Cytotoxic T-lymphocyte antigen 4 haplotype correlates with relapse and survival after allogeneic hematopoietic SCT

Genetic Polymorphisms of Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) and clinical outcomes post-allogeneic hematopoietic stem cell transplantation: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Although HLA matching is considered as a key genetic predictor of allo-HSCT outcomes, genetic polymorphisms in non-HLA genes, especially in genes encoding immunoregulatory proteins, have also been proposed as additional risk factors linked to the occurrence of transplant complications. This study aimed to carry out a systematic review and meta-analysis from all eligible cohort studies to determine the effect of CTLA-4 gene polymorphisms, including rs231775, rs3087243, rs4553808, rs5742909, and rs733618, on clinical outcomes in patients receiving an allo-HSCT.

METHODS

A systematic literature search in PubMed, Web of Science, and Scopus was performed to identify the relevant studies, and related information was extracted. The effect size (ES) and corresponding 95% confidence intervals (CIs) were calculated to estimate the association.

RESULTS

16 studies were eligible and included in the meta-analysis. The pooled results showed that only the dominant models of rs3087243 were significantly associated with chronic GVHD (cGVHD), while other SNPs were not significantly associated with overall survival, disease-free survival, relapse, and GVHD.

CONCLUSIONS

Our study represents, for the first time, a comprehensive meta-analysis on the role of CTLA-4 polymorphisms on outcomes after allo-HSCT. The results indicate that the CT60 CTLA-4 polymorphism could be a significant risk factor for cGVHD.

The Role of CTLA4 and Its Polymorphisms in Solid Organ and Haematopoietic Stem Cell Transplantation

HLA matching, transplantation technique, or underlying disease greatly influences the probability of long-term transplantation success. It has been hypothesised that genetic variation affecting antigen presentation also contributes to the outcomes of both solid organ transplantation and allogeneic haematopoietic stem cell transplantation (AHSCT). Those genes, along with those responsible for innate and adaptive immunity, have become targets of investigation. In this review, we focus on the role of CTLA4 in the process of acute graft rejection and summarise the progress in our understanding of its role in predicting the outcome. We present the results of the latest studies investigating the link between CTLA4 gene variability and AHSCT, as well as organ transplantation outcomes. While some studies found a link between +49 A/G and −318 C/T and transplantation outcomes, comprehensive meta-analyses have failed to present any association. The most recent field reviews suggest that the −1772 T/C (rs733618) CC genotype is weakly associated with a lower risk of acute graft rejection, while +49 A/G might be clinically meaningful when investigated in the context of combinations with other polymorphisms. Studies verifying associations between 12 CTLA4 gene SNPs and AHSCT outcomes present inexplicit results. Some of the most commonly studied polymorphisms in this context include +49 A/G (rs231775) and CT60 A/G (rs3087243). The results signify that, in order to understand the role of CTLA4 and its gene polymorphisms in transplantology, further studies must be conducted.

Umbilical cord blood transplantation and the impact of the CTLA4 genotype on outcomes

Background: Umbilical cord blood transplantation is an effective method of curing multiple diseases when there is no donor available for allogeneic hematopoietic stem cell transplantation (AHSCT). It has been recently suggested that polymorphisms in genes affecting antigen presentation could potentially affect cord blood transplantation (CBT) outcomes.Areas covered: In this review, we present the results of the latest studies investigating the link between CTLA4 gene variability and umbilical cord blood transplantation outcomes.Expert opinion: The search for genetic variants that influence the immune response, both innate and adaptive immunity, may lead to more optimal therapies. Promising candidate genes are those that regulate the expression of proteins associated with T-cell activation. Many genetic variants could be therapeutically important, including those related to innate and adaptive immunity, cytokines, chemokines, drug-metabolizing enzymes, drug transporters, and inflammatory enzymes. The development of an algorithm that includes the determination of selected genetic variants could be helpful for an appropriate donor-recipient CBT matching.

Donor single nucleotide polymorphism in ACAT1 affects the incidence of graft-versus-host disease after bone marrow transplantation

Acyl-coenzyme A: cholesterol acyltransferase 1 (ACAT1) is an enzyme that converts cholesterol to cholesteryl esters. A recent in vivo study reported that inhibiting ACAT1 enzyme activity upregulates the membrane cholesterol levels of T cells, enhancing their cytotoxic function. In the present study, we investigated whether the presence of the ACAT1 single nucleotide polymorphism rs11545566 in transplant donors affected the risk of graft-versus-host disease (GVHD) in 116 adult patients who underwent bone marrow transplantation from human leukocyte antigen-identical sibling donors, and who received GVHD prophylaxis with short-term methotrexate and cyclosporine. The frequencies of the AA, AG, and GG genotypes in the donors were 31%, 45%, and 24%, respectively. The cumulative incidences of grade II-IV acute GVHD on day 100 in patients whose donors had AA vs. non-AA genotypes were 6% and 18%, respectively, and those of extensive chronic GVHD at 2 years were 7% and 32%, respectively. Multivariate analyses demonstrated that donor rs11545566 non-AA genotypes showed a trend toward a higher incidence of grade II-IV acute GVHD (P = 0.079), and were significantly associated with a higher incidence of extensive chronic GVHD (P = 0.021). These results suggest that donor ACAT1 rs11545566 genotype may be predictive of GVHD.

