Hispanic Kidney Transplant Research Articles

Influence of Cyclooxygenase-2 (COX-2) gene promoter-1195 and allograft inflammatory factor-1 (AIF-1) polymorphisms on allograft outcome in Hispanic kidney transplant recipients

Cyclooxygenase-2 (COX-2) alleles have been associated with allograft outcomes in kidney transplant recipients; however, these alleles may be in linkage with other genes. Human allograft inflammatory factor-1 (AIF-1) is a cytoplasmic protein and is produced by macrophages. Its synthesis is regulated by several cytokines, including interferon gamma. We investigated whether polymorphisms of gene encoding COX-2 and AIF-1 were associated with allograft outcomes among Hispanic renal transplant recipients (RTRs). A total of 527 de novo RTRs of Hispanic ethnicity were included in this study transplanted at St. Vincent Medical Center (SVMC) during 2000-2009. Patients were genotyped for the following: COX-2 (-1195C>T rs689466, intron 6 rs2066826) and AlF1 (rs2269475). Analysis of the results showed that COX-2-1195 CC genotype (OR=1.92, CI%=1.00-3.67, p=0.04) were more frequent, but COX-2-1195 CT genotype was less frequent in kidney allograft acute rejection in comparison with control group (OR=0.59, CI%=0.38-0.91, p=0.017). The genetic variant TT/CT of the AIF-1 gene was associated with a lower risk of rejection (OR=0.63, CI%=0.41-0.98, p=0.038). No association of COX-2 (rs2066826) was observed with allograft rejection. We are unable to find statistically significant association between COX-2 and AIF-1 gene polymorphisms and allograft survival. The -1195C>T in the COX-2 promoter and AIF-1 gene polymorphisms could be a potential predictor of allograft rejection in our Hispanic kidney transplant recipients.

Association between granzyme B and perforin I polymorphisms and allograft outcomes in Hispanic kidney transplant recipients

Granzyme B (GZMB) and perforin 1 gene (PRF1) are key effector molecules of cytotoxic T lymphocytes, in causing acute and chronic solid organ transplant rejection. In this study, we analyzed the impact of GZMB and PRF1 polymorphism on kidney allograft outcomes. In all, 527 de novo kidney Hispanic allograft recipients were genotyped for PRF1 (rs10999426, rs35947132) and GZMB (rs8192917, rs7144366). PRF1 (rs10999426, rs35947132) G alleles and GG genotypes were negatively associated with allograft rejection, demonstrating protection against allograft rejection (OR=0.61, p=0.005 for rs1099946; OR=0.4, p=0.01 for rs 35947132). On the other hand, the GA heterozygosity of PRF1 was found marginally associated with the rejection group (OR=1.53, p=0.05 for rs10999426; OR=2.24, p=0.07 for rs35947132). There was a significant increase in allograft survival in time period studied for the PRF1 (rs10999426) GG genotype, while the GA heterozygosity was associated with graft failure. We found no association for polymorphic markers in GZMB gene with allograft rejection. Survival was significantly improved for patients who were homozygous TT for the GZMB (rs8192917) (TT vs. CC/TT, p=0.041). The result suggests that PRF1 and GZMB gene polymorphisms may determine the incidence of acute rejection or graft survival among Hispanic allograft recipients.

Association of Vitamin D Binding Protein Polymorphism With Long-Term Kidney Allograft Survival in Hispanic Kidney Transplant Recipients

Association of Vitamin D Binding Protein Polymorphism With Long-Term Kidney Allograft Survival in Hispanic Kidney Transplant Recipients

Association of vitamin D binding protein polymorphism with long-term kidney allograft survival in Hispanic kidney transplant recipients

