Polymorphisms in cytotoxic T lymphocyte associated antigen-4 influence the rate of acute rejection after renal transplantation in 167 Chinese recipients

Impact of CD 28, CD86, CTLA-4 and PD-1 genes polymorphisms on acute renal allograft rejection and graft survival among Egyptian recipients

To study the impact of four gene polymorphisms on acute renal allograft rejection (AR) and graft survival among Egyptian population. These 4 gene polymorphisms include: (1) CD 28 (rs3116496), (2) CD86 (rs1129055), (3) CTLA-4 (rs3087243), (4) PD-1 (rs2227982). This is a non-concurrent cohort study including 50 kidney transplant recipients diagnosed histopathologically as (AR) [study group] and another 50 matched allograft recipients without AR [control group]. Blood samples were taken from both groups and subjected to genotyping for the selected four genetic polymorphisms by TaqMan genotyping assay. The difference in genotypic distribution of CD 28: rs3116496 and CD86: rs1129055 wasn't statistically significant between the study and control groups (P = 0.22 and 0.33 respectively) and also both polymorphisms had no effect on graft survival (P = 0.36 and 0.74 respectively) while the addition of C allele to IVS3 +17T/C polymorphism in CD28 gene showed a protective effect against AR (P = 0.03). CTLA-4: rs3087243 AG genotype showed a protective effect against AR as it was more frequent in no rejection group compared to those with AR (P = 0.001) with a statistically significant impact on graft survival (P < 0.001), while PD-1: rs2227982 AG genotype was equally distributed between both groups (variant of unknown significance). There was no detected association between CD86 polymorphism: rs1129055 and CD 28 polymorphism: rs3116496 with the development of AR. However, C allele of CD 28 IVS3 +17T/C polymorphism and CTLA-4 polymorphism: rs3087243AG genotype both demonstrated a protective effect against AR.

Are the Costimulatory Molecule Gene Polymorphisms (CTLA-4) Associated With Infection in Organ Transplantation? A Meta-Analysis

Organ transplantation has been linked to certain gene polymorphisms. The effect of gene polymorphisms-associated organ transplantation gene on infection, on the other hand, is yet unknown. The research studying the link between the CTLA-4 rs5742909, rs733618, rs4553808, rs231775, and polymorphisms of the organ transplantation gene and infection were found in PubMed, Web of Science, Scopus, and Embase, and the published articles from 2012 to 2020 were gathered. For the best estimation of the intended results, a random-effects model was used in this meta-analysis. In this study, 1,567 studies were initially included and 9 eligible studies were eligible for further analyses. A significant correlation between CTLA4+49 [A/G-231775 odds ratio (OR) = 077, 0.59-0.95] and CTLA4 [rs5742909TT OR: 0.09, 0.27-0.45] gene polymorphism with infection in organ transplantation was observed. Also, no significant association was found between other CTLA4 gene polymorphisms with infection in organ transplantation. Further studies involving gene-gene and gene-diet interactions should be conducted to investigate this association with infection.

Influence of cytotoxic T lymphocyte antigen 4 genetic variants on acute rejection in kidney transplant patients: precision medicine perspective

Background

The most effective and common treatment for end-stage renal disease is kidney transplantation.The personalized approach to kidney transplantation, which utilizes precision medicine principles, determines distinctive genomics characteristics of candidates/recipients that must be taken into account. Cytotoxic T lymphocyte associated protein 4 (CTLA4) may be a suitable candidate gene for studying allograft rejection. The aim of this study was to understand whether we can consider two common variants of the CTLA4 gene as a risk factor of transplant rejection in a group of Iranian population.

Methods

Totally, 169 kidney transplant recipients, including acute rejections (N=39) and non-rejection (N=130) groups who underwent transplantation were included in this study. The genotyping of rs5742909 (-318C/T) and rs231775 (+49A/G) variants of the CTLA4 gene were performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique.

Results

The AG genotype frequency of rs231775 variant was the same in both patients with and without a history of rejection while, none of those groups had homozygote genotype. In rs5742909, both CT and TT frequencies of patients with rejected transplant were lower than patients with a normal outcome.

Conclusions

The results of the presented study suggest that rs231775 and rs5742909 of CTLA4 genetic variants are not linked to acute rejection who underwent kidney transplantation. So, these variants cannot be considered as risk factors of acute allograft rejection in a group of Iranian renal transplantation recipients. However, the transplantation precision medicine may be an important area for the improvement of patients outcome as the precision medicine has already entered clinical practice in kidney transplantation.

