Theologia Sarafidou

Pharmacogenetic analysis of TNF, TNFRSF1A, and TNFRSF1B gene polymorphisms and prediction of response to anti-TNF therapy in psoriasis patients in the Greek population.

AbstractBackground: Although biologic therapies have revolutionized the treatment of psoriasis, patients exhibit a substantial heterogeneous response that could be due to complex genetic heterogeneity. Objective: The aim of this study was to investigate the possible influence of tumor necrosis factor-α (TNF), TNF receptor I (TNFRSF1A), and TNF receptor II (TNFRSF1B) gene polymorphisms on anti-TNF treatment responsiveness in psoriasis patients. Methods: A Greek multicenter collaboration was established to recruit a cohort of patients (n = 80) with psoriasis treated with anti-TNF drugs. Single nucleotide polymorphisms (SNPs) in TNF -238G>A, -308G>A, -857C>T), TNFRSF1A (36A>G), and TNFRSF1B (676T>G) were genotyped by PCR-restriction fragment length polymorphism assays. SNPs and haplotypes, including stratification by comorbidity status, were analyzed for association with treatment response after 6 months of therapy, defined as a reduction in the Psoriasis Area and Severity Index (PASI) score by >75% (responders) or ≤50% (nonresponders). Results: Sixty-three patients (78.8%) were defined as responders (PASI score reduction >75%) and 17 patients (21.2%) were defined as nonresponders (PASI score reduction ≤50%). Carriage of TNF -857C or TNFRSF1B 676T alleles was associated with positive response to drug treatment in patients treated with etanercept (p = 0.002 and p = 0.001, respectively). None of the genotyped SNPs were associated with responsiveness to treatment with infliximab or adalimumab. Additionally, when patients were stratified by comorbidity status, none of the genotyped SNPs were alone associated with responsiveness to drug treatment. Conclusion: This study is the first in the field of psoriasis demonstrating a strong association between genetic markers and positive response to drug treatment. Validation of this result in larger studies, as well as analysis of other drug treatments, could provide the basis for individually tailored treatment, along with increased cost effectiveness and reduced unnecessary exposure to toxicity.

Major histocompatibility complex variation at class II DQA locus in the brown hare (Lepus europaeus)

The major histocompatability complex (MHC) is a multigene family of receptors that bind and present antigenic peptides to T‐cells. Genes of the MHC are characterized by an outstanding genetic polymorphism, which is considered to be maintained by positive selection. Sites involved in peptide binding form binding pockets (P) that are collectively termed the peptide‐binding region (PBR). In this study, we examined the level of MHC genetic diversity within and among natural populations of brown hare (Lepus europaeus) from Europe and Anatolia choosing for analysis of the second exon of the DQA locus, one of the most polymorphic class II loci. We aimed at an integrated population genetic analysis of L. europeaus by (i) correlating MHC polymorphism to genetic variability and phylogenetic status estimated previously from maternally (mtDNA) and biparentally (allozymes, microsatellites) inherited loci; and (ii) comparing full‐length exon amino acid polymorphism with functional polymorphism in the PBR and the binding pockets P1, P6 and P9. A substantial level of DQA exon 2 polymorphism was detected with two completely different set of alleles between the Anatolian and European populations. However, the phylogeny of full‐length exon 2 Leeu‐DQA alleles did not show a strong phylogeographic signal. The presence of balancing selection was supported by a statistically significant excess of nonsynonymous substitutions over synonymous in the PBR and a trans‐species pattern of evolution detected after phylogenetic reconstruction. The differentiating patterns detected between genetic and functional polymorphism, i.e. the number and the distribution of pocket variants within and among populations, indicated a hierarchical action of selection pressures.

Association of FCGR2A with the response to infliximab treatment of patients with rheumatoid arthritis.

Objectives We aimed to assess a functional polymorphism in FCGR2A H131R, for association with the treatment response to Fc-containing inhibitors of tumor necrosis factor (TNF). Methods A total of 429 biologic-naive patients with rheumatoid arthritis collected in two sets (299 and 130) were treated during standard care with infliximab (INX), etanercept, or adalimumab. Response to the treatment was evaluated at 3, 6, and 12 months of follow-up as the change in the Disease Activity Score (DAS) 28 from baseline and as the response by the European League Against Rheumatism (EULAR) criteria. These variables were analyzed for association with linear and logistic regression models that included sex, inhibitors of TNF, and baseline DAS28 as covariates. Results Significant association was found between the FCGR2A H131R polymorphism and the response to treatment with INX, but not with the other two TNF inhibitors. The 131R allele was associated with a lower change in DAS28 (P=0.04–0.008 at different times) in the first set of patients and confirmed in the second group of patients (P=0.026 at 3 months of follow-up). Association was also found in the comparison between nonresponders and responders to INX by the EULAR criteria. Conclusion We found an association of the FCGR2A 131R allele with poor response to INX. This finding could be of utility to understand the mechanisms behind treatment failure and contribute to biomarker panels for INX response prediction.

