Association of IL-6 gene polymorphism with the outcome of allogeneic haematopoietic stem cell transplantation in Czech patients

Interleukin-10 GCC/GCC haplotype is associated high risk of acute GVHD in patients undergoing allogeneic HSCT in the southern of Brazil

INTRODUCTION

Hematopoietic Stem Cell Transplant (HSCT) is currently an important curative treatment for many patients with malignant and non-malignant diseases. Graft versus host disease (GVHD) represents a major complication in allogeneic HSCT recipients. Several polymorphisms in cytokine genes have recently been investigated as candidates for risk factors for acute-GVHD (aGVHD) in allogeneic hematopoietic stem cell transplantation (allo-HSCT).

OBJECTIVE

In this study, we analyzed specific interleukin (IL)-10 haplotypes polymorphisms, in a cohort of 99 patients and their respective allo-HSCT donors for aGVHD and risk.

RESULTS

An association was found between IL-10 promoter haplotype polymorphisms at positions -1082, -819 and - 592 with the occurrence of aGVHD. Patients who have the GCC/GCC haplotype are at increased risk of aGVHD (P = 0.017, HR: 5.42 (95% CI: 1.34-21.84). In the donors group and severity of aGVHD as not found statistical significancy.

CONCLUSION

The results obtained show the IL-10 GCC/GCC haplotype can be an important biomarker to identify the greatest risk of aGVHD in the patient undergoing HSCT.

Association of recipient and donor interleukin 6 polymorphisms 174 and 597 with outcome after allogeneic hematopoietic stem cell transplantation in children

Purpose

The success of allogeneic hematopoietic stem cell transplantation (HSCT) is compromised by complications such as infection, relapse, and graft-versus-host disease (GVHD). The investigation of non-HLA immunogenetics, particularly of cytokines, could identify predictors of an unfavorable outcome after allogeneic HSCT. In this study, we examined the impact of single nucleotide polymorphisms (SNPs) within the promoter region of interleukin 6 (IL6) on the development of GVHD after pediatric allogeneic HSCT.

Methods

In this retrospective analysis, we included 320 pediatric patients with a median age of 10 years who underwent an allogeneic HSCT and their respective donors. We used TaqMan real-time polymerase chain reaction to analyze the SNPs IL6-174 (G/C) and IL6-597 (G/A). The IL6-174 polymorphism was examined in 300 recipients and 295 donors. The IL6-597 polymorphism was analyzed in 299 recipients and 296 donors. We investigated the influence of the IL6-174 and IL6-597 polymorphisms on overall survival, event-free survival, relapse incidence, transplant-related mortality, and the occurrence of GVHD.

Results

G polymorphism at position 174 of the recipient IL6 gene was associated with a higher incidence of acute GVHD (GG vs. GC/CC; P = 0.024). Patients with IL6-597 GG genotype developed acute GVHD more frequently than individuals with an A allele (GG vs. GA vs. AA; P = 0.013). IL6-174 GG homozygous recipients had a more frequent occurrence of chronic GVHD (GG vs. GC/CC; P = 0.049). We observed a significant increased risk of chronic GVHD in recipients with IL6-597 GG genotype (GG vs. GA vs. AA; P = 0.043). Polymorphisms of donors did not affect the incidence of acute GVHD and chronic GVHD. In multivariate analysis, the IL6-174 and IL6-597 SNPs were independent significant risk factors for acute GVHD (P = 0.030; P = 0.007, respectively) as well as for chronic GVHD (P = 0.045; P = 0.015, respectively). In addition, older age at time of transplantation turned out to be a significant risk factor for chronic GVHD (P = 0.003).

Conclusion

Our study identified the IL6-174 and IL6-597 GG genotypes of pediatric allogeneic HSCT recipients as genetic risk factors for the development of acute GVHD and chronic GVHD. After evaluations in further studies, these findings could implicate the adjustment of prophylactic measures to reduce the occurrence of acute GVHD and chronic GVHD.

