Association of Foxp3 Polymorphism With Allograft Outcome in Kidney Transplantation

Genetic variation in FOXP3 and ROR-γ genes in pediatric acute lymphocytic leukemia (ALL) patients: correlation with associated cytokines

BACKGROUND

FOXP3 and ROR-γ genes are master regulators of the Treg and Th17 differentiation, respectively. This work was planned to investigate the impact of FOXP3 (rs3761548C/A and rs3761549C/T) and ROR-γ (rs9017A/G & rs9826A/G) gene polymorphism on the vulnerability of pediatric Egyptians to acute lymphoblastic leukemia (ALL). Furthermore, we evaluated the impact of these genetic variations on Treg/Th17-related cytokines.

METHODS

FOXP3 SNPs were genotyped using PCR-based restriction fragment length polymorphism (PCR-RFLP), while ROR-γ SNPs polymorphism were performed by PCR-sequence-specific primer (PCR-SSP). An Enzyme-linked immunosorbent assay (ELISA) was used to assess the levels of Treg/Th17 associated cytokines on 128 ALL children and 124 healthy donors.

RESULTS

Compared to controls, patients had a significant increase (p < 0.01/p < 0.05) in FOXP3rs3761548CC genotype and a significant decrease (p < 0.001/p < 0.01) inrs3761548CA genotype. A significant elevation (p < 0.001/p < 0.01) in ROR-γ rs9017AA genotype and a significant reduction (p < 0.01/p < 0.05) in rs9017AG genotype were detected in ALL patients versus controls. An insignificant change in FOXP3 (rs3761549C/T) and ROR-γ (rs9826A/G) genotypes was demonstrated between both groups. ROR-γ GG and GA haplotypes were significantly decreased (p < 0.05/p < 0.05; p < 0.05/p < 0.05) in ALL subjects compared to healthy ones. Relapsed patients had a significantly higher (p < 0.05/P < 0.05) frequency of FOXP3 rs3761548CA genotype than non-relapsed subjects. ROR-γ rs9017AG and rs9826GG genotypes might be associated with the increase in IL-23 plasma level.

CONCLUSIONS

Our preliminary data provided evidence for the impact ofFOXP3 (rs3761548C/A) and ROR-γ (rs9017A/G) gene polymorphisms and the occurrence of ALL in Egyptian children. Another large-scale prospective study should be conducted to validate these findings.

Donor–Recipient Non-HLA Variants, Mismatches and Renal Allograft Outcomes: Evolving Paradigms

Despite significant improvement in the rates of acute allograft rejection, proportionate improvements in kidney allograft longevity have not been realized, and are a source of intense research efforts. Emerging translational data and natural history studies suggest a role for anti-donor immune mechanisms in a majority of cases of allograft loss without patient death, even when overt evidence of acute rejection is not identified. At the level of the donor and recipient genome, differences in highly polymorphic HLA genes are routinely evaluated between donor and recipient pairs as part of organ allocation process, and utilized for patient-tailored induction and maintenance immunosuppression. However, a growing body of data have characterized specific variants in donor and recipient genes, outside of HLA loci, that induce phenotypic changes in donor organs or the recipient immune system, impacting transplant outcomes. Newer mechanisms for “mismatches” in these non-HLA loci have also been proposed during donor–recipient genome interactions with transplantation. Here, we review important recent data evaluating the role of non-HLA genetic loci and genome-wide donor-recipient mismatches in kidney allograft outcomes.

Gender bias in the genetic vulnerability towards type 2 diabetes and diabetic nephropathy: Role of forkhead box Protein3 transcription factor gene variants

