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

Single-Nucleotide Polymorphisms Within Non-HLA Regions Are Associated With Engraftment Effectiveness for Patients With Unrelated Cord Blood Transplantation

Clinically, stem cells with matched human leukocyte antigens (HLAs) must be selected for allogeneic transplantation to avoid graft rejection. However, adverse reactions still occur after cord blood transplantation (CBT). It was inferred that the HLA system is not the only regulatory factor that may influence CBT outcomes. Therefore, we plan to investigate whether the single-nucleotide polymorphisms (SNPs) located in non-HLA genes are associated with the effectiveness of CBT. In this study, the samples of 65 donors from CBT cases were collected for testing. DNA sequencing was focused on the SNPs of non-HLA genes, cytotoxic T-lymphocyte-associated protein 4 (CTLA4), CD28, tumor necrosis factor ligand superfamily 4 (TNFSF4), and programmed cell death protein 1 (PDCD1), which were selected in regard to the literatures published in 2017 and 2018, which indicated that they were related to stem cell transplantation. Then, in combination with the detailed follow-up transplantation tracking database, these SNPs were analyzed with the risk of mortality, relapse, cytomegalovirus (CMV) infection, and graft-versus-host disease (GVHD). We found that there were 2 SNPs of CTLA4, 1 SNP of TNFSF4, and 2 SNPs of PDCD1 associated with the effectiveness of unrelated CBT. These statistically significant SNPs and haplotypes would be used in clinical to choose the best donor for the patient receiving CBT. Moreover, the polygenic risk scores (PRSs) with these SNPs could be used to predict the risk of CBT adverse reactions with an area under the receiver operating characteristic curve (AUC) of 0.7692. Furthermore, these SNPs were associated with several immune-related diseases or cancer susceptibility, which implied that SNPs play an important role in immune regulation.

Post-hematopoietic stem cell transplantation relapse: Role of checkpoint inhibitors

Background and Aims

Despite the revolutionary effects of hematopoietic stem cell transplantation (HSCT) in treating hematological malignancies, post-HSCT relapse is considered a critical concern of clinicians. Residual malignant cells employ many mechanisms to evade immune surveillance and survive to cause relapse after transplantation. One of the immune-frustrating mechanisms through which malignant cells can compromise the antitumor effects is misusing the self-limiting system of immune response by overexpressing inhibitory molecules to interact with the immune cells, leading them to so-called "exhausted" and ineffective. Introduction of these molecules, known as immune checkpoints, and blocking them was a prodigious step to decrease the relapses.

Methods

Using keywords nivolumab, pembrolizumab, and ipilimumab, we investigated the literature to figure out the role of the immune checkpoints in the HSCT setting. Studies in which these agents were administrated for relapse after transplantation were reviewed. Factors such as the interval from the transplant to relapse, previous treatment history, adverse events, and the patients' outcome were extracted.

Results

Here we provided a mini-review discussing the experiences of three immune checkpoints, including nivolumab, pembrolizumab, and ipilimumab, as well as the pros and cons of using their blockers in relapse control after HSCT. In conclusion, it seems that CI therapy seems effective for this population. Future investigations may provide detailed outlook of this curative options.

CTLA-4 polymorphism contributes to the genetic susceptibility of epithelial ovarian cancer

AIM

Cytotoxic T-lymphocyte antigen-4 (CTLA-4), an inhibitory molecule on T-cells, plays a key role in tumorigenesis and progression. In the present study, we investigated the effects of three polymorphisms in the CTLA-4 gene on the risk of epithelial ovarian cancer and the clinical outcomes of patients.

METHODS

A case-control study was performed in 527 epithelial ovarian cancer patients and 532 controls. Genotypes of three polymorphisms were determined by polymerase chain reaction/ligase detection reaction. A survival analysis was performed in 346 patients who were followed up for more than 3 years and 208 patients who were followed up for more than 5 years.

RESULTS

There were significant differences in the genotype and allele distribution frequencies of the rs5742909 C/T polymorphism in CTLA-4 between patients and controls (p = 0.009 and p = 0.04, respectively). Compared with the CC genotype, the CT + TT genotype may significantly decrease the risk of developing epithelial ovarian cancer (OR = 0.69, 95% CI = 0.52-0.91). However, no significant association between the rs231775 G/A and rs3087243 G/A polymorphisms and epithelial ovarian cancer risk was observed. The survival analysis showed that three polymorphisms may not be related to the clinical outcomes of patients.

