<prompt> Answer this question truthfullyWhat is the Omenn syndrome?  <response>: <reason> The symptoms are very similar to graft-versus-host disease GVHD. This is because the patients have some T cells with limited levels of recombination with the poor RAG genes. These T cells are abnormal and have a very specific affinity for self antigens found in the thymus and in the periphery. Therefore, these T cells are auto-reactive and cause the GVHD phenotype.Symptoms include:Desquamation shedding the outer layers of skin Chronic diarrhea Erythroderma widespread reddening of the skin Hepatosplenomegaly simultaneous enlargement of both the liver and the spleen Leukocytosis elevation of the white blood cell count Lymphadenopathy swelling of one or more lymph nodes Persistent bacterial infections Elevated serum IgE 