Forkhead Box Protein3 Transcription Factor (FOXP3) gene is an essential role player in the function and differentiation of regulatory T cells. Polymorphisms/mutations in FOXP3 gene cause Treg cell dysfunction, promote autoimmunity and inflammation. Based on this presumption, we screened 600 subjects from south India (equal number of diabetic (T2DM), diabetic nephropathy (T2DN) and healthy controls) for promoter and intronic (rs3761548C/A and rs2294021C/T) polymorphisms of FOXP3 gene. PCR-RFLP method used for genotyping, revealed an association of promoter SNP for both T2DM (OR = 2.41, 95% C.I = 1.67-3.49; p < 0.0001) and T2DN (OR = 2.16, 95% C.I = 1.45-3.24; p < 0.005). While intronic polymorphism with T2DN (OR = 1.91, 95% C.I = 1.28-2.84; p < 0.05). Further, in females rs3761548C/A showed 2.6 and 5.5-fold; rs2294021C/T showed 2.2- and 2.5-fold predisposition towards T2DM and T2DN respectively. Males exhibited a twofold risk (OR = 2.01, 95% C.I = 1.22-3.30; p < 0.05) towards T2DM with promoter and no association with intronic polymorphism. The combined genotypes in females with AA-CC; AA-TT predisposed and CA-CC; CA-CT protected heading towards T2DM and T2DN respectively, suggesting irrespective of type of allele at intronic locus AA and CA at promoter locus promote or protect the individual for diabetes and diabetic nephropathy, further confirmed by MLR. To our knowledge, the current study is the first of its kind that revealed an association of these polymorphisms of FOXP3 gene and gender influence on T2DM and T2DN among South Indians. Functional and cell-based studies on Treg cells are warranted to confirm our results that help to develop FOXP3/Treg based therapeutic interventions. Lack of data on Treg cells is the limitation of this study.

Non-HLA donor-recipient mismatches in kidney transplantation-A stone left unturned

In kidney transplantation, short-term allograft survival has improved due to improvements in acute rejection episodes without corresponding improvements in long-term survival. Although current organ allocation algorithms take into account human leukocyte antigen (HLA) matching to reduce antidonor alloimmune responses, it is likely that genomic variation at non-HLA loci (ie, non-HLA donor-recipient [D-R] pair mismatches) play a role in the "non-self" responses and ultimately affect long-term allograft survival. Existing data from both animal models and human studies suggest an association between non-HLA D-R mismatches and kidney allograft outcomes. In this minireview, we examine existing and emerging data and discuss putative mechanisms on the role of non-HLA D-R mismatches on long-term allograft outcomes in kidney transplantation.

The rs3761548 FOXP3 variant is associated with multiple sclerosis and transforming growth factor β1 levels in female patients

OBJECTIVE

The aim of this study was to evaluate the association between rs3761548 FOXP3 (-3279 C > A) variant and multiple sclerosis (MS), disability, disability progression, as well as transforming growth factor (TGF)-β1 and interleukin (IL)-10 plasma levels in MS patients.

METHODS AND SUBJECTS

The study included 170 MS patients and 182 controls. Disability was evaluated using Expanded Disability Status Scale (EDSS) and categorized as mild (EDSS ≤ 3) and moderate/high (EDSS > 3). Disability progression was evaluated using Multiple Sclerosis Severity Score (MSSS). The rs3761548 variant was determined with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Plasma levels of TGF-β1 and IL-10 were determined using immunofluorimetric assay.

RESULTS

CA and AA genotypes were associated with MS [odds ratio (OR) 2.03, 95% confidence interval (CI) 1.66-3.53, p = 0.012; OR 8.19, 95% CI 3.04-22.07, p < 0.001, respectively). With the dominant model, the CA + AA genotypes were associated with MS (OR 2.57, 95% CI 1.50-4.37, p < 0.001). In the recessive model, the AA genotype was also associated with MS (OR 5.38, 95% CI 2.12-13.64, p < 0.001). After adjustment by age, ethnicity, BMI and smoking, all these results remained significant, as well as female patients carrying the CA + AA genotypes showed higher TGF-β1 than those carrying the CC genotype (OR 1.35, 95% CI 1.001-1.054, p = 0.043). No association was observed between the genotypes and disability, disability progression and IL-10 levels.

CONCLUSION

These results suggest that the A allele of FOXP3 -3279 C > A variant may exert a role in the T regulatory cell function, which could be one of the factors involved in the susceptibility for MS in females.

Impact of TBX21, GATA3, and FOXP3 gene polymorphisms on acute cellular rejection after liver transplantation

The single nucleotide polymorphisms (SNPs) rs4794067, rs2275806, rs2232365, and rs3761548 map in the genes of TBX21, GATA3, and FOXP3 involved in mediating acute cellular rejection. We investigated whether these SNPs are associated with acute cellular liver transplant rejection. The SNPs were analyzed in recipients with early acute cellular rejection (n = 97), recipients with late acute cellular rejection (n = 49), and recipients without rejection (n = 149). There was no association between acute cellular rejection and SNPs rs4794067, rs2275806, and rs2232365. In contrast, the allele -3279A of FOXP3 SNP rs3761548 exhibited a higher frequency in recipients with late acute cellular rejection as compared with recipients without rejection. This result indicates that the allele -3279A of the SNP rs3761548 may predispose to the development of late acute cellular rejection.

