10. Improved detection of karyotype abnormalities in mature B-cell neoplasms through the utilization of CpG-oligonucleoties and interleukin-2 for B-lymphocyte stimulation

Abstract

Detection of cytogenetic abnormalities is essential for diagnosis, sub-classification, risk stratification, and prognosis assessment for a variety of cancers. However, the utilization of chromosome analysis for the diagnosis of mature B-cell neoplasms, including chronic lymphocytic leukemia (CLL) and non-CLL specimens, is limited. CLL and other B-cell neoplasms are clonal diseases of the B-lymphocytes, a cell type that often becomes arrested in the G0G1 phase of the cell cycle, precluding metaphase chromosomal analysis. Fluorescence in-situ hybridization (FISH) can provide better resolution, but is limited to specific regions of the genome by probe design and often fails to capture karyotype complexity. To overcome the lack of B-lymphocyte cell division in mature B-cell specimens, our laboratory has now employed CpG-oligonucleotides (OL) in conjunction with interleukin-2 (IL-2) to stimulate B-lymphocyte division. This in vitro culture condition increased the mitotic index of B-lymphocytes, leading to a >28% increase in the detection rate of abnormal karyotypes in B-cell neoplasms over the standard culture conditions. In addition, the quality of the metaphases of the CpG/IL-2 treated cultures was similar if not improved when compared to the standard culture conditions. These findings demonstrate the clinical utility of employing CpG-oligonucleotides and interleukin-2 for the improved detection of karyotype abnormalities in mature B-cell neoplasms.