Unusual immunoglobulin gene rearrangements in patients with immunodeficiency

In a 64-year-old patient with typical common variable immunodeficiency (CVID) DNA prepared from peripheral blood lymphocytes (PBL) showed a prominent immunoglobulin heavy chain (IgH) gene rearrangement; the immunoglobulin light chain (IgL) genes were found to be in the germline configuration. In contrast, a 13-year-old girl with a hitherto unidentified immunodeficiency showed polyclonal IgH gene rearrangements and a dominant IgL gene rearrangement. In both cases neither monoclonal B-lymphocytes nor monoclonal immunoglobulins were detectable. Our explanation for this unusual observation is that V-gene use in a given B-cell is not entirely random. This may be the consequence of a maturation arrest of B-cells.