Expression of Programmed Cell Death 1 and Helios Genes Correlates With rs872071A>G and rs12203592C>T Single-Nucleotide Polymorphisms of InterferonRegulatory Factor 4 in Patients with T-Cell-Mediated Rejection of Renal Allograft.

OBJECTIVES: Acute T-cell-mediated rejection of the renal allograft is a serious posttransplant challenge that requires administration of high-dose immunosuppressive drugs with considerable side effects; therefore, specific targeting of T-cell responses may improve both prevention and treatment of T-cell-mediated rejection. A potential candidate for this purpose is interferon regulatory factor 4 because of its implication in differentiation and function of T cells. Our aim was to evaluate the frequency of the rs872071A>G and rs12203592C>T single-nucleotide polymorphisms of the interferon regulatory factor 4 gene and association of these 2 polymorphisms with the gene expression of programmed cell death 1 and Helios in patients with T-cell-mediated rejection versus stable recipients. MATERIALS AND METHODS: Sixty recipients with T-cell- mediated rejection and 60 age-matched and sex-matched stable recipients were recruited. Two single-nucleotide polymorphisms of interferon regulatory factor 4 gene, as well as the expression of programmed cell death 1 and Helios genes in peripheral blood mononuclear cells, were investigated with real-time polymerase chain reaction. RESULTS: Programmed cell death 1 gene expression was reduced in patients with T-cell-mediated rejection versus stable recipients (P = .03). The frequency of rs872071A>G and rs12203592C>T single-nucleotide polymorphisms showed no significant difference between groups. Presence of the rs12203592C>T single-nucleotide polymorphism was directly correlated with the expression of programmed cell death 1 gene (P = .049), and rs872071A>G positivity was directly correlated with Helios gene expression (P = .008), which suggests an inhibitory role for interferon regulatory factor 4 on programmed cell death 1 and Helios molecules. CONCLUSIONS: Programmed cell death 1 gene expression was lower in patients with T-cell-mediated rejection versus stable recipients. Low-expressing singlenucleotide polymorphisms of interferon regulatory factor 4 could enhance the downstream gene expression of programmed cell death 1 and Helios immunoregulatory molecules. Therefore, specific inhibition of interferon regulatory factor 4 may promote tolerance induction in the allograft.

The Relationship Between Serum Level of 25-hydroxy Vitamin D and Cytomegalovirus Infection in Kidney Transplant Recipients.

INTRODUCTION: Kidney transplant recipients are at risk of opportunisticinfections; previous studies demonstrated the association betweenlow level of vitamin D and the risk of viral infections. This studywas designed to evaluate the relationship between serum 25-hydroxyvitamin D level and active Cytomegalovirus infection / disease inkidney transplant recipients. METHODS: A total number of 83 kidney transplant recipients enrolledin this case-control study from June 2013 to January 2014. 38patients had active CMV infection / disease and 45 patients hadno evidence of active CMV infection. Serum level of 25-hydroxyvitamin D was measured in these two groups and classified asdifferent levels of sufficient (more than 30ng/mL), insufficient (15-30ng/mL), and deficient (less than 15 ng/mL). Data were analyzedin SPSS 21 statistical software by using statistical tests of Pearsoncorrelation coefficient, chi-square and t-test. RESULTS: Mean serum 25-hydroxy vitamin D level was 14.42 ng/mL in case group and 17.52 ng/mL in control group. There wasno significant difference between the groups in terms of patients'characteristics (P > .05). No significant statistical difference wasfound between mean 25-hydroxy vitamin D level in case and controlgroups (P > .05) but Vitamin D deficiency (serum 25-hydroxy vitaminD less than 15 ng/mL) was noticed in 63.1% of CMV infected groupversus 42.2% of control group. Thus vitamin D deficiency was seenmore prevalent in the CMV infected group (P > .05). CONCLUSION: Although we did not find a statistically significantrelationship between vitamin D levels and the CMV infection, CMVinfected patients had lower vitamin D level compared with noninfectedrecipients, hence vitamin D deficiency can be consideredas a risk factor for CMV reactivation after renal transplantation.