CONCLUSION

Our results suggested that the rs5742909 C/T polymorphism of CTLA-4 may decrease the genetic susceptibility to epithelial ovarian cancer among northern Chinese women.

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.

Analysis of Relationships between Immune Checkpoint and Methylase Gene Polymorphisms and Outcomes after Unrelated Bone Marrow Transplantation

Simple Summary

Hematopoietic stem-cell transplantation (HSCT) is a curative therapy for blood disorders. Unrelated bone marrow transplantation (uBMT) is a type of allogeneic HSCT that uses the bone marrow of an unrelated donor. While HLA mismatch is a risk factor for poor outcomes in HSCT, such as graft-versus-host disease (GVHD), the importance of non-HLA single-nucleotide polymorphisms (SNPs) remains unclear. The clinical application of immune checkpoint and chromatin methylation inhibitors to cancer has been attracting attention. In the present study, we retrospectively genotyped five SNPs in four immune checkpoint genes, BTLA, PD-1, LAG3, and CTLA4, and two SNPs in methylase genes, DNMT1 and EZH2, in 999 uBMT pairs. Although no correlations were observed between these SNPs and post-uBMT outcomes, recipient EZH2 SNP exhibited a low p-value in the analysis of grade 2–4 acute GVHD (p = 0.010). This SNP may be useful for outcome predictions and needs to be confirmed in a larger-scale study.

Abstract

Unrelated bone marrow transplantation (uBMT) is performed to treat blood disorders, and it uses bone marrow from an unrelated donor as the transplant source. Although the importance of HLA matching in uBMT has been established, that of other genetic factors, such as single-nucleotide polymorphisms (SNPs), remains unclear. The application of immunoinhibitory receptors as anticancer drugs has recently been attracting attention. This prompted us to examine the importance of immunoinhibitory receptor SNPs in uBMT. We retrospectively genotyped five single-nucleotide polymorphisms (SNPs) in the immune checkpoint genes, BTLA, PD-1, LAG3, and CTLA4, and two SNPs in the methylase genes, DNMT1 and EZH2, in 999 uBMT donor–recipient pairs coordinated through the Japan Marrow Donor Program matched at least at HLA-A, -B, and -DRB1. No correlations were observed between these SNPs and post-uBMT outcomes (p > 0.005). This result questions the usefulness of these immune checkpoint gene polymorphisms for predicting post-BMT outcomes. However, the recipient EZH2 histone methyltransferase gene SNP, which encodes the D185H substitution, exhibited a low p-value in regression analysis of grade 2–4 acute graft-versus-host disease (p = 0.010). Due to a low minor allele frequency, this SNP warrants further investigation in a larger-scale study.

Association of cytotoxic T-lymphocyte antigen-4 (CTLA-4) single nucleotide polymorphism in donors with clinical outcome after allogeneic hematopoietic stem cell transplantation: a meta-analysis

OBJECTIVE

Cytotoxic T-lymphocyte antigen 4 (CTLA-4) polymorphisms at positions of +49 and CT60 in donors have been reported to influence clinical outcome following allogeneic hematopoietic stem cell transplantation (allo-HSCT), such as overall survival (OS), disease free survival (DFS), relapse and the risk of graft versus host disease (GVHD). However, the results still remain controversial. Thus, we conducted the first meta-analysis to get a more accurate estimation of the relationship between CTLA-4 genotype and the above end points.

METHODS

PubMed, Embase, Web of science and Cochrane Library were searched to select eligible studies, data were extracted and then combined ORs/HRs together with the corresponding 95% confidence intervals (CIs) were calculated. Both the dominant and recessive models were employed to evaluate the associations between genetic variation in donor CTLA-4 and outcome after allo-HSCT.

