-174G/C interleukin-6 gene polymorphism and the risk of transplanted kidney failure or graft loss during a 5-year follow-up period

Interleukin-6 blockade with tocilizumab increases Tregs and reduces T effector cytokines in renal graft inflammation: A randomized controlled trial

Interleukin-6 (IL-6) is a proinflammatory cytokine and key regulator of Treg: T effector cell (Teff) balance. We hypothesized that IL-6 blockade with tocilizumab, a monoclonal antibody to IL-6R, would increase Tregs, dampen Teff function, and control graft inflammation. We conducted a randomized controlled clinical trial (2014-2018) of clinically stable kidney transplant recipients on calcineurin inhibitor, mycophenolate mofetil, and prednisone, with subclinical graft inflammation noted on surveillance biopsies during the first year posttransplant. Subjects received tocilizumab (8 mg/kg IV every 4 weeks; 6 doses; n = 16) or no treatment (controls; n = 14) on top of usual maintenance immunosuppression. Kidney biopsies pre- and post-treatment were analyzed using Banff criteria. Blood was analyzed for serum cytokines, Treg frequencies, and T cell effector molecule expression (IFN-γ, IL-17, granzyme B) post-stimulation ex vivo. Tocilizumab-treated subjects were more likely to show improved Banff ti-score (62.5% vs. 21.4%, p = .03), increased Treg frequency (7.1% ± 5.55% vs. 3.6% ± 1.7%, p = .0168), and a blunted Teff cytokine response compared to controls. Changes in Banff i- and t-scores were not significantly different. The treatment was relatively well tolerated with no patient deaths or graft loss. Blockade of IL-6 is a novel and promising treatment option to regulate the T cell alloimmune response in kidney transplant recipients. NCT02108600.

Influence of Interferon Gamma +874 T>A (rs2430561) Polymorphism on Renal Allograft Rejection: A Meta-analysis

BACKGROUND

Reported associations of the interferon gamma (IFNG) +874T/A (rs2430561) polymorphism with post-kidney transplantation allograft rejection (AR) have been inconsistent, prompting a meta-analysis to obtain more precise estimates.

METHODS

Eighteen articles (22 studies) were included in the meta-analysis. Operating on the hypothesis that IFNG rs2430561 either increases or reduces AR risk, we used a genetic model-free approach to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Subgrouping was based on ethnicity (white, Middle Eastern, black, and mixed) and rejection type (ACR: acute rejection and CHR: chronic rejection). Quality of the associative effects was assessed with sensitivity treatment and test for publication bias.

RESULTS

The overall analysis in the dominant model indicated increased risk (OR = 1.26; P^a = .02) was validated in the ACR subgroup (OR = 1.29; P^a = .01), which contrasted with the CHR subgroup, with a nonsignificant effect indicating reduced risk (OR = 0.83; P^a = .68). Only the black subgroup showed significant increased risk (OR = 2.87; P^a = .04), but the association was tenuous on account of low sample size (n = 2) and imprecise effect (95% CI, 1.07-7.73).

CONCLUSIONS

Increased risk associations (overall and ACR) of IFNG rs2430561 with AR is significant, robust, statistically powered, and lacking bias. Contrasting ACR (1.3-fold increased risk) and CHR (7% protective) effects may be clinically relevant in the genetics of renal transplantation.

TNF, IL-6, and IL-10 cytokines levels and their polymorphisms in renal function and time after transplantation

