Molecular characterization of a Tunisian B-lineage leukemia using Kde gene rearrangements

Background: Molecular approaches applied to the study of B-lineage leukemia have made significant contributions to understanding and to characterizing the disease. The Kde rearrangement was targeted as clonal marker to characterize Tunisian B-chronic lymphocytic leukemia (B-CLL) and B-acute lymphoblastic leukemia (B-ALL). Objective: We used a multiplex PCR to amplify deletional Kde rearrangements and Southern blot assay with Cκ and Kde probes in seven B-CLL and two B-ALL. Direct sequencing was performed in order to determine the n region. Results: An interesting RSS-Kde biallelic rearrangement was found in one adult male patient with B-ALL, since only Vκ-Kde rearrangement has been reported in adult B-ALL. In B-CLL, one case with two clonal cell proliferations in favor of oligoclonality which is very infrequent in B-CLL was identified and might be associated with bad outcome. These first results need more investigation to establish correlation between molecular characteristic and the poor outcome. Conclusion: The molecular approach was successfully improved and applied for clonality assessment of B-lineage leukemia for a better diagnosis and performing monitoring minimal residual disease.