Polymorphisms in CTLA-4 predict de novo donor specific antibody formation after kidney transplantation

The post-transplant development of donor-specific antibodies (DSAs) initiates the antibody-mediated rejection, which is associated with an increased rate of graft loss. Therefore, risk prediction of de novo DSA (dnDSA) is important for understanding long-term prognostic implications for kidney transplantation outcomes. Cytotoxic T lymphocyte antigen-4 (CTLA-4), a cell surface molecule, suppresses T cell responses. Single-nucleotide polymorphisms (SNPs) in CTLA-4 are known to be associated with acute rejection; however, their association with dnDSA formation is not established. In the present study, we investigated the impact of CTLA-4 SNPs on dnDSA formation after kidney transplantation (KT) by analyzing three CTLA-4 SNPs (rs231775, rs3087243, and rs5742909) in 88 recipients. Patients with the GG genotype of CTLA-4 SNPs rs231775 and rs3087243 had higher rates of dnDSA formation than patients with the AA genotype or heterozygous genotypes. In conclusion, our findings indicate that CTLA-4 SNPs are predisposing factors for dnDSA formation after KT.

CTLA-4 rs231775 and risk of acute renal graft rejection: an updated meta-analysis with trial sequential analysis

Contrasting results exist on the association between CTLA-4 rs231775 and acute rejection in kidney transplant recipients. We herein conducted an updated systematic review with meta-analysis and trial sequential analysis (TSA) to clarify this relationship and to establish whether the current evidence is sufficient to draw firm conclusions. In addition, noteworthiness of significant pooled odds ratios (ORs) was estimated by false positive report probability (FPRP). A comprehensive search was performed through PubMed, Web of Knowledge, Cochrane Library and Open Grey up to October 2019. Fifteen independent cohorts, including a total of 5,401 kidney transplant recipients, were identified through the systematic review. Overall, no association was detected with the allelic (OR 1.07, 95% CI 0.88-1.30, P = 0.49), dominant (OR 0.94, 95% CI 0.73-1.22, P = 0.66) or the recessive (OR 1.18, 95% CI 0.97-1.43, P = 0.096) model of CTLA-4 rs231775. In each genetic model, the cumulative Z-curve in TSA crossed the futility boundary and entered the futility area. In addition, none of the significant genetic comparisons detected in the subsequent and sensitivity analyses or in previously reported meta-analyses were found to be noteworthy by FPRP. In conclusion, this study provides strong evidence that CTLA-4 rs231775 is not a clinically-relevant genetic risk determinant of acute rejection after renal transplantation.

Analysis of 75 Candidate SNPs Associated With Acute Rejection in Kidney Transplant Recipients: Validation of rs2910164 in MicroRNA MIR146A

BACKGROUND

Identifying kidney allograft recipients who are predisposed to acute rejection (AR) could allow for optimization of clinical treatment to avoid rejection and prolong graft survival. It has been hypothesized that a part of this predisposition is caused by the inheritance of specific genetic variants. There are many publications reporting a statistically significant association between a genetic variant, usually in the form of a single-nucleotide polymorphism (SNP), and AR. However, there are additional publications reporting a lack of this association when a different cohort of recipients is analyzed for the same single-nucleotide polymorphism.

METHODS

In this report, we attempted to validate 75 common genetic variants, which have been previously reported to be associated with AR, using a large kidney allograft recipient cohort of 2390 European Americans and 482 African Americans.

RESULTS

Of those variants tested, only 1 variant, rs2910164, which alters the expression of the microRNA MIR146A, was found to exhibit a significant association within the African American cohort. Suggestive variants were found in the genes CTLA and TLR4.

CONCLUSIONS

Our results show that most variants previously reported to be associated with AR were not validated in our cohort. This shows the importance of validation when reporting the associations with complex clinical outcomes such as AR. Additional work will need to be done to understand the role of MIR146A in the risk of AR in kidney allograft recipients.

