Autoimmune lymphoproliferative syndrome–like disease with somatic KRAS mutation

Autoimmune lymphoproliferative syndrome (ALPS) is classically defined as a disease with defective FAS-mediated apoptosis (type I-III). Germline NRAS mutation was recently identified in type IV ALPS. We report 2 cases with ALPS-like disease with somatic KRAS mutation. Both cases were characterized by prominent autoimmune cytopenia and lymphoadenopathy/splenomegaly. These patients did not satisfy the diagnostic criteria for ALPS or juvenile myelomonocytic leukemia and are probably defined as a new disease entity of RAS-associated ALPS-like disease (RALD).