Transcriptomic meta-analysis characterizes molecular commonalities between psoriasis and obesity.

Despite the abundance of epidemiological evidence for the high comorbid rate between psoriasis and obesity, systematic approaches to common inflammatory mechanisms have not been adequately explored. We performed a meta-analysis of publicly available RNA-sequencing datasets to unveil putative mechanisms that are postulated to exacerbate both diseases, utilizing both late-stage, disease-specific meta-analyses and consensus gene co-expression network (cWGCNA). Single-gene meta-analyses reported several common inflammatory mechanisms fostered by the perturbed expression profile of inflammatory cells. Assessment of gene overlaps between both diseases revealed significant overlaps between up- (n = 170, P value = 6.07 × 10-65) and down-regulated (n = 49, P value = 7.1 × 10-7) genes, associated with increased T cell response and activated transcription factors. Our cWGCNA approach disentangled 48 consensus modules, associated with either the differentiation of leukocytes or metabolic pathways with similar correlation signals in both diseases. Notably, all our analyses confirmed the association of the perturbed T helper (Th)17 differentiation pathway in both diseases. Our novel findings through whole transcriptomic analyses characterize the inflammatory commonalities between psoriasis and obesity implying the assessment of several expression profiles that could serve as putative comorbid disease progression biomarkers and therapeutic interventions.

Association between variants in TCF7L2, CTRB1/2, and GLP-1R genes and response to therapy with glucagon-like peptide-1 receptor agonists.

OBJECTIVES: The factors determining the response to treatment with glucagon-like peptide-1 receptor agonists (GLP-1- RAs) have not been clarified. The present study investigated the association between polymorphisms in TCF7L2, CTRB1/2, and GLP-1 R genes and response to GLP-1 RAs regarding glycemic control and weight loss among Greek patients with type 2 diabetes mellitus (T2DM). METHODS: Patients (n = 191) treated with GLP-1 RAs for at least 6 months were included. Participants were genotyped for TCF7L2 rs7903146 (C>T), CTRB1/2 rs7202877 (T>G) and GLP-1 R rs367543060 (C>T) polymorphisms. Clinical and laboratory parameters were measured before, 3, and 6 months after treatment initiation. The patients were classified into responders and non-responders according to specific criteria. RESULTS: Carriers of at least one rs7903146 'T' allele and rs7202877 'G' allele presented similar glucose control and weight loss response to GLP-1 RAs with the respective homozygous wild-type genotypes [odds ratio (OR): 1.08, 95% confidence interval (CI): 0.5, 2.31, p = 0.85 and OR: 1.35, 95% CI: 0.66, 2.76, p = 0.42; OR: 1.4, 95% CI: 0.56, 3.47, p = 0.47 and OR: 1.28, 95% CI: 0.55, 2.98, p = 0.57, respectively]. Regarding the GLP-1 R polymorphism, all participants were homozygous for the wild-type allele; thus, no comparisons were feasible. Female sex (p = 0.03) and lower baseline weight (p = 0.024) were associated with an improved glycemic and weight loss response, respectively. CONCLUSION: There is no evidence suggesting a role for the variants studied in response to GLP-1 RA therapy in people with T2DM. However, specific demographic and clinical factors may be related to a better response to treatment with these agents.

Disentangling the complexity of psoriasis in the post-genome-wide association era.

In recent years, genome-wide association studies (GWAS) have been instrumental in unraveling the genetic architecture of complex diseases, including psoriasis. The application of large-scale GWA studies in psoriasis has illustrated several associated loci that participate in the cutaneous inflammation, however explaining a fraction of the disease heritability. With the advent of high-throughput sequencing technologies and functional genomics approaches, the post-GWAS era aims to unravel the functional mechanisms underlying the inter-individual variability in psoriasis patients. In this review, we present the key advances of psoriasis GWAS in under-represented populations, rare, non-coding and structural variants and epistatic phenomena that orchestrate the interplay between different cell types. We further review the gene-gene and gene-environment interactions contributing to the disease predisposition and development of comorbidities through Mendelian randomization studies and pleiotropic effects of psoriasis-associated loci. We finally examine the holistic approaches conducted in psoriasis through system genetics and state-of-the-art transcriptomic analyses, discussing their potential implication in the expanding field of precision medicine and characterization of comorbidities.

Candidate Gene Association Studies in Atopic Dermatitis in Participants of European and Asian Ancestry: A Systematic Review and Meta-Analysis.

