In 1975, Purtilo et al1 described a fatal X-linked condition that affected boys in the Duncan kindred. The investigators surmised correctly that the disease stemmed from a genetic inability to mount an effective immune response to the Epstein-Barr virus (EBV). This discovery was particularly novel for it represented the first genetically determined immunodeficiency characterized by a selective vulnerability to a specific virus. The condition is now known as X-linked lymphoproliferative (XLP) disease. This article provides an overview of XLP and describes the function of The XLP Registry, founded by David T. Purtilo, MD, in 1978.
THE EPSTEIN-BARR VIRUS
The EBV, one of six known human herpesviruses, has strong trophism for B lymphocytes. In vitro, B cells are infected, immortalized polyclonally, and induced to produce immunoglobulins.2 In vivo, the virus also infects and replicates in the salivary glands and oropharyngeal epithelial cells.3 From these latter sites, it