Genetics of acute rejection after kidney transplantation

Treatment of acute rejection (AR) following kidney transplantation has improved in recent years, but there are still limitations to successful outcomes. This review article covers literature in regard to recipient and donor genetics of AR kidney and secondarily of liver allografts. Many candidate gene and some genome-wide association studies (GWASs) have been conducted for AR in kidney transplantation. Genetic associations with AR in kidney and liver are mostly weak, and in most cases, the associations have not been reproducible. A limitation in the study of AR is the lack of sufficiently large populations that account for population stratification to study the AR phenotype which in this era occurs in <10% of transplants. Furthermore, the AR phenotype has been difficult to define and the definitions of classifications have evolved over time. Literature related to the pharmacogenomics of tacrolimus is robust and has been validated in many studies. Associations between gene expression and AR are emerging as markers of outcomes and AR classification. In the future, combinations of pretransplant genotype for AR risk prediction, genotype-based immune suppressant dosing, and pharmacogenomic markers to select AR maintenance or treatment and expression markers from biopsies may provide valuable clinical tools for guiding treatment.

Relationship between cytotoxic T-lymphocyte antigen 4 -318C/T (rs5742909) gene polymorphism and the risk of acute rejection in renal transplantation

Results on the relationship between CTLA4 -318C/T (rs5742909) gene polymorphism and risk of acute rejection in renal transplantation are still conflicting. This meta-analysis was performed to update the association between CTLA4 -318C/T and risk of acute rejection in renal transplantation. The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method. Twelve reports were included in this meta-analysis for the association of CTLA4 -318C/T gene polymorphism with acute rejection risk in renal transplantation, consisting of 728 acute rejection patients and 1628 non-acute rejection controls. The association between CTLA4 -318C/T gene polymorphism and acute rejection risk in renal transplantation for overall populations was not found in this meta-analysis (T allele: OR=0.96, 95% CI: 0.60-1.54, P=.88; TT genotype: OR=0.90, 95% CI: 0.47-1.71, P=.74; CC genotype: OR=1.00, 95% CI: 0.62-1.59, P=.98). Interestingly, T allele was associated with the risk of acute rejection in renal transplantation in African population. In conclusion, CTLA4 -318C/T gene polymorphism is not associated with the risk of acute rejection in renal transplantation in overall populations.

Association of cytotoxic T-lymphocyte antigen 4 +49A/G gene polymorphism with acute rejection risk in renal transplantation

The conclusions on the association between cytotoxic T-lymphocyte antigen 4 (CTLA4) +49A/G gene polymorphism and acute rejection risk in renal transplantation are still debated. This meta-analysis was performed to update the association between CTLA4 +49A/G and acute rejection risk in renal transplantation. The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method. Fourteen reports were included into this meta-analysis for the association of CTLA4 A/G gene polymorphism and acute rejection risk in renal transplantation, consisting of 962 acute rejection patients and 2084 non-acute rejection controls. The association between CTLA4 G allele/GG genotype and acute rejection risk in renal transplantation was found in this meta-analysis (G allele: OR=1.21, 95% CI: 1.03-1.44, P=.02; GG genotype: OR=1.37, 95% CI: 1.10-1.69, P=.004). However, the AA genotype was not associated with acute rejection risk in renal transplantation. In conclusion, CTLA4 G allele/GG genotype is associated with the acute rejection risk in renal transplantation.

IL-3 and CTLA4 gene polymorphisms may influence the tacrolimus dose requirement in Chinese kidney transplant recipients

The highly variable pharmacokinetics and narrow therapeutic window of tacrolimus (TAC) has hampered its clinical use. Genetic polymorphisms may contribute to the variable response, but the evidence is not compelling, and the explanation is unclear. In this study we attempted to find previously unknown genetic factors that may influence the TAC dose requirements. The association of 105 pathway-related single nucleotide polymorphisms (SNPs) with TAC dose-adjusted concentrations (C0/D) was examined at 7, 30 and 90 d post-operation in 382 Chinese kidney transplant recipients. In CYP3A5 non-expressers, the patients carrying the IL-3 rs181781 AA genotype showed a significantly higher TAC logC0/D than those with the AG genotype at 30 and 90 d post-operation (AA vs AG, 2.21±0.06 vs 2.01±0.03, P=0.004; and 2.17±0.06 vs 2.03±0.03, P=0.033, respectively), and than those with the GG genotype at 30 d (AA vs GG, 2.21±0.06 vs 2.04±0.03, P =0.011). At 30 d, the TAC logC0/D in the grouped AG+GG genotypes of CTLA4 rs4553808 was significantly lower than that in the AA genotype (P =0.041) in CYP3A5 expressers, but it was higher (P=0.008) in the non-expressers. We further validated the influence of CYP3A5 rs776746, CYP3A4 rs2242480 and rs4646437 on the TAC C0/D; other candidate SNPs were not associated with the differences in TAC C0/D. In conclusion, genetic polymorphisms in the immune genes IL-3 rs181781 and CTLA4 rs4553808 may influence the TAC C0/D. They may, together with CYP3A5 rs776746, CYP3A4 rs2242480 and rs4646437, contribute to the variation in TAC dose requirements. When conducting individualized therapy with tacrolimus, these genetic factors should be taken into account.

