Oligoclonal T Cells and B Cells in an Amish Girl With Atypical RAG-1 Deficient Severe Combined Immunodeficiency

We report a 5-month-old Amish girl with atypical recombinase-activating gene (RAG)-deficient severe combined immunodeficiency disease. There was a lys992glu RAG-1 substitution leading to impaired RAG activity. Immunological studies revealed mildly decreased CD3+ T cells, markedly decreased CD4+ T cells, and oligoclonal T-cell receptor-Vβ T cells. B cells were markedly decreased but serum immunoglobulin levels were normal with monoclonal IgG and IgM antibodies.