Effect of Alemtuzumab on Gene Expression Profile of Mononuclear Cells Score in Cardiac Transplant Patients

Abstract Abstract 4549 Steroid-refractory acute graft-versus-host disease (aGVHD) remains to be the major complication of allogeneic hematopoietic stem cells transplantation (allo-HSCT). aGVHD is characterized by tissue injury and is associated with high morbidity and mortality, most notably in cases of severe course and/or resistance to corticoids. aGVHD appears usually within the first 100 days after transplantation. This study should lead to identification of molecular patterns characterizing patients’ sensitivity or resistance to corticoid therapy. We performed an oligonucleotide microarray analysis (whole genome Human OneArray, Phalanx) of 13 patients with hematological malignancies who received allo-HSCT. Peripheral blood samples were collected at the time of aGVHD manifestation and subsequently mononuclear cells were isolated (Ficoll-Paque gradient). In total, five patients with resistance, and eight patients with sensitivity to corticoids were included in the analysis. The significance analysis of micorarrays (SAM) revealed a set of differentially expressed genes: GBP5 (guanylate binding protein 5), PRG3 (proteoglycan 3), CDK5RAP2 (CDK5 regulatory subunit associated protein 2), and, especially, ARG1 gene (arginase, liver) whose expression was significantly higher in the group of resistant patients (with 4.89-fold change). As published earlier, arginase is released from human granulocytes during purulent inflammatory reactions and induces a suppression of T-cell proliferation and cytokine synthesis (Munder et al., 2006). These findings might confirm our hypothesis that expression levels of ARG1 gene could reflect the severity of aGVHD. ARG1 gene was detected apparently in a fraction of immature forms of granulocytes which are released into the peripheral blood after allo-HSCT. Thus, both immature granulocytes and mononuclear cells are then isolated using Ficoll-Paque gradient. To validate arginase as a marker of unfavorable grade of aGVHD, it is necessary to examine expression profile of ARG1 gene in neutrophils. Therefore, it is important to separate both mature and immature forms of neutrophils (using different method than Ficoll gradient), as well as examine gene expression profile of a down-regulated CD3ζ chain in T-cells. Down-regulation of CD3ζ chain is due to arginase-mediated depletion of arginine in the T-cell environment (Munder et al., 2006). We assume that ARG1 gene expression profile might have a potential to influence patients′ response to corticoid therapy of unfavorable grade of aGVHD. This study is in progress and further analyses will be focused on monitoring of ARG1 and CD3ζ chain expression levels in a larger cohort. Supported by IGA MZ CR NS9683-4/2008 and MSMT CR MSM0021622430. Disclosures: No relevant conflicts of interest to declare.

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Comparison of genomic and gene expression profile between cancer and healthy samples.

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.15_suppl.e13001 ◽

2017 ◽

Vol 35 (15_suppl) ◽

pp. e13001-e13001

Author(s):

Ioannis Papasotiriou ◽

Dimitrios Ntanovasilis ◽

Panagiotis Apostolou

Keyword(s):

Gene Expression ◽

Gene Expression Profile ◽

Expression Profile ◽

Mononuclear Cells ◽

Comparative Genomic ◽

Peripheral Blood Mononuclear ◽

Developmental Abnormalities ◽

Dna And Rna ◽

Significant Difference ◽

Expression Microarrays

e13001 Background: A variety of chromosomal aberrations underlie developmental abnormalities and cancer. Use of techniques such as microarrays provides an opportunity to perform gene expression analysis. A recent approach is the use of array based comparative genomic hybridization (aCGH) to detect genomic abnormalities in human tumors. The aim of this study is to compare genomic and gene expression profile between cancer patients and healthy individuals. Methods: DNA and RNA were isolated from peripheral blood mononuclear cells from 9 patients, with different types of cancer and 4 normal donors. aCGH (Agilent-60K) and gene expression microarrays (Microarrays Inc.-whole genome platform) were performed using commercial reference samples. Data were analyzed with Array-Pro analyzer and Cytogenomics software. Results: The aCGH data demonstrated the majority of gains and amplifications were observed in cancer samples, while the deletions and losses were higher in normal individuals. Among aberrations, common genes in both types of samples were detected. These genes included ACAD8, ACP1, B3GAT1, IDI1, IDI2, IGSF9B, IRX1, IRX2, JAM3, MYT1L, NTM, OPCML, PXDN, THYN1, TPO. However, there were abnormalities that included genes, which appeared only in cancer samples, like cadherins ( CDH11, CDH8 and CDH5) and EPHA5, while genes such as ACOX1, PTPRN2, TYMS and genes of zinc-finger proteins were observed only in normal samples. No statistical significant difference in gene expression, between cancer and normal samples, was observed. On the contrary, overexpression was observed in genes that were not detected in aCGH. Conclusions: Whereas it is acceptable that great achievements have been carried out in cancer field, the mechanism of tumorigenesis is not clear understood. The present study demonstrated that even though genomic aberrations exist, these are not always representative at gene expression level. However, the combination of both techniques could be used for more accurate and reliable data. This requires study in more samples including different cancer types so to be used at clinical level.

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