Investigation of Killer Immunoglobulin-like Receptor (KIR) and HLA Genotypes to Predict the Occurrence of Acute Allograft Rejection after Kidney Transplantation.

After kidney transplantation, natural killer (NK) cells play a pivotal role in triggering the immune response to the allogeneic grafts primarily by their killer-cell immunoglobulin-like receptors (KIR). This process may be one mechanism that contributes to graft rejection. In this study, we have evaluated whether acute rejection after kidney transplantation was associated with predicted NK cell alloreactivity based on KIR gene and ligand along with KIR/HLA compound genotype analysis. After kidney transplantation, natural killer (NK) cells play a pivotal role in triggering the immune response to the allogeneic grafts primarily by their killer-cell immunoglobulin-like receptors (KIR). This process may be one mechanism that contributes to graft rejection. In this study, we have evaluated whether acute rejection after kidney transplantation was associated with predicted NK cell alloreactivity based on KIR gene and ligand along with KIR/HLA compound genotype analysis. DNA from 65 patients with biopsy-proven acute kidney allograft rejection (AKAR), 61 clinically stable graft function (SGF) recipients and 176 healthy subjects were identified for the presence or absence of 10 variable KIR genes (both activating and inhibitory receptors) and their HLA ligands using polymerase chain reaction-sequence specific primers (PCR-SSP) assay. Although no significant difference in the frequency of individual KIR genes, was found the gene content, and the haplotypic distribution between the three categories were detected, the frequency of the KIR3DL1+HLA-Bw4*A allele combination was significantly lower in AKAR patients compared to SGF recipients (p=0.004, OR=0.34, CI=0.16-0.72) and healthy subjects (p=0.019, OR=0.47, CI=0.25-0.89). Kaplan-Meier survival test showed that the KIR3DL1+HLA-Bw4*A allele combination could be considered protective for AKAR (p=0.04 by log-rank). The results of this study suggest that KIR/HLA polymorphism may be a genetic susceptibility factor to alloreactivity dysfunction in the NK cells of patients with AKAR. It is likely that a KIR/HLA combinatorial study can be beneficial in predicting AKAR occurrence for the purpose of selecting donors appropriately.

Soluble major histocompatibility complex class I chain-related antigen A level in chronic allograft dysfunction.

INTRODUCTION: Soluble major histocompatibility complex class I chain-related antigen A (soluble MICA) has recently been considered as an inhibitory molecule which is shed from tumors and protects them against natural killers and some subgroups of T cells' cytolysis. In transplantation, soluble MICA is also a foreign antigenic molecule that can induce allospecific responses. This study aimed to clarify its possible role in long-term kidney allograft outcome. MATERIALS AND METHODS: Thirty patients with biopsy-proven chronic allograft dysfunction (CAD) were pair-matched with kidney allograft recipients with 30 stable graft function. Fifteen healthy individuals were enrolled as controls. Soluble MICA antigen and anti-HLA antibodies were measured in their serum. RESULTS: There was no significant difference between CAD patients, stable recipients, and healthy volunteers in frequency or titer of soluble MICA; however, soluble MICA-positive patients were more frequent in the stable group was than the CAD group (43.4% versus 33.3%). In addition, a high level of soluble MICA was accompanied by enhanced humoral responses. No significant difference was found in anti-HLA antibodies production between the CAD and stable groups. CONCLUSIONS: Our data suggest that soluble MICA, at least in a defined range, can protect the allograft against natural killers and T cell cytolysis; nonetheless, its excessive amounts might stimulate immune system to exert enhanced humoral response. In order to confirm the protective or detrimental role of soluble MICA in kidney transplantation, conducting larger studies is necessary.

Does kidney transplantation with deceased or living donor affect graft survival?

