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

Higher relapse and worse overall survival in recipients with CTLA-4 AA genotype of rs231775 following single-unit cord blood transplantation in adults

We retrospectively investigated the impact of CTLA-4 polymorphism on outcomes for adult patients who received single-unit cord blood transplantation (CBT) at our institution. CTLA-4 genotyping was performed using real-time polymerase chain reaction with the TaqMan® SNP genotyping assay for rs231775. This study included 143 recipient-donor pairs. The multivariate analysis showed that recipient rs231775 AA was associated with worse overall survival (OS) (hazard ratio [HR], 2.92; p = 0.008) and a higher relapse rate (HR, 4.79; p = 0.002), but donor rs231775 was not. The rs231775 polymorphism in recipients and donors did not affect non-relapse mortality, hematopoietic recovery, or acute and chronic graft-versus-host disease. The beneficial effects of rs231775 GG+GA recipients on OS and relapse were notable in subgroups of patients with high-risk disease status and those with myeloid diseases. The polymorphism of CTLA-4 rs231775in recipients might be associated with the clinical outcomes of single-unit CBT.

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.

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.

Incidence, risk factors and outcome of extramedullary relapse after allogeneic hematopoietic stem cell transplantation in patients with adult acute lymphoblastic leukemia

Extramedullary relapse (EMR) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) continues to remain a clinical challenge. The data on EMR in acute lymphoblastic leukemia (ALL) are currently limited. Herein, a retrospective analysis of 268 adult ALL patients who underwent allo-HSCT in our center between March 2008 and December 2017 was performed to analyze post-HSCT EMR. Ninety patients (33.58%) experienced relapse; 51(19.03%) experienced bone marrow relapse (BMR), whereas 39 (14.55%) experienced EMR. The 5-year cumulative EMR incidence (CEMRI) revealed that matched sibling donor (MSD)-HSCTs were more likely to develop EMR than unrelated donor (URD)- and haploidentical-related donor (HRD)-HSCTs (CEMRI: 24.02%, 7.69%, and 14.69% for MSD, URD, and HRD, respectively). Notably, MSD-HSCTs (URD vs MSD hazard ratio (HR) = 0.26, p = 0.015; HRD vs MSD HR = 0.46, p = 0.032), history of extramedullary disease (EMD) (HR = 2.45, p = 0.041), and T cell ALL (HR = 2.80, p = 0.012) were independent risk factors for EMR in the multivariate analysis. The median overall survival (OS) for all patients was 15.23 months. However, the OS of EMR patients was significantly longer (19.50 months) than that of BMR patients (12.90 months) (p = 0.003). Multivariate analyses revealed that the leading risk factors for post-relapse deaths were shorter intervals between HSCT and relapse (> 12 months vs ≤ 12 months, HR = 0.30, p < 0.001) and BMR (HR = 0.41, p = 0.002). In conclusion, EMR patients have better survival than BMR patients. ALL patients with allo-HSCT from MSDs, a history of EMD, and the T cell type were significantly associated with EMR.

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.

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.

TNFα Variation During the Menstrual Cycle and Thereafter: A New Explanation for Gender-Based Disparities in ICU Admission Rates, Trauma Outcomes, and General Mortality

BACKGROUND

Multiple studies have found gender-based disparities in intensive care unit (ICU) admission rates and in complications following trauma. Female gender was associated with lower mortality when comparing patients less than 50 years of age. These data suggest an important role for cycle rather than gender itself. Our previous results indicate a crucial role for tumor necrosis factor alpha (TNFα) in inducing nososocomial infections.

HYPOTHESIS

Cycle is important for TNF and other female hormone productions.

METHODS

Six older than 60 years old volunteers in both genders, 40 young female volunteers (no contraceptive drug, n = 18, contraceptive drug, n = 9, lactation, n = 9, pregnant, n = 4) were collected with following exclusion criteria, malignant disease, inflammation, infection, trauma and taking non-steroid anti-inflammatory drugs and antibiotics. Females were studied on days 1 and 14 of cycle. Serum TNFα was determined by HS TNF ELISA. Female hormones were also determined.

