Association studies of Toll-like receptor gene polymorphisms with allograft survival in renal transplant recipients of North India

Organ transplantation itself inevitably activates the innate immune system by Toll-like receptors (TLRs), potentially leading to allograft rejection and graft failure. We evaluated the possible association of TLR2, TLR3, and TLR9 polymorphisms of donor-recipient pairs and acute rejection in renal transplant patients of North India. TLR2 (-196 to -174 del), TLR3 (c.1377C/T; rs 3775290), and TLR9 (+2848 G/A; rs 352140) were genotyped using DNA samples from 200 donor-recipient pairs of live donor kidney transplantation by applying Restriction Fragment Length Polymorphism (RFLP) methodology. The variant allele frequency of TLR2 (-196 to -174 del) was significantly different between recipients and donors (7.5% vs. 5.0%; p = 0.049; OR = 3.9; 95% CI = 1.01-15.32). However, no significant association for allograft rejection was observed in transplant recipients for TLR3 and TLR9. Interestingly, a low prevalence of AA genotype of TLR9 + 2848 G>A was observed in rejecters when compared with non-rejecters, demonstrating protective association with allograft rejection (OR = 0.30, 95% CI = 0.12-0.88, p = 0.028). An allele in patients was also observed to be associated with higher rejection-free survival (log-rank = 0.044). These TLR gene polymorphisms, upon further evaluation, may be helpful in elucidation of immunobiological mechanisms associated with renal graft rejection.     

Association between serum resistin level and outcomes in kidney transplant recipients

Resistin is an adipocytokine that is associated with inflammation, coronary artery disease, and other types of cardiovascular disease among patients with normal kidney function. However, little is known about the association of resistin with outcomes in kidney transplant recipients. We collected socio‐demographic and clinical parameters, medical and transplant history, and laboratory data from 988 prevalent kidney transplant recipients enrolled in the Malnutrition‐Inflammation in Transplant—Hungary Study (MINIT‐HU study). Serum resistin levels were measured at baseline. Associations between serum resistin level and death with a functioning graft over a 6‐year follow‐up period were examined in unadjusted and adjusted models. The mean±SD age of the study population was 51 ± 13 years, among whom 57% were men and 21% were diabetics. Median serum resistin concentrations were significantly higher in patients who died with a functioning graft as compared to those who did not die during the follow‐up period (median [IQR]: 22[15–26] vs. 19[14–22] ng/ml, respectively; P < 0.001). Higher serum resistin level was associated with higher mortality risk in both unadjusted and fully adjusted models: HRs (95% CI): 1.33(1.16–1.54) and 1.21(1.01–1.46), respectively. In prevalent kidney transplant recipients, serum resistin was an independent predictor of death with a functioning graft.     

Cardiac allograft vasculopathy in pediatric heart transplant recipients

Metabolic parameters for coronary allograft vasculopathy (CAV) have not been well defined in children. CAV (by angiography or autopsy) was studied in 337 heart recipients on a cyclosporine-based steroid-sparing regimen. Freedom from CAV for all was 79% at 10 years. Fifty-nine patients (18%) developed CAV at a mean of 6.5 +/- 3 years post-transplant. First year rejections were significantly higher in CAV, mean 2.3 vs. 1.4, P = 0.003, odds ratio (OR) 1.8. Rejection with hemodynamic compromise beyond 1 year post-transplant was associated with CAV, P < 0.001, OR 8.4. There was no significant correlation among human leukocyte antigen DR (HLA DR) mismatch, pacemaker use or homocysteine levels and the development of CAV. Maximum cholesterol and low density lipoprotein (LDL) levels were not significantly different. Neither diabetes nor hypertension was significant predictors of CAV on multivariate logistic regression analysis. In conclusion, frequent and severe rejection episodes may predict pediatric CAV. Neither glucose intolerance nor lipid abnormalities appeared to alter risk for CAV in this population.     

