Genetic markers of treatment response to tumour necrosis factor-α inhibitors in the treatment of psoriasis

The Role of Genetics on Psoriasis Susceptibility, Comorbidities, and Treatment Response

This review highlights advances made in psoriasis genetics, including findings from genome-wide association studies, exome-sequencing studies, and copy number variant studies. The impact of genetic variants on various comorbidities and therapeutic responses is discussed.

Psoriasis: Striving for Potential Biomarkers

Psoriasis is a chronic disease that is caused by multiple factors and is identified by itchiness, unpleasant, red, or white scaly patches on the skin, particularly on regularly chafed body regions such as the lateral areas of the limbs. Reports suggest that globally around 2%-3% of the population suffers from psoriasis. In this review, we have discussed the clinical classification of psoriasis and also the ideal characteristics of the biomarkers. An overview regarding the discovery of the biomarker and method for validating the study has been discussed. A growing body of research suggests a link to certain other systemic symptoms such as cardiovascular disorder, metabolic syndrome, and few other comorbidities such as hypertension and nonalcoholic fatty liver disease. Natural killer (NK) cells are lymphocyte cells that concentrate on the destruction of virally infected and malignant cells; these tend to produce a wide range of inflammatory cytokines, some of which are associated with the etiology of psoriasis. Detailed information on the molecular pathogenesis of psoriasis in which interleukin (IL)-17, IL-23, tumor necrosis factor-α (TNF-α), and CCL20 play a very significant role in the development of psoriasis. In this review, we have discussed an overview of the recent state of the biomarkers available for the diagnosis and treatment of psoriasis by emphasizing on the available biomarkers such as epigenomic, transcriptomic, glycomic, and metabolomic. The most recent advancements in molecular-targeted therapy utilizing biologics and oral systemic therapy (methotrexate, apremilast) enable to adequately treat the most serious psoriatic symptoms and also the studies have validated the efficacy of biologic therapy such as TNF-α antagonist (infliximab, adalimumab), IL-23 antagonist (guselkumab, risankizumab), and IL-17 antagonist (secukinumab, ixekizumab). Finally, an overview about the technological opportunities as well as various challenges has been discussed.

Genetic Influence on Treatment Response in Psoriasis: New Insights into Personalized Medicine

Psoriasis is a chronic inflammatory disease with an established genetic background. The HLA-Cw*06 allele and different polymorphisms in genes involved in inflammatory responses and keratinocyte proliferation have been associated with the development of the disease. Despite the effectiveness and safety of psoriasis treatment, a significant percentage of patients still do not achieve adequate disease control. Pharmacogenetic and pharmacogenomic studies on how genetic variations affect drug efficacy and toxicity could provide important clues in this respect. This comprehensive review assessed the available evidence for the role that those different genetic variations may play in the response to psoriasis treatment. One hundred fourteen articles were included in this qualitative synthesis. VDR gene polymorphisms may influence the response to topical vitamin D analogs and phototherapy. Variations affecting the ABC transporter seem to play a role in methotrexate and cyclosporine outcomes. Several single-nucleotide polymorphisms affecting different genes are involved with anti-TNF-α response modulation (TNF-α, TNFRSF1A, TNFRSF1B, TNFAIP3, FCGR2A, FCGR3A, IL-17F, IL-17R, and IL-23R, among others) with conflicting results. HLA-Cw*06 has been the most extensively studied allele, although it has only been robustly related to the response to ustekinumab. However, further research is needed to firmly establish the usefulness of these genetic biomarkers in clinical practice.

Impact of Functional Polymorphisms on Drug Survival of Biological Therapies in Patients with Moderate-to-Severe Psoriasis