Polymorphism of genes encoding components of the vitamin D pathway including vitamin D receptor (VDR) and vitamin D binding protein (VDBP), have been widely explored due to the complex role played by vitamin D in renal transplant outcomes. In this study, we investigated whether polymorphisms of genes encoding VDR and VDBP were associated with allograft survival or acute rejection (AR) among a Hispanic kidney transplant population. A total of 502 Hispanic renal allograft recipients at the St. Vincent Medical Center between 2001 and 2010 were genotyped for four different single nucleotide polymorphisms of VDR: FokI C>T (rs2228570), BsmI G>A (rs1544410), ApaI T>G (rs7975232), and TaqI T>C (rs731236). We also performed genotyping for one common polymorphism in the VDBP gene (rs4588). Survival was significantly improved for patients who were homozygous GG for the rs4588 G>T allele in the VDBP gene (GG vs. GT+TT, OR=0.63, p=0.02) while GT genotype was associated with a higher risk of graft loss (GT vs. GG+TT, OR=1.67, p=0.01). We found no association for polymorphic markers in VDR with allograft survival and AR. The frequency of the haplotype GTCG (in the order of VDR FokI C>T, BsmI G>A, ApaI T>G, and TaqI T>C), was significantly different in the patients with graft rejection compared to the control (p=0.007) while ACCA haplotype was found to be associated with graft loss (p=0.02). Hence, the VDBP G>T polymorphism (rs4588) and two haplotypes (GTCG and ACCA) of VDR appear to be associated with renal allograft outcomes among Hispanic allograft recipients.

Genetic Polymorphisms of the Transcription Factor NFATc4 and Development of New-Onset Diabetes After Transplantation in Hispanic Kidney Transplant Recipients

Transcription factors of the nuclear factor of activated T cells (NFAT) family regulate both immune activation and insulin production. Calcineurin inhibitors (CNIs) target NFAT activation. Hence, CNIs not only prevent organ transplant rejection but also contribute to the development of new-onset diabetes after transplantation (NODAT). Given individual variation in the susceptibility to NODAT, we hypothesized that polymorphisms in the cytoplasmic NFAT (NFATc)4 gene, which is expressed in pancreatic islets, may be associated with NODAT. Haplotype-tagging single-nucleotide polymorphisms (SNPs) of the NFATc4 gene were genotyped in Hispanic renal transplant patients. Cumulative incidences of NODAT were compared between recipients of different NFATc4 genotypes and haplotypes. The Cox proportional hazard model was used to examine risks for NODAT. Nongenetic and genetic characteristics were included in the multivariate risk model. The SNP (rs10141896) T allele was associated with a lower cumulative incidence of NODAT (P=0.02). This is a tagging SNP for one of the five dominant NFATc4 haplotypes, T-T-T-T-G, and CNI-treated recipients with this haplotype had a reduced adjusted risk for NODAT (hazard ratio: 0.45; 95% confidence interval: 0.19-1.01). Conversely, patients homozygous for the C-C-C-G-G haplotype were at an increased risk (hazard ratio: 2.13; 95% confidence interval: 1.01-4.46) for NODAT in subanalysis. Of the nongenetic factors, use of tacrolimus, sirolimus, and older age were associated with increased risk for NODAT. Polymorphisms in the NFATc4 gene may confer certain protection or predisposition for NODAT.

Genetic and Clinical Risk Factors of New-Onset Diabetes After Transplantation in Hispanic Kidney Transplant Recipients

