Human leukocyte antigen (HLA) and single nucleotide polymorphisms (SNPs) tumor necrosis factor (TNF)-alpha -238 and -308 as genetic markers of susceptibility to psoriasis and severity of the disease in a long-term follow-up Brazilian study

Association between tumor necrosis factor-alpha polymorphisms (rs361525, rs1800629, rs1799724, 1800630, and rs1799964) and risk of psoriasis in studies following Hardy-Weinberg equilibrium: A systematic review and meta-analysis

Objective

Psoriasis is a disease with an immunogenetic background in which cytokines have important effects on its prevalence and incidence. The present meta-analysis evaluated the relationship between tumor necrosis factor-alpha (TNF-α) polymorphisms (rs361525, rs1800629, rs1799724, 1800630, and rs1799964) and psoriasis risk in studies following Hardy-Weinberg equilibrium (HWE).

Materials and methods

Four databases were searched to retrieve relevant studies reporting the distributions of TNF-α polymorphisms in psoriasis cases compared to controls. The effect sizes were the 95% confidence intervals (CIs) and odds ratios (ORs). Subgroup analysis, sensitivity analyses, publication bias, trial sequential analysis (TSA), and meta-regression were performed on the initial pooled results of TNF-α polymorphisms.

Results

Thirty-six articles with 71 studies were included in the meta-analysis (twenty-six: rs361525, twenty-seven: rs1800629, nine: rs1799724, four: 1800630, and five: rs1799964). The pooled ORs for -238 G/A rs361525 polymorphism were 2.33 (p < 0.00001), 2.79 (p < 0.0001), 2.35 (p < 0.00001), 2.44 (p < 0.00001), and 2.45 (p < 0.00001), as well as 1.57 (p < 0.00001), 1.98 (p = 0.01), 1.61 (p < 0.00001), 1.64 (p < 0.00001), and 1.79 (p < 0.00001) for -857 C/T rs1799724 polymorphism in allelic, homozygous, heterozygous, dominant, and recessive models, respectively. Ethnicity, psoriasis type, and sample size affected the pooled results of rs361525, rs1800629, and rs1799724 polymorphisms. Based on TSA, there were just sufficient cases for -238 G/A rs361525 polymorphism in five genetic models and -857C/T rs1799724 polymorphism in allelic, heterozygous, and dominant models.

Conclusions

The A allele and GA and GG genotypes of -238 G/A rs361525 polymorphism and T allele, TT and CT genotypes of -857C/T rs1799724 polymorphism were related to increased risks in psoriasis cases. Well-designed studies (with no deviation from HWE in controls) with more cases are recommended in the future.

TNFα gene -238G>A polymorphism is associated with psoriasis patients

BACKGROUND

Tumor Necrosis Factor α (TNFα) is a protein that plays a key role in the pathophysiology of chronic inflammatory disorders like psoriasis.

AIMS

The goal of this study was to see if the TNFα gene -238G>A polymorphism was linked to psoriasis susceptibility.

METHODS

This study comprised ninety psoriasis patients and ninety healthy controls. For the TNFa gene -238G>A polymorphism, genomic DNA was extracted and genotyped using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) studies.

RESULTS

Psoriasis patients had higher frequencies of the A allele and the AA genotype than the control group, and psoriasis was linked to the AA genotype (OR = 4.25, 95% CI = 1.37-13.1, p = 0.008) and the A allele (OR = 1.55, 95% CI = 1.01-2.34, p = 0.04). Patients with a family history of psoriasis showed an increase in the frequency of the AA genotype compared to GG and GA genotypes (respectively, 46.7%, 36.7%, and 16.7%, p = 0.003). Furthermore, psoriasis patients with the AA genotype were discovered more commonly among those under 30 years old and male patients than those with the GG and GA genotypes, but the differences were not statistically significant.

CONCLUSION

The TNFa gene -238G>A polymorphism has been related to an increased incidence of psoriasis.

Tumor Necrosis Factor-α 308 G/A polymorphism and psoriasis risk: A pooled analysis in different populations

More and more researches have been carried out on the association between the tumor necrosis factor-α (TNF-α) 308 G/A polymorphism and psoriasis, however, controversial results have emerged in these studies. This meta-analysis was performed to quantitatively clarify the relationship between TNF-α 308 G/A polymorphism and the risk of psoriasis in different populations. Databases of PubMed, Springer Link, Ovid, Chinese Wanfang Data Bases, Chinese National Knowledge Infrastructure and Chinese Biology Medicine were investigated until June 2019. The association between the TNF-α 308 G/A polymorphism and psoriasis was evaluated by calculating the pooled odds ratio (OR) and 95% confidence intervals (CIs). A total of 26 studies including 3657 patients and 3197 controls were screened out. In the overall population, the pooled results showed a reduced psoriasis risk with the TNF-α 308 G/A polymorphism (A vs G: OR = 0.77, 95% CI = 0.67-0.89; AA+GA vs GG: OR = 0.72, 95% CI = 0.61-0.86). In the subgroup analysis stratified by geographic locations, the TNF-α 308 G/A polymorphism was significantly associated with a reduced risk of psoriasis in Germany (A vs G: OR = 0.67, 95% CI = 0.57-0.78; AA+GA vs GG: OR = 0.62, 95% CI = 0.52-0.75), as well as in China (AA+GA vs GG: OR = 0.71, 95% CI = 0.52-0.98) and Poland (A vs G: OR = 0.61, 95% CI = 0.38-0.97; AA+GA vs GG: OR = 0.59, 95% CI = 0.35-0.99). This study indicated a significantly reduced psoriasis risk associated with the TNF-α 308 G/A polymorphism in Germans, as well as in Chinese and Poles populations compared with other populations. Ethnicity and geographic locations probably play a pivotal role in the genetic association of psoriasis.