Atopic dermatitis (AD) has been extensively investigated for genetic associations utilizing both candidate gene approaches and genome-wide scans. Here, we comprehensively evaluated the available literature to determine the association of candidate genes in AD to gain additional insight into the etiopathogenesis of the disease. We systematically screened all studies that explored the association between polymorphisms and AD risks in cases of European and Asian ancestry and synthesized the available evidence through a random-effects meta-analysis. We identified 99 studies that met our inclusion/exclusion criteria that examined 17 candidate loci in Europeans and 14 candidate genes in Asians. We confirmed the significant associations between FLG variants in both European and Asian populations and AD risk, while synthesis of the available data revealed novel loci mapped to IL18 and TGFB1 genes in Europeans and IL12RB1 and MIF in Asians that have not yet been identified by genome-wide association studies. Our findings provide comprehensive evidence for AD risk loci in cases of both European and Asian ancestries, validating previous associations as well as revealing novel loci that could imply previously unexplored biological pathways.

Transcriptional repression of lncRNA and miRNA subsets mediated by LRF during erythropoiesis.

Non-coding RNA (ncRNA) species, mainly long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been currently imputed for lesser or greater involvement in human erythropoiesis. These RNA subsets operate within a complex circuit with other epigenetic components and transcription factors (TF) affecting chromatin remodeling during cell differentiation. Lymphoma/leukemia-related (LRF) TF exerts higher occupancy on DNA CpG rich sites and is implicated in several differentiation cell pathways and erythropoiesis among them and also directs the epigenetic regulation of hemoglobin transversion from fetal (HbF) to adult (HbA) form by intervening in the γ-globin gene repression. We intended to investigate LRF activity in the evolving landscape of cells' commitment to the erythroid lineage and specifically during HbF to HbA transversion, to qualify this TF as potential repressor of lncRNAs and miRNAs. Transgenic human erythroleukemia cells, overexpressing LRF and further induced to erythropoiesis, were subjected to expression analysis in high LRF occupancy genetic loci-producing lncRNAs. LRF abundance in genetic loci transcribing for studied lncRNAs was determined by ChIP-Seq data analysis. qPCRs were performed to examine lncRNA expression status. Differentially expressed miRNA pre- and post-erythropoiesis induction were assessed by next-generation sequencing (NGS), and their promoter regions were charted. Expression levels of lncRNAs were correlated with DNA methylation status of flanked CpG islands, and contingent co-regulation of hosted miRNAs was considered. LRF-binding sites were overrepresented in LRF overexpressing cell clones during erythropoiesis induction and exerted a significant suppressive effect towards lncRNAs and miRNA collections. Based on present data interpretation, LRF's multiplied binding capacity across genome is suggested to be transient and associated with higher levels of DNA methylation. KEY MESSAGES: During erythropoiesis, LRF displays extensive occupancy across genetic loci. LRF significantly represses subsets of lncRNAs and miRNAs during erythropoiesis. Promoter region CpG islands' methylation levels affect lncRNA expression. MiRNAs embedded within lncRNA loci show differential regulation of expression.

Intrinsic Effects of Exposome in Atopic Dermatitis: Genomics, Epigenomics and Regulatory Layers.

Atopic dermatitis (AD) or atopic eczema is an increasingly manifested inflammatory skin disorder of complex etiology which is modulated by both extrinsic and intrinsic factors. The exposome includes a person's lifetime exposures and their effects. We recently reviewed the extrinsic exposome's environmental risk factors that contribute to AD. The periods of pregnancy, infancy, and teenage years are recognized as crucial stages in the formation of AD, where the exposome leads to enduring impacts on the immune system. However, research is now focusing on the interactions between intrinsic pathways that are modulated by the extrinsic exposome, including genetic variation, epigenetic modifications, and signals, such as diet, stress, and microbiome interactions. As a result, immune dysregulation, barrier dysfunction, hormonal fluctuations, and skin microbiome dysbiosis are important factors contributing to AD development, and their in-depth understanding is crucial not only for AD treatment but also for similar inflammatory disorders.

Pharmaco-Omics in Psoriasis: Paving the Way towards Personalized Medicine.