Cytokine polymorphisms can influence their plasma levels and thus affect the immune response in renal transplantation. A total of 146 renal transplant recipients (RTR) were classified into groups according to the estimated glomerular filtration rate (R1: < 60 and R2: ≥ 60 mL/min/1.73 m²) and time after transplantation (T1: 1 to 24, T2: 25 to 60, T3: 61 to 120, and T4: > 120 months after transplantation). The polymorphisms were genotyped by single specific primer-polymerase chain reaction. IL-10 was measured by ELISA and IL-6, and TNF levels were determined using Miliplex®. A higher frequency of the - 308G allele and the - 308G/G genotype, low-producer, was observed in the R1 group compared with R2. In addition, a higher frequency of the - 308A carriers, high-producer, was found in the R2 group. However, no significant difference was observed in cytokine levels when both groups were compared. Higher levels of IL-6 were observed in T1 compared with T2 and T4 groups. Lower IL-6 levels were found in T2 compared with T3 group. Lower levels of IL-10 were also found in T1 group in relation to T2, while higher levels of this cytokine were observed in T2 group compared with T3. The results suggest that the - 308G > A polymorphism in the TNF gene is associated with filtration function after renal transplantation, and IL-6 and IL-10 levels change according to the time after transplantation. Thus, the joint evaluation of - 308G > A polymorphism in TNF gene and IL-6 and IL-10 levels would provide a broader and effective view on the clinical monitoring of RTR.

Biomarkers and Pharmacogenomics in Kidney Transplantation

This review is focused on present and future biomarkers, along with pharmacogenomics used in clinical practice for kidney transplantation. It aims to highlight biomarkers that could potentially be used to improve kidney transplant early and long-term graft survival, but also potentially patient co-morbidity. Future directions for improving outcomes are discussed, which include immune tolerance and personalising immunosuppression regimens.

Impact of Immune-Modulatory Drugs on Regulatory T Cell

Immunosuppression strategies that selectively inhibit effector T cells while preserving and even enhancing CD4FOXP3 regulatory T cells (Treg) permit immune self-regulation and may allow minimization of immunosuppression and associated toxicities. Many immunosuppressive drugs were developed before the identity and function of Treg were appreciated. A good understanding of the interactions between Treg and immunosuppressive agents will be valuable to the effective design of more tolerable immunosuppression regimens. This review will discuss preclinical and clinical evidence regarding the influence of current and emerging immunosuppressive drugs on Treg homeostasis, stability, and function as a guideline for the selection and development of Treg-friendly immunosuppressive regimens.

Interleukin-10-1082 G/a polymorphism and acute renal graft rejection: a meta-analysis

OBJECTIVE

The aim of this study was to investigate the association between interleukin (IL)-10-1082 (G/A) promoter polymorphism and acute rejection (AR) in renal transplant recipients.

METHODS

We searched MEDLINE, EMBASE, Web of Science, and Cochrane Central Register from the inception to March 2015 for relevant studies. Data concerning publication information, population characteristics, and transplant information were extracted. Odds ratios (ORs) was calculated for the association between IL-10-1082 GG genotype (or IL-10-1082 G allele) and AR risk.

RESULTS

This meta-analysis included 22 case-control studies including 2779 cases of renal transplant recipients. The pooled estimate showed that the IL-10-1082 GG genotype was not significantly associated with AR risk (ORrandom=1.07, 95% CI 0.80-1.43, p = 0.64). Similarly, the pooled estimate showed that the IL-10-1082 G allele was not significantly associated with AR risk (ORfixed=1.02, 95% CI 0.90-1.16, p = 0.74). None of subgroup analyses yielded significant results in the association between IL-10-1082 GG genotype (or IL-10-1082 G allele) and AR risk. Meta-regression confirmed that there was no significant correlation between the pre-selected trial characteristics and our study results.

CONCLUSIONS

This meta-analysis suggests that IL-10-1082 G/A polymorphism is not significantly associated with AR risk in renal transplant recipients.

Combined effects of TGFB1 +869 T/C and +915 G/C polymorphisms on acute rejection risk in solid organ transplant recipients: a systematic review and meta-analysis

Background

Transforming growth factor-beta 1(TGF-β1) is involved in the development of acute rejection (AR) episodes in solid organ transplant recipients; and a number of studies have been conducted to investigate the combined effects of human TGF-β1 gene (TGFB1) +869 T/C and +915 G/C polymorphisms on AR risk. However, the results obtained are inconclusive.