Biological therapies (BTs) indicated for psoriasis are highly effective; however, not all patients obtain good results, and loss of effectiveness is the main reason for switching. Genetic factors may be involved. The objective of this study was to evaluate the influence of single-nucleotide polymorphisms (SNPs) on the drug survival of tumor necrosis factor inhibitors (anti-TNF) medications and ustekinumab (UTK) in patients diagnosed with moderate-to-severe psoriasis. We conducted an ambispective observational cohort study that included 379 lines of treatment with anti-TNF (n = 247) and UTK (132) in 206 white patients from southern Spain and Italy. The genotyping of the 29 functional SNPs was carried out using real-time polymerase chain reaction (PCR) with TaqMan probes. Drug survival was evaluated with Cox regression and Kaplan-Meier curves. The multivariate analysis showed that the HLA-C rs12191877-T (hazard ratio [HR] = 0.560; 95% CI = 0.40-0.78; p = 0.0006) and TNF-1031 (rs1799964-C) (HR = 0.707; 95% CI = 0.50-0.99; p = 0.048) polymorphisms are associated with anti-TNF drug survival, while TLR5 rs5744174-G (HR = 0.589; 95% CI = 0.37-0.92; p = 0.02), CD84 rs6427528-GG (HR = 0.557; 95% CI = 0.35-0.88; p = 0.013) and PDE3A rs11045392-T together with SLCO1C1 rs3794271-T (HR = 0.508; 95% CI = 0.32-0.79; p = 0.002) are related to UTK survival. The limitations are the sample size and the clustering of anti-TNF drugs; we used a homogeneous cohort of patients from 2 hospitals only. In conclusion, SNPs in the HLA-C, TNF, TLR5, CD84, PDE3A, and SLCO1C1 genes may be useful as biomarkers of drug survival of BTs indicated for psoriasis, making it possible to implement personalized medicine that will reduce financial healthcare costs, facilitate medical decision-making and improve patient quality of life. However, further pharmacogenetic studies need to be conducted to confirm these associations.

Psoriasis improvements and inflammatory biomarker normalization with secukinumab: the randomized ObePso-S study

BACKGROUND

The IL-17A inhibitor secukinumab has demonstrated consistent efficacy and safety in patients with moderate-to-severe plaque psoriasis, with normalization of molecular and histopathologic psoriasis markers.

OBJECTIVE

To investigate treatment effects of secukinumab on clinical signs and psoriatic inflammation markers over 52 weeks in patients with psoriasis.

METHODS

In the ObePso-S study (NCT03055494), patients with psoriasis were randomized 2:1 to receive secukinumab 300 mg (n = 54) or placebo (n = 28), stratified by body weight (<90 or ≥90 kg), for 52 weeks. At Week 12, patients receiving placebo were switched to secukinumab. Psoriasis Area and Severity Index improvement of 90% (PASI90) and Investigator's Global Assessment modified 2011 0/1 responses were assessed at Weeks 12 and 52. Immunohistochemistry for keratin 16 (K16) and gene expression profiles were evaluated in lesional and non-lesional skin biopsies collected at baseline, Week 12, and Week 52.

RESULTS

Of patients receiving secukinumab, 55.8% and 59.6% achieved PASI90 at Weeks 12 and 52, respectively. K16 was absent in 93.1% of Week 12 PASI90 responders and 93.6% of Week 52 PASI90 responders, which mirrored the down-regulated expression of psoriatic inflammation. Week 52 PASI90 non-responders experienced regression of clinical and inflammatory marker responses toward baseline levels. Lower control of inflammatory gene expression at Week 12 was associated with suboptimal clinical responses at Week 52.

CONCLUSION

Sustained clinical responses with secukinumab were associated with rapid and sustained normalization of K16 and inflammatory gene expression in most patients. Molecular anti-inflammatory effects of secukinumab at Week 12 were associated with clinical responses at Week 52.