The emergence of high-throughput approaches has had a profound impact on personalized medicine, evolving the identification of inheritable variation to trajectory analyses of transient states and paving the way for the unveiling of response biomarkers. The utilization of the multi-layered pharmaco-omics data, including genomics, transcriptomics, proteomics, and relevant biological information, has facilitated the identification of key molecular biomarkers that can predict the response to therapy, thereby optimizing treatment regiments and providing the framework for a tailored treatment plan. Despite the availability of multiple therapeutic options for chronic diseases, the highly heterogeneous clinical response hinders the alleviation of disease signals and exacerbates the annual burden and cost of hospitalization and drug regimens. This review aimed to examine the current state of the pharmaco-omic approaches performed in psoriasis, a common inflammatory disease of the skin. We sought to identify central studies that investigate the inter-individual variability and explore the underlying molecular mechanisms of drug response progression via biological profiling in psoriatic patients administered with the extended therapeutic armamentarium of psoriasis, incorporating conventional therapies, small molecules, as well as biological drugs that inhibit central pathogenic cytokines involved in the disease pathogenesis.

The Imprint of Exposome on the Development of Atopic Dermatitis across the Lifespan: A Narrative Review.

Atopic dermatitis (AD) is a chronic inflammatory skin condition that affects more than 200 million people worldwide, including up to 20% of children and 10% of the adult population. Although AD appears frequently in childhood and often continues into adulthood, about 1 in 4 adults develop the adult-onset disease. The prenatal period, early childhood, and adolescence are considered critical timepoints for the development of AD when the exposome results in long-lasting effects on the immune system. The exposome can be defined as the measure of all the exposures of an individual during their lifetime and how these exposures relate to well-being. While genetic factors could partially explain AD onset, multiple external environmental exposures (external exposome) in early life are implicated and are equally important for understanding AD manifestation. In this review, we describe the conceptual framework of the exposome and its relevance to AD from conception and across the lifespan. Through a spatiotemporal lens that focuses on the multi-level phenotyping of the environment, we highlight a framework that embraces the dynamic complex nature of exposome and recognizes the influence of additive and interactive environmental exposures. Moreover, we highlight the need to understand the developmental origins of AD from an age-related perspective when studying the effects of the exposome on AD, shifting the research paradigm away from the per se categorized exposome factors and beyond clinical contexts to explore the trajectory of age-related exposome risks and hence future preventive interventions.

Pharmacogenetic Analysis of the MIR146A rs2910164 and MIR155 rs767649 Polymorphisms and Response to Anti-TNF Treatment in Patients with Crohn's Disease and Psoriasis.

The clinical heterogeneity regarding the response profile of the antitumor necrosis factor (anti-TNF) in patients with Crohn's disease (CD) and psoriasis (PsO) is attributed, amongst others, to genetic factors that influence the regulatory mechanisms which orchestrate the inflammatory response. Here, we investigated the possible associations between the MIR146A rs2910164 and MIR155 rs767649 variants and the response to anti-TNF therapy in a Greek cohort of 103 CD and 100 PsO patients. We genotyped 103 CD patients and 100 PsO patients via the PCR-RFLP method, utilizing the de novo formation of a restriction site for the SacI enzyme considering the MIR146A rs2910164, while Tsp45I was employed for the MIR155 rs767649 variant. Additionally, we investigated the potential functional role of the rs767649 variant, exploring in silico the alteration of transcription factor binding sites (TFBSs) mapped on its genomic location. Our single-SNP analysis displayed a significant association between the rare rs767649 A allele and response to therapy (Bonferroni-corrected p value = 0.012) in patients with PsO, a result further enhanced by the alteration in the IRF2 TFBS caused by the above allele. Our results highlight the protective role of the rare rs767649 A allele in the clinical remission of PsO, implying its utilization as a pharmacogenetic biomarker.

Protein network and pathway analysis in a pharmacogenetic study of cyclosporine treatment response in Greek patients with psoriasis.

Although cyclosporine comprises a well-established systemic therapy for psoriasis, patients show important heterogeneity in their treatment response. The aim of our study was the pharmacogenetic analysis of 200 Greek patients with psoriasis based on the cyclosporine pathway related protein-protein interaction (PPI) network, reconstructed through the PICKLE meta-database. We genotyped 27 single nucleotide polymorphisms, mapped to 22 key protein nodes of the cyclosporine pathway, via the utilization of the iPLEX®GOLD panel of the MassARRAY® System. Single-SNP analyses showed statistically significant associations between CALM1 rs12885713 (P = 0.0108) and MALT1 rs2874116 (P = 0.0006) polymorphisms with positive response to cyclosporine therapy after correction for multiple comparisons, with the haplotype analyses further enhancing the predictive value of rs12885713 as a pharmacogenetic biomarker for cyclosporine therapy (P = 0.0173). Our findings have the potential to improve our prediction of cyclosporine efficacy and safety in psoriasis patients, as well as provide the framework for the pharmacogenetics of biological therapies in complex diseases.