miR-145 Antagonizes SNAI1-Mediated Stemness and Radiation Resistance in Colorectal Cancer

Epithelial-to-mesenchymal transition (EMT) has been closely linked with therapy resistance and cancer stem cells (CSCs). However, EMT pathways have proven challenging to therapeutically target. MicroRNA 145 (miR-145) targets multiple stem cell transcription factors and its expression is inversely correlated with EMT. Therefore, we hypothesized that miR-145 represents a therapeutic target to reverse snail family transcriptional repressor 1 (SNAI1)-mediated stemness and radiation resistance (RT). Stable expression of SNAI1 in DLD1 and HCT116 cells (DLD1-SNAI1; HCT116-SNAI1) increased expression of Nanog and decreased miR-145 expression compared to control cells. Using a miR-145 luciferase reporter assay, we determined that ectopic SNAI1 expression significantly repressed the miR-145 promoter. DLD1-SNAI1 and HCT116-SNAI1 cells demonstrated decreased RT sensitivity and, conversely, miR-145 replacement significantly enhanced RT sensitivity. Of the five parental colon cancer cell lines, SW620 cells demonstrated relatively high endogenous SNAI1 and low miR-145 levels. In the SW620 cells, miR-145 replacement decreased CSC-related transcription factor expression, spheroid formation, and radiation resistance. In rectal cancer patient-derived xenografts, CSC identified by EpCAM+/aldehyde dehydrogenase (ALDH)+ demonstrated high expression of SNAI1, c-Myc, and Nanog compared with non-CSCs (EpCAM+/ALDH-). Conversely, patient-derived CSCs demonstrated low miR-145 expression levels relative to non-CSCs. These results suggest that the SNAI1:miR-145 pathway represents a novel therapeutic target in colorectal cancer to overcome RT resistance.

CTLA-4 polymorphisms: influence on transplant-related mortality and survival in children undergoing allogeneic hematopoietic stem cell transplantation

PURPOSE

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative approach for a variety of hematological diseases; however, it is still associated with substantial morbidity and mortality. Transplant-related mortality (TRM) after HSCT depends mainly on the toxicity of the conditioning regimen, infections, and graft-versus-host disease. The purpose of this study was to identify the association between CTLA-4 single nucleotide polymorphisms and TRM in children undergoing allogeneic HSCT.

METHODS

153 donors and 153 children with acute lymphoblastic leukemia, acute myeloid leukemia or juvenile myelomonocytic leukemia who had undergone allogeneic HSCT were genotyped of CTLA-4 gene for rs3087243 (CT60G>A), rs231775 (+ 49 A>G) and rs4553808 using TaqMan real-time polymerase chain reaction.

RESULTS

We observed a significant association between the donor's CLTA-4 genotype of rs3087243 and TRM in children undergoing allogeneic HSCT. Genotype AG was found in 78 donors (51%), GG in 44 donors (29%) and 31 donors (20%) were homozygous for AA. 30 patients died as a result of transplant-related causes. Interestingly, we observed a significantly reduced TRM in children who were transplanted from a donor with the CTLA-4 genotype GG in comparison to genotype AG or AA (9 versus 19 versus 36%, P = 0.013). In addition, we found significant differences of event-free survival (EFS) depending on the donor's genotype. The EFS was 64, 46 or 32% if the patient was transplanted from a donor with CTLA-4 genotype GG, AG or AA, respectively (P = 0.043). In multivariate analysis, CTLA-4 genotype of rs3087243 was an independent risk factor for TRM (P = 0.011) and EFS (P = 0.035).

CONCLUSION

This study provides first evidence that the CTLA-4 polymorphisms are significant risk factors for TRM and survival in children undergoing allogeneic HSCT and should be evaluated in further trials.

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.

CTLA-4 polymorphisms and haplotype correlate with survival in ALL after allogeneic stem cell transplantation from related HLA-haplotype-mismatched donor

Background

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been established as an effective treatment for patients with hematological malignancies. Disease relapse remains a major cause of transplant failure. T cell homeostasis is critical to determine the potency of the GVT effect. Recent studies have shown the association of the CTLA-4 polymorphisms with the outcome after HLA-identical sibling allogeneic HSCT.

Methods

In this study, we focused on four CTLA-4 polymorphisms, and analyzed the impact of donor genotypes and haplotypes on the conditions of 152 acute leukemia patients (ALL 83) after related HLA-haplotype- mismatched transplantation. The four SNP genotypes (−1661, −318, CT60 and +49) were determined by TaqMan SNP genotyping assays.

