ImmunoDeficiency Resource (IDR)

Herpes simplex encephalitis (HSE) is a rare complication of infection with herpes simplex virus-1 (HSV-1), which infects an estimated 80% of young adults worldwide. HSE susceptibility may be inherited as a monogenic trait resulting in the specific impairment of immunity to HSV-1. This notion of pathogen-specific mendelian immunodeficiency contrasts with the dominant paradigm, in which rare single-gene lesions confer vulnerability to multiple infections, whereas more common infections in otherwise healthy patients reflect polygenic predisposition. Onset may occur at any age but is most common in adults. This disease, which affects only a small minority of HSV1-infected individuals, could result from a genetic predisposition. A mutation in the UNC-93B gene, inducing impaired production of interferon, an anti-infectious factor necessary to fight the herpetic virus infection in nervous tissue, has been identifiedin two children and may be responsible for the disease. The disease course is severe, with a mortality rate of 80% and severe sequelae among surviving patients.