We could document several immunological features specifically associated with ALPS and the profound dysregulation secondary to impaired apoptosis, including the accumulation of cycling DNT-cells, ALPS-FAS-specific phenotypic features (CD45R B220 expression on DNT-cells) as well as the changes in cytokines involved in the regulation of T-cells function and inflammation (IL-10, IL-8, TNFα, IL-18, and decreased MDC). The gene discussed is FAS; the disease is autoimmune lymphoproliferative syndrome.