Abstract

Autoimmune Lymphoproliferative syndrome (ALPS) is a rare childhood disorder characterized by chronic nonmalignant lymphoproliferation and autoimmunity. Recently, it has been shown that defective apoptosis due to heritable mutations in Fas, Fas ligand and caspase 10 genes, which regulate lymphocyte apoptosis may play a role in pathogenesis. Lymphadenopathy, hepatosplenomegaly, a positive Direct Coomb's test, autoimmune hemolytic anemia, idiopathic immune thrombocytopenia are the most comman features in ALPS. Hypergammaglobulinemia, elevated numbers and pecentages (>%1) of double-negative CD4-CD8- T cells, and characteristic pathologic findings in lymph nodes or spleen are diagnostic features. In this report, we presented a 14-month-old male ALPS patient who was found to have severe hepatosplenomegaly and trombocytopenia without infectious or malignant etiology, and high CD4-CD8- T-cell ratio and low Fas (CD95) expression.