Increased lymphocyte Fas expression and high incidence of common variable immunodeficiency disorder in childhood Evans' syndrome.

Evans' syndrome (ES) is characterized by autoimmune hemolytic anemia and thrombocytopenia and has been associated with immune deficiency and lymphoproliferation in some cases. Abnormalities of Fas-mediated apoptosis have been reported in various immune dysregulation disorders associated with autoimmunity and lymphoproliferation. We measured lymphocyte Fas expression and Fas-mediated T lymphocyte apoptosis in 7 children with ES, 7 with acute idiopathic thrombocytopenic purpura (ITP) and 9 with non-immune-mediated disorders. Patients with ES had higher Fas expression on peripheral blood T and B lymphocytes (P<0.001 and P=0.046, respectively) and increased Fas-mediated elimination of activated T lymphocytes compared with the control groups. While two ES patients had panhypogammaglobulinemia at testing, three more developed it later, reaching a frequency of 83%. Some children with ES have increased lymphocyte Fas expression and Fas-mediated T lymphocyte apoptosis and these may be early signs of common variable immunodeficiency disorder in ES.