T and B Cell Characteristics in Combined Immunodeficiency

To the Editor: Recently Geha et al. (N Engl J Med 290:726–728, 1974) described a six-month-old male infant with severe combined immunodeficiency (SCID) who had no detectable T cells by spontaneous sheep-cell rosette formation, but who had a high percentage of IgM-bearing cells that lacked C3 surface receptors. These cells behaved like B cells, since they transformed in the presence of pokeweed mitogen and secreted an IgG similar to the M component found in the patient's serum. In a 2 1/2-year-old male patient with SCID, who had been maintained in a Trexler isolator since birth, we detected a high percentage ….