunosuppressive treatment for ankylosing spondylitis. He had seizures, a decline in mental status, and progressive impairment of consciousness, with a fatal outcome. Despite severely deficient cellular immunity, the elevated antimeasles antibody titers and CSF findings indicated that humoral immunity was not impaired. Histologic, electron microscopic, and immunocytochemical studies revealed the typical intranuclear inclusions of paramyxovirus nucleocapsids, and measles virus antigen in neurons and oligodendrocytes.