Background: The introduction of biology and molecular genetics in the hematological laboratory has brought about a new and spectacular advance in the study of cloning and cytological characterization of malignant hemopathies. The principal aim of the present study was to analyze the contribution of this new technology in the diagnosis of acute leukemia (AL) and chronic lymphoproliferative syndromes (CLS) through analysis of lymphoid clonality and genetic rearrangement proper to the lymphoid differentiation of the B and T cells.
Methods: The genetic rearrangement of the heavy chain immunoglobulins (IgH) and the beta (beta) and gamma (gamma) chains of the T receptor (TRC) in 121 patients with the following malignant hemopathies: acute myeloid leukemia (AML), 28 cases; acute lymphoblastic leukemia (ALL), 27 cases; and CLS, 66 cases. The Southern method was used.
Results: Clonality analysis: presence of genetic rearrangement (clonality) in all the cases of lymphoblastic AL (ALL) and CLS and in 5 of 28 cases of AML (3 IgH and 2 TRC). Strain analysis: presence of absolute coincidence (exclusive rearrangement of the IgH or TRC genes in proliferations of the B or T strain, respectively) in 18 of 27 cases (67%) of ALL, in 14 of 15 cases (93%) of T-CLS and in all cases (100%) of B-CLS.
Conclusions: In malignant hemopathies the analysis of genetic rearrangement constitutes a method of great practical use for determining the presence of lymphoid clonality and is a good complement to conventional morphological and immunophenotypic procedures for cytological characterization of the same.