Immunoglobulin heavy chain and T-cell receptor beta chain gene rearrangements in acute non lymphoid leukemia

The occurrence of immunoglobulin heavy chain (IgH) and/or T-cell receptor (TcR) gene rearrangements has been reported in some cases of acute non lymphoid leukemia (ANLL), and variously interpreted as reflecting "aberrant gene expression" or "lineage promiscuity" of the leukemic cell. In an attempt to verify the incidence, FAB distribution and immunophenotypic correlates of gene rearrangements in ANLL, we analyzed the configuration of IgH and TcR beta chain genes in 70 patients with ANLL. In all cases myeloid (CD13, CD33, CD14, CD15) and lymphoid (CD7, CD2, CD10, CD19, TdT) antigenic determinants were analyzed in conjunction with conventional morpho-cytochemical characterization. Clonal rearrangements of the IgH gene were identified in 6/70 ANLL patients (8.6%), whereas in only 2/48 (4.2%) were T beta rearrangements documented. Concerning FAB subtypes, IgH or T beta rearrangements were detected in the less differentiated forms MO and M1 (3 cases), as well as in 2 M4 and 1 M5a cases. With the exception of a higher incidence of gene rearrangements in TdT+ ANLL, no significant correlation was found with other immunophenotypic markers.