Lack of validation of genetic variants associated with anti-tumor necrosis factor therapy response in rheumatoid arthritis: a genome-wide association study replication and meta-analysis

IntroductionIn this study, our aim was to elucidate the role of four polymorphisms identified in a prior large genome-wide association study (GWAS) in which the investigators analyzed the responses of patients with rheumatoid arthritis (RA) to treatment with tumor necrosis factor inhibitors (TNFi). The authors of that study reported that the four genetic variants were significantly associated. However, none of the associations reached GWAS significance, and two subsequent studies failed to replicate these associations.MethodsThe four polymorphisms (rs12081765, rs1532269, rs17301249 and rs7305646) were genotyped in a total of 634 TNFi-treated RA patients of Spanish Caucasian origin. Four outcomes were evaluated: changes in the Disease Activity Score in 28 joints (DAS28) after 6 and 12 months of treatment and classification according to the European League Against Rheumatism (EULAR) response criteria at the same time points. Association with DAS28 changes was assessed by linear regression using an additive genetic model. Contingency tables of genotype and allele frequencies between EULAR responder and nonresponder patients were compared. In addition, we combined our data with those of previously reported studies in a meta-analysis including 2,998 RA patients.ResultsNone of the four genetic variants showed an association with response to TNFi in any of the four outcomes analyzed in our Spanish patients. In addition, only rs1532269 yielded a suggestive association (P = 0.0033) with the response to TNFi when available data from previous studies were combined in the meta-analysis.ConclusionOur data suggest that the rs12081765, rs1532269, rs17301249 and rs7305646 genetic variants do not have a role as genetic predictors of TNFi treatment outcomes.

Association Between Polymorphisms in MTHFR and APOA5 and Metabolic Syndrome in the Greek Population

Impaired energy homeostasis and low-grade inflammation have been related to components of the metabolic syndrome (MetS) such as dyslipidemia, obesity, and insulin resistance. Single-nucleotide polymorphisms in the genes encoding for IL-6 (g.-634G>C; c.174G>C), TNFα (g.-308G>A), methylenetetrahydrofolate reductase (MTHFR) (c.677C>T), APOC3 (c.3175C>G), and APOA5 (g.-1131T>C) have been implicated in the processes of inflammation and energy intake that take place in the development of MetS manifestations. The aim of this study was to investigate the association between these polymorphisms and MetS, as defined by the National Cholesterol Education Program-Adult treatment Panel III criteria, in the Greek population. Overall, 30 unrelated subjects who met the criteria of MetS and 60 matched control subjects from central Greece were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis. There was a significant association between both MTHFR c.677C>T (odds ratio: 4.02; confidence interval: 1.496-10.777; p=0.003) and APOA5 g.-1131T>C (odds ratio: 3.514; confidence interval: 1.065-11.585; p=0.035) and MetS. Analysis of constructed haplotypes showed a highly significant association between 677C-1131T-3175C haplotype and MetS (p<0.0001). Carriers of both MTHFR c.677T and APOA5 g.-1131C were associated with increased triglyceride levels (p=0.001 and p=0.003, respectively), compared with noncarriers. These results support a role for MTHFR and APOA5 as risk factors for MetS and suggest their further validation in larger independent populations.

Replication of PTPRC as genetic biomarker of response to TNF inhibitors in patients with rheumatoid arthritis

Genetic biomarkers could be useful for orienting treatment of patients with rheumatoid arthritis (RA), but none has been convincingly validated yet. Putative biomarkers include 14 single nucleotide polymorphisms that have shown association with response to TNF inhibitors (TNFi) in candidate gene studies and that we assayed here in 755 RA patients. Three of them, in the PTPRC, IL10 and CHUK genes, were significantly associated with response to TNFi. The most significant result was obtained with rs10919563 in PTPRC, which is a confirmed RA susceptibility locus. Its RA risk allele was associated with improved response (B=0.33, P=0.006). This is the second independent replication of this biomarker (P=9.08 × 10−8 in the combined 3003 RA patients). In this way, PTPRC has become the most replicated genetic biomarker of response to TNFi. In addition, the positive but weaker replication of IL10 and CHUK should stimulate further validation studies.

A pharmacogenetic study of ABCB1 polymorphisms and cyclosporine treatment response in patients with psoriasis in the Greek population.