Towards Personalized Medicine in Psoriasis: Current Progress

Although innovative targeted therapies have positively revolutionized psoriasis treatment shifting treatment goals to complete or almost complete skin clearance, primary or secondary lack of efficacy is still possible. Hence, identifying robust biomarkers that reflect the various clinical psoriasis phenotypes would allow stratify patients in subgroups or endotypes, and tailor treatments according to the characteristics of each individual (precision medicine). To sum up the current progress in personalized medicine for psoriasis, we performed a review on the available evidence on biomarkers predictive of response to psoriasis treatments, with focus on phototherapy and systemic agents. Relevant literature published in English was searched for using the following databases from the last five years up to March 20, 2022: PubMed, Embase, Google Scholar, EBSCO, MEDLINE, and the Cochrane library. Currently, more evidence exists towards biologicals, as justified by the huge health care costs as compared to phototherapy or conventional systemic drugs. Among them, most of the studies focused on anti-TNF and IL12/23, with still few on IL17 (mainly secukinumab). The most discussed biomarker gene is the HLA-C*02:06 status that has been shown to be associated with psoriasis, and also differential response to biologicals. Although its positivity is associated with great response to MTX, debatable results were retrieved concerning both anti-TNF and IL12/23 while it seems not to affect secukinumab response. Personalized treatment in psoriasis would provide excellent outcome minimizing the risk of side effects. To date, although several candidates were proposed and assessed, the scarcity and heterogeneity of the results do not allow the identification of the gold-standard biomarker per each treatment. Anyway, the creation of a more comprehensive panel would be more reliable for the treatment decision process.

Clinical Application of Pharmacogenetic Markers in the Treatment of Dermatologic Pathologies

Dermatologic pathologies are the fourth most common cause of non-fatal disease worldwide; however, they produce a psychosocial, economic, and occupational impact equal to or greater than other chronic conditions. The most prevalent are actinic keratosis, followed by basal-cell carcinoma, in a lesser proportion acne vulgaris, psoriasis, and hidradenitis suppurativa, among others, and more rarely dermatitis herpetiformis. To treat actinic keratosis and basal-cell carcinoma, 5-fluorouracil (5-FU) 0.5% is administered topically with good results, although in certain patients it produces severe toxicity. On the other hand, dapsone is a drug commonly used in inflammatory skin conditions such as dermatitis herpetiformis; however, it occasionally causes hemolytic anemia. Additionally, biologic drugs indicated for the treatment of moderate-to-severe psoriasis and hidradenitis suppurativa have proved to be effective and safe; nevertheless, a small percentage of patients do not respond to treatment with biologics in the long term or they are ineffective. This interindividual variability in response may be due to alterations in genes that encode proteins involved in the pathologic environment of the disease or the mechanism of action of the medication. Pharmacogenetics studies the relationship between genetic variations and drug response, which is useful for the early identification of non-responsive patients and those with a higher risk of developing toxicity upon treatment. This review describes the pharmacogenetic recommendations with the strongest evidence at present for the treatments used in dermatology, highlighting those included in clinical practice guides. Currently, we could only find pharmacogenetic clinical guidelines for 5-FU. However, the summary of product characteristics for dapsone contains a pharmacogenetic recommendation from the United States Food and Drug Administration. Finally, there is an enormous amount of information from pharmacogenetic studies in patients with dermatologic pathologies (mainly psoriasis) treated with biologic therapies, but they need to be validated in order to be included in clinical practice guides.

Biomarkers predictive of treatment response in psoriasis and psoriatic arthritis: a systematic review

AIMS

The ability to predict response to treatment remains a key unmet need in psoriatic disease. We conducted a systematic review of studies relating to biomarkers associated with response to treatment in either psoriasis vulgaris (PsV) or psoriatic arthritis (PsA).

METHODS

A search was conducted in PubMed, Embase and the Cochrane library from their inception to 2 September 2020, and conference proceedings from four major rheumatology conferences. Original research articles studying pre-treatment biomarker levels associated with subsequent response to pharmacologic treatment in either PsV or PsA were included.

RESULTS

A total of 765 articles were retrieved and after review, 44 articles (22 relating to PsV and 22 to PsA) met the systematic review's eligibility criteria. One study examined the response to methotrexate, one the response to tofacitinib and all the other studies to biologic disease-modifying antirheumatic drugs (DMARDs). Whilst several studies examined the HLA-C*06 allele in PsV, the results were conflicting. Interleukin (IL)-12 serum levels and polymorphisms in the IL-12B gene show promise as biomarkers of treatment response in PsV. Most, but not all, studies found that higher baseline levels of C-reactive protein (CRP) were associated with a better clinical response to treatment in patients with PsA.

CONCLUSION

Several studies have identified biomarkers associated with subsequent response to treatment in psoriatic disease. However, due to the different types of biomarkers, treatments and outcome measures used, firm conclusions cannot be drawn. Further validation is needed before any of these biomarkers translate to clinical practice.

