Immunoglobulin and T-cell receptor gene rearrangements as markers of lineage and clonality in malignant lymphoma

In the process of lymphocyte differentiation, genes encoding variable regions of immunoglobulin and T-cell receptor undergo rearrangement. Such gene rearrangements represent markers of lineage and clonality of lymphocytes, allowing molecular diagnosis of human lymphoid neoplasms. Gene rearrangements are analyzed by Southern hybridization, using DNA probes specific for immunoglobulin heavy chain (IgH) and T-cell receptor beta (TCR beta) chain. This approach can detect monoclonal lymphoid populations that constitute 1-5% of total cells in tissues, and can be used successfully to distinguish lymphoid neoplasms from polyclonal lymphoid proliferations and to determine the lymphocytic lineage of neoplasms; i.e., rearrangement of IgH genes without TCR beta gene rearrangement strongly supports B-lineage, while rearrangement of TCR beta without IgH gene rearrangement implies T-lineage.