A prospective study of anaemia and long-term outcomes in kidney transplant recipients.

BACKGROUND: Anaemia is prevalent in kidney transplant recipients (KTR), and only few KTR with anaemia receive treatment with erythropoietin. Some have claimed that this undertreatment might contribute to suboptimal outcomes such as mortality and cardiovascular events in these patients. However, no evidence is currently available that anaemia is actually associated with such risks in KTR. METHODS: We merged two cohorts of KTR to study the associations between anaemia and two outcomes: all-cause mortality and kidney allograft loss. Detailed information on the demographic and clinical characteristics of these 825 patients was available at baseline. As recommended by the American Society of Transplantation, anaemia was considered present if the haemoglobin concentration was < or =13 g/dl in men or < or =12 g/dl in women. Patients were followed using the Austrian Dialysis and Transplant Registry. RESULTS: After 8.2 years of follow-up, 251 patients died and 401 allografts were lost. In multivariate analyses, anaemia was not associated with all-cause mortality (HR: 1.08; 95% CI: 0.80-1.45), but it was associated with 25% greater risk of allograft loss (HR = 1.25; 95% CI: 1.02-1.59). This association was even more pronounced in death-censored analyses. Analyses using haemoglobin as a continuous variable or in categories also found no association with mortality. CONCLUSIONS: Anaemia may not be associated with mortality in KTR. In light of the recent findings of increased mortality in chronic kidney disease patients with higher haemoglobin treatment target, further evidence is needed to guide clinicians in the treatment of anaemia in these patients.     

Genetic association of FOXP3 gene polymorphisms with allograft rejection in renal transplant patients

Aim: FOXP3 gene is known to be important for regulatory T cell development and function, and is associated with the rejection of human kidney transplants. The present study was therefore conducted to determine the effect of FOXP3 polymorphisms on allograft rejection in renal transplant recipients. Methods: A total of 166 adult patients were categorized into either a Rejection group (65 patients) or a No rejection group (101 patients). Rs3761547, rs3761548 and rs2232365 variant alleles in the FOXP3 gene were genotyped using a TaqMan probe technique, and their relationships with rejection were investigated. Results: There was no significant difference in the genotype frequencies of rs3761547 and rs2232365 variants between patients with and without rejection history (P > 0.05). Binary logistic regression analysis showed that the rs3761548 AA genotype carriers were associated with about a fourfold greater risk for rejection compared with CC genotype (5 years post‐transplant: odds ratio 3.95, 95% confidence interval 1.27–12.29, P = 0.018). Kaplan–Meier analysis revealed a lower mean time to the first rejection in rs3761548 AA compared with CC genotype patients (Log rank = 4.303, P = 0.038). Multivariate Cox regression analysis indicated that rs3761548 AA genotype carriers have up to about a twofold (hazard ratio 2.37, 95% confidence interval 1.17–4.80, P = 0.017) higher risk for rejection than CC carriers. Conclusion: Our study suggests an association between FOXP3 rs3761548 polymorphisms and allograft rejection in renal transplantation. This association should be further proven in large prospective studies because of the small sample size and confounding factors in this retrospective study.     

The effect of histopathologic and clinical features on allograft survival in renal transplant patients with antibody-mediated rejection

Background: Antibody-mediated rejection is a frequent cause of graft failure; however, prognostic indications of this complication have not been well defined. The aim of this study was to evaluate the association of histopathological and clinical features and to determine the effect of these findings on allograft survival in patients with AMR.

Methods: Fifty-two patients suffered from AMR (30 male; mean age 39?±?11 years) were included in the study. Data were investigated retrospectively and graft survival was analyzed. All transplant biopsies were evaluated according to Banff 2009 classification.