Contribution of the Environment, Epigenetic Mechanisms and Non-Coding RNAs in Psoriasis.

Despite the increasing research and clinical interest in the predisposition of psoriasis, a chronic inflammatory skin disease, the multitude of genetic and environmental factors involved in its pathogenesis remain unclear. This complexity is further exacerbated by the several cell types that are implicated in Psoriasis's progression, including keratinocytes, melanocytes and various immune cell types. The observed interactions between the genetic substrate and the environment lead to epigenetic alterations that directly or indirectly affect gene expression. Changes in DNA methylation and histone modifications that alter DNA-binding site accessibility, as well as non-coding RNAs implicated in the post-transcriptional regulation, are mechanisms of gene transcriptional activity modification and therefore affect the pathways involved in the pathogenesis of Psoriasis. In this review, we summarize the research conducted on the environmental factors contributing to the disease onset, epigenetic modifications and non-coding RNAs exhibiting deregulation in Psoriasis, and we further categorize them based on the under-study cell types. We also assess the recent literature considering therapeutic applications targeting molecules that compromise the epigenome, as a way to suppress the inflammatory cutaneous cascade.

Pharmacogenetic analysis of canonical versus noncanonical pathway of NF-kB in Crohn's disease patients under anti-tumor necrosis factor-α treatment.

OBJECTIVES: This study explores the potential of gene polymorphisms in the canonical and noncanonical NF-kB signaling pathway as a prediction biomarker of anti-tumor necrosis factor (TNF)α response in Crohn's patients. MATERIALS AND METHODS: A total of 109 Greek patients with Crohn's disease (CD) were recruited, and the genotype of TLR2 rs3804099, LTA rs909253, TLR4 rs5030728, and MAP3K14/NIK rs7222094 single nucleotide polymorphisms was investigated for association with response to anti-TNFα therapy. Patient's response to therapy was based on the Crohn's Disease Activity Index, depicting the maximum response within 24 months after initiation of treatment. RESULTS: Seventy-three patients (66.7%) were classified as responders while 36 as nonresponders (33.3%). Comparing allelic frequencies between responders and nonresponders, the presence of TLR2 rs3804099 T allele was associated with nonresponse (P = 0.003), even after stratification by anti-TNFα drugs (infliximab: P = 0.032, adalimumab: P = 0.026). No other association was identified for the rest of the polymorphisms under study. Haplotype analysis further enhanced the association of rs3804099 T allele with loss of response, even though the results were NS (P = 0.073). CONCLUSION: Our results suggest that polymorphisms in the canonical NF-kB pathway genes could potentially act as a predictive biomarker of anti-TNFα response in CD.

Gene Expression Meta-Analysis of Potential Shared and Unique Pathways between Autoimmune Diseases under Anti-TNFα Therapy.

While anti-TNFα has been established as an effective therapeutic approach for several autoimmune diseases, results from clinical trials have uncovered heterogeneous patients' response to therapy. Here, we conducted a meta-analysis on the publicly available gene expression cDNA microarray datasets that examine the differential expression observed in response to anti-TNFα therapy with psoriasis (PsO), inflammatory bowel disease (IBD) and rheumatoid arthritis (RA). Five disease-specific meta-analyses and a single combined random-effects meta-analysis were performed through the restricted maximum likelihood method. Gene Ontology and Reactome Pathways enrichment analyses were conducted, while interactions between differentially expressed genes (DEGs) were determined with the STRING database. Four IBD, three PsO and two RA datasets were identified and included in our analyses through our search criteria. Disease-specific meta-analyses detected distinct pro-inflammatory down-regulated DEGs for each disease, while pathway analyses identified common inflammatory patterns involved in the pathogenesis of each disease. Combined meta-analyses further revealed DEGs that participate in anti-inflammatory pathways, namely IL-10 signaling. Our analyses provide the framework for a transcriptomic approach in response to anti-TNFα therapy in the above diseases. Elucidation of the complex interactions involved in such multifactorial phenotypes could identify key molecular targets implicated in the pathogenesis of IBD, PsO and RA.

PARP-1 Expression and BRCA1 Mutations in Breast Cancer Patients' CTCs.