Influence of Genetic Polymorphisms on Response to Biologics in Moderate-to-Severe Psoriasis

Psoriasis is a chronic inflammatory skin pathology of autoimmune origin and unknown etiology. There are various therapies for treating it, including a wide range of biopharmaceuticals indicated in moderate-to-severe psoriasis. Depending on their therapeutic target, they are classified as tumor necrosis factor inhibitors (anti-TNF) or cytokine inhibitors (interleukin-12, 23, and 17 antagonists). Although they have proved effective and safe, in clinical practice, many patients show a short- and long-term suboptimal response and even varying degrees of toxicity. This variability in response may be influenced by genetic factors, such as polymorphisms in the genes involved in the pathological environment, metabolism or mechanism of action of the drug that could affect the effectiveness and toxicity of biological therapies. This review assesses pharmacogenetic studies of the impact of genetic factors on response to biopharmaceuticals and toxicity in patients diagnosed with moderate-to-severe psoriasis. The results suggest that polymorphisms detected in the HLA genes, in genes that encode cytokines (TNF, IL genes, TNFAIP3), transporters (PDE3A-SLCO1C1, SLC12A8), receptors (TNFRSF1B, CD84, FCGR2A and FCGR3A, IL17RA, IL23R, TLR genes, PGLYRP4) and associated proteins (TNFAIP3, LY96, TIRAP, FBXL19), as well as other genes implicated in the pathogenesis of psoriasis (CDKAL1, CARD14, PTTG1, MAP3K1, ZNF816A, GBP6, CTNNA2, HTR2A, CTLA4, TAP1) can be used in the future as predictive markers of treatment response and/or toxicity with biological therapies in patients diagnosed with moderate-to-severe psoriasis, tailoring treatment to the individual patient.

HLA-Cw6 status and treatment responses between psoriasis patients

Background

The number of treatment options in psoriasis has increased considerably, so biomarkers should be searched to assist in the selection of the optimal treatment agent. The most common of these biomarkers is HLA-Cw6.

Objective:

The aim was to determine whether there is a relationship between HLA-Cw6-positivity (HLA-Cw6-POS) and the response of treatment agents in psoriasis.

Methods:

Blood samples of 124 patients were subjected to genetic study for HLA-Cw6.

Results:

Psoriasis area severity index (PASI) score of more than 75% (PASI75) response was received in 34 (73.9%) of the HLA-Cw6-POS methotrexate-treated patients, 30 (78.9%) of the HLA-Cw6-POS cyclosporine-treated patients, and 8 (37.5%) of the HLA-Cw6-POS acitretin-treated patients. The differences were not statistically significant (P = 0.634-0.071-0.409). PASI75 response was received in 73 (68.2%) of the HLA-Cw6-POS patients in patients treated with conventional agents. In adalimumab-treated patients, PASI75 response was received in 8 (53.3%) of the HLA-Cw6-POS patients, 6 (75%) of the HLA-Cw6-POS infliximab-treated patients, and 4 (57.1%) of the HLA-Cw6-POS ustekinumab-treated patients. The differences were not statistically significant (P = 0.245-1.00-0.322). PASI75 response was received in 24 (64.9%) of the HLA-Cw6-POS and 33 (84.6%) of HLA-Cw6 negative (HLA-Cw6-NEG) patients with biological agents. The biological agent response was statistically significantly lower in HLA-Cw6-POS.

Conclusion:

None of the agents were affected by HLA-Cw6. When biological agents were evaluated collectively, the treatment response of HLA-Cw6-POS patients was lower.