Results: Of the 52 cases, 45 were transplanted from living-donors. Twenty-one patients were diagnosed in the first 3-months after transplantation. Graft survival was 65% at 12 months and 54% at 36 months. Mean serum creatinine at time of biopsy was 3.8?±?3.6?mg/dL. Thirty-five of the 52 cases showed diffuse C4d positivity, 12 cases showed focal and 5 remained C4d negative. One of the patients died, 13 experienced graft loss and 38 survived with functioning grafts. Serum creatinine levels at time of biopsy were correlated with graft survival (p?=?.021: OR?=?1.10: 95 % CI?=?1.015–1.199). In terms of the impact of pathological findings; tubulitis (p=.007: OR?=?2.62: 95 % CI?=?1.301–5.276), intimal arteritis (p=.017: OR?=?2.85: 95% CI?=?1.205–6.744) and interstitial infiltration (p=.004: OR?=?3.37: 95% CI?=?1.465–7.752) were associated with graft survival.

Conclusions: Serum creatinine at time of biopsy, tubulitis, intimal arteritis and interstitial infiltration were significantly associated with graft survival. Antibody-mediated rejection is associated with reduced long-term graft survival.     

Standard criteria donor pancreas donation status is associated with improved kidney transplant outcomes

Abstract: Background: Organ donor characteristics can be used to predict outcomes in kidney transplantation. We hypothesized that pancreas donation status could reflect organ quality and be predictive of kidney graft outcomes following Standard Criteria Donor (SCD) kidney transplantation. Methods: We performed a retrospective analysis of deceased donor kidney alone (DD KA) transplants reported to SRTR from 1992 to 2005. Group 1 = kidney alone recipients from pancreas donors (KA, P+) and Group 2 = kidney alone recipients from non‐pancreas donors (KA, P?). We compared patient and graft survival between groups at 10‐yr post‐transplant. Results: Group 1 (KA, P+) comprised 19 633 (20%) recipients and Group 2 (KA, P?) comprised 78 737 (80%) recipients. Ten‐yr graft survival for Group 1 vs. Group 2 was 42.6% and 36.9% (p < 0.0001), respectively. Pancreas donation status (non‐pancreas donor) was associated with a hazard ratio for graft loss of 1.23 on univariate analysis (p < 0.0001), and KA, P‐remained an independent risk factor for graft failure at 10 yr, HR 1.09 (p < 0.0001). Conclusion: Donor pancreas donation status is an independent predictor of improved outcomes of SCD kidney recipients. Further study of the pancreas organ donor pre‐procurement is warranted to optimize not only pancreas utilization but also kidney graft outcomes.     

Association of diagnosed obstructive sleep apnea with kidney transplant outcomes

Obstructive sleep apnea (OSA) is common but underdiagnosed among patients with kidney disease. This study examines whether the diagnosis of OSA in kidney transplant recipients (KTR) affected death, death‐censored graft failure (DCGF), and acute rejection (AR). We analyzed the records of KTR who underwent transplant between 2000 and 2015. A total of 4014 kidney transplants were performed during the study period. Of these, 415 (10.3%) had a diagnosis of pretransplant OSA. Pretransplant OSA was associated with a higher risk of death in unadjusted analyses. After adjustment for potential confounders, pretransplant OSA was not associated with risk of death (HR = 1.04, 95% CI: 0.80‐1.36). Similarly, pretransplant OSA was associated with a slightly higher incidence of DCGF or AR but neither associations were significant (HR: 1.23, 95% CI: 0.85‐1.47 for DCGF; HR 1.10, 95% CI: 0.90‐1.36 for AR). A total of 117 (3.3%) were diagnosed with de novo OSA after transplant. Similar to the pretransplant OSA, unadjusted HR for death was significantly higher in the de novo OSA group (HR: 1.48, 95% CI: 1.19‐1.84); however, after adjustment, de novo OSA was not significantly associated with risk of death (HR: 1.15, 95% CI: 0.92‐1.45). Similarly, DCGF and AR rates were not significantly associated with de novo OSA (HR: 1.10, 95% CI: 0.84‐1.44 for DCGF; HR 1.10, 95% CI: 0.90‐1.33 for AR). Our work did not detect significant associations between OSA and risk of death, graft failure, and rejection but the estimates might be underestimated due to underdiagnosis of OSA.     

