Association between several immune response-related genes and the effectiveness of biological treatments in patients with moderate-to-severe psoriasis.

Biological therapies are safer and more effective against psoriasis than conventional treatments. Even so, 30-50% of psoriatic patients show an inadequate response, which is associated with individual genetic heterogeneity. Pharmacogenetic studies have identified several single nucleotide polymorphisms (SNPs) as possible predictive and prognostic biomarkers for psoriasis treatment response. The objective of this study was to determine the link between several SNPs and the clinical response to biological therapies in patients with moderate-severe psoriasis. A set of 21 SNPs related to psoriasis and/or other immunological diseases were selected and analysed from salivary samples of patients (n = 88). Treatment effectiveness and patient improvement was assessed clinically through Relative Psoriasis Area and Severity Index (PASI), also called 'PASI response', as well as absolute PASI. Associations between SNPs and PASI factors were assessed at 3 and 12 months for every treatment category of IL-17, IL-23, IL-12&23 and TNF-α inhibitors. Multivariate correlation analysis and Fisher's exact test were used to analyse the relationship between SNPs and therapy outcomes. Several SNPs located in the TLR2, TLR5, TIRAP, HLA-C, IL12B, SLC12A8, TNFAIP3 and PGLYRP4 genes demonstrated association with increased short and long-term therapy-effectiveness rates. Most patients achieved values of PASI response ≥75 or absolute PASI<1, regardless of the biological treatment administered. In conclusion, we demonstrate a relationship between different SNPs and both short- and especially long-term effectiveness of biological treatment in terms of PASI. These polymorphisms may be used as predictive markers of treatment response in patients with moderate-to-severe psoriasis, providing personalized treatment.

Genetic variants associated with skin photosensitivity in a southern European population from Spain.

BACKGROUND/PURPOSE: Recent GWAS studies, mostly performed in populations of North European origin, have identified the genetic loci associated with pigmentation, sun sensitivity, freckling and skin cancer susceptibility. Here, we aimed at addressing the genetic determinants of sunlight sensitivity in Spain, a southern European population. METHODS: Nine SNPs located in 8 pigmentation-related genes (IRF4, TYR, ASP, HERC2, OCA2, BNC2, SLC24A4 and SLC45A2) were genotyped in 456 Spaniards. Additionally, the complete sequence of the MC1R gene was obtained, testing each nonsynonymous mutation supported by the classification as R or r alleles. A standardised questionnaire was used to collect demographic characteristics, pigmentation and sun sensitivity traits, as well as sun exposure habits. RESULTS: MC1R R alleles and IRF4 rs12203592 were significantly associated with sunlight sensitivity at the Bonferroni-corrected level (P-value < 4.54 × 10-3 ). Genetic variants in SLC45A2 (rs16891982) and HERC2 (rs12913832) were also found to be significantly associated with skin photosensitivity in our Spanish sample. Interaction analysis using the MDR method revealed epistatic effects when these four variants were considered together. CONCLUSION: MC1R, IRF4, HERC2 and SLC45A2 play a significant role in skin sensitivity to sunlight in the Spanish population. Moreover, interaction among these four loci seems to modulate the ability of the skin to respond to UV radiation.

Topical application of the adenosine A2A receptor agonist CGS-21680 prevents phorbol-induced epidermal hyperplasia and inflammation in mice.

The nucleoside adenosine is a known regulator of immunity and inflammation that mediates, at least in part, the anti-inflammatory effect of methotrexate, an immunosuppressive agent widely used to treat autoimmune inflammatory diseases. Adenosine A2A receptors play a key role in the inhibition of the inflammatory process besides promoting wound healing. Therefore, we aimed to determine the topical effect of a selective agonist, CGS-21680, on a murine model of skin hyperplasia with a marked inflammatory component. Pretreatment with either CGS-21680 (5 µg per site) or the reference agent dexamethasone (200 µg/site) prevented the epidermal hyperplasia and inflammatory response induced by topical application of 12-O-tetradecanoylphorbol-13-acetate (TPA, 2 nmol/site) for three consecutive days. The histological analysis showed that both CGS-21680 and dexamethasone produced a marked reduction of inflammatory cell infiltrate, which correlated with diminished myeloperoxidase (MPO) activity in skin homogenates. Both treatments reduced the levels of the chemotactic mediators LTB4 and CXCL-1, and the inflammatory cytokine TNF-α, through the suppression of NFκB phosphorylation. The immunohistochemical analysis of the hyperproliferative markers cytokeratin 6 (CK6) and Ki67 revealed that while both agents inhibit the number of proliferating cells in the epidermis, CGS-21680 treatment promoted dermal fibroblasts proliferation. Consistently, increased collagen deposition in dermis was observed in tissue sections from agonist-treated mice. Our results showed that CGS 21680 efficiently prevents phorbol-induced epidermal hyperplasia and inflammation in mice without the deleterious atrophic effect of topical corticosteroids.

Improved effectiveness from individualized dosing of self-administered biologics for the treatment of moderate-to-severe psoriasis: a 5-year retrospective chart review from a Spanish University Hospital.