Pharmacogenetics Update on Biologic Therapy in Psoriasis

Background and objectives: Psoriasis is a chronic immune-mediated skin disease caused by several complex factors, both environmental and genetic, many of which are still not fully understood. Nowadays, several groups of biological drugs are being used for psoriasis treatment. Although these therapies are very effective, they show significant variability in efficacy among individuals. Therefore, there is a need for biomarkers to predict treatment outcomes in order to guide personalized therapeutic decisions. Pharmacogenetics is the study of variations in DNA sequences related to drug response. Materials and Methods: In this article, we review pharmacogenetics studies on the treatment of moderate-to-severe psoriasis focusing on anti-interleukin (IL) 12/23 (ustekinumab) and anti-IL17 drugs (secukinumab and ixekizumab), as well as recent studies concerning anti-TNF drugs. Results: Several polymorphisms have been studied over the years in reference to anti-TNF drugs; some of the most recent studies included the performance of a genome-wide association study (GWAS) and pharmacogenetics studies focused on the optimization of a treatment regimen. Various polymorphisms in different genes have been related to ustekinumab response; among them, the most commonly studied is the HLA-C*06:02 allele. Conclusions: Although not confirmed in some studies, most studies have shown that patients carrying this allele present a significantly higher response rate to ustekinumab. Some polymorphisms have been studied in patients treated with anti-IL17 drugs, mostly related to secukinumab; however, up to now, no association has been found between any of these polymorphisms and response. Nevertheless, further studies involving larger cohorts are needed in order to confirm these results before the implementation of this biomarker in clinical practice.

Assessment of the Relationship between Clinical Variants of Psoriasis and Killer Immunoglobulin-like Receptor (KIR) Genes: A Systematic Review with Meta-analysis

BACKGROUND

Psoriasis (Ps) is an autoimmune dermatosis. Previous studies have shown an association between KIR genes and susceptibility to some clinical variants of Ps. Therefore, we conducted an exhaustive systematic review with meta-analysis to evaluate the relationship between KIR genes and susceptibility to clinical variants of Ps in the overall population and according to ethnicity.

METHODS

According to PRISMA guidelines, we performed a systematic review through PubMed and Web of Science to identify relevant available scientific publications about KIR genes and Ps. The quality of the studies was evaluated using the Newcastle-Ottawa scale. Odds ratios (OR) and 95% confidence intervals (95%CI) were estimated using random and fixed effect models for the analyzed genes. Heterogeneity was tested using Cochran's Q-Statistic and I², and the risk of bias was tested using the Begg test and Egger linear regression.

RESULTS

A total of 10 case-control studies were included, comprising a variable number of KIR typified genes and psoriasis vulgaris (PsV) as the main clinical variant studied. In the total pooled results, the KIR2DS1 gene (OR = 1.518, p = .010, 95%CI: 1.105 to 2.086) was related to higher susceptibility to PsV, while the KIR2DS4 (OR = 0.563, p = .005, 95%CI: 0.376 to 0.842) and KIR3DL1 (OR = 0.602, p = .040, 95%CI: 0.370 to 0.977) genes were related to protection against PsV.

CONCLUSION

This meta-analysis demonstrates that subjects that carry the KIR2DS1 gene could have a potential risk factor for the development of PsV. Conversely, KIR2DS4 and 3DL1 genes appear to confer protection against PsV.

Applying precision medicine to unmet clinical needs in psoriatic disease

Psoriatic disease (PsD) is a heterogeneous condition that can affect peripheral and axial joints (arthritis), entheses, skin (psoriasis) and other structures. Over the past decade, considerable advances have been made both in our understanding of the pathogenesis of PsD and in the treatment of its diverse manifestations. However, several major areas of continued unmet need in the care of patients with PsD have been identified. One of these areas is the prediction of poor outcome, notably radiographic outcome in patients with psoriatic arthritis, so that stratified medicine approaches can be taken; another is predicting response to the numerous current and emerging therapies for PsD, so that precision medicine can be applied to rapidly improve clinical outcome and reduce the risk of toxicity. In order to address these needs, novel approaches, including imaging, tissue analysis and the application of proteogenomic technologies, are proposed as methodological solutions that will assist the dissection of the critical immune-metabolic pathways in this complex disease. Learning from advances made in other inflammatory diseases, it is time to address these unmet needs in a multi-centre partnership aimed at improving short-term and long-term outcomes for patients with PsD.