NFKB1 gene single-nucleotide polymorphisms: implications for graft-versus-host disease in allogeneic hematopoietic stem cell transplantation

Graft-versus-host disease (GVHD) represents a significant cause of mortality after allogeneic hematopoietic stem cell transplantation (HSCT). NF-kB system is a master regulator of innate immunity responses. It controls the expression of various cytokines and chemokines many of which are involved in GVHD pathogenesis. Chemo(radio) therapy administered during conditioning induces DNA damage and activates DNA damage response (DDR) signaling resulting in irreversible cell cycle arrest - cellular senescence which has been described to be associated with robust pro-inflammatory secretion mostly controlled by NF-kB. The NFKB1 gene encodes the DNA-binding subunit of the NF-kB complex. Using the candidate gene approach, we analyzed possible association of two single-nucleotide polymorphisms (SNPs) rs3774937 C/T and rs3774959 A/G of the NFKB1 gene with GVHD and transplant-related mortality (TRM) occurrence in 109 recipients allografted from HLA-identical donor. Both SNPs in recipients were found to be strongly associated with acute GVHD. Nevertheless, no significant association with chronic GVHD and TRM was found. Presented pilot results contribute to pre-clinical observations and suggest that NF-kB may be an important regulator of HSCT-related inflammatory reactions such as acute GVHD. Novel pathogenic mechanisms of GVHD may arise from perspectives of DDR and cellular senescence where NF-kB plays an essential role.

The effects of gene polymorphisms on susceptibility to acute GVHD and survival of allogeneic HSCT recipients: IL-10 gene polymorphisms as a more accessible target to predict prognosis

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a therapeutic modality commonly used to treat hematological and immunological disorders. Among the main complications of allo-HSCT is the acute graft-versus-host disease (a-GVHD), a condition which accounts for a high incidence of mortality. Several genes encoding inflammatory mediators may present polymorphisms, which have been implicated in the risk of developing a-GVHD. In our study, we investigated the association between genotypes of cytokine-encoding genes and the incidence and severity of a-GVHD and survival of HSCT recipients. No statistically significant association was found between IL and 6-174 G/C, INF-γ + 874 T/A, TNF-α -238 A/G, -308 A/G and IL-10-819C/T, -592 A/C polymorphisms and the presence or severity of a-GVHD. A higher risk of a-GVHD was associated with the IL-10-1082 GG genotype compared to the AA + AG genotypes of recipients and donors. The IL-10-1082 genotype can be used as a prognostic determinant to predict which HSCT recipient will be more responsive to the transplant. Thus, cytokine gene assays may be useful in the individualization of prophylactic regimens and for an appropriate selection of immunosuppressants based on the HSCT recipient's responsiveness.

Genetic Polymorphism in Cytokines and Costimulatory Molecules in Stem Cell and Solid Organ Transplantation

There is growing evidence supporting the genetic variability outside of HLA system that is contributing to the variation in transplant outcomes. Determining novel predictors could help to identify patients at risk and tailor their immunosuppressive regimens. This article discusses the various single nucleotide polymorphisms in costimulatory molecules and cytokines that have been evaluated for their effect on transplantation. An overview of how gene polymorphism studies are conducted and factors to consider in the experimental design to ensure meaningful data can be concluded are discussed.

Graft versus Host Disease: From Basic Pathogenic Principles to DNA Damage Response and Cellular Senescence

Graft versus host disease (GVHD), a severe immunogenic complication of allogeneic hematopoietic stem cell transplantation (HSCT), represents the most frequent cause of transplant-related mortality (TRM). Despite a huge progress in HSCT techniques and posttransplant care, GVHD remains a significant obstacle in successful HSCT outcome. This review presents a complex summary of GVHD pathogenesis with focus on references considering basic biological processes such as DNA damage response and cellular senescence.

Replication and validation of genetic polymorphisms associated with survival after allogeneic blood or marrow transplant

Multiple candidate gene-association studies of non-HLA single-nucleotide polymorphisms (SNPs) and outcomes after blood or marrow transplant (BMT) have been conducted. We identified 70 publications reporting 45 SNPs in 36 genes significantly associated with disease-related mortality, progression-free survival, transplant-related mortality, and/or overall survival after BMT. Replication and validation of these SNP associations were performed using DISCOVeRY-BMT (Determining the Influence of Susceptibility COnveying Variants Related to one-Year mortality after BMT), a well-powered genome-wide association study consisting of 2 cohorts, totaling 2888 BMT recipients with acute myeloid leukemia, acute lymphoblastic leukemia, or myelodysplastic syndrome, and their HLA-matched unrelated donors, reported to the Center for International Blood and Marrow Transplant Research. Gene-based tests were used to assess the aggregate effect of SNPs on outcome. None of the previously reported significant SNPs replicated at P < .05 in DISCOVeRY-BMT. Validation analyses showed association with one previously reported donor SNP at P < .05 and survival; more associations would be anticipated by chance alone. No gene-based tests were significant at P < .05. Functional annotation with publicly available data shows these candidate SNPs most likely do not have biochemical function; only 13% of candidate SNPs correlate with gene expression or are predicted to impact transcription factor binding. Of these, half do not impact the candidate gene of interest; the other half correlate with expression of multiple genes. These findings emphasize the peril of pursing candidate approaches and the importance of adequately powered tests of unbiased genome-wide associations with BMT clinical outcomes given the ultimate goal of improving patient outcomes.

