To analyze the relationship between the cellular composition of peripheral blood allografts and clinical outcome, we performed a prospective study in 45 adult patients who underwent allogeneic peripheral blood hematopoietic stem cell transplantation (HSCT) from a histocompatibility leukocyte antigen identical sibling donor for different hematological malignancies. The dose of CD34+, CD3+, CD4+, CD8+, and CD19+ lymphocytes, natural killer (NK) cells, natural killer T (NKT) cells, type 1 and type 2 dendritic cells (DC1 and DC2), as well as regulatory T (Treg) lymphocytes was analyzed. All patients were conditioned with busulphan and cyclophosphamide (BuCy2) +/- VP-16 and received a short course of methotrexate and cyclosporin-A as graft-versus-host disease (GVHD) prophylaxis. Acute GVHD (aGVHD) was present in 9 of 43 (21%) patients, and chronic GVHD (cGVHD) developed in 18 of 39 (46%) patients. There was a significantly higher incidence of aGVHD in patients receiving more than 6x10(6)/kg CD34+ cells. In univariate analysis, variables associated with better survival were as follows: a dose of less than 1.5x10(7)/kg NKT cells and less than 1.7x10(6)/kg DC2 for disease-free survival (DFS), and a dose of less than 3x10(7)/kg NK cells, less than 1.5x10(7)/kg NKT cells, less than 3x10(6)/kg DC1, and less than 1.7x10(6)/kg DC2 for overall survival (OS). In the Cox regression analysis, the dose of NKT cells was the only variable associated with better DFS, while the doses of NK, NKT, and CD34+ cells (less than 8x10(6)/kg) were associated with better OS. In conclusion, different circulating cell populations, other than CD34+ cells, are also of relevance in predicting the clinical outcome after allogeneic peripheral blood HSCT.

Chronic Myeloid Leukemia (CML) is sustained by a small population of cells with stem cell characteristics known as Leukemic Stem Cells that are positive to BCR-ABL fusion protein, involved with several abnormalities in cell proliferation, expansion, apoptosis and cell cycle regulation. Current treatment options for CML involve the use of Tirosine Kinase Inhibitor (Imatinib, Nilotinib and Dasatinib), that efficiently reduce proliferation proliferative cells but do not kill non proliferating CML primitive cells that remain and contributes to the persistence of the disease.In order to understand the role of Cyclin Dependent Kinase Inhibitors in CML LSC permanence after TKI treatment, in this study we analyzed cell cycle status, the levels of several CDKIs and the subcellular localization of such molecules in different CML cell lines, as well as primary CD34+CD38−lin− LSC and HSC.Our results demonstrate that cellular location of p18INK4c and p57Kip2 seems to be implicated in the antiproliferative activity of Imatinib and Dasatinib in CML cells and also suggest that the permanence of quiescent stem cells after TKI treatment could be associated with a decrease in p18INK4c and p57Kip2 nuclear location. The differences in p18INK4cand p57Kip2activities in CML and normal stem cells suggest a different cell cycle regulation and provide a platform that could be considered in the development of new therapeutic options to eliminate LSC.

Background: Chronic myeloid leukemia (CML) is one of the most frequent hematopoietic malignancies in the elderly population; however, knowledge is limited regarding the genetic factors associated with increased risk for CML. Polymorphisms affecting microRNA (miRNA) biogenesis or mRNA:miRNA interactions are important risk factors in the development of different types of cancer. Thus, we carried out a case-control study to test the association with CML susceptibility of gene variants located in the miRNA machinery genes AGO1 (rs636832) and GEMIN4 (rs2740348), as well as in the miRNA binding sites of the genes BRCA1 (rs799917) and KRAS (rs61764370). Materials and Methods: We determined the genotype of 781 Mexican-Mestizo individuals (469 healthy subjects and 312 CML cases) for the four polymorphisms using TaqMan probes to test the association with CML susceptibility. Results: We found a borderline association of the minor homozygote genotype of the KRAS_rs61764370 polymorphism with an increased risk for CML susceptibility (P = 0.06). After gender stratification, this association was significant only for women (odds ratio [OR] = 13.41, P = 0.04). The distribution of the allelic and genotypic frequencies of the four studied SNPs was neither associated with advanced phases of CML nor treatment response. Conclusions: To the best of our knowledge, this study is the first to show a significant association of the KRAS_rs61764370 SNP with CML. To further determine such an association of with CML susceptibility, our results must be replicated in different ethnic groups.

In this study, we determined the gene expression profiles of bone marrow‐derived cell fractions, obtained from normal subjects and Chronic Myeloid Leukemia (CML) patients, that were highly enriched for hematopoietic stem (HSCs) and progenitor (HPCs) cells. Our results indicate that the profiles of CML HSCs and HPCs were closer to that of normal progenitors, whereas normal HSCs showed the most different expression profile of all. We found that the expression profiles of HSCs and HPCs from CML marrow were closer to each other than those of HSCs and HPCs from normal marrow. The major biologic processes dysregulated in CML cells included DNA repair, cell cycle, chromosome condensation, cell adhesion, and the immune response. We also determined the genomic changes in both normal and CML progenitor cells under culture conditions, and found that several genes involved in cell cycle, steroid biosynthesis, and chromosome segregation were upregulated, whereas genes involved in transcription regulation and apoptosis were downregulated. Interestingly, these changes were the same, regardless of the addition of Imatinib (IM) to the culture. Finally, we identified three genes—PIEZO2, RXFP1, and MAMDC2‐ that are preferentially expressed by CML primitive cells and that encode for cell membrane proteins; thus, they could be used as biomarkers for CML stem cells.