New-onset diabetes after transplantation (NODAT) is one of the major complications after transplantation and is associated with reduced overall patient and graft survival. The objective of this study was to determine the genetic and clinical risk factors for NODAT in Hispanic kidney transplant recipients. Hispanic kidney allograft recipients without evidence of preexisting diabetes who developed NODAT (n=133) were studied using Hispanic kidney transplant recipients with no evidence of diabetes as a control group (n=170). NODAT was defined as fasting glucose levels ≥126 mg/dL on two or more occasions or patients taking any insulin or oral hypoglycemic agents 1 month or later after kidney transplantation. Fourteen alleles in nine genes were genotyped and other patients' clinical data with genotype data were analyzed by logistic regression. Among 14 alleles, hepatocyte nuclear factor 4 alpha (HNF4A) AA (rs2144908, odds ratio [OR]=1.96, confidence interval [CI]=1.08-3.50, P=0.010), HNF4A TT (rs1884614, OR=2.44, CI=1.42-4.48, P=0.002), and insulin receptor substrate 1 AA+AG (rs1801278, OR=2.71, CI=1.16-6.89, P=0.021) remained significant after logistic regression. Among the clinical factors, average age (OR=1.01, CI=1.00-1.08, P=0.048), sirolimus (OR=5.36, CI=3.02-10.4, P=0.001), deceased donor (OR=1.96, CI=1.16-2.94, P=0.015), and acute rejection (OR=2.92, CI=1.31-5.77, P=0.009) remained significant after logistic regression. This study indicates that polymorphism of two alleles of HNF-4A gene (rs2144908 and rs1884614) and insulin receptor substrate 1 (rs1801278) are significantly associated with NODAT in kidney transplant patients with Hispanic ethnicity. In the case of clinical factors, older age (>50 year), deceased donor type, acute rejection, and sirolimus use are associated with NODAT in Hispanic kidney transplant recipients.

Gene polymorphism of vascular endothelial growth factor −1154 G>A is associated with hypertensive nephropathy in a Hispanic population

The aim of this study was to determine the association between hypertensive nephropathy and gene polymorphisms of vascular endothelial growth factor (VEGF) in a self-reported Hispanic patient group. A total of 155 Hispanic living kidney donors as controls and a total of 86 Hispanic kidney transplant patients, whose renal failure was attributed to hypertensive nephropathy after ruling out diabetes mellitus or other causes, were genotyped for four different single nucleotide polymorphisms of VEGF: -2578 C>A (rs699947), -1154 G>A (rs1570360), -460 C>T (rs833061), and +936 C>T (rs3025039). The homozygous mutant type (AA) of VEGF -1154 G>A (rs1570360) was found with significantly higher frequency in the hypertensive nephropathy patients than in controls. On the other hand, homozygous wild type (GG) was found less frequently in the hypertensive nephropathy patient group than in the control group. Linkage disequilibrium (LD) analyses revealed a high degree of LD among VEGF -2578 C>A (rs699947), VEGF -1154 G>A (rs1570360), and VEGF -460 C>T (rs833061). The haplotype analysis revealed that two haplotypes, CGTC and CATC (in the order of VEGF -2578 C>A (rs699947), -1154 G>A (1570360), -460 C>T (rs833061), and +936 C>T (3025039)), were significantly associated with hypertensive nephropathy in Hispanic patients. Hence, the -1154 G>A polymorphism (rs1570360) and two haplotypes (CGTC and CATC) of VEGF appear to be associated with hypertensive nephropathy in Hispanic patients who developed end-stage renal disease requiring kidney transplant.

Factors and outcome in BK virus nephropathy in a Hispanic kidney transplant population