The HLA-Cw6 Dilemma: Is It Really an Outcome Predictor in Psoriasis Patients under Biologic Therapy? A Monocentric Retrospective Analysis

HLA-Cw6 is one of the most strongly associated psoriasis susceptibility alleles. Data regarding correlation between HLA-Cw6 status and biologic treatment outcomes are divergent. The aim of our study in our cohort of psoriatic patients was to explore if the HLA-Cw6 status influences the response rate to biologic therapies at 16 and 48 weeks. One hundred and one psoriatic patients eligible for biologic therapies were enrolled. HLA-C*06 alleles were detected from their blood samples. The effectiveness of antipsoriatic treatments was reported as 90% Psoriasis Area and Severity Index reduction (PASI90). All biologics showed efficacy at week 16, without significant differences between one another. HLA-Cw6 status did not seem to affect baseline characteristics, or treatment response at week 16. At week 48, IL-12/23 and IL-17 targeting drugs were more effective on Cw6-positive patients than on Cw6-negative patients. Conversely, TNF-targeting drugs seemed to be more effective on Cw6- negative patients than on Cw6-positive patients. The HLA-Cw6 test could well deserve to be integrated into the clinical laboratory work-up supporting the choice of the correct biologic.

Predictors of drug survival of biologic therapies in psoriasis patients

INTRODUCTION

We aimed to investigate the clinical, immunological, and genetic factors affecting the response to anti-TNFα (tumor necrosis factor-α) and interleukin-12/23 therapies and drug survivals.

METHODS

A total of 180 patients were divided into two groups: 89 patients who used at least two biologic agents, with the initial biologic agent used less than 12 months (group A), and 91 biologic-naive patients who have been receiving a single biologic agent for more than 12 months (group B). ELISA (enzyme-linked immunosorbent assay) was used to analyze anti-drug antibodies (ADAs) in blood samples. Clinical data of the patients were retrospectively analyzed. HLA-SSO (sequence-specific oligonucleotide) Typing Kits were used for HLA-C typing. IBM SPSS v.21 was used for statistical analysis.Results: Infliximab had the longest drug survival as the first biologic agent in group A (p = .015). Etanercept had the lowest ADA count compared to the other anti-TNF agents (p = .001). HLA-Cw6 negativity, late-onset psoriasis, smoking and alcohol use were determined to be risk factors for treatment failure in group A. HLA-Cw6 was found to be associated with type I psoriasis (p = .000).

CONCLUSIONS

Although our study is retrospective of a relatively low number of patients, this is a preliminary study focusing on two different patient populations based on therapy response.

Pharmacogenetics and Pharmacogenomics in Moderate-to-Severe Psoriasis

Pharmacogenetics is the study of variations in DNA sequence related to drug response. Moreover, the evolution of biotechnology and the sequencing of human DNA have allowed the creation of pharmacogenomics, a branch of genetics that analyzes human genes, the RNAs and proteins encoded by them, and the inter-and intra-individual variations in expression and function in relation to drug response. Pharmacogenetics and pharmacogenomics are being used to search for biomarkers that can predict response to systemic treatments, including those for moderate-to-severe psoriasis. Psoriasis is a chronic inflammatory disease with an autoimmune contribution. Although its etiology remains unknown, genetic, epigenetic, and environmental factors play a role in its development. Diverse systemic and biologic therapies are used to treat moderate-to-severe psoriasis. However, these treatments are not curative, and patients exhibit a wide range of responses to them. Moderate-to-severe psoriasis is usually treated with systemic immunomodulators such as acitretin, ciclosporin, and methotrexate. Anti-tumor necrosis factor (TNF) drugs (adalimumab, etanercept, or infliximab) are the first-line treatment for patients resistant to conventional systemic therapies. Although these therapies are very efficient, around 30-50% of patients have inadequate response. Ustekinumab is a monoclonal antibody that targets interleukin (IL)-12 and IL-23 and is used for moderate-to-severe psoriasis. New drugs (apremilast, brodalumab, guselkumab, ixekizumab, and secukinumab) have recently been approved for psoriasis. However, response rates to systemic treatments for moderate-to-severe psoriasis range from 35 to 80%, so it is necessary to identify non-invasive biomarkers that could help predict treatment outcomes of these therapies and individualize care for patients with psoriasis. These biomarkers could improve patient quality of life and reduce health costs and potential side effects. Pharmacogenetic studies have identified potential biomarkers for response to biologic treatments for moderate-to-severe psoriasis. These biomarkers need to be validated in clinical trials involving large cohorts of patients before they can be translated to the clinic. We review pharmacogenetics and pharmacogenomics studies for the treatment of moderate-to-severe plaque psoriasis.