Effect of CTLA-4 gene polymorphisms on long-term kidney allograft function in Han Chinese recipients

Single nucleotide polymorphisms (SNPs) of cytotoxic T lymphocyte associated antigen-4 gene (CTLA-4) have been associated with graft rejection and long-term clinical outcome after organ transplantation. Our aim was to examine the association between CTLA-4 SNPs (rs733618, rs4553808, rs5742909, rs231775, rs3087243) and long-term allograft function in Chinese renal transplant recipients. Genotyping of CTLA-4 SNPs was performed in 292 renal transplantation recipients. To assess long-term allograft function, the estimated glomerular filtration rate (eGFR) was determined 1, 3, 6, 12, 24, 36, 48 and 60 months after renal transplantation. CTLA-4 rs733618 and rs3087243 alleles and genotypes as well as the rs5742909 and rs231775 genotypes were significantly associated with long-term allograft function after transplantation (P<0.05). Patients with favorable genotypes had higher allograft function during the 60 months after transplantation. The TACGG, CACAG and CGTAA haplotypes were also associated with long-term kidney function after renal transplantation (P<0.05 or P<0.01). In sum, the favorable CTLA-4 rs5742909TT genotype, CTLA-4 rs733618C and rs3087243A alleles, and CACAG and CGTAA haplotypes, as well as the unfavorable rs733618TT, rs3087243GG and rs231775GG genotypes and TACGG haplotype could potentially serve as effective indicators of long-term allograft function in Chinese renal transplantation recipients.

Cytotoxic T-lymphocyte antigen 4 gene polymorphism influences the incidence of symptomatic human cytomegalovirus infection after renal transplantation

BACKGROUND

The role of CTLA4 gene polymorphisms in T-cell-mediated immunity in association with human cytomegalovirus (HCMV) infection after transplantation is poorly understood. In the present study, we have made an attempt to investigate the impact of CTLA4 single nucleotide polymorphisms (SNPs) (rs231775, rs5742909, rs11571317, rs16840252, rs4553808, rs3087243) and dinucleotide (AT)n repeat polymorphism on the incidence of symptomatic HCMV infection (disease) among 270 renal allograft recipients.

MATERIALS AND METHODS

Genotyping of CTLA4 SNPs was performed by a PCR, followed by a restriction fragment length polymorphism assay. The detection of the dinucleotide (AT)n repeat polymorphism was carried out by PCR-polyacrylamide gel electrophoresis.

RESULTS

An almost three-fold increased risk was observed for the incidence of symptomatic HCMV infection in mutant genotype carriers of rs231775 and rs3087243 SNPs under additive and recessive models, respectively. The mutant haplotype carriers of six studied SNPs (rs231775, rs5742909, rs11571317, rs16840252, rs4553808 and rs3087243) showed an almost two-fold higher risk for symptomatic HCMV cases, whereas wild-type haplotype combinations of these six SNPs showed a protective effect. Subsequently, no correlation was observed in the promoter region SNPs of CTLA4, namely, rs5742909, rs11571317, rs16840252 and rs4553808 in symptomatic HCMV cases at the genotypic/allelic level. Survival analysis showed that the mutant genotypes of rs231775 and rs3087243 SNPs were associated with the lowest HCMV disease-free survival compared with heterozygous and wild genotypes. The crude and adjusted hazard ratios showed an almost three-fold and 2.5-fold increased risk in univariate and multivariate Cox regression models, respectively, for HCMV disease-free survival against mutant genotypes of rs231775 and rs3087243 SNPs. CTLA4 dinucleotide (AT)n repeat analysis showed that the smaller allele (102 bp) was associated with a protective effect, whereas the longer (110 and 116 bp) alleles showed a susceptible effect for symptomatic HCMV cases.