BK virus nephropathy (BKVN) is an increasingly recognized cause of kidney allograft loss and is thought to be related to the newer, more potent immunosuppressive agents. Conflicting information has been reported on risk factors for BK infection. To determine incidence, associated factors, and outcome of BKVN in our kidney transplant population in order to improve identification and management. Kidney transplants from January 2000 to December 2005 were retrospectively reviewed. Data were collected for patients with biopsy-proven BKVN including age, sex, body mass index (BMI), etiology of renal failure, other medical diseases, donor type, surgical complications, rejection and infection, time to diagnosis, induction, immunosuppressive and antiviral therapy, and clinical outcome. A control group of patients matched for sex, age, type of graft, etiology of kidney disease, and BMI, was established for comparison. During this period, 20 (4%) of 497 transplanted patients were diagnosed with BKVN. Thirteen (65%) were males, 8 (40%) were young adults (ages 21-40), and 18 (90%) received grafts from cadaveric donors (P=0.05). Twelve (60%) had hypertensive renal disease, 2 (10%) also had diabetes, and 16 (80%) had a BMI >25 (P=0.01). Lymphoceles occurred in 5 patients (25%). Mean creatinine level at diagnosis was 2.7 mg/dL and mean time to diagnosis was 23 months. Ten patients (50%) had leukopenia at or within a year before biopsy (P=0.001). Viruses other than BK occurred in 9 patients: varicella zoster virus in 3, cytomegalovirus in 2, herpes simplex virus in 1, molluscum contagiosum in 1, Epstein-Barr virus in 1, and human papillomavirus in 1. Eighteen patients (90%) had related rejection (P= 0.001) and 4 (20%) suffered allograft loss (P= 0.001). Basiliximab (living donors) and anti-thymocyte globulin (cadaver donors) were given for induction. All patients were on triple therapy; 15 on prednisone and sirolimus, with either tacrolimus in 8, cyclosporine in 4, mycophenolate in 1, or mycophenolate and tacrolimus in 2. The other 5 received prednisone with tacrolimus and mycophenolate. Graft loss occurred in 2 patients on tacrolimus and mycophenolate, 1 patient on tacrolimus and sirolimus, and 1 patient on cyclosporine and sirolimus. Immunosuppression was decreased in all patients. Two were given cidofovir for 6 months and had stable creatinine levels at the end of the study. Records were reviewed until April 2007. There were no deaths in this cohort. The number of rejections experienced by patients with BKV was much higher (P<0.0001), but the rate of graft loss was similar between the 2 groups (P=0.19). Viral co-infection was more frequent in patients with BKV (P=0.04). No episodes of leukopenia were reported for any of the patients in the control group (P=0.001). Immunosuppression with tacrolimus and sirolimus was more frequent in the BKV group, but this was not statistically significant (P=0.18, 0.28, respectively). The number of lymphoceles was larger in patients with BKV, but the difference was not statistically significant (P=0.35). BKVN is present in our transplant population and results in a high rate of allograft rejection with varying rates of graft loss. Associated factors were deceased donor and immunosuppression with potent agents, particularly tacrolimus and sirolimus. We also found a higher frequency of obesity, viral co-infection, and leukopenia. Routine screening and timely biopsy could prove cost-effective and significantly reduce morbidity.

Increased risk of post‐transplant diabetes mellitus despite early steroid discontinuation in Hispanic kidney transplant recipients

Early steroid discontinuation (ESD) has been associated with a lower incidence of post-transplant diabetes mellitus (PTDM). We retrospectively reviewed the incidence of PTDM in relation to racial groups in kidney transplant recipients treated with ESD. Between January 2002 and September 2003, 125 consecutive primary adult kidney transplants were performed. Group A (n = 91) had steroids discontinued on postoperative day 6 and maintenance immunosuppression of Tacrolimus and mycophenolate mofetil. Group B (n = 34), received the same immunosuppression but was maintained on steroids indefinitely. Induction consisted of thymoglobulin in African-Americans; all others received Simulect. At 1 yr, patient/graft survival, serum creatinine and rate of acute rejection were similar in both groups. The incidence of PTDM was significantly lower in group A (7%) compared with group B (26%, p = 0.0209). The incidence of PTDM in group A was limited to Hispanic patients with a family history of diabetes mellitus. African-Americans and Caucasians in group A did not experience PTDM (p = 0.005 compared with African-American in group B). Our steroid free protocol nearly eliminated the incidence of PTDM in African-Americans and Caucasians, but was still associated with significant rate of PTDM in Hispanic recipients. Alternative immunosuppression may benefit this population.

Prevalence and clinical spectrum of skin diseases in kidney transplant recipients

Cutaneous lesions can be a significant problem in kidney transplant recipients. Factors such as climate and skin types have been implicated as modifiers of these clinical manifestations. With the purpose of determining the prevalence and clinical spectrum of skin diseases in a group of Hispanic kidney transplant recipients in a tropical climate, 82 serial unselected patients were examined. Seventy-eight were found to have some type of skin disease. Infections of the skin were the most common, followed by drug-induced changes and malignant or pre-malignant cutaneous tumors. Except for the preponderance of superficial mycotic infections, the overall results in our population are in agreement with other series.