Psoriasis affects 2–3% of the population, causing significant morbidity and financial burden. Immunosuppressive drugs such as cyclosporine are first line systemic therapies for moderate-to-severe forms. However, patients exhibit heterogeneity in their response to therapy, possibly due to genetic factors. The aim of the present study was to assess the ABCB1 T-129C, G1199A, C1236T, G2677T and C3435T single-nucleotide polymorphisms (SNPs) as candidate predictive markers of response to cyclosporine treatment in 84 psoriasis patients. 62% of the patients were defined as responders and 38% as nonresponders. All SNPs complied with Hardy–Weinberg equilibrium. SNP and haplotype analyses were performed to access responsiveness to treatment. Association analysis revealed statistically significant association of SNP 3435 T with negative response (P=0.0075), a result that was further validated in haplotype analysis. This study is the first in the field of the pharmacogenetics of cyclosporine in psoriasis whose results merit further exploitation in larger independent cohorts.

FCGR polymorphisms in the treatment of rheumatoid arthritis with Fc-containing TNF inhibitors.

OBJECTIVES Reproducible association of a functional polymorphism in FCGR2A with response to a TNF inhibitor (TNFi) in patients with rheumatoid arthritis (RA) led us to explore other FcγR functional polymorphisms. METHODS Functional polymorphisms FCGR3A F158V, FCGR2B I223T and promoter VNTR in FCGRT were analyzed in up to 429 patients with RA. Response to TNFi was recorded during standard care at 3, 6 and 12 months of follow-up. Fixed effects meta-analysis of studies addressing FCGR3A F158V polymorphism, which is the most studied of these polymorphisms, was conducted with inverse variance weighting. RESULTS None of the functional polymorphisms were associated with change in DAS28. Meta-analysis of the seven studies (899 patients) with available data addressing association of FCGR3A F158V with response to TNFi in RA showed no association (OR: 1.11, 95% CI: 0.8-1.5; p = 0.5). CONCLUSION None of the three functional polymorphisms in FcγR genes showed association with response to TNFi in patients with RA. These negative results were obtained in spite of the larger size of this study relative to previous studies addressing the same polymorphisms. In addition, meta-analysis of FCGR3A F158V was also negative against the results provided by previous studies. Original submitted 17 September 2014; Revision submitted 9 December 2014.

FCGR3A-V158F polymorphism is a disease-specific pharmacogenetic marker for the treatment of psoriasis with Fc-containing TNFα inhibitors.

Psoriasis is a multifactorial skin disease affecting ~2% of world’s population, causing a dramatic decrease in patients’ quality of life and a significant increase in health-care expenses. Biological agents such as the anti-TNFα ones had an enormous impact in patients’ therapy; however, a significant proportion of them do not respond well, an outcome attributed mainly to genetic factors. Recently, in a large European cohort of rheumatoid arthritis patients we have shown association with variation in the receptors that correspond to the Fc portion of the biological agents. As both diseases share common immunological fingerprints, we examined the hypothesis that they share common pharmacogenetic markers. Analysis of FCGR2A-H131R and FCGR3A-V158F polymorphisms in 100 psoriasis patients showed association only with respect to FCGR3A-V158F and response to etanercept (P=0.018). Interestingly, no association was found between FCGR2A-H131R and response to anti-TNFα therapy (P=0.882). This study suggests a role for FCGR3A-V158F polymorphism unique for psoriasis.

Patterns of variability at the major histocompatibility class I and class II loci in populations of the endangered cyprinid Ladigesocypris ghigii

The patterns of MHC diversity were studied at UAA and DAB1 loci and the two domains involved in the recognition of antigenic peptides (α2 and β1, respectively) in eight Ladigesocypris ghigii populations inhabiting streams and a concrete reservoir, in order to understand the significance of these genes in bottlenecked populations of an endemic species and develop conservation rationale. In agreement with previous study employing RAPD and mtDNA markers (Mamuris et al., Freshw Biol 50:1441–1453, 2005), both loci exhibited a very low level of polymorphism with only two and four alleles detected for UAA and DAB1, respectively. The functional MHC diversity was even lower since UAA alleles were distinguished by a single synonymous substitution. The type of habitat did not affect the level of polymorphism. Our data suggest that DAB1 polymorphism might be the outcome of the positive selection, imposed by the temporal and spatial variation of pathogen load, and the genetic drift as a result of successive habitat shrinkage and deterioration by water abstraction year after year. The populations studied were significantly less diverged at MHC loci than expected based on nuclear and mtDNA markers, suggesting that common parasites might act as causative factors to homogenize selection. Sufficient epidemiological data are required for the interpretation of the results and decision-making on suitable conservation actions.