BACKGROUND: There are growing numbers of patients with end-stage renal disease globally at an unexpected rate. Today, the most serious challenge in transplantation is organ shortage; hence, using deceased donor is increasingly encouraged. OBJECTIVES: The aim of the study was to investigate the differences in survival rates between kidney transplant recipients with deceased donor and living donor. PATIENTS AND METHODS: In a retrospective cohort study, 218 patients who had undergone kidney transplantation in our institute from April 2008 to September 2010 were recruited. Demographics and post-transplantation follow-up data including immunosuppression regimens, rejection episodes, and survival rates were evaluated. The patients were assigned to two groups according to the donor kidney transplantation: group I, living donor kidney transplants; and group II, deceased donor kidney transplants. RESULTS: Although there were no significant differences in one-year survival rates of patient and graft between study groups, three-years survival rates of patient and graft were significantly longer in living donor kidney transplants in comparison with the deceased donor kidney recipients (P = 0.006 and P = 0.004, respectively). In Cox-regression model after adjusting for other confounding factors such as age, sex, diabetes mellitus, and first- or second-time transplantation, overall patient and graft survivals were also significantly shorter in deceased kidney transplantation than those who received kidney from a living donor (HR, 3.5; 95% CI, 1.2-10.4; and P = 0.02 for patient survival; and HR, 5.4; 95% CI, 1.5-19.5; and P = 0.009 for graft survival). CONCLUSIONS: We found acceptable short-term survival in both groups; however, living donor recipients continue to have better long-term patient and graft survival rates.

Comparison of the Th1, IFN-γ secreting cells and FoxP3 expression between patients with stable graft function and acute rejection post kidney transplantation.

There are limited clinical investigations identifying the percentage of T helper 1 (Th1) and T regulatory (Treg) cells in stable as well as rejected kidney allografts, a concept which needs to be more studied. The aim of our study was to compare the percentage of CD4+ IFN-γ+ cells, the number of IFN-γ secreting cells and the amount of FoxP3 expression in patients with or without stable graft function, to determine the roles of these immunological factors in stable and rejected renal allografts. In this prospective study, 3 months after transplantation 30 patients who received renal transplants from unrelated living donors were enrolled and divided into two groups, 20 patients with stable graft function and 10 patients with biopsy proven acute rejection. The percentage of Th1 CD4+ IFN-γ+ cells was determined on PBMC by flow cytometry and the number of IFN-γ secreting cells by ELISPOT method. Furthermore, FoxP3 expression of PBMCs was measured by Real Time PCR method. The results of these assessments in both groups were statistically analyzed by SPSS 14.0. Our results showed that the percentage of Th1 CD4+ IFN-γ+ cells and the number of IFN-γ secreting cells were significantly higher in the patients with acute rejection in comparison to the stable graft function group (p<0.001). In addition, the level of FoxP3 gene expression was higher in the group with stable graft compared to the acute rejection group. The higher percentage of CD4+ IFN-γ+Th1 subset and number of IFN-γ secreting cells and also the lower expression of Foxp3 could prone the patients to acute rejection episode post transplantation. By these preliminary data, it is suggested that monitoring of Th1 cells post transplantation, as an immunologic marker could predict the possibility of rejection episodes.

Mycophenolic Acid pharmacokinetics early after kidney transplant.

OBJECTIVES: To determine the mycophenolic acid pharmacokinetic profile early after transplant in Iranian kidney graft recipients. MATERIALS AND METHODS: A cross-sectional study was performed during 6 months in 31 patients who recently had kidney transplant and received fixed doses of mycophenolate mofetil (2 g/d). The plasma levels of mycophenolic acid were determined by high performance liquid chromatography. RESULTS: The mean first mycophenolic acid peak level was 10 ± 5 mg/L. The mean mycophenolic acid area under the curve was 26 ± 19 mgh/L and apparent clearance was 57 ± 55 L/h. The mycophenolic acid area under the curve values of only 8 patients (26%) were within the therapeutic range (30-60 mgh/L). The first, second, and third mycophenolic acid peak levels correlated significantly with mycophenolic acid area under the curve (P < .05). Mycophenolic acid concentration at 10 hours had the highest correlation with mycophenolic acid area under the curve (r=0.962; P < .05). No statistically significant differences were evident in the mean mycophenolic acid area under the curve between men and women. CONCLUSIONS: There was a high degree of variation between different patients in mycophenolic acid pharmacokinetics early after kidney transplant.