Gaurav Tripathi

Paraoxonase 1 gene polymorphisms contribute to coronary artery disease risk among north Indians

BACKGROUND Polymorphisms in paraoxonase 1 (PON1) coding for PON1 enzyme have been studied as genetic markers of coronary artery disease (CAD). PON1 Q192R and PON1 L55M polymorphisms have been analyzed extensively, but data on association and role of these polymorphisms in the etiology of CAD are conflicting. In this study, we tested the genetic association between PON1 Q192R and PON1 L55M polymorphisms and CAD among north Indians. MATERIALS AND METHODS Two hundred eighty-five angiographically proven patients with coronary artery disease and 200 sex-matched and ethnically matched controls were genotyped for 2 PON1 polymorphisms by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Genotype/ allele frequencies were compared in patients and controls using the chi-square test. RESULTS At PON1-192 locus, there were significant differences between patients and controls (P< 0.05), leading to significant odds ratios for RR genotype (OR= 1.92, CI: 1.19-3.10) and *R allele (OR= 1.30, CI: 1.00-1.70). These odds ratios were higher in the sub-sample of smokers (2.84 and 1.45, respectively). Binary logistic regression analysis also confirmed that *R allele carriers (QR and RR) have a higher risk of CAD (OR= 3.54, CI: 1.67-5.53). PON1-55 locus did not show significant differences between patients and controls, but LL genotype and *L allele were significant risk factors in the nonsmoker group. RL haplotype was also significantly associated with CAD risk (OR= 1.44, CI: 1.08-1.93). CONCLUSIONS PON1-192R allele and RR genotype are significantly associated with CAD patients from the north Indian population (Uttar Pradesh). This association was stronger in smokers, supporting the conclusion that an interaction between PON1 activity and smoking augments CAD risk. Further studies with larger sample size are warranted to confirm these associations in different Indian populations.

Relationship between GSTs Gene Polymorphism and Susceptibility to End Stage Renal Disease among North Indians

Background and Objective. Glutathione-S-transferase (GST) is the superfamily of genes that provides protection to the cells against reactive oxygen species and plays a vital role in phase II of biotransformation of many substances. Overexpression of GST (EC 2.5.1.18) has been documented in the erythrocytes of patients with chronic renal failure, which may be of clinical relevance. Keeping this background in mind, we have investigated the relationship between human GST gene polymorphism in end stage renal disease (ESRD) patients. Design and Methods. We have assessed 184 patients with ESRD and 569 age-and sex-matched controls from North India. The GSTT1 and GSTM1 null genotypes were identified by polymerase chain reaction (PCR). GSTP1–313 A/G mutation was determined by PCR followed by restriction enzyme digestion. Results. The gene frequency of GSTM1, GSTT1, and GSTP1 polymorphism were evaluated. We observed that GSTM1 null genotype was present in 46.74% of the ESRD patients while GSTT1 null genotype was present in 58.7% of the ESRD subjects. The genotypic distribution of GSTP1 was Ile105/Ile105 in 47.3%, Ile105/Val105 in 30.97% and Val105/Val105 in 21.74% of ESRD patients. There was a significant association of null alleles of the GSTM1 (p = 0.0386; OR = 1.445, 95% CI = 1.033–2.021) and GSTT1 (p ≤ 0.0001; OR = 4.568, 95% CI = 3.215–6.492) and in the -313 G alleles (Val) of the GSTP1 gene (p = 0.0032; OR = 1.956, 95% CI = 1.265–3.024) with end stage renal disease. The combined analysis of the three genotypes showed a further increased risk to ESRD (p ≤ 0.0001; OR = 9.01, 95% CI = 5.55–14.626). Interpretations and Conclusions. The null / low polymorphism of the detoxifying enzymes GSTT1, GSTM1, and GSTP1 are associated with the risk of developing ESRD in North Indian patients.