BRCA1 and PARP are involved in DNA damage repair pathways. BRCA1 mutations have been linked to higher likelihood of triple negative breast cancer (TNBC). The aim of the study was to determine PARP-1 expression and BRCA1 mutations in circulating tumor cells (CTCs) of BC patients. Fifty patients were enrolled: 23 luminal and 27 TNBC. PARP expression in CTCs was identified by immunofluorescence. Genotyping was performed by PCR-Sanger sequencing in the same samples. PARP-1 expression was higher in luminal (61%) and early BC (54%), compared to TNBC (41%) and metastatic (33%) patients. In addition, PARP-1 distribution was mostly cytoplasmic in luminal patients (p = 0.024), whereas it was mostly nuclear in TNBC patients. In cytokeratin (CK)-positive patients, those with the CK+PARP+ phenotype had longer overall survival (OS, log-rank p = 0.046). Overall, nine mutations were detected; M1 and M2 were completely new and M4, M7 and M8 were characterized as pathogenic. M7 and M8 were predominantly found in metastatic TNBC patients (p = 0.014 and p = 0.002). Thus, PARP-1 expression and increased mutagenic burden in TNBC patients' CTCs, could be used as an indicator to stratify patients regarding therapeutic approaches.

Clinical and Genetic Predictors of Glycemic Control and Weight Loss Response to Liraglutide in Patients with Type 2 Diabetes.

Background: Evidence suggests a heterogeneous response to therapy with glucagon-like peptide-1 receptor agonists (GLP-1 RAs) in patients with type 2 diabetes mellitus (T2DM). The aim of this study is to identify the genetic and clinical factors that relate to glycemic control and weight loss response to liraglutide among patients with T2DM. Methods: The medical records of 116 adults with T2DM (51% female, mean body mass index 35.4 ± 6.4 kg/m2), who had been on treatment with liraglutide for at least 6 months and were genotyped for CTRB1/2 rs7202877 (T > G) polymorphism, were evaluated. Clinical and laboratory parameters were measured at baseline, 3, and 6 months after initiating liraglutide treatment. The good glycemic response was defined as one of the following: (i) achievement of glycated hemoglobin (HbA1c) < 7% (ii) reduction of the baseline HbA1c by ≥1%, and (iii) maintenance of HbA1c < 7% that a patient already had before switching to liraglutide. Weight loss responders were defined as subjects who lost ≥3% of their baseline weight. Results: Minor allele frequency was 16%. Individuals were classified as glycemic control and weight loss responders (81 (70%) and 77 (66%), respectively). Carriers of the rs7202877 polymorphic allele had similar responses to liraglutide treatment in terms of glycemic control (odds ratio (OR): 1.25, 95% confidence interval (CI): 0.4, 3.8, p = 0.69) and weight loss (OR: 1.12, 95% CI: 0.4, 3.2, p = 0.84). In the multivariable analysis, higher baseline HbA1c (adjusted OR: 1.45, 95% CI: 1.05, 2.1, p = 0.04) and lower baseline weight (adjusted OR: 0.97, 95% CI: 0.94, 0.99, p = 0.01) were associated with better glycemic response to liraglutide, while higher baseline weight was associated with worse weight response (adjusted OR: 0.97, 95% CI: 0.95, 0.99, p = 0.02). Conclusions: Specific patient features can predict glycemic and weight loss response to liraglutide in individuals with T2DM.

Exploring pharmacogenetic variants for predicting response to anti-TNF therapy in autoimmune diseases: a meta-analysis.

Aim: The aim of this study is to explore how SNPs may affect the response to anti-TNF-α therapy in the major autoimmune diseases, such as psoriasis, rheumatoid arthritis, inflammatory bowel diseases and Spondyloarthritis. Methodology: We conducted a systematic overview on the field, by assessing all studies that examined the association between polymorphisms and response to anti-TNF-α therapy in participants of European descent. Results: In total, six independent SNPs located in FCGR2A, FCGR3A, TNF-α and TNFRSF1B genes were significantly associated with response to TNF-α blockers, found mainly in disease-subgroup analyses. Conclusion: No common pharmacogenetic variant was identified for all autoimmune diseases under study, suggesting the requirement of more studies in the field in order to capture such predictive variants that will aid treatment selection.

Pharmacogenetics of the Glucagon-like Peptide-1 Receptor Agonist Liraglutide: A Step Towards Personalized Type 2 Diabetes Management.

