Prospective gene rearrangement studies and multiparameter analysis of acute myeloid leukemia

Twenty-six cases of acute myeloid leukemia (AML) with cytochemical and immunophenotypic data were studied prospectively for immunoglobulin and T-cell receptor gene rearrangement. Dysmyelopoiesis was seen in 100% and Auer rods in 18%. Sudan black B was positive in 83% of the cases, peroxidase in 76%, nonspecific esterase in 74% (fluoride-inhibited in 82%), chloroacetate in 70%, acid phosphatase and PAS in 100%, and immunoperoxidase stains for platelet glycoprotein IIIa and factor VIII in 0% of the cases studied. Flow cytometry revealed myeloid phenotype in 19 of 20 cases. In four cases 5-86% of cells were TdT positive. Heavy-chain gene rearrangement was demonstrated in three cases (12%) and kappa light chain gene rearrangement in one; clinically significant rearrangement of the T-cell receptor gene was not found. Rearrangements of immunoglobulin genes are found occasionally in AML; these may represent nonspecific findings or coexistent lymphoid differentiation in AML.