Does cytokine gene polymorphism affect steroid responses in idiopathic nephrotic syndrome

BACKGROUND Immunological responses may be possibly involved in the pathogenesis of idiopathic nephrotic syndrome (INS). Cytokines act as a potent immunomodulator. Pathogenesis of INS is associated with Th1 and Th2 cytokines imbalance. AIMS, SETTINGS AND DESIGN: We have investigated the association of IL-4, IL-6, and TNF-alpha gene polymorphisms and analyzed the data to evaluate the effect of these polymorphisms on the pathogenesis and clinical course of INS. MATERIALS AND METHODS One hundred fifty children with INS were selected. Children were analyzed for IL-4, IL-6, and TNF-alpha gene polymorphisms by using polymerase chain reaction and restriction fragment length polymorphism. STATISTICAL ANALYSIS USED Chi-square test was used for different comparisons. The synergistic effects of IL-4, IL-6, and TNF-alpha gene polymorphisms were evaluated by using logistic regression analysis. RESULTS AND CONCLUSIONS We compared the steroid-resistant (SR) and steroid-responsive (SS) groups. Our results showed strong association of IL-6 -G174C, and IL-4 -C590T at genotypic level (P = 0.0121, OR = 14.71, 95% CI = 1.59-136.46; and P = 0.0386, OR = 7.29, 95% CI = 1.26-41.69). TNF-alpha revealed a strong association at genotypic level (P = 0.0121, OR = 14.71, 95% CI = 1.59-136.46), as well as at allelic level (P = 0.0433, OR = 2.251, 95% CI = 1.09-4.66), demonstrating that it may be considered one of the genetic risk factors affecting the steroid response in INS patients. The GG genotype of IL-6 -G174C, TT genotype of IL-4 -C590T, and AA genotype of TNF-alpha -G308A cytokine gene polymorphisms may be causative factors for nonresponsiveness towards steroid therapy among INS children.

Association of proinflammatory cytokines with end stage renal disease

CONTEXT Cytokines play an important role in the pathogenesis of kidney disease and its progression to ESRD. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that is released by macrophages and lymphocytes and interferon-gamma (IFN-gamma) plays an important pathogenetic role in several inflammatory diseases. OBJECTIVES We have explored the role of MIF -173 G/C, INF-gamma +874 A/T and INF-gamma CA repeat microsatellite gene polymorphisms as a susceptibility for ESRD. PARTICIPANTS AND METHODS We genotyped MIF and IFN-gamma gene polymorphisms in 258 patients with ESRD and 569 healthy controls free of any renal disease using PCR-RFLP, gene sequencing and gene scanning methods. RESULTS The frequency of high producer MIF -173 CC genotype was higher (10.1%) in ESRD than in controls (1.2%) (p=0.0001, OR=8.9; 95%CI=3.8-21.0). It was observed that there was significant differences in the genotype frequencies of the IFN-gamma +874 A/T at genotypic as well as at allelic level (p=0.0023 and p=0.001) among patients and controls. A significant difference was found in the frequency distribution between the two groups at IFN-gamma CA microsatellite polymorphism (p=0.0001) (CA(17))/(CA(17)). Combined analysis revealed a higher risk ( approximately 9-fold) in ESRD patients with high MIF -173 G/C and high INF-gamma +874 A/T protein producing phenotypes. CONCLUSIONS These results highlight the role of MIF and IFN-gamma in ESRD disease.

Donor-Recipient Matching for KIR Genotypes Reduces Chronic GVHD and Missing Inhibitory KIR Ligands Protect against Relapse after Myeloablative, HLA Matched Hematopoietic Cell Transplantation

