Clinical and immunological findings in four infants with Omenn's syndrome: a form of severe combined immunodeficiency with phenotypically normal T cells, elevated IgE, and eosinophilia.

We report four cases of Omenn's syndrome (OS), an autosomal recessive disease characterized by early erythrodermia, protracted diarrhea, severe infections, lymphadenopathy, hepatosplenomegaly, failure to thrive, and leukocytosis with marked eosinophilia. The immunological investigations revealed B lymphopenia with increased levels of serum IgE and marked depression of T-cell activation, not restored by the addition of exogenous interleukin 2 (IL-2). IL-2 and interferon-gamma (IFN-gamma) production in vitro were very low or absent. One patient was treated with HLA-identical bone marrow transplant with a complete remission of the clinical picture and the immunological defect. The infant died of graft versus host disease 4 months after the graft. For the remaining three infants the outcome was also fatal within the first year of life. In conclusion, OS should be considered a severe combined immunodeficiency disease with peculiar clinical, immunological, and histological findings.