CONCLUSION

These results suggested that CTLA4 variants might be involved in the clinical manifestation of HCMV diseases.

CTLA-4 and MDR1 polymorphisms increase the risk for ulcerative colitis: A meta-analysis

AIM: To evaluate the correlations between cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and multi-drug resistance 1 (MDR1) genes polymorphisms with ulcerative colitis (UC) risk.

METHODS: PubMed, EMBASE, Web of Science, Cochrane Library, CBM databases, Springerlink, Wiley, EBSCO, Ovid, Wanfang database, VIP database, China National Knowledge Infrastructure, and Weipu Journal databases were exhaustively searched using combinations of keywords relating to CTLA-4, MDR1 and UC. The published studies were filtered using our stringent inclusion and exclusion criteria, the quality assessment for each eligible study was conducted using Critical Appraisal Skill Program and the resultant high-quality data from final selected studies were analyzed using Comprehensive Meta-analysis 2.0 (CMA 2.0) software. The correlations between SNPs of CTLA-4 gene, MDR1 gene and the risk of UC were evaluated by OR at 95%CI. Z test was carried out to evaluate the significance of overall effect values. Cochran’s Q-statistic and I² tests were applied to quantify heterogeneity among studies. Funnel plots, classic fail-safe N and Egger’s linear regression test were inspected for indication of publication bias.

RESULTS: A total of 107 studies were initially retrieved and 12 studies were eventually selected for meta-analysis. These 12 case-control studies involved 1860 UC patients and 2663 healthy controls. Our major result revealed that single nucleotide polymorphisms (SNPs) of CTLA-4 gene rs3087243 G > A and rs231775 G > A may increase the risk of UC (rs3087243 G > A: allele model: OR = 1.365, 95%CI: 1.023-1.822, P = 0.035; dominant model: OR = 1.569, 95%CI: 1.269-1.940, P < 0.001; rs231775 G > A: allele model: OR = 1.583, 95%CI: = 1.306-1.918, P < 0.001; dominant model: OR = 1.805, 95%CI: 1.393-2.340, P < 0.001). In addition, based on our result, SNPs of MDR1 gene rs1045642 C > T might also confer a significant increases for the risk of UC (allele model: OR = 1.389, 95%CI: 1.214-1.590, P < 0.001; dominant model: OR = 1.518, 95%CI: 1.222-1.886, P < 0.001).

CONCLUSION: CTLA-4 gene rs3087243 G > A and rs231775 G > A, and MDR1 gene rs1045642 C > T might confer an increase for UC risk.

The influence of CTLA-4 single nucleotide polymorphisms on acute kidney allograft rejection in Turkish patients

Cytotoxic T-lymphocyte antigen-4 (CTLA-4) is a cell surface protein, which down-regulates the immune response at CTLA-4/CD28/B7 pathway. We aimed to investigate the influence of the -318 C/T, +49 A/G, -1661 A/G and CT60A/G, and CTLA-4 gene polymorphisms on acute rejection of kidney allograft in Turkish patients. The study design was a case-control study that consists of three groups: Group 1 (n = 34) represented the kidney transplant (Ktx) recipients who experienced acute rejection, Group 2 (n = 47) was randomly assigned Ktx recipients without acute rejection, and Group 3 (n = 50) consisting of healthy volunteers to evaluate the normal genomic distribution. The polymerase chain reaction-restriction fragment length polymorphism technique was used to determine the polymorphisms. Genotype and allele frequencies among three groups denoted similar distributions for +49 A/G, -1661 A/G, and CT60A/G. Conversely, -318 C/T genotype was three times more frequent in the acute rejection group than in the non-rejection group (OR = 3.45; 95%CI = 1.18-10.1, p = 0.015) and two times more frequent than the healthy control group (OR = 2.45; 95% CI = 0.98 - 6.11, p = 0.047). Additionally, having a T allele at -318 position was significantly associated with acute rejection (0.147 vs. 0.043, OR = 3.45; 95% CI = 1.13-10.56, p = 0.02). 318C/T gene polymorphism and T allelic variant were found to be associated with increased acute rejection risk in Turkish kidney allograft recipients.

