Non-malignant, non-infectious lymphoproliferation: challenges in the diagnosis and treatment of autoimmune lymphoproliferative syndrome

The autoimmune lymphoproliferative syndrome is a rare genetic disorder causing immunodeficiency. In the background of the disease, germline or somatic mutations of genes participating in the extrinsic apoptotic pathway and the consequential defect in the negative selection of activated lymphocytes were discovered. The clinical appearance of autoimmune lymphoproliferative syndrome consists of non-malignant lymphoproliferation, lymphadenopathy and splenomegaly, it is frequently accompanied by autoimmune disorders such as autoimmune haemolytic anaemia or autoimmune thrombocytopenia. The main diagnostic laboratory findings of this disease are the following: an elevation in alpha beta(+); CD4(-)/CD8(-) double-negative T cell count, elevated serum levels of soluble Fas-ligand, interleulcin-10, interleukin-18 and vitamin B-12. Other useful laboratory tests are the in vitro Fas-mediated apoptotic functional assay and the genetic screening for gene mutations. Differential diagnosis should exclude malignant lymphoproliferation in lymphomas and non-malignant autoimmune lymphoprolipherative syndrome-like diseases. The main aim of the treatment is the amelioration of the accompanying autoimmune disease with immunosuppressive therapy.