Cytogenetic abnormalities play a major role in the prognosis of patients with chronic lymphocytic leukemia (CLL). Several methods have emerged to try to best identify these abnormalities. We used fluorescence in situ hybridization (FISH) to determine the frequency of cytogenetic changes in our CLL patient population. We also evaluated the effectiveness of multiplex ligation-dependent probe amplification (MLPA) in detecting these abnormalities. Sixty-two B-CLL patients and 20 healthy controls were enrolled, and FISH and MLPA analyses were performed on peripheral blood samples. Using FISH , genomic aberrations were found in 73% of patients and presented as follows: single 13q14.3 deletion (60%) , trisomy 12 (7%) , ATM deletion (6%) , 17p13.1 deletion (2%). MLPA analyses done on 61/62 patients showed sensitivity and specificity values of 90% and 100% respectively. MLPA revealed several additional copy number changes , the most common being 19p13 (LDLR and CDKN2D). Moreover , the cost for MLPA analysis, including technical time and reagents , is 86% less than FISH. In conclusion , cytogenetic abnormalities are a common finding in CLL patients , and MLPA is a reliable approach that is more cost effective and faster than FISH. Despite MLPA limitations of sensitivity, it can be used as a first-line screen and complementary test to FISH analysis.

A recent phase III trial comparing granulocyte colony-stimulating factor (G-CSF)-stimulated bone marrow (G-BM) and G-CSF-mobilized peripheral blood (G-PB) in matched sibling allograft recipients showed that G-BM produced a similar hematologic recovery but a reduced incidence of extensive chronic graft-versus-host disease, indicating differences in the cell populations infused. As a first step toward identifying these differences, we treated a group of healthy adult humans with 4 daily doses of G-CSF 10 microg/kg and monitored the effects on various hematopoietic and immune cell types in the PB and BM over 12 days. G-CSF treatment caused rapid and large but transient increases in the number of circulating CD34+ cells, colony-forming cells, and long-term culture-initiating cells and in the short-term repopulating activity detectable in nonobese diabetic/severe combined immunodeficiency/beta2-microglobulin-null mice. Similar but generally less marked changes occurred in the same cell populations in the BM. G-CSF also caused transient perturbations in some immune cell types in both PB and BM: these included a greater increase in the frequency of naive B cells and CD123+ dendritic cells in the BM. The rapidity of the effects of G-CSF on the early progenitor activity of the BM provides a rationale for the apparent equivalence in rates of hematologic recovery obtained with G-BM and G-PB allotransplants. Accompanying effects on immune cell populations are consistent with a greater ability of G-BM to promote tolerance in allogeneic recipients, and this could contribute to a lower rate of chronic graft-versus-host disease.

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