Dual Rearrangement of Immunoglobulin and T-cell Receptor Genes in a Case of Philadelphia Chromosome-positive Acute Leukemia

Abstract

A 48-year-old patient was admitted to our hospital for leukocytosis. The blastcells were positive for peroxidase and he was tentatively diagnosed as acute myeloid leukemia according to the French-American-British criteria. By flow cytometry, the bone marrow cells were positive for CD10, CD13, CD33 and HLA-DR, but two-color analysis revealed that most of the CD13-and CD33-positive cells did not express CD1 O. The marrow cells had Philadelphia chromosome with no additional abnormalities. Major bcr-abl fusion gene was observed by the reverse transcriptase-polymerase chain reaction method. Southern blot analysis disclosed rearrangement of both immunoglobulin heavy chain and T-cell receptor beta chain genes. He received combined chemotherapy for myeloid lineage and lymphoid lineage, but the response was quite poor. Hedied64 daysafteradmission due to pulmonary bleeding. Although the association of Ph 1 with multilineage differentiation is unclear, our case has significant implication for further investigation of the relationship between Ph1-positive cells and lineage selection.

Rare lymphoid neoplasms coexpressing B- and T-cell antigens. The role of PAX-5 gene methylation in their pathogenesis

“…The Pax-5 gene is transcribed from 2 distinct promoters, resulting in alternative splicing of different 5′-end exons to the common coding sequences of exons 2 to 10. The Pax-5 α is expressed in B-lymphoid tissues and pro-B, pre-B, and Bmature cells, but not in terminally differentiated plasma cells; Pax 5 β is expressed by all Pax-5-expressing tissues, such as embryos, adult testis, spleen, and B-cell lines [28,29]. The results of methylation analysis of PAX5 α and β promoters are illustrated in Fig.…”