RESULTS

Serum TNFα, estradiol, and progesterone individual values in volunteers with cycle (no contraceptive drug) demonstrate marked interindividual differences on day 1 and day 14 of cycle. It can be seen beside interindividual differences the personal difference between TNFα, estradiol, and progesterone values on day 1 and day 14.Serum TNFα, estradiol, and progesterone individual values in volunteers with no cycle (contraceptive drug yes) demonstrate marked interindividual differences on day 1 and day 14 of cycle. It can be seen beside interindividual differences the personal difference between TNFα, estradiol, and progesterone values on day 1 and day 14; furthermore, seemingly lower estradiol values on day 1 and day 14 between groups can be seen. A significant decrease was demonstrated in serum progesterone values on day 14 of group with contraceptive drug compared with group with no contraceptive one.A significant negative correlation is demonstrated between serum progesterone and serum TNFα values on day 14.A marked significant difference in serum TNFα values between volunteers with cycle and with no cycle, like contraceptive, lactation pregnancy (trimesters P1, P2, P3), and climax.

CONCLUSION

For homogenous group of female patients not the gender and age are important but the cycle itself.

The Influence of Genetic Variations in the CD86 Gene on the Outcome after Allogeneic Hematopoietic Stem Cell Transplantation

CD86 molecule is the ligand for both costimulatory (CD28) and coinhibitory (CTLA-4) molecules, and it regulates immune response after allogeneic hematopoietic stem cell transplantation (alloHSCT). Therefore, we postulate that CD86 gene variations might influence the outcome after alloHSCT. Altogether, 295 adult patients (pts) undergoing related (105 pts) and unrelated (190 pts) donor-matched HSCT were genotyped for the following CD86 gene polymorphisms: rs1129055, rs9831894, and rs2715267. Moreover, the donors' rs1129055 polymorphism was determined. None of the investigated SNPs alone were associated with aGvHD and rate of relapse. However, we showed that rs2715267 SNP influenced overall survival (OS) after alloHSCT. The 24-month OS for the rs271526GG recipients was worse than that for the recipients possessing T allelle (TT or GT genotypes) (p = 0.009). Moreover, analysis of gene-gene interaction between CD86 and CTLA-4 showed that having both the A allele for CD86 rs1129055 and the CTLA-4 CT60GG genotype in recipients increased the risk of aGvHD about 3.5 times. Interestingly, the donors' rs1129055GG genotype and the recipients' CT60GG genotype also increased the risk of aGvHD about 2.7-fold. We postulate that recipients' CD86 gene polymorphisms influence the overall survival after alloHSCT and, together with CTLA-4 polymorphisms, might be considered a risk factor for aGvHD.

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.

The prognostic value of cytotoxic T-lymphocyte antigen 4 in cancers: a systematic review and meta-analysis

The outcomes of studies analyzing the prognostic role of CTLA-4 in cancers are controversial. Therefore, the aim of our meta-analysis was to clarify the correlation between CTLA-4 expression and OS in different cancer cases. Relevant literature was searched using PubMed, EMBASE, Web of Science, and the Cochrane Library. The clinicopathological features, hazard ratio (HR) and 95% confidence intervals (CI) were collected from these studies and were analyzed using Stata version 12.0 software. The pooled HR values showed no significant correlation between CTLA-4 expression levels and OS in relation to tumors (HR: 1.24, 95% CI: 0.98–1.56, I2 = 71.7%, P = 0.000). Further subgroup analyses were conducted and categorized by experimental methods, CTLA-4 sources and cancer types. The survey showed a significant correlation (HR: 1.47, 95% CI: 1.14–1.89) between high expression of CTLA-4 and OS in the SNP subgroup, and subgroups analyzing by PCR (HR: 1.50, 95% CI: 1.20–1.86) and flow cytometry (HR: 2.76, 95% CI: 1.49–5.14). In addition, our analysis observed significant differences between patients and controls in inCTLA-4+CD4+ lymphocytes, surCTLA-4+CD4+ lymphocytes, inCTLA-4+CD8+ lymphocytes, and surCTLA-4+CD8+ lymphocytes. Knowledge of the effects of CTLA-4 could potentially be used to effectively guide appropriate prognosis and therapeutic strategies in cancer patients.