Interleukin-6 in Allogeneic Stem Cell Transplantation: Its Possible Importance for Immunoregulation and As a Therapeutic Target

Allogeneic stem cell transplantation is associated with a high risk of treatment-related mortality mainly caused by infections and graft-versus-host disease (GVHD). GVHD is characterized by severe immune dysregulation and impaired regeneration of different tissues, i.e., epithelial barriers and the liver. The balance between pro- and anti-inflammatory cytokine influences the risk of GVHD. Interleukin-6 (IL-6) is a cytokine that previously has been associated with pro-inflammatory effects. However, more recent evidence from various autoimmune diseases (e.g., inflammatory bowel disease, rheumatoid arthritis) has shown that the IL-6 activity is more complex with important effects also on tissue homeostasis, regeneration, and metabolism. This review summarizes the current understanding of how pro-inflammatory IL-6 effects exerted during the peritransplant period shapes T-cell polarization with enhancement of Th17 differentiation and suppression of regulatory T cells, and in addition we also review and discuss the results from trials exploring non-selective IL-6 inhibition in prophylaxis and treatment of GVHD. Emerging evidence suggests that the molecular strategy for targeting of IL-6-initiated intracellular signaling is important for the effect on GVHD. It will therefore be important to further characterize the role of IL-6 in the pathogenesis of GVHD to clarify whether combined IL-6 inhibition of both trans- (i.e., binding of the soluble IL-6/IL-6 receptor complex to cell surface gp130) and cis-signaling (i.e., IL-6 ligation of the IL-6 receptor/gp130 complex) or selective inhibition of trans-signaling should be tried in the prophylaxis and/or treatment of GVHD in allotransplant patients.

Analysis of a Genetic Polymorphism in the Costimulatory Molecule TNFSF4 with Hematopoietic Stem Cell Transplant Outcomes

Despite stringent procedures to secure the best HLA matching between donors and recipients, life-threatening complications continue to occur after hematopoietic stem cell transplantation (HSCT). Studying single nucleotide polymorphism (SNP) in genes encoding costimulatory molecules could help identify patients at risk for post-HSCT complications. In a stepwise approach we selected SNPs in key costimulatory molecules including CD274, CD40, CD154, CD28, and TNFSF4 and systematically analyzed their association with post-HSCT outcomes. Our discovery cohort analysis of 1157 HLA-A, -B, -C, -DRB1, and -DQB1 matched cases found that patients with donors homozygous for the C variant of rs10912564 in TNFSF4 (48%) had better disease-free survival (P = .029) and overall survival (P = .009) with less treatment-related mortality (P = .006). Our data demonstrate the TNFSF4C variant had a higher affinity for the nuclear transcription factor Myb and increased percentage of TNFSF4-positive B cells after stimulation compared with CT or TT genotypes. However, these associations were not validated in a more recent cohort, potentially because of changes in standard of practice or absence of a true association. Given the discovery cohort, functional data, and importance of TNFSF4 in infection clearance, TNFSF4C may associate with outcomes and warrants future studies.

ATM gene single nucleotide polymorphisms predict regimen-related gastrointestinal toxicity in patients allografted after reduced conditioning

