S1640 POLYMORPHISMS IN CYTOKINES, CHEMOKINES AND THEIR RECEPTORS GENES CONTRIBUTED TO CYTOMEGALOVIRUS REACTIVATION AFTER ALLOGENEIC STEM CELL TRANSPLANTATION

Abstract

Background: Cytomegalovirus (CMV) is the most common viral infection after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Without prophylaxis, 80% of CMV-seropositive patients experience CMV infection after allo-HSCT. Cytokines and chemokines are the first line of defence against viral infections and recent studies have shown that gene polymorphisms result in inter-individual differences in cytokine production. Aims: To determine the genotype of Cytokines and chemokines in the donor (D) and recipient (R) and their association with the CMV reactivation of patients receiving an allo-HSCT. Methods: Eighty-five patients who received allo-HSCT from an HLA-identical sibling donor from 2000 to 2015 were included. CMV DNAemia was evaluated until approximately day 100 after allo-HSCT. CMV reactivation was defined as the detection of CMV DNAemia ≥100 copies/ml in plasma. All of patients were classified according to epidemiological risk factors of clinical interest. Fifty genes were selected for their potential role in the pathogenesis of CMV: C-C Motif Chemokine Ligand (CCL) and Receptor (CCR), C-X-C Motif Chemokine Ligand (CXCL) and Receptor (CXCR), Forkhead Box P3 (FOXP3), CD48 Molecule (CD48), Interferon (IFN), Interleukin (IL), Killer Cell Immunoglobulin Like Receptor (KIR), Transforming Growth Factor Beta (TGFB), tumor necrosis factor alpha (TNF) and Lymphotoxin Alpha (LTA). Genomic DNA was purified from 170 PB (D and R) using Maxwell® RSC Blood DNA Kit (Promega, USA). Libraries were performed using an enrichment-capture gene panels according to the manufacturer's protocol. Paired-end 2x101 bp was performed using the Illumina HiSeq platform (Illumina, USA). Variants located in coding region, splicing sites and intronic polymorphisms were analyzed. Synonymous variants were excluded. During the variant calling process, the values of Depth, variant allele frequency (VAF) and the minor allele frequency (MAF) in European population are obtained and used to variants filtration (Depth ≥ 30, VAF ≥ 0.4 and MAF≥ 10%). Differences among groups were evaluated by Chi-Squared and Fischer Exact Test. Results: CMV reactivation was observed in 51/85 (60%) patients. Initial episodes of CMV DNAemia occurred at a median of 48 days (2–151) after transplant. Clinical variables are not associated with CMV reactivation: age, gender, stem cells, hematological disease, conditioning regimen, serology status and prior autologous transplant. Twenty-four patients (47.1%) had only one episode of CMV reactivation, 12 (23.5%) had two episodes and 15 (29.3%) had more than two episodes after allo-HSCT. Using filters discussing previously, 221 polymorphisms were detected in D and R. Although 209 variants studied had no apparent impact on the features of CMV reactivation, but we found that 12 variants in 7 different genes were associated significantly with the development or protection of CMV reactivation (Table 1). Our data showed that determined polymorphism in TNF-α, IL12A, TGBF2, IL1RN and CD48 play an important role to protection against CMV. On other hand, KIR3DL1 and CXCL12 represent examples of how receptor polymorphism can influence CMV development.Summary/Conclusion: The data presented suggest that screening of patients and donor pre-transplantation could help to predict the individual risk of the development of CMV infection. These results might also enable the identification of patients at high risk of CMV reactivation, enabling pre-emptive therapy or attempts to cure the infection by administrating antiviral therapy or CMV-specific T lymphocytes.