A deeper understanding of the association between CTLA4 +49A/G and acute rejection in renal transplantation: an updated meta-analysis

To reevaluate the association between the costimulatory molecule cytotoxic T lymphocyte-associated antigen4 (CTLA4) single nucleotide polymorphism (SNP) +49A/G and acute rejection (AR) in renal transplantation, nine studies published before June 2013 were analyzed. Meta-analysis and cumulative meta-analysis (metacum) were performed for each genotype in a random/fixed effect model. The combined odds ratios (OR) with 95% confidence intervals (CI) were calculated to estimate the strength of the association. In the sensitivity analysis, a single study involved in the meta-analysis was deleted each time to investigate the influence of the individual data sets on the pooled ORs. Meta-analysis regression was used for some influence factors, such as year of publication, total number in each group (AR group and control group), ethnicity, the ratio of GG to GA + AA, the ratio of G to A in CTLA4 +49A/G. Overall, a significant correlation was noted between the CTLA4 SNP (+49A/G) and the risk of AR (for GG vs. AG + AA: OR = 1.35, 95% CI = 1.05-1.73, p = 0.02; for G vs. A: OR = 1.21, 95% CI = 1.03-1.42, p = 0.02), especially in the Asian subgroup (for GG vs. AG + AA: OR = 1.79, 95% CI = 1.15-2.78, p = 0.009; for G vs. A: OR = 1.47, 95% CI = 1.04-2.07, p = 0.03). Of the influence factors, the ratio of GG to GA+AA (p = 0.046) and the ratio of G to A (p = 0.017) were significant factors. In conclusion, our results suggest that CTLA4 +49A/G contribute to the risk of AR following renal transplantation.

Association between co-stimulatory molecule gene polymorphism and acute rejection of allograft

Co-stimulatory molecules play important roles in T cell-mediated immune response and transplantation. Numerous epidemiological studies have evaluated the association between CD28, CTLA-4 gene variant and allograft rejection. However, the results of these studies on the association remain conflicting. The main purpose of this study was to integrate previous results and explore whether the CD28 IVS3 +17T/C variant, CTLA-4, CD86 and PDCD1 gene polymorphisms were associated with allograft rejection susceptibility. PubMed and Embase (before 2014-3-25), were searched for studies on the relationship of CD28, CTLA-4, CD86 and PDCD1 gene polymorphisms and the incidence of allograft rejection susceptibility. Eligible articles were included for data extraction. The main outcome was the frequency of co-stimulate molecule gene polymorphisms between rejection and non-rejection populations. Comparison of the distribution of SNP was mainly performed using Review Manager 5.0. The odds ratio (OR) and its 95% confidence interval (95% CI) were used to assess the strength of association. Significant associations of the CD28 IVS3 +17T/C variant with acute allograft rejection susceptibility were found (CC +CT/TT OR, 1.45; 95% CI, 1.08-1.94; P=0.01). Also we found an association of the CD28 IVS3 +17T/C variant with kidney allograft rejection cases (CC +CT/TT OR, 1.72; 95% CI, 1.19-2.49; P=0.004) and (C allele OR, 1.74; 95% CI, 1.11-2.75; P=0.02), but not established for liver allograft rejection cases (CC +CT/TT OR, 1.19; 95% CI, 0.47-2.98; P=0.72) and (C allele OR, 0.96; 95% CI, 0.67-1.39; P=0.84). And we found an association of the CD86 +1057G/A variant with non-allograft rejection cases (AA +AG/GG OR, 0.35; 95% CI, 0.14-0.85; P=0.02). This meta-analysis demonstrates that the CD28 IVS3 +17T/C variant might increase acute allograft rejection risk in kidney transplant but not in liver transplant, and there was an association between CD86 +1057G/A variant and reduced acute rejection risk. Further studies will be needed to confirm our findings.

Association of CTLA-4 gene polymorphism with end-stage renal disease and renal allograft outcome

Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is upregulated in effector-T-cells after activation that may alter signal transduction and subsequently cytokine production. The present study was designed to investigate the impact of CTLA-4+49 A>G (rs231775), -318 C>T (rs5742909), -658 C>T (rs11571317), -1147 C>T (rs16840252), -1661 A>G (rs4553808), +6230 A>G (rs3087243) SNPs, and microsatellite (AT)n repeat polymorphism among end-stage renal disease (ESRD), acute allograft rejection (AR), and delayed graft function (DGF) cases. In this regard, 350 ESRD patients and 350 controls were included. Polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis method was used for genotyping of CTLA-4 SNPs, while PCR-polyacrylamide gel electrophoresis method was adopted for studying CTLA4 (AT)n polymorphism. The mutant genotype GG of CTLA-4+49A>G,+6230 A>G, and longer alleles of (AT)n repeats polymorphisms were risk associated with ESRD, AR, and DGF cases. The distribution of haplotype+49G:+6230G and GCTTGG (constructed by using 6 studied SNPs) showed risk association for ESRD, DGF, and AR cases. Further, linkage analysis demonstrated strong to moderate linkage disequilibrium in our study populations. The meta-analysis also revealed risk associations for AR cases against GG genotype of CTLA-4+49A>G SNP, while CTLA-4 -318C>T polymorphism showed no correlation against TT genotype among AR cases. Subsequently, no correlation was established against the CTLA-4 -318C>T, -658 C>T, -1147 C>T, and -1661 A>G SNPs in the promoter region. Survival analysis revealed risk associations against GG genotype of CTLA-4+49A>G, +6230 A>G SNP's with overall survival (OS), and higher hazard for the OS. These results suggested that CTLA-4 variants might be involved in susceptibility to ESRD, AR, and DGF.

CTLA4 gene polymorphisms influence the incidence of infection after renal transplantation in Chinese recipients

Background

Immunosuppressive therapy is usually administered following renal transplantation to protect the graft from rejection. However, this often causes complications such as infections to occur. Single nucleotide polymorphisms (SNPs) within the CTLA4 gene, such as −1772T/C (rs733618), +49A/G (rs231775) and +6230 G/A (rs3087243), can affect graft rejection and the long-term clinical outcome of organ transplantation. The role of CTLA4 SNPs in T cell-mediated immunity in renal transplantation and association with infection after transplantation is unknown.

Methods

In this study, the risk of infection according to CTLA4 SNPs was investigated in 304 patients who received kidney graft transplants between 2008 and 2012.

Results

The frequency of the rs4553808 GG genotype was significantly higher in recipients with viral infection (14.89%) than in those without infections (3.50%) (Bonferroni-adjusted p = 0.005). A significant difference (p = 0.001) in patients with the rs4553808 GG genotype from those with the AA+AG genotypes was found in the viral cohort using the log-rank test. A significant association was found between the rs4553808 genotype and onset of viral infection in transplant recipients (p = 0.001). The frequencies of the CGTAG and CGCAG haplotypes were significantly higher in the viral infection group (9.6% and 5.3%) than in the non-viral infection group (3.8% and 1.4%) (p = 0.0149 and p = 0.0111). No association between any CTLA4 SNP and bacterial infection was found. Multivariate analyses revealed that one risk factor, the use of antibody induction therapy (p = 0.007), was associated with bacterial infection, and two risk factors, antibody use (p = 0.015) and recipient rs4553808 genotype (p = 0.001), were associated with viral infection.

Conclusions

The rs4553808 GG genotype may be a risk factor for viral infection in kidney transplantation. The CTLA4 haplotypes CGTAG and CGCAG were partially associated with the development of viral infection in Chinese kidney transplant recipients.

Polymorphisms in CTLA4 influence incidence of drug-induced liver injury after renal transplantation in Chinese recipients

Genetic polymorphisms in cytotoxic T lymphocyte-associated antigen 4 (CTLA4) play an influential role in graft rejection and the long-term clinical outcome of organ transplantation. We investigated the association of 5 CTLA4 single-nucleotide polymorphisms (SNPs) (rs733618 C/T, rs4553808 A/G, rs5742909 C/T, rs231775 A/G, and rs3087243 G/A) with drug-induced liver injury (DILI) in Chinese renal transplantation (RT) recipients. Each recipient underwent a 24-month follow-up observation for drug-induced liver damage. The CTLA4 SNPs were genotyped in 864 renal transplantation recipients. A significant association was found between the rs231775 genotype and an early onset of DILI in the recipients. Multivariate analyses revealed that a risk factor, recipient rs231775 genotype (p = 0.040), was associated with DILI. Five haplotypes were estimated for 4 SNPs (excluding rs733618); the frequency of haplotype ACGG was significantly higher in the DILI group (68.9%) than in the non-DILI group (61.1%) (p = 0.041). In conclusion, CTLA4 haplotype ACGG was partially associated with the development of DILI in Chinese kidney transplant recipients. The rs231775 GG genotype may be a risk factor for immunosuppressive drug-induced liver damage.