Combining therapeutic antibodies using basiliximab and etanercept for severe steroid-refractory acute graft-versus-host disease: A multi-center prospective study

Acute graft versus host disease (aGVHD) remains a major problem after allogeneic hematopoietic stem cell transplantation. Standard frontline therapy for aGVHD involves corticosteroids. However, fewer than half of patients have a lasting complete response. The long-term mortality rate of steroid-refractory aGVHD (SR-aGVHD) remains around 70%. To date, no consensus has been reached regarding the optimal salvage treatment for SR-aGVHD. We performed the first prospective, multi-center clinical trial to assess the efficacy and safety of a novel approach to treat severe (grades III-IV) SR-aGVHD with the combination of basiliximab and etanercept. Sixty-five patients with severe SR-aGVHD from six centers were included. The median number of basiliximab infusions was 4 (range 2-11) and of etanercept was 9 (range 2-12). At day 28 after starting the combination treatment, overall response (complete and partial response: CR+PR) to second-line treatment was 90.8% with 75.4% being CR. The incidences of CR per organ were 100%, 73.8%, and 79.7% for skin, liver, and gut involvement, respectively. Patients >30-y old (p = 0.043, RR = 3.169), development of grades III-IV liver aGVHD (p = 0.007, RR = 5.034) and cytomegalovirus (CMV) reactivation (p = 0.035, RR = 4.02) were independent predictors for incomplete response. Combined treatment with basiliximab and etanercept resulted in improved CR to visceral aGVHD and significantly superior 2-y overall survival (54.7% vs. 14.8%, p <0.001) compared with classical salvage treatments. Our data suggest that the combination of basiliximab and etanercept may constitute a promising new treatment option for SR-aGVHD.

The Association Between Viral Infections and Co-stimulatory Gene Polymorphisms in Kidney Transplant Outcomes

Background

The surveillance of kidney transplant patients depends on function of different immunologic markers like co-stimulatory molecules. These molecules may also be associated with post kidney transplant viral related outcomes.

Objectives

The aim of this study was to investigate the possible associations between co-stimulatory molecule gene polymorphisms and viral infections in kidney transplant patients.

Patients and Methods

In total, 172 kidney transplant patients were included in this study. Single nucleotide polymorphisms in loci of co-stimulatory molecules including: PDCD.1, CD28, CTLA4 and ICOS, were analyzed in the studied patients by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. Active Cytomegalovirus (CMV) infection and history of hepatitis C virus (HCV) infection were analyzed in each kidney transplant patient using the CMV antigenemia kit and HCV antibody assay, according to the manufacturer’s instructions.

Results

CMV active infection was found in 31 of 172 (18.02%) kidney transplant patients. HCV infection was only found in two of the 172 (1.16%) studied patients. Significant associations were found between TT and TC genotypes of CTLA4 -1722T/C and T allele with acute rejection in CMV infected kidney transplant patients. A significant association was also found between the T allele of CD28 + 17 C/T genetic polymorphism and acute rejection in CMV infected kidney transplant patients. Significantly higher frequency of AA genotype and A allele of CTLA4 + 49AG polymorphism were found in CMV infected female patients. Also a significantly higher frequency of GG genotype and G allele of PDCD-1.3A/G polymorphisms were found in CMV infected female patients.

Conclusions

Based on these results, CTLA4 and CD28 genetic polymorphisms, which regulate T-cell activation, can influence active CMV infection in kidney transplant patients. These results should be confirmed by further investigations.

A CT60G>A polymorphism in the CTLA-4 gene of the recipient may confer susceptibility to acute graft versus host disease after allogeneic hematopoietic stem cell transplantation

