X-linked lymphoproliferative (XLP) syndromes and related autosomal disorders are severe primary immune deficiencies triggered by infection with Epstein–Barr virus (EBV), the causative agent of infectious mononucleosis. Recent findings reviewed herein provided key new insights into the genetic and immunological basis of these diseases. They also improved our comprehension of the immunological mechanisms controlling EBV infection.
Mutations of an X-linked gene, SH2D1A, which encodes the signaling lymphocytic activation molecule (SLAM)-associated protein (SAP), are responsible for most cases of XLP disorders. More recently, other genetic causes for XLP syndromes and autosomal recessive variants of this disease were elucidated. Mutations in genes such as XIAP, ITK, and CD27 were identified. The clinical manifestations and immunological defects seen in these patients were characterized.
The similarities and differences in immunological defects and clinical manifestations between XLP syndromes and related autosomal recessive disorders enabled important new insights into the pathogenesis of these diseases. They also helped our comprehension of the mechanisms implicated in the control of EBV infection. They suggested that CD8+ T cells, natural killer (NK) cells, and NKT cells are critically involved.
aLaboratory of Molecular Oncology, Clinical Research Institute of Montréal
bDepartment of Medicine, University of Montréal
cDepartment of Medicine, McGill University, Montréal, Québec, Canada
dUnité INSERM 768, Laboratoire du Développement Normal et Pathologique du Système Immunitaire, Hôpital Necker Enfants-Malades, Paris, France
Correspondence to André Veillette, IRCM, 110 Pine Avenue West, Montréal, QC H2W1R7, Canada. Tel: +1 514 987 5561; fax: +1 514 987 5562; e-mail: firstname.lastname@example.org