RESUMEN
X-linked lymphoproliferative syndrome (XLP or Duncan disease) is characterized by extreme sensitivity to Epstein-Barr virus (EBV), resulting in a complex phenotype manifested by severe or fatal infectious mononucleosis, acquired hypogammaglobulinemia and malignant lymphoma. We have identified a gene, SH2D1A, that is mutated in XLP patients and encodes a novel protein composed of a single SH2 domain. SH2D1A is expressed in many tissues involved in the immune system. The identification of SH2D1A will allow the determination of its mechanism of action as a possible regulator of the EBV-induced immune response.
Asunto(s)
Proteínas Portadoras/genética , Infecciones por Herpesviridae/complicaciones , Herpesvirus Humano 4 , Péptidos y Proteínas de Señalización Intracelular , Trastornos Linfoproliferativos/genética , Mutación , Dominios Homologos src/genética , Antígenos CD , Linfocitos B/inmunología , Linfocitos B/virología , Proteínas Portadoras/metabolismo , Clonación Molecular , Femenino , Ligamiento Genético , Glicoproteínas/metabolismo , Infecciones por Herpesviridae/inmunología , Infecciones por Herpesviridae/virología , Humanos , Inmunoglobulinas/metabolismo , Trastornos Linfoproliferativos/complicaciones , Trastornos Linfoproliferativos/inmunología , Trastornos Linfoproliferativos/virología , Masculino , Datos de Secuencia Molecular , Linaje , Receptores de Superficie Celular , Alineación de Secuencia , Eliminación de Secuencia , Proteína Asociada a la Molécula de Señalización de la Activación Linfocitaria , Miembro 1 de la Familia de Moléculas Señalizadoras de la Activación Linfocitaria , Linfocitos T/inmunología , Linfocitos T/virología , Cromosoma XRESUMEN
A 5-month-old male presented with fever, hepatosplenomegaly, leukocytosis with atypical lymphoblasts, anemia and thrombocytopenia. Severe combined imunodeficiency syndrome (T-, B+, NK+), B lymphoproliferative disease and hemophagocytic lymphohistiocytosis triggered by Epstein-Barr virus (EBV) were diagnosed. As his clinical situation deteriorated rapidly, BMT was performed with unmanipulated marrow stem cells from his EBV-positive HLA-identical sister after conditioning with dexamethasone (1.75 mg/kg/day), cyclophosphamide (114 mg/kg) and etoposide (10 mg/kg), with no immunosuppression given post transplant. Engraftment occurred on day 6 with explosive proliferation of donor CD8(+) T cells. The patient died 3 days later from acute respiratory distress syndrome. Autopsy revealed full donor engraftment and no signs of hemophagocytic lymphohistiocytosis or B lymphoproliferative disease. Thus, transplanted T cells can expand very rapidly within days after BMT and clear EBV lymphoproliferative disease and hemophagocytic lymphohistiocytosis.