Results

ALL recipients of donors with +49 GG showed significantly lower OS (67.7 vs. 90.3 %, P = 0.015) than those with GA+AA. Multivariate analyses showed that +49 GG was an independent risk factor for OS (HR: 0.306, 95 % CI 0.111–0.842, P = 0.022) .23 ALL patients receiving mDLI showed significantly lower OS with +49 GG donor than those with GA+AA (30.0 vs. 83.1 %, P = 0.003). The haplotype analysis revealed only three haplotypes in the donor population −1661/−318/CT60/+49 i.e., ACGG, ACAA and GTGA, the frequencies were 64.1, 19.4 and 16.5 %, respectively. Donors with and without the ACGG/ACGG haplotype had the same effect on transplant outcomes as those with +49 GG and +49 GA+AA.

Conclusion

In summary, the CTLA-4 +49 GG and the haplotype ACGG/ACGG reduced the overall survival in ALL after allo-HSCT from the related HLA-haplotype-mismatched donor, knowledge of the CTLA-4 polymorphism and haplotype may provide useful information for donor selection and individual application of immunosuppressive agents and immunotherapy.

CTLA-4 polymorphism and clinical outcome post allogeneic hematopoietic stem cell transplantation

CTLA-4 inhibitory molecule plays an important role in regulating T cell activation. It is considered a crucial element in keeping the immune balance and has been implicated in cancer, autoimmunity and transplantation immunology. Inconsistent observations are reported regarding its association with hematopoietic stem cell transplantation (HSCT). Genotyping of CTLA-4 was performed in recipients and their HLA-matched donors for +49A/G and CT60 polymorphisms (80 and 94 pairs, respectively) using PCR-RFLP. No association was encountered between both polymorphisms in patients and donors and acute or chronic graft versus host disease. Significant association was observed between recipient +49A/G G allele and lower disease-free survival and overall survival compared to AA genotype (HR: 2.17, p = 0.03, 95% CI: 1.05-4.48 and HR: 2.54, p = 0.01, 95% CI: 1.16-5.54), respectively. Our results suggest that CTLA-4 genotyping may predict outcome in patients post HSCT. To validate our results, further studies on a larger cohort are needed.

Genetic variations in T-cell activation and effector pathways modulate alloimmune responses after allogeneic hematopoietic stem cell transplantation in patients with hematologic malignancies

BACKGROUND

Recently, several important polymorphisms have been identified in T-cell activation and effector pathway genes and have been reported to be associated with inter-patient variability in alloimmune responses. The present study was designed to assess the impact of these genetic variations on the outcomes of allogeneic hematopoietic stem cell transplantation.

DESIGN AND METHODS

We first investigated ten single nucleotide polymorphisms in six genes, CD28, inducible co-stimulator, cytotoxic T-lymphocyte antigen 4, granzyme B, Fas and Fas ligand, in 138 pairs of patients and their unrelated donors and a second cohort of 102 pairs of patients and their HLA-identical sibling donors.

RESULTS

We observed that patients receiving stem cells from a donor with the cytotoxic T-lymphocyte antigen 4 gene CT60 variant allele (AA genotype) had a reduced incidence of grades II-IV acute graft-versus-host disease; however, they experienced early cytomegalovirus infection and relapsed more frequently, which suggested an interaction between the donor cytotoxic T-lymphocyte antigen 4 gene CT60 AA genotype and reduced T-cell alloreactivity. Furthermore, an unrelated donor with the granzyme B +55 variant genotype (AA) was an independent risk factor for development of grades II-IV acute graft-versus-host disease (P=0.024, RR=1.811). Among patients with acute myelogenous leukemia, those with the Fas -670 TT genotype were at higher risk of relapse (P=0.003, RR=3.823). The presence of these susceptible alleles in the donor and/or patient resulted in worse overall survival (54.9% versus 69.5%, P=0.029).

CONCLUSIONS

Our data suggest that genotype analysis of T-cell activation and effector pathway genes can be used for risk assessment for patients with hematologic malignancies before hematopoietic stem cell transplantation.

Single nucleotide polymorphisms and outcome risk in unrelated mismatched hematopoietic stem cell transplantation: an exploration study

Genetic risk factors contribute to adverse outcome of hematopoietic stem cell transplantation (HSCT). Mismatching of the HLA complex most strongly determines outcomes, whereas non-HLA genetic polymorphisms are also having an impact. Although the majority of HSCTs are mismatched, only few studies have investigated the effects of non-HLA polymorphisms in the unrelated HSCT and HLA-mismatched setting. To understand these effects, we genotyped 41 previously studied single nucleotide polymorphisms (SNPs) in 2 independent, large cohorts of HSCT donor-recipient pairs (n = 460 and 462 pairs) from a homogeneous genetic background. The study population was chosen to pragmatically represent a large clinically homogeneous group (acute leukemia), allowing all degrees of HLA matching. The TNF-1031 donor-recipient genotype mismatch association with acute GVHD grade 4 was the only consistent association identified. Analysis of a subgroup of higher HLA matching showed consistent associations of the recipient IL2-330 GT genotype with risk of chronic GVHD, and the donor CTLA4-CT60 GG genotype with protection from acute GVHD. These associations are strong candidates for prediction of risk in a clinical setting. This study shows that non-HLA gene polymorphisms are of relevance for predicting HSCT outcome, even for HLA mismatched transplants.