BACKGROUND: Type 2 Diabetes Mellitus (T2DM) is a chronic metabolic disorder with increasing prevalence and a significant burden of long-term complications. Glucagon-like Peptide-1 receptor agonists (GLP-1 RAs) are a novel treatment option for T2DM, exerting optimal effects on glucose control and weight loss, and pleiotropic actions. Pharmacogenetics, a promising research field of precision medicine, investigates how gene variations can affect individual response to drug therapy, assuming that the diverse genetic architecture of patients with T2DM could be partly associated with the considerable inter-individual variability in the therapeutic response to GLP-1 RAs. This review aims to summarize current evidence related to T2DM risk variants, affecting the incretin pathway, focus on the pharmacogenetics of the GLP-1 RA liraglutide, and discuss their potential clinical implications in the management of this complex disorder. METHODS: A literature search was performed using electronic biomedical databases, and the findings of key studies are summarized and discussed in this narrative review. RESULTS: Available evidence suggests the involvement of genetic polymorphisms in GLP-1 Rgene in variation in glycemic response, metabolic parameters and gastric emptying in people treated with liraglutide. Polymorphisms in CNR1, CTRB1/2, TMEM114 and CHST3 loci were also shown to be implicated in the disturbance of the incretin homeostasis in T2DM. These findings warrant further investigation by future studies. CONCLUSION: Robust findings from pharmacogenetic studies might be used to identify good responders to liraglutide treatment, in terms of both glycemic and weight control, thus reinforcing the patient-centered approach of T2DM management.

Evaluation of 12 GWAS-drawn SNPs as biomarkers of rheumatoid arthritis response to TNF inhibitors. A potential SNP association with response to etanercept.

Research in rheumatoid arthritis (RA) is increasingly focused on the discovery of biomarkers that could enable personalized treatments. The genetic biomarkers associated with the response to TNF inhibitors (TNFi) are among the most studied. They include 12 SNPs exhibiting promising results in the three largest genome-wide association studies (GWAS). However, they still require further validation. With this aim, we assessed their association with response to TNFi in a replication study, and a meta-analysis summarizing all non-redundant data. The replication involved 755 patients with RA that were treated for the first time with a biologic drug, which was either infliximab (n = 397), etanercept (n = 155) or adalimumab (n = 203). Their DNA samples were successfully genotyped with a single-base extension multiplex method. Lamentably, none of the 12 SNPs was associated with response to the TNFi in the replication study (p > 0.05). However, a drug-stratified exploratory analysis revealed a significant association of the NUBPL rs2378945 SNP with a poor response to etanercept (B = -0.50, 95% CI = -0.82, -0.17, p = 0.003). In addition, the meta-analysis reinforced the previous association of three SNPs: rs2378945, rs12142623, and rs4651370. In contrast, five of the remaining SNPs were less associated than before, and the other four SNPs were no longer associated with the response to treatment. In summary, our results highlight the complexity of the pharmacogenetics of TNFi in RA showing that it could involve a drug-specific component and clarifying the status of the 12 GWAS-drawn SNPs.

Validation study of genetic biomarkers of response to TNF inhibitors in rheumatoid arthritis.

Genetic biomarkers are sought to personalize treatment of patients with rheumatoid arthritis (RA), given their variable response to TNF inhibitors (TNFi). However, no genetic biomaker is yet sufficiently validated. Here, we report a validation study of 18 previously reported genetic biomarkers, including 11 from GWAS of response to TNFi. The validation was attempted in 581 patients with RA that had not been treated with biologic antirheumatic drugs previously. Their response to TNFi was evaluated at 3, 6 and 12 months in two ways: change in the DAS28 measure of disease activity, and according to the EULAR criteria for response to antirheumatic drugs. Association of these parameters with the genotypes, obtained by PCR amplification followed by single-base extension, was tested with regression analysis. These analyses were adjusted for baseline DAS28, sex, and the specific TNFi. However, none of the proposed biomarkers was validated, as none showed association with response to TNFi in our study, even at the time of assessment and with the outcome that showed the most significant result in previous studies. These negative results are notable because this was the first independent validation study for 12 of the biomarkers, and because they indicate that prudence is needed in the interpretation of the proposed biomarkers of response to TNFi even when they are supported by very low p values. The results also emphasize the requirement of independent replication for validation, and the need to search protocols that could increase reproducibility of the biomarkers of response to TNFi.