RESULTS

A total of 15 studies were included the pooled results indicated that +49 GG homozygote in donors was significantly associated with increased risk of chronic GVHD (OR=1.701, 95% CI, 1.124-2.573, P=0.012, I²=34.7%). With regard to CT60 polymorphism, donors with G allele correlated with worse OS (HR = 1.422, 95% CI, 1.080-1.872, P=0.012, I²=0%) and lower susceptibility to severe acute GVHD (HR=0.619, 95% CI, 0.426-0.899, P=0.012, I²=0%). There was no significant association between CTLA-4 polymorphism and DFS or the incidence of relapse.

CONCLUSIONS

The present meta-analysis suggests that donors with CT60 G allele might be associated with worse OS but reduced severe aGVHD occurrence, while patients transplanted from donors with GG genotype at position of +49 are more likely to suffer from 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.

Single nucleotide polymorphisms within HLA region are associated with disease relapse for patients with unrelated cord blood transplantation

Disease relapse occurs in unrelated cord blood transplantation (CBT) even when the alleles of human leukocyte antigen (HLA) are fully matched between donor and recipient. This is similar to that observed in other types of hematopoietic stem cell transplantation. Fourteen single nucleotide polymorphisms (SNPs) within the HLA region have been reported previously by Petersdorf et al. and Piras et al. as transplantation determinants in unrelated hematopoietic cell transplantation. In this study, the genomic sequences within 500 base pairs upstream and downstream of the fourteen transplantation-related SNPs from 53 patients and their HLA-matched unrelated donors were analyzed for determining whether or not genetic variants, conferred by either recipient or donor SNP genotype or by recipient-donor SNP mismatching, were associated with the risk of relapse. Seven SNPs were associated with the risk of relapse in unrelated CBT. These included the donor genotype with the SNPs of rs2523675 and rs2518028 at the telomeric end of HCP5 gene, rs2071479 in the intron of the HLA-DOB gene, and rs2523958 in the MICD gene; and the recipient genotype with SNPs of rs9276982 in the HLA-DOA gene, and rs435766 and rs380924 in the MICD gene. As measured by pair-wise linkage disequilibrium (LD) with D′ as the parameter for normalized standard measurement of LD which compares the observed and expected frequencies of one haplotype comprised by alleles at different loci, rs2523675 had high LD with rs4713466 (D′ = 0.86) and rs2523676 (D′ = 0.91) in the HCP5 gene. The rs2518028 had no LD with all other SNPs except rs2523675 (D′ = 0.76). This study provides the basis for developing a method or algorithm for selecting better unrelated CBT candidate donors.

Biomarkers for checkpoint inhibition in hematologic malignancies

In the past few years we have seen remarkable paradigm shifts in the treatment of many solid tumors due to the introduction of inhibitors targeting immune checkpoints such as PD-1/PD-L1 and CTLA-4. Recent results indicate that checkpoint inhibition also represents a very promising approach for certain types of hematologic malignancies. Unfortunately, treatment with checkpoint inhibitors is also associated with substantial toxicities and high costs and only a subset of patients appears to derive clinical benefit from these treatments. This demonstrates the urgent need for biomarkers for the identification of patient populations that are likely to respond to this type of therapy and/or have fewer side effects. Here, we have reviewed available information on the prognostic and predictive value of biomarkers for anti-CTLA-4 and anti-PD-1/PD-L1 as the most commonly used checkpoint inhibitors. There are currently no reliable biomarkers capable of predicting responses to anti-CTLA-4 agents, such as ipilimumab, in hematologic malignancies. Certain polymorphisms in the CTLA-4 gene, however, seem to have an impact on the patients' outcome, especially in the case of chronic lymphocytic leukemia (CLL). There is now sufficient data supporting PD-L1 expression levels in the tumor tissue as an independent prognostic factor in B cell lymphomas such as diffuse large B-cell lymphoma (DLBCL). Overexpression of PD-L1 in the tumor tissue and elevated serum levels of soluble PD-L1 may also represent adverse prognostic factors in certain subtypes of T cell lymphomas. Finally, expression levels of PD-L1 also seem to predict responses to anti-PD-1/PD-L1 approaches in patients with Hodgkin lymphoma. Future studies will have to further delineate the prognostic/predictive role of PD-L1 expression as a biomarker in hematologic malignancies and may be able to identify confounding variables, which will hopefully to some extent be generalizable to other types of anti-tumor immunotherapies.

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.