Recipient age and risk of chronic allograft nephropathy in primary deceased donor kidney transplant

Single center and registry data studies have had conflicting results regarding the impact of recipient age on chronic allograft nephropathy (CAN). We tested the hypothesis that advanced recipient age is a risk factor for graft failure due to CAN. All patients who underwent primary deceased donor kidney transplant between January 1, 1995 and December 31, 2000 recorded in the United Network of Organ Sharing (UNOS) database were analyzed for the occurrence of death censored graft loss and by two different definitions of graft loss due to CAN. Kaplan-Meier analysis based on the recipient age, and Cox proportional hazard regression was used to estimate the independent effect of recipient age on the three endpoints of interest. For all endpoints, after age of 9 years, the risk of graft loss declined with each successive decade increase in age. This pattern of risk was similar for both Caucasian and African-American recipients, although for any given age the risk of graft loss was always higher in African-American recipients. Analysis of UNOS data does not support the hypothesis that advanced recipient age is a risk factor for CAN.     

Patterns of emergency department utilization between transplant and non-transplant centers and impact on clinical outcomes in kidney recipients

There is a high rate of Emergency Department (ED) utilization in kidney recipients post-transplant; ED visits are associated with readmission rates and lower survival rates. However, utilization within and outside transplant centers may lead to different outcomes. The objective was to analyze ED utilization patterns at transplant and non-transplant centers as well as common etiologies of ED visits and correlation with hospitalization, graft, and patient outcomes. This was a longitudinal, retrospective, single-center cohort study in kidney transplant recipients evaluating ED utilization. Comparator groups were determined by ED location, time from transplant, and disposition/readmission from ED visit. 1,106 kidney recipients were included in the study. ED utilization dropped at the transplant center after the 1st year (P < .001), while remaining at a similar rate at non-transplant centers (0.22 vs 1.06 VPPY). Infection and allograft complications were the most common causes of ED visits. In multivariable Cox modeling, an ED visit due to allograft complication at a non-transplant center >1 year post-transplant was associated with higher risk for graft loss and death (aHR 2.93 and aHR 1.75, P < .0001). The results of this study demonstrate an increased risk of graft loss among patients who utilize non-transplant center emergency departments. Improved communication and coordination between transplant centers and non-transplant centers may contribute to better long-term outcomes.     

细胞因子基因多态性与移植肾慢性排斥反应的关系

目的探讨供、受者细胞因子基因多态性与移植肾慢性排斥反应的关系。方法用序列特异引物聚合酶链反应（PCR-SSP）方法，对144例肾移植受者和65例部分供者进行5种细胞因子[肿瘤坏死因子α（TNF-α）、白细胞介素6（IL-6）、白细胞介素10（IL-10）、转化生长因子β1（TGF-βt）、干扰素7（IFN-7）]基因型检测。结果TGF-β1。高分泌型的受者与中低分泌型受者相比，移植肾慢性排斥反应发生率明显升高，差异有统计学意义（P〈0．01）。TGF-β1高分泌型的供者与中低分泌型供者相比，移植肾慢性排斥反应发生率差异无统计学意义（P〉0．05）。TGF-β1，基因型为供者高分泌／受者高分泌组合时，移植肾慢性排斥反应发生率比所有其它基因型组合者高（P〈0．01）；而TGF-β1。基因型为供者中低分泌／受者中低分泌组合时，移植肾慢性排斥反应发生率比所有其它基因型组合者低（P〈0．01）。TNF-α、IL6、IL-10及IFN-γ的基因型与移植肾慢性排斥反应发生率的关系不明显。结论同时检测供、受者TGF-β1，基因多态性对预测移植肾慢性排斥反应发生率有指导意义。     

Lesions of T-Cell-Mediated Kidney Allograft Rejection in Mice Do Not Require Perforin or Granzymes A and B

