Modification of cellular and humoral immunity by somatically reverted T cells in X-linked lymphoproliferative syndrome type 1

Human SH2D1A mutations resulting in X-linked lymphoproliferative syndrome type 1 (XLP1) are associated with a unique susceptibility to the EBV. This susceptibility is attributed to impaired activation and cytotoxicity of CD8+ T cells by antigen-presenting B cells but not by other antigen-presenting cells.1 Impaired function of CD4+ T cells contributes to humoral immunodeficiency independent of EBV infection.2 In clinical situations, fatal infectious mononucleosis (FIM)/hemophagocytic lymphohistiocytosis (HLH) have high mortality rates, and hematopoietic stem cell transplantation (HSCT) is the only curative therapy.