Methods

Eligible studies that investigated the haplotypic association between TGFB1 +869 T/C and +915 G/C polymorphisms and AR risk were comprehensively searched in the PUBMED, EMBASE, China National Knowledge Infrastructure, and Wanfang Database. Statistical analyses were performed by using STATA 12.0 and Review Manager 5.0.

Results

Fourteen eligible studies with 565 AR cases and 1219 non-AR cases were included. Overall, a significantly decreased risk was detected in patients carried with intermediate producer (IP) haplotypes (T/C G/C, T/T G/C, and C/C G/G) and/or low producer (LP) haplotypes (C/C G/C, C/C C/C, T/T C/C, and T/C C/C) compared with high producer (HP) haplotypes (T/T G/G and T/C G/G; IP vs. HP: OR = 0.75, 95% CI, 0.58–0.96, P _{heterogeneity}  = 0.238; IP/LP vs. HP: OR  = 0.77, 95% CI, 0.61–0.98, P _{heterogeneity}  = 0.144). In addition, subgroup analysis by transplant types demonstrated a similar association in patients receiving heart transplant (IP vs. HP: OR  = 0.32, 95% CI, 0.14–0.73, P _{heterogeneity}  = 0.790; IP/LP vs. HP: OR  = 0.41, 95% CI, 0.20–0.85, P _{heterogeneity}  = 0.320).

Conclusions

The current meta-analysis and systematic review indicated that recipient TGFB1 HP haplotypes were significantly associated with an increased risk for AR in solid organ transplant recipients, particularly patients receiving cardiac allograft.

Association between interferon gamma +874 T>A polymorphism and acute renal allograft rejection: evidence from published studies

Interferon gamma is involved in the acute rejection (AR) episodes of transplant recipients. However, results from published studies on the association of interferon gamma (IFNG) +874 T>A (rs2430561) polymorphism with AR of renal allograft are conflicting. To investigate the association between IFNG +874 T>A polymorphism with AR after renal transplantation, relevant studies were selected from PUBMED, EMBASE, Wanfang database and China National Knowledge Infrastructure until March 1st 2013. According the predesigned selection criteria, a total of 525 AR cases and 1,126 non-AR cases from 13 case-control studies were included to identify the strength of association with odds ratio (OR) and 95 % confidence intervals (95 % CI). Overall, a significant correlation between IFNG +874 T>A polymorphism and susceptibility to AR was detected (T allele vs. A allele: OR = 1.19, 95 % CI 1.02-1.38; TT/AT vs. AA: OR = 1.36, 95 % CI 1.07-1.73; TT vs. AA: OR = 1.42, 95 % CI 1.05-1.93; AT vs. AA: OR = 1.30, 95 % CI 1.01-1.68). In addition, ethnicity subgroup analysis revealed that high produce genotype (TT/AT) was associated with an increased risk of AR for Caucasians (TT/AT vs. AA: OR = 1.56, 95 % CI 1.14-2.12; TT vs. AA: OR = 1.64, 95 % CI 1.18-2.26). Furthermore, donor source subgroup analysis observed an increased risk for patients undergoing cadaveric kidney transplantation (TT/AT vs. AA: OR = 1.90, 95 % CI 1.12-3.24; TA vs. AA: OR = 2.16, 95 % CI 1.24-3.74). In conclusion, this meta-analysis suggested that IFNG +874 T>A polymorphism was associated with AR of renal transplant recipients, especially among Caucasians and those receiving cadaveric renal allograft. Additional well-designed studies with large sample size are warranted to validate our conclusion.

Recipient IL-6-572C/G genotype is associated with reduced incidence of acute rejection following liver transplantation

OBJECTIVE

Acute rejection resulting from alloimmune responses is a major risk factor affecting patient survival following liver transplantation. Since interleukin (IL)-6 can mediate acute rejection, the association between IL-6 gene single nucleotide polymorphisms (SNPs) and incidence of acute rejection in liver transplant recipients was investigated.

METHODS

Patients who received liver transplant between January 2005 and December 2010 were typed for IL6-572C/G (rs1800796) polymorphisms using the snapshot technique. Association between genotype and acute rejection was analysed using the SNP Statistics website: http://bioinfo.iconcologia.net/snpstats/start.htm. Allelic and genotypic distributions for rs1800796 were compared among 335 patients with or without acute rejection within the first 6 months following liver transplant.

