Severe combined immunodeficiency (SCID) in man: B cell-negative (B-) SCID patients exhibit an irregular recombination pattern at the JH locus.

Human severe combined immunodeficiency (SCID) patients were analyzed by a polymerase chain reaction assay for their recombination capability at the DHQ52-JH region of the immunoglobulin heavy chain locus. Five patients with B cells (B+ SCID) exhibited a recombination pattern also observed in healthy persons. In contrast, six patients lacking B cells (B- SCID) showed a grossly altered rearrangement pattern characterized by the (partial) absence of regular DHQ52-JH recombinations and the presence of abnormal rearrangements. These events were caused by deletions surpassing the boundaries of immunoglobulin coding elements and thus resemble the pattern of deletional recombinations previously described in SCID mice.