Polymorphisms in mTOR and Calcineurin Signaling Pathways Are Associated With Long-Term Clinical Outcomes in Kidney Transplant Recipients

Monitoring of immunosuppressive drugs, such as calcineurin and mTOR inhibitors, is essential to avoid undesirable kidney transplant outcomes. Polymorphisms in pharmacokinetics-related genes have been associated with variability in blood levels of immunosuppressive drugs and adverse effects, but influence of pharmacodynamics-related genes remains to be elucidated. The influence of polymorphisms in genes of the mTOR and calcineurin signaling pathways on long-term clinical outcomes was investigated in Brazilian kidney transplant recipients within the 1-year post-transplant. Two-hundred and sixty-nine kidney transplant recipients were enrolled at a kidney transplant center in São Paulo city, Brazil, and treated with tacrolimus plus everolimus or mycophenolate sodium (clinical trial NCT01354301). Clinical and laboratory data, including renal function parameters and drug blood levels were recorded. Genomic DNA was extracted from blood samples. Polymorphisms in MTOR rs1057079 (c.4731G>A), rs1135172 (c.1437T>C), and rs1064261 (c.2997C>T); PPP3CA rs3730251 (c.249G>A); FKBP1A rs6033557 (n.259+24936T>C); FKBP2 rs2159370 (c.-2110G>T); and FOXP3 rs3761548 (c.-23+2882A>C) and rs2232365 (c.-22-902A>G) were analyzed by real-time PCR. Frequencies of gene polymorphisms did not differ among the treatment groups. Analysis of primary outcomes showed that patients carrying MTOR c.1437CC and FOXP3 c.-23+2882CC genotypes had higher serum creatinine than non-carriers (p < 0.05) at 1-year post-transplant. MTOR c.4731G allele (AG+GG genotype) was associated with increased risk for acute rejection (OR = 3.53, 95% CI = 1.09-11.48, p = 0.037). Moreover, 1-year cumulative incidence of rejection was higher in MTOR c.4731G allele carriers compared to AA genotype carriers (p = 0.027). Individually, analysis of secondary outcomes revealed that FKBP2 c.-2110GG genotype carriers had higher risk of leukopenia, FKBP1A n.259+24936C allele carriers had increased risk of constipation, and FOXP3 c.-22-902A or c.-23+2882A allele had higher risk of gastrointestinal disorders (p < 0.05). However, these results were not maintained in the multivariable analysis after p-value adjustment. In conclusion, variants in genes of mTOR and calcineurin pathways are associated with long-term impaired renal function, increased risk of acute rejection, and, individually, with adverse events in Brazilian kidney transplant recipients.

Diminished circulating concentration of interleukin-35 in Helicobacter pylori-infected patients with peptic ulcer: Its association with FOXP3 gene polymorphism, bacterial virulence factor CagA, and gender of patients

BACKGROUND

IL-35 modulates immune and inflammatory responses during infections. Here, we investigated IL-35 levels and a single nucleotide polymorphism, rs3761548, in FOXP3 gene in Helicobacter pylori-infected patients with peptic ulcer (PU), to clarify possible associations.

MATERIALS AND METHODS

This study includes 100 H. pylori-infected PU patients, 100 H. pylori-infected asymptomatic subjects (AS), and 100 noninfected healthy subjects (NHSs). Serum IL-35 levels and the genotyping were determined using ELISA and RFLP-PCR methods, respectively.

RESULTS

In PU patients, the IL-35 levels were lower than AS and NHS groups (P < .001). The IL-35 levels in CagA⁺ H. pylori-infected participants from PU and AS groups were lower than individuals infected with CagA^- strains (P < .02 and P < .04, respectively). Women had higher IL-35 levels than men among PU, AS, and NHS groups (P < .0001). In PU patients, AA genotype and A allele at rs3761548 were more frequent than total healthy subjects (AS + NHS groups) and associated with an increased PU risk (AA genotype: OR = 5.51, P < .0001; A allele: OR = 3.857, P < .002). In PU and AS groups, IL-35 levels were lower in subjects displaying AA genotype or A allele than subjects displaying CC genotype or C allele, respectively (P < .0001 and P < .03 for PU patients; P < .001 and P < .02 for AS group, respectively).

CONCLUSIONS

Decreased IL-35 levels could be involved in PU development in H. pylori-infected individuals. IL-35 levels are affected by CagA status of H. pylori, participants gender, and genetic variations at rs3761548. The AA genotype and A allele at rs3761548 could represent a risk factor for PU development.