Background Allogeneic hematopoietic cell transplantation (HCT) can be curative for many hematologic diseases. However, complications such as graft-versus-host disease (GVHD) and relapse of primary malignancy remain significant and are the leading causes of morbidity and mortality. Effects of killer Ig-like receptors (KIR)-influenced NK cells on HCT outcomes have been extensively pursued over the last decade. However, the relevance of the reported algorithms on HLA matched myeloablative HCT with rabbit antithymocyte globulin (ATG) is used for GVHD prophylaxis remains elusive. Here we examined the role of KIR and KIR-ligands of donor-recipient pairs in modifying the outcomes of ATG conditioned HLA matched sibling and unrelated donor HCT Methods and Findings The study cohort consisted of 281 HLA matched sibling and unrelated donor-recipient pairs of first allogeneic marrow or blood stem cell transplantation allocated into ‘discovery’ (135 pairs) and ‘validation’ (146 pairs) cohorts. High resolution HLA typing was obtained from the medical charts and KIR gene repertoires were obtained by a Luminex® based SSO method. All surviving patients were followed-up for a minimum of two years. KIR and HLA class I distributions of HCT pairs were stratified as per applicable definitions and were tested for their association with cause specific outcomes [acute GVHD grade II-IV (aGVHD), chronic GVHD needing systemic therapy (cGVHD) and relapse] using a multivariate competing risks regression model as well as with survival outcomes [relapse-free survival (RFS), cGVHD & relapse free survival (cGRFS) and overall survival (OS)] by multivariate Cox proportional hazards regression model. A significant association between KIR genotype mismatching (KIR-B/x donor into KIR-AA recipient or vice versa) and cGVHD was found in both discovery (p = 0.001; SHR = 2.78; 95%CI: 1.50–5.17) and validation cohorts (p = 0.005; SHR = 2.61; 95%CI: 1.33–5.11). High incidence of cGVHD associated with KIR genotype mismatching was applicable to both sibling and unrelated donors and was specific to recipients who had one or two C1 bearing HLA-C epitopes (HLA-C1/x, p = 0.001; SHR = 2.40; 95%CI: 1.42–4.06). When compared with KIR genotype mismatched transplants, HLA-C1/x patients receiving grafts from KIR genotype matched donors had a significantly improved cGRFS (p = 0.013; HR = 1.62; 95%CI: 1.11–2.39). Although there was no effect of KIR genotype matching on survival outcomes, a significantly reduced incidence of relapse (p = 0.001; SHR = 0.22; 95%CI: 0.10–0.54) and improved relapse-free survival (p = 0.038; HR = 0.40; 95%CI: 0.17–0.95) was observed with one or more missing ligands for donor inhibitory KIR among the recipients of unrelated donor transplants. Conclusions The present study for the first time presents the beneficial effects of KIR genotype matching in reducing cGVHD in myeloablative transplant setting using HLA matched (sibling and unrelated) donors. The findings offer a clinically applicable donor selection strategy that can help control cGVHD without affecting the risk of relapse and/or identify patients at a high risk of developing cGVHD as potential candidates for preemptive therapy. The findings also affirm the beneficial effect of one or more missing inhibitory KIR ligands in the recipient in reducing relapse and improving a relapse free survival in unrelated donor transplants.

Role of Thrombotic Risk Factors in End-Stage Renal Disease

Introduction: Genetic polymorphisms that are found among factors of the coagulation cascade are factor V leiden mutation (FVL), prothrombin (PT), and methylenetetrahydrofolate reductase (MTHFR), reported for thrombotic complications. We have investigated the associations of these gene polymorphisms in patients with end-stage renal disease (ESRD). Methods: We genotyped 258 patients for FV G1691A, PT G20210A, and MTHFR (C677T, A1298C) gene by using polymerase chain reaction—restriction fragment length polymorphism (PCR-RFLP) analysis and were compared with 569 healthy controls. Serum folate, total homocysteine (tHcys), and vitamin B12 were measured in both patients with ESRD and controls. Results: No homozygous individuals for the mutant AA genotype of FVL G1691A were observed in this study. The frequency of the heterozygous genotypes was (11.2%), which was nearly 3 times higher than that observed in controls (3.2%), with a odds ratio of 3.87 (P = .0001, 95% CI = 2.11-7.11). PT G20210A mutation was missing in both patients and the controls. At MTHFR locus, TT genotype of C677T was present in 9.6% among ESRD, while CC genotype of A1298C was present in 11.7% of the ESRD. In control group, it was significantly low that is, 4.2% and 3.2%, respectively (P = .0034; OR = 2.44, 95% CI = 1.36-4.36 and P < .0001; OR = 4.03; 95% CI = 2.2-7.37). The combined analysis of the 2 genotypes showed further increased risk in ESRD ~15 folds. Further, the carrier of TT and CC genotypes of C677T and A1298C had significantly higher total homocysteine (tHcys) level than those with CC and AA genotypes (P < .001). Conclusion: The carrier of FVL, TT genotype of C677T, and CC genotype of A1298C polymorphisms may act as risk factors for ESRD.

Vitamin D Receptor Gene Polymorphisms in Indian Children with Idiopathic Nephrotic Syndrome

Abstract Idiopathic nephrotic syndrome (INS) is the most common glomerular disorder of childhood. In the present study we have investigated the prevalence of VDR gene polymorphisms in INS patients and healthy controls in North Indian population to assess the role of VDR genes in INS as these patients are at high risk to develop metabolic bone disease. Genotyping of four polymorphic sites (FokI, ApaI, TaqI and BsmI) in the Vitamin D receptor (VDR) gene of 108 unrelated nephrotic patients and 569 healthy controls were performed by PCR-based method. The genotype frequencies were compared among INS and controls. There was significant difference at three polymorphic sites except at TaqI. When the two high risk genotype ff of FokI and BB of BsmI of VDR were combined we found that the risk was increased to ~3.5 folds. Our results revealed the VDR gene polymorphism may have a significant role.