Contributions
Abstract: PB1859
Type: Publication Only
Background
Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults and is characterized by clinical and biological heterogeneity. This heterogeneity is caused in some cases by structural aberrations in malignant cells, as evidenced by the presence of an abnormal karyotype. It is known that, in addition to cytogenetic aberrations, mutations of several genes involved in the pathogenesis of the disease and determining its differential prognosis are considered as important prognostic factors of CLL.
Aims
To identify the relationship of a number of immune response genes mutational status to the existing of numerical and structural changes in chromosomes in patients with CLL.
Methods
Sixty patients with CLL in the onset of the disease were examined, aged of 39 to 79 years (median - 62 years). Men - 37 (61.7%), women - 23 (38.3%). All patients underwent FISH-diagnostics of nuclei of interphase bone marrow cells with DNA probes Kreatech FISH Probe. Genotyping of 20 polymorphic locus of the 13 immune response genes of peripheral blood leukocytes genomic DNA was carried out by polymerase chain reaction with allele-specific primers (single nucleotide polymorphism - SNP).
Results
The patients were divided into two groups. The first group included 26 (43.3%) patients with CLL who had no chromosomal abnormalities in the FISH analysis. The second group consisted of 34 (56.7%) patients with various cytogenetic aberrations in the form of monosomy, trisomy 12 and 13 chromosomes, del13q14, del11q22, del17p13. Comparing the obtained cytogenetic data with the results of detection of the immune response genes SNP, it was found that the presence of mutant alleles in the haplotypes of the Toll-like receptor (TLR) gene 9 (TLR9, T-1237C) and interleukin (IL) 2 (T-330G) is almost 14 (p=0.01) and 5 times (p=0.03), respectively, reduces the frequency of cytogenetic aberrations detection in CLL. Survival and proliferation of CLL cells are directly dependent on external factors - pathogen-associated (PAMPs) and damage-associated molecular patters (DAMPs). PAMPs and DAMPs initiate the development of the malignant process and its progression by stimulating the B-cell receptor and others, including TLRs. The TLR9 agonist - CpG-ODN upon binding to the receptor lead to activation of malignant CLL cells. The response of transformed cells to CpG-ODN is significantly different with IgVH-non-mutated and mutated CLL. In the first case, CpG-ODN protect CLL cells from spontaneous apoptosis and trigger their proliferation, whereas in case of mutated CLL, induction of programmed cell death is observed, which is reflected in a different clinical course of the disease. The study of this mechanism can provide additional information on the pathogenesis of CLL and, thus, leads to the development of new therapeutic strategies. Experimental dates have shown that CpG-ODNs induce proliferation, cytokine production and expression of the high-affinity receptor for IL-2 on malignant cells in CLL. IL-2 weakens the apoptosis of proliferating B cells and increases the frequency of their detection, which is used in the FISH analysis to increase their ability to stimulate the proliferation of T lymphocytes and their production of IL-4 and IL-5, which in the future can be used in immunotherapy for CLL.
Conclusion
Cytogenetic and molecular genetic studies in CLL are used to predict the course of the disease, and are one of the bases for the development of new targeted therapy drugs.
Session topic: 5. Chronic lymphocytic leukemia and related disorders – Biology & Translational Research
Keyword(s): Chronic Lymphocytic Leukemia, Cytogenetic abnormalities, Gene polymorphism, prognosis
Abstract: PB1859
Type: Publication Only
Background
Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults and is characterized by clinical and biological heterogeneity. This heterogeneity is caused in some cases by structural aberrations in malignant cells, as evidenced by the presence of an abnormal karyotype. It is known that, in addition to cytogenetic aberrations, mutations of several genes involved in the pathogenesis of the disease and determining its differential prognosis are considered as important prognostic factors of CLL.
Aims
To identify the relationship of a number of immune response genes mutational status to the existing of numerical and structural changes in chromosomes in patients with CLL.
Methods
Sixty patients with CLL in the onset of the disease were examined, aged of 39 to 79 years (median - 62 years). Men - 37 (61.7%), women - 23 (38.3%). All patients underwent FISH-diagnostics of nuclei of interphase bone marrow cells with DNA probes Kreatech FISH Probe. Genotyping of 20 polymorphic locus of the 13 immune response genes of peripheral blood leukocytes genomic DNA was carried out by polymerase chain reaction with allele-specific primers (single nucleotide polymorphism - SNP).
Results
The patients were divided into two groups. The first group included 26 (43.3%) patients with CLL who had no chromosomal abnormalities in the FISH analysis. The second group consisted of 34 (56.7%) patients with various cytogenetic aberrations in the form of monosomy, trisomy 12 and 13 chromosomes, del13q14, del11q22, del17p13. Comparing the obtained cytogenetic data with the results of detection of the immune response genes SNP, it was found that the presence of mutant alleles in the haplotypes of the Toll-like receptor (TLR) gene 9 (TLR9, T-1237C) and interleukin (IL) 2 (T-330G) is almost 14 (p=0.01) and 5 times (p=0.03), respectively, reduces the frequency of cytogenetic aberrations detection in CLL. Survival and proliferation of CLL cells are directly dependent on external factors - pathogen-associated (PAMPs) and damage-associated molecular patters (DAMPs). PAMPs and DAMPs initiate the development of the malignant process and its progression by stimulating the B-cell receptor and others, including TLRs. The TLR9 agonist - CpG-ODN upon binding to the receptor lead to activation of malignant CLL cells. The response of transformed cells to CpG-ODN is significantly different with IgVH-non-mutated and mutated CLL. In the first case, CpG-ODN protect CLL cells from spontaneous apoptosis and trigger their proliferation, whereas in case of mutated CLL, induction of programmed cell death is observed, which is reflected in a different clinical course of the disease. The study of this mechanism can provide additional information on the pathogenesis of CLL and, thus, leads to the development of new therapeutic strategies. Experimental dates have shown that CpG-ODNs induce proliferation, cytokine production and expression of the high-affinity receptor for IL-2 on malignant cells in CLL. IL-2 weakens the apoptosis of proliferating B cells and increases the frequency of their detection, which is used in the FISH analysis to increase their ability to stimulate the proliferation of T lymphocytes and their production of IL-4 and IL-5, which in the future can be used in immunotherapy for CLL.
Conclusion
Cytogenetic and molecular genetic studies in CLL are used to predict the course of the disease, and are one of the bases for the development of new targeted therapy drugs.
Session topic: 5. Chronic lymphocytic leukemia and related disorders – Biology & Translational Research
Keyword(s): Chronic Lymphocytic Leukemia, Cytogenetic abnormalities, Gene polymorphism, prognosis