T cell activation plays a crucial role in the development of acute graft versus host disease (aGvHD). Cytotoxic T cell antigen-4 (CTLA-4) is a co-inhibitory molecule that negatively regulates T cell activation, differentiation, and proliferation. Single-nucleotide polymorphisms (SNPs) in CTLA-4 gene may affect its function. Inconsistent observations have been reported regarding the associations of CTLA-4 SNPs with complications after hematopoietic stem cell transplantation (HSCT). Moreover, the majority of the observations were focused on the donors' SNPs. Recently, a few studies have shown that recipients' genetic variations in the CTLA-4 gene might influence HSCT results. The aim of our study was to determine the influence of the CTLA-4 gene polymorphisms of the donors and the recipients on the outcome of HSCT. Altogether, 312 donor-recipient pairs were genotyped for the CTLA-4c.49A>G (rs231775) and CT60G>A (rs3087243) SNPs using the TaqMan®SNP Genotyping Assays. In this study, it was shown that the recipients' CT60G>A[GG] genotype, the myeloablative conditioning regimen, and HSCT from an unrelated donor were independent aGvHD risk factors (odds ratio (OR) 2.63, 95% confidence intervals (95% CI) 1.45-4.59, p = 0.001; OR 2.68, 95% CI 1.65-4.07, p = 0.00003; and OR 1.87, 95 % CI 1.02-3.24, p = 0.04, respectively). Moreover, haplotype analysis revealed that possessing allele A in both of the SNPs decreased the risk of aGvHD approximately 1.5-fold (RR 0.69, p = 0.008). Our data suggest that the CT60G>A[GG] genotype in the recipient has an impact on aGvHD development, especially in patients receiving transplants from unrelated donors together with the myeloablative conditioning regimen.

T-cell-replete haploidentical HSCT with low-dose anti-T-lymphocyte globulin compared with matched sibling HSCT and unrelated HSCT

We developed an approach of T-cell-replete haploidentical hematopoietic stem cell transplantation (HSCT) with low-dose anti-T-lymphocyte globulin and prospectively compared outcomes of all contemporaneous T-cell-replete HSCT performed at our center using matched sibling donors (MSDs), unrelated donors (URDs), and haploidentical related donors (HRDs). From 2008 to 2013, 90 patients underwent MSD-HSCT, 116 underwent URD-HSCT, and 99 underwent HRD-HSCT. HRDs were associated with higher incidences of grades 2 to 4 (42.4%) and severe acute graft-versus-host disease (17.2%) and nonrelapse mortality (30.5%), compared with MSDs (15.6%, 5.6%, and 4.7%, respectively; P < .05), but were similar to URDs, even fully 10/10 HLA-matched URDs. For high-risk patients, a superior graft-versus-leukemia effect was observed in HRD-HSCT, with 5-year relapse rates of 15.4% in HRD-HSCT, 28.2% in URD-HSCT (P = .07), and 49.9% in MSD-HSCT (P = .002). Furthermore, 5-year disease-free survival rates were not significantly different for patients undergoing transplantation using 3 types of donors, with 63.6%, 58.4%, and 58.3% for MSD, URD, and HRD transplantation, respectively (P = .574). Our data indicate that outcomes after HSCT from suitably matched URDs and HRDs with low-dose anti-T-lymphocyte globulin are similar and that HRD improves outcomes of patients with high-risk leukemia. This trial was registered at www.chictr.org (Chinese Clinical Trial Registry) as #ChiCTR-OCH-12002490.

Donor TLR9 gene tagSNPs influence susceptibility to aGVHD and CMV reactivation in the allo-HSCT setting without polymorphisms in the TLR4 and NOD2 genes

Owing to ethnicity of the population, those best confirmed polymorphisms in the TLR (toll-like receptor)4 and NOD2 genes with significantly prognostic impact on allogeneic hematopoietic SCT (allo-HSCT) seem to be more applicable to Europeans and are nonpolymorphic in the Asian population. The influence of innate immunity gene polymorphisms on the outcomes of allo-HSCT in those populations has been questioned. We evaluated the influence of 10 candidate single nucleotide polymorphisms (SNPs) in the TLR1, TLR2, TLR3, TLR8 and TLR9 genes on the outcomes of allo-HSCT in a Chinese population including 138 pairs of patients and unrelated donors and a second cohort of 102 pairs of patients and HLA-identical sibling donors. We found that two tagSNPs in the TLR9 gene in the donor side, +1174 A/G (rs352139) and +1635 C/T (rs352140), influenced the risk of acute GVHD (aGVHD) and CMV reactivation. Furthermore, the presence of the susceptible haplotype (A-C) in donor may be an informative predicator of worse OS at 5 years compared with those with the G-C and G-T haplotypes (58% vs 82.9%, P=0.024). Our data suggested an unrecognized association between donor TLR9 tagSNPs and the risk of HSCT-related complications in a population without polymorphisms in the TLR4 and NOD2 genes.

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.