Detection of immunoglobulin heavy chain gene rearrangement with PCR for MRD analysis in lymphoproliferative disorders

Abstract: Immunoglobulin heavy chain (IGH) gene rearrangement occurs during early B-lymphocyte differentiation, assembling the different IGH gene segments to a functional gene, which can serve as a marker for study of lineage association and detection of Minimal Residual Disease (MRD) in clonal diseases deriving from B-lymphocytes or their early differentiation stages. Use of a molecular marker for the leukemic cells could help improve treatment by monitoring therapeutic efficacy, predicting relapse, and identifying very small amounts of tumour cells contaminating autografts after purging or enrichment of stem cells.This work focused on the task of improving the specificity of clonality and MRD tests by developing simple laboratory methods based on Polymerase Chain Reaction (PCR) with which to distinguish monoclonal from polyclonal cells. These methods were compared with conventional histopathological and immunocytological techniques in a retrospective study concerning the possibility of predicting recurrence of childhood pre-B Acute Lymphoblastic Leukemia (ALL). Clonal evolution in childhood pre-B ALL was also studied by comparing the rearrangements at diagnosis versus at relapse. A highly sensitive clonospecific PCR-method was utilized to detect small amounts of monoclonal cells before and after stem cell purging in mobilized peripheral blood stem cells from multiple myeloma patients.