Organ allograft rejection is strongly associated with the presence of alloreactive cytotoxic T cells but the role of cytotoxicity in the pathologic lesions is unclear. Previous studies showed that the principal lesions of kidney rejection - interstitial infiltration, tubulitis, and endothelial arteritis - are T-cell-dependent and antibody-independent. We studied the role of cytotoxic granule components perforin and granzymes A and B in the evolution of the T-cell-mediated lesions of mouse kidney transplant rejection. By real-time RT-PCR, allografts rejecting in wild-type hosts at days 5, 7, 21, and 42 showed massively elevated and persistent expression of perforin and granzymes A and B, but evolution of tubulitis and arteritis did not correlate with increasing granzyme or perforin expression. Allografts transplanted into hosts with disrupted genes for perforin or granzymes A and B showed no change in tubulitis, arteritis, or MHC induction. Thus the development of the histologic lesions diagnostic of T-cell-mediated kidney transplant rejection are associated with but not mediated by perforin or granzyme A or B. Together with previous graft survival studies, these results indicate that the granule-associated cytotoxic mechanisms of T cells are not the effectors of T-cell-mediated allograft rejection.     

No association between renin-angiotensin system gene polymorphisms and early and long-term allograft dysfunction in kidney transplant recipients.

BACKGROUND: Genes determining the activity of the renin-angiotensin system (RAS) may be alloantigen-independent factors influencing kidney allograft function. We determined if gene polymorphisms of the RAS are associated with early and long-term post-transplantation graft dysfunction in 405 Caucasian kidney recipients with graft survivals of >2 years. METHODS: We calculated the slopes of serum creatinine(-1)/year and urinary protein excretion/year to follow graft function over time. Subjects were genotyped for the deletion (D) polymorphism of the gene encoding angiotensin I-converting enzyme, the angiotensin II-receptor type1 gene 1166A-C polymorphism and the M235T polymorphism of the angiotensinogen gene. RESULTS: The frequencies of factors predicting graft function were similar in patients with different genotypes. None of the polymorphisms influenced need for dialysis in the first week after transplantation, occurrence of at least one rejection episode, the slope of serum creatinine(-1)/year or the slope of urinary protein excretion/year. Results were independent of blood pressure or the use of angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers or calcineurin inhibitors. The combination of genotypes did not influence the indicators of early and long-term graft dysfunction. CONCLUSIONS: Neither the investigated gene polymorphisms of the RAS in kidney allograft recipients nor their combinations have an impact on early and long-term graft dysfunction.     

尿穿孔素和粒酶B mRNA检测在诊断移植肾急性排斥反应中的意义

目的　探讨尿穿孔素、粒酶BmRNA检测在诊断移植肾急性排斥反应中的作用价值。　方法　应用竞争PCR方法对 34例肾移植患者 4 5份尿样中的穿孔素和粒酶BmRNA进行定量检测。　结果　急性排斥反应组 (n =10 )尿中穿孔素mRNA值 (1.2± 0 .4 )fg/μg总RNA ,粒酶BmR NA值 (1.1± 0 .5 )fg/μg总RNA ,显著高于非排斥组 [n =2 4 ,分别为 (- 0 .6± 0 .3)fg/μg总RNA和(- 0 .8± 0 .2 )fg/μg总RNA],P <0 .0 0 1。尿中细胞毒性分子mRNA水平与急性排斥反应发生时间和严重程度 (Banff分类级别 )无显著相关。当穿孔素mRNA值为 0 .9fg/μg总RNA时 ,诊断急性排斥反应的灵敏度和特异度分别为 85 %和 83% ,粒酶BmRNA值为 0 .4fg/μg总RNA时 ,诊断急性排斥反应的灵敏度和特异度分别为 81%和 78%。　结论　尿中穿孔素及粒酶BmRNA水平检测可以监测和诊断急性排斥反应的发生。