RESULTS

Incidence of acute rejection was 11.94%. A heterozygous CG genotype for IL6-572C/G was associated with a lower acute rejection rate compared with homozygous CC or GG genotypes.

CONCLUSION

IL6-572 CG genotype may be related to protection from acute rejection following liver transplant in Han Chinese patients.

Genetic polymorphisms located in TGFB1, AGTR1, and VEGFA genes are associated to chronic renal allograft dysfunction

BACKGROUND

Persistent inflammation and fibrosis have been related to active progression of renal deterioration and reduced survival of kidney transplant. The aim of this study was to determine the impact of single-nucleotide polymorphisms (SNPs) located in regions related to inflammatory and immune processes on the development of chronic renal allograft dysfunction (CRAD).

METHODS

A retrospective study was carried out on 276 patients who received kidney transplant (KT). SNPs were genotyped via the SNPlex platform. Statistical analysis was performed with SNPstat and regression logistic analyses were adjusted by age and gender of recipients and donors, cold ischemia time and the number of human leukocyte antigen (HLA) mismatches.

RESULTS

From 276 patients with KT, 118 were non-CRAD and 158 were CRAD. Three SNPs showed significant associations with CRAD development: rs1800471 in transforming growth factor beta 1 (TGFB1), rs5186 in angiotensin II receptor type 1 (AGTR1), and rs699947 in vascular endothelial growth factor A (VEGFA). GC genotype of rs1800471 was associated with increased odds of CRAD compared to GG genotype (OR=2.65 (95% confidence interval (CI)=1.09; 6.47), p=0.025), as well as AC and AA genotype of rs699947 assuming a dominant model (OR=1.80 (95% CI=1.02; 3.20), p=0.044). Besides, AC and CC genotypes of rs5186 were associated with reduced odds of CRAD assuming a dominant model (OR=0.56 (95% CI=0.33; 0.96), p=0.033).

CONCLUSION

Our findings suggest that three genes related to immunity and inflammation (rs1800471, rs5186 and rs699947) are associated to susceptibility or protection to CRAD, and might have diagnostic utility in predicting the likelihood of developing CRAD.

Association between IL-6 -174G/C polymorphism and acute rejection of renal allograft: evidence from a meta-analysis

BACKGROUND

Results from published studies on the association of donor or recipient IL-6 -174G/C (rs1800795) polymorphism with acute rejection (AR) of renal allograft are conflicting. We performed a meta-analysis to estimate the possible association.

METHODS

Studies were identified by searching PUBMED and EMBASE until July 1, 2011. Meta-analysis was performed in a fixed/random effects model using Revman 5.0.25 and STATA10.0.

RESULTS

Seven studies addressing the association between donor high producer genotype (G/G and G/C) of IL-6 -174G/C polymorphism and acute rejection of renal allograft were identified. Pooled OR based on 341 cases (whose recipient developed acute rejection) and 702 controls (whose recipient did not develop acute rejection) was 0.59 (95% CI, 0.26-1.33; p=0.20), with a strong between-study heterogeneity. No association was observed in the subgroup analysis based on ethnicity. 13 studies evaluating the association between recipient IL-6 -174G/C polymorphism and acute rejection were identified. Pooled OR based on 451 cases (patients did not develop acute rejection) and 848 controls was 1.00 (95% CI=0.72-1.37; p=0.98), with a weak between-study heterogeneity.

CONCLUSIONS

Donor high producer genotype (G/G and G/C) of IL-6 -174G/C polymorphism had a tendency of decreased risk for acute rejection, although it was not statistically significant. Recipient high producer genotype was not associated with acute rejection of renal allograft. Additional well designed studies with larger sample size are needed to support our findings, especially for the association between donor high producer genotype (G/G and G/C) of IL-6 -174G/C polymorphism and acute renal allograft rejection.