HLA-Cw6 and psoriasis

Psoriasis is a multifactorial disease with a strong genetic background. HLA-Cw6 is one of the most strongly associated psoriasis susceptibility alleles. It is repeatedly observed to affect disease course, phenotypic features, severity, comorbidities and treatment outcomes. To the best of our knowledge, the roles of HLA-Cw6 in psoriasis have not yet been thoroughly reviewed. The worldwide frequency of the HLA-Cw6 allele varies greatly, with it being generally higher in white people than in Asians. The allele is associated with type I early-onset psoriasis. Stress, obesity and streptococcal pharyngitis are commonly observed in HLA-Cw6-positive patients. Phenotypically, HLA-Cw6 has been found to be associated with guttate psoriasis. In addition, patients carrying the allele are more likely to have arm, leg and trunk involvement, and the Koebner phenomenon. Patients with psoriatic arthritis with HLA-Cw6 more often have early onset and tend to show cutaneous symptoms before musculoskeletal symptoms. HLA-Cw6-positive patients have been shown in several studies to be more responsive to methotrexate and ustekinumab. However, this difference in ustekinumab efficacy was only moderate in a post-hoc analysis of a pivotal phase III study. HLA-Cw6 positivity also tends to be less frequent in high-need patients who fail conventional therapy. Small studies have also investigated the role of HLA-Cw6 in remission of psoriasis during pregnancy, and with the comorbidities of photosensitivity and atherosclerosis. Given the diverse nature of psoriasis pathogenesis, as well as the difference of HLA-Cw6 positivity in different ethnic groups, more studies are needed to confirm the role of HLA-Cw6 in psoriasis.

The Pathophysiological Mechanisms and the Quest for Biomarkers in Psoriasis, a Stress-Related Skin Disease

Psoriasis is a physically, emotionally, and socially invalidating multifactorial disorder, with a significant impact on the patients' quality of life. Stress is one of the leading triggers for psoriasis and has been associated with disease onset and subsequent flare-ups, while the flare-ups by themselves often lead to psychological discomfort. The treatment of psoriasis is individualized, depending on the patients' measurable severity of illness, as well as the impact the skin condition has on patients' quality of life, as assessed by standardized questionnaires. The clinical scales used nowadays for measuring the severity of psoriasis are characterized by low reproducibility and high variability between examiners. Hence, there is a real need to identify objectively measurable biomarkers to standardize the assessment of the severity of psoriasis. We aim to review the pathophysiological mechanisms involved in psoriasis, focusing on the most critical advances in psoriasis biomarker discovery, pointing out those biomarkers which have also been studied in other stress-related conditions, thus emphasizing the relationship between psoriasis and stress.

Polymorphisms associated with adalimumab and infliximab response in moderate-to-severe plaque psoriasis

Aim: This study evaluated the influence of pharmacogenetics in psoriatic patients treated with adalimumab and/or infliximab. Materials & methods: Prospective observational study evaluating the association of 124 polymorphisms with the response to adalimumab or infliximab (PASI75) in patients with moderate-to-severe plaque psoriasis at 3 months (n = 95) and 6 months of treatment (n = 90). Significant SNPs for univariate analysis were subjected to multivariate analysis. Results: Five SNPs were associated with PASI75 at 3 months: rs6661932 (IVL), rs2546890 (IL-12B), rs2145623 (NFKBIA), rs9304742 (ZNF816A) and rs645544 (SLC9A8). Furthermore, rs1061624 (TNFR1B) was associated with PASI75 at 6 months. Conclusion: Nevertheless, these biomarkers should be validated in large-scale studies before implementation in clinical practice.

A systematic review of pharmacogenetic studies on the response to biologics in patients with psoriasis

BACKGROUND

Biologics are indicated for treating moderate-to-severe psoriasis. As the number of biologics registered for the treatment of psoriasis increases, so does the need for biomarkers to guide personalized therapeutic decisions. Genetic variants might serve as predictors for treatment response, a field of research known as pharmacogenetics.