Polymorphisms of genes involved in innate and adaptive immunity have become an object of major interest in regard to hematopoietic stem cell transplantation (HSCT) complications. Regimen-related gastrointestinal toxicity (RR-GIT) is the dominant complication during the pre-engraftment period and has been linked to increased risk of graft-versus-host disease (GVHD) development. According to our hypothesis, functional variants of genes participating in DNA damage response (DDR) may have an impact on the extent of tissue damage caused by the conditioning regimen. In our single-center study, we analyzed 62 patients who underwent HSCT from HLA-identical donors after reduced conditioning. The patients were genotyped for 5 single nucleotide polymorphisms (SNPs, rs4585 T/G, rs189037 A/G, rs227092 T/G, rs228590 C/T, and rs664677 T/C) of the ATM gene-the essential member of the DDR pathways, using allele-specific matrix-assisted laser desorption/ionization, time-of-flight (MALDI-TOF) mass spectrometry assay. Because of almost absolute linkage disequilibrium observed among all 5 SNPs, association of 2 major ATM haplotypes (ATM1/ATM2) with RR-GIT and acute GVHD (aGVHD) was analyzed. Importantly, the univariate and multivariate analysis showed that patients homozygous for ATM2 haplotype (rs4585*T, rs189037*A, rs227092*T, rs228590*C, and rs664677*T) are more likely to suffer from high-grade RR-GIT than ATM1 homozygous patients. The association with aGVHD was not significant. To our knowledge, this is the first report showing the ATM gene variability in relation to RR-GIT in the allogeneic HSCT setting.

A meta-analysis of the effects of interleukin-6 -174 G>C genetic polymorphism on acute graft-versus-host disease susceptibility

BACKGROUND

The interleukin-6 (IL-6) -174 G>C genetic polymorphism has been implicated to play an important role in acute graft-versus-host disease (aGVHD). However, previous studies have yielded inconclusive results as to its role in patient susceptibility to aGVHD, and no study to date has systematically analyzed this polymorphism.

OBJECTIVE

A meta-analysis of the published evidence was conducted to estimate the true effect of the IL-6 -174 G>C genetic polymorphism in allogeneic hematopoietic stem cell transplantation (alloHSCT) patients and donors on the risk of aGVHD.

METHODS

Seven cohort studies, comprising 1287 recipient and donor pairs, were included after eliminating 62 studies that met the following exclusion criteria: irrelevant studies other than cohort studies, without sufficient data, and with overlapping data. Although interstudy heterogeneity existed, most studies were conducted in the United States or Europe and included adult patients with hematologic disease who received alloHSCT from human leukocyte antigen-matched or identical sibling donors. The effect of the polymorphism on aGVHD risk (grades I-IV, II-IV, and III-IV) was estimated from odds ratios with 95% confidence intervals for the dominant genetic model and recessive model, respectively.

RESULTS

Patients who received grafts from donors with the IL-6 G allele experienced more frequent grade I-IV aGVHD (odds ratio = 3.304 [95% confidence interval, 1.456-7.494]) and grade II-IV aGVHD (odds ratio = 1.738 [95% CI, 1.006 - 3.001]).

CONCLUSIONS

To our knowledge, this is the first meta-analysis to evaluate the relation between a non-human leukocyte antigen gene polymorphism and the risk of aGVHD. Our meta-analysis combined the results of several studies and demonstrated that the donor IL-6 G allele is associated with an increased risk of grades I-IV and II-IV aGVHD.

Role of IL6 –174C/G gene polymorphism in development of chronic HCV infection

In the investigation it has been estimated the functional importance of gene interleukin 6 (IL6) polymorphism in progressing the chronic hepatitis C virus (HCV) infection. It has been determined the analysis of polymorphism –174 C/G frequency in gene IL6 promote zone at healthy donors and patients with chronic HCV-infection who are the Caucasian representatives of Tomsk region. The genotype GG carriers definitely dominated at patients with high activity rate of inflammatory process: it shows that G allele carriership have an impact on aggravation of inflammatory process activity in the liver patients with HCV-infections. In contrast to, carriership of C/G and C/C genotypes of polymorphism –174 C/G of gene IL6 have met more often at patients with minimal and moderate degree of inflammatory process.

Immunoregulatory gene polymorphisms and graft-versus-host disease

Graft-versus-host disease (GVHD) remains a significant complication that greatly enhances morbidity and mortality associated with hematopoietic stem cell transplantation. Key immunoregulatory molecules have been implicated in the pathogenesis of GVHD, but the mechanisms by which these molecules affect the incidence and severity of GVHD have not been fully elucidated. The effects of genetic polymorphisms in immunoregulatory molecules, including cytokines, costimulatory and adhesion molecules, pharmacogenes and growth factors, have been shown to play a central role in GVHD. The results of these polymorphism studies contribute to the identification of predictive risk factors for GVHD based on individual polymorphism makeup. This review summarizes investigations of genetic polymorphisms in immunoregulatory molecules significantly associated with GVHD over the last 5 years.