Background: Biologics for moderate-to-severe psoriasis are expensive and treatment substitutions may vastly increase cost. Moreover, administration regimens in routine practice may differ from recommended guidelines.Objectives: To evaluate long-term effectiveness, regimen, drug-survival, and efficiency of self-administered biologics in clinical practice.Methods: We performed a 5-year retrospective study in 72 patients (44 ± 14 years old) with moderate-to-severe psoriasis at the University Hospital La Plana (Vila-real, Spain), treated with subcutaneous biologics. We determined the effectiveness (PASI 75 or PASI < 5), and drug-survival using Kaplan-Meier estimates, and analyzed reasons for treatment interruption, drug substitution patterns, and costs.Results: Etanercept was less effective (45%) than ustekinumab (85%) and adalimumab (71%). In 15% of patients, optimal responses were maintained despite dose intervals lengthening. Drug-survival was significantly lower for etanercept than for the other biologics (p < .005). Most adalimumab and etanercept discontinuations were due to adverse events or lack of effectiveness; for ustekinumab the causes were unrelated to drug effects. Ustekinumab was 100% effective as a secondary biologic.Conclusion: Ustekinumab was the safest and most efficient treatment. Etanercept showed the highest treatment failure rate, incurring higher costs. Dosage individualization according to patient needs improves the therapy efficiency, reducing therapeutic failure and derived costs.

Defective Induction of COX-2 Expression by Psoriatic Fibroblasts Promotes Pro-inflammatory Activation of Macrophages.

Fibroblasts play an important role as members of the innate immune system through the secretion of COX-2-derived inflammatory mediators such as prostaglandin E2 (PGE2). However, it has been described that dermal fibroblasts behave like mesenchymal stem cells reducing lymphocyte recruitment and dendritic cell activation through PGE2 release. As the role of fibroblasts in psoriasis remains poorly characterized, in the present study we have evaluated the possible influence of PGE2 derived from dermal fibroblasts as modulator of the immune response in psoriatic skin. Our results indicate that under inflammatory conditions, psoriatic fibroblasts showed defective induction of COX-2, which resulted in diminished production of PGE2, in contrast to healthy fibroblasts. This phenotype correlated with deficient c-Jun N-terminal kinase (JNK) activation, in accordance with the hypothesis that alterations in members of the JNK pathway are associated with psoriasis. Furthermore, conditioned medium from psoriatic fibroblasts promoted the polarization of monocytic cells toward a pro-inflammatory profile, effect that was mimicked in healthy fibroblasts after pre-incubation with indomethacin. These results are consistent with a prominent role of dermal fibroblasts in the regulation of inflammatory response through the participation of COX-derived metabolites. This resolutive behavior seems to be defective in psoriatic fibroblasts, offering a possible explanation for the chronification of the disease and for the exacerbation triggered by nonsteroidal anti-inflammatory drugs (NSAIDS) such as indomethacin.

Adenosine A2A and A2B Receptors Differentially Modulate Keratinocyte Proliferation: Possible Deregulation in Psoriatic Epidermis.

Adenosine is a potent regulator of inflammation and immunity, but the role of adenosine receptors in keratinocytes remains controversial. We determined that in addition to A2B receptors, human epidermal keratinocytes also express A2A receptors, although to a lower extent. Through the use of selective adenosine receptor agonists and antagonists, we showed that physiological concentrations of adenosine activate A2B receptors in normal human keratinocytes, inducing cell cycle arrest through the increase of intracellular calcium but not through cAMP signaling. In contrast, the selective activation of A2A receptors by CGS-21680 induces keratinocyte proliferation via p38-mitogen-activated protein kinase activation. Adenosine and selective A2A and A2B agonists presented anti-inflammatory profiles independent of adenosine receptors but mediated by membrane phosphatase activation. Finally, keratinocyte exposure to diverse inflammatory cytokines altered adenosine receptor expression by reducing A2B and increasing A2A, a pattern also observed in psoriatic epidermis. Because increased epidermal turnover and inflammatory response are characteristics of psoriatic disease, further studies are needed to assess the role and consequences of the altered adenosine receptor expression in lesional and nonlesional psoriatic keratinocytes.

A customized pigmentation SNP array identifies a novel SNP associated with melanoma predisposition in the SLC45A2 gene.

As the incidence of Malignant Melanoma (MM) reflects an interaction between skin colour and UV exposure, variations in genes implicated in pigmentation and tanning response to UV may be associated with susceptibility to MM. In this study, 363 SNPs in 65 gene regions belonging to the pigmentation pathway have been successfully genotyped using a SNP array. Five hundred and ninety MM cases and 507 controls were analyzed in a discovery phase I. Ten candidate SNPs based on a p-value threshold of 0.01 were identified. Two of them, rs35414 (SLC45A2) and rs2069398 (SILV/CKD2), were statistically significant after conservative Bonferroni correction. The best six SNPs were further tested in an independent Spanish series (624 MM cases and 789 controls). A novel SNP located on the SLC45A2 gene (rs35414) was found to be significantly associated with melanoma in both phase I and phase II (P<0.0001). None of the other five SNPs were replicated in this second phase of the study. However, three SNPs in TYR, SILV/CDK2 and ADAMTS20 genes (rs17793678, rs2069398 and rs1510521 respectively) had an overall p-value<0.05 when considering the whole DNA collection (1214 MM cases and 1296 controls). Both the SLC45A2 and the SILV/CDK2 variants behave as protective alleles, while the TYR and ADAMTS20 variants seem to function as risk alleles. Cumulative effects were detected when these four variants were considered together. Furthermore, individuals carrying two or more mutations in MC1R, a well-known low penetrance melanoma-predisposing gene, had a decreased MM risk if concurrently bearing the SLC45A2 protective variant. To our knowledge, this is the largest study on Spanish sporadic MM cases to date.