OBJECTIVES

To assess which genetic variants are associated with response to biologics in patients with psoriasis according to current literature.

METHODS

A systematic search was performed in Embase, MEDLINE, the Cochrane Library and Web of Science. In total, 26 papers were included in this systematic review; 24 original studies and two meta-analyses. Quality was assessed using a predesigned form and risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

The majority of studies reported a candidate gene approach, focusing on polymorphisms in genes related to the therapeutic target or to psoriasis susceptibility. Studied populations were small and results were divergent, especially for studies investigating tumour necrosis factor inhibitors. The evidence for the role of HLA-Cw6 in ustekinumab efficacy shows minimal heterogeneity, with a higher response rate among patients who were positive for HLA-Cw6 reported across three of five studies.

CONCLUSIONS

Pharmacogenetic studies in psoriasis have generated divergent results. Replication of findings in larger cohorts is required. Large-scale hypothesis-free searches for genetic biomarkers are needed to uncover the complete genetic background of outcomes for treatment with biologics.

HLA-C and TNF gene polymorphisms are associated with psoriasis in Brazilian patients

BACKGROUND

Polymorphisms at the human leukocyte antigens (HLA-C) and tumor necrosis factor (TNF) genes have been associated with susceptibility to psoriasis in several worldwide populations. In this study, HLA-C and TNF (-238/-308) polymorphisms were performed in 125 Brazilian patients and 202 healthy controls.

METHODS

HLA-C and TNF promoter region alleles were typed by polymerase chain reaction using sequence-specific primer-polymerase chain reaction.

RESULTS

The presence of HLA-C*06 was associated with psoriasis onset, particularly in younger patients, being more frequent for patients with disease onset before the age of 20 years (P = 0.03), 25 years (P = 0.01), or 30 years (P = 0.03). No association between HLA-C*06 and psoriasis was observed for patients older than 35 years. Susceptibility to psoriatic arthritis was associated with the TNF -238 G/A genotype (P = 0.02). The TNF -308A allele was overrepresented in patients (P = 0.0061), and the TNF -308 G/A genotype was increased in generalized forms (erythrodermic and generalized pustular psoriasis) compared to plaque psoriasis (P < 0.001). The TNF -238A/HLA-C*06 haplotype was overrepresented in patients (P = 0.025), while the TNF -238G/HLA-C*15 haplotype was increased in controls (P = 0.037).

CONCLUSIONS

The strong association of HLA-C*06 allele with disease susceptibility, particularly in early onset psoriasis, indicates that younger ages could be considered to stratify psoriasis into early and late types. TNF -308 polymorphisms can be associated with psoriasis susceptibility and severity. Potential genetic markers of psoriasis in populations with a complex mixture of ethnicities should be investigated.

Development of clinical prediction models for good or bad response to classic systemic drugs, anti-TNFs, and ustekinumab in psoriasis, based on the BIOBADADERM cohort

BACKGROUND

Identifying patients likely to have very good or bad results from systemic psoriasis therapy could improve efficiency of therapy.

OBJECTIVE

To develop prognostic models for good or bad response to classic systemic drugs, anti-TNFs, and ustekinumab in psoriasis.

METHODS

Multivariable logistic regression of a prospective multicenter cohort of psoriatic patients in clinical practice (6449 person-years of follow-up). We used as possible predictors demographic characteristics, comorbidities, characteristics of the psoriasis (type, PASI, arthritis), history of past therapy at entry in the cohort, and history of response to previous cycles while in the cohort. We defined good response to a treatment cycle as either cycle end due to disease remission or a cycle longer than 2 years that does not end later due to inefficacy in the follow-up period. Bad response to a treatment cycle was defined as a cycle that is finished due to inefficacy, based on the physician judgment, after more than 3 months of treatment.

RESULTS

Patients with fewer previous therapies, lower body mass index, older at start of therapy, and with previous history of good responses to therapy are more likely to have positive results of therapy. However, the predictive characteristics of models are poor.

CONCLUSION

Predictive models of clinical response to systemic drugs in psoriasis with the studied variables do not seem to outperform drug selection by a dermatologist.