Cytokines in psoriasis

Psoriasis is chronic, immune-mediated, inflammatory disease with a multifactorial etiology that affects the skin tissue and causes the appearance of dry and scaly lesions of anywhere on the body. The study of the pathophysiology of psoriasis reveals a network of immune cells that, together with their cytokines, initiates a chronic inflammatory response. Previously attributed to T helper (Th)1 cytokines, currently the Th17 cytokine family is the major effector in the pathogenesis of psoriatic disease and strongly influences the inflammatory pattern established during the disease activity. In addition, the vast network of cells that orchestrates the pathophysiology makes psoriasis complex to study. Along with this, variations in genes that code the cytokines make psoriasis more clinically heterogeneous and present a challenge for the development of drugs that can be used in the treatment of the patients with this disease. Therefore, it is important to clarify the mechanisms by which the cytokines are involved in the pathophysiology of psoriasis and how this knowledge is translated to the medical practice.

Hypomethylation of HLA-DRB1 and its clinical significance in psoriasis

Increasing evidences indicate that the abnormal DNA methylation is involved in the pathogenesis of psoriasis. A number of SNPs in HLA-DRB1 have been found being associated with the risk of psoriasis, however it is unclear that metylation status within HLA-DRB1 in psoriasis. Here, DNA and RNA were obtained from epidermis of 56 patients with plaque psoriasis and 28 healthy volunteers served as the control group. For the first time, we discovered mean methylation rate for HLA-DRB1 is 52.2%, 64.3% and 68.1% in epidermis from psoriatic lesions, psoriatic non-lesions and healthy controls, respectively. HLA-DRB1 methylation in psoriatic lesions is significantly lower than in psoriatic non-lesions (t = 13.077, p < 0.001). However, there is no significant difference for HLA-DRB1 methylation between in psoriatic non-lesions and in healthy controls (t = 1.046, p = 0.299). HLA-DRB1 methylation in psoriatic lesions is negatively correlated to PASI score (r = -0.431, p = 0.001). HLA-DRB1 methylation in psoriatic lesions of the patients with onset age≤18 years is significantly lower than the other patients (t = 3.968, p < 0.001). Meanwhile, HLA-DRB1 mRNA expression is significantly increased in psoriatic lesions comparing to psoriatic non-lesions (t = 12.119, p < 0.001). There are no significant difference for HLA-DRB1 mRNA expression between in psoriatic non-lesions and in healthy controls (t = 1.172, p = 0,245). Moreover, HLA-DRB1 mRNA expression is negatively associated with HLA-DRB1 methylation in psoriatic lesions (r = 0.932, p < 0.001). In conclusions, our results showed hypomethylation of HLA-DRB1 is associated with HLA-DRB1 mRNA expression and severity of the disease, indicating that hypomethylation of HLA-DRB1 may play roles in the pathogenesis of psoriasis.

Geographic tongue and psoriasis: clinical, histopathological, immunohistochemical and genetic correlation - a literature review

Geographic tongue is a chronic, inflammatory, and immune-mediated oral lesion of unknown etiology. It is characterized by serpiginous white areas around the atrophic mucosa, which alternation between activity, remission and reactivation at various locations gave the names benign migratory glossitis and wandering rash of the tongue. Psoriasis is a chronic inflammatory disease with frequent cutaneous involvement and an immunogenetic basis of great importance in clinical practice. The association between geographic tongue and psoriasis has been demonstrated in various studies, based on observation of its fundamental lesions, microscopic similarity between the two conditions and the presence of a common genetic marker, human leukocyte antigen (HLA) HLA-C*06. The difficulty however in accepting the diagnosis of geographic tongue as oral psoriasis is the fact that not all patients with geographic tongue present psoriasis. Some authors believe that the prevalence of geographic tongue would be much greater if psoriatic patients underwent thorough oral examination. This study aimed to develop a literature review performed between 1980 and 2014, in which consultation of theses, dissertations and selected scientific articles were conducted through search in Scielo and Bireme databases, from Medline and Lilacs sources, relating the common characteristics between geographic tongue and psoriasis. We observed that the frequency of oral lesions is relatively common, but to establish a correct diagnosis of oral psoriasis, immunohistochemical and genetic histopathological analyzes are necessary, thus highlighting the importance of oral examination in psoriatic patients and cutaneous examination in patients with geographic tongue.

Tumor necrosis factor alpha gene promoter -238G/A polymorphism increases the risk of psoriasis vulgaris in Indian patients

BACKGROUND

Tumor necrosis factor alpha (TNFα) gene -238G/A polymorphism (rs361525) is associated with psoriasis in several populations worldwide. To the best of our knowledge, there is no information about this polymorphism in Indian psoriatic patients. This study was undertaken to fill the gap in knowledge.

METHODS

This case-control study involved 72 patients with psoriasis vulgaris (PsV) and 72 age and gender matched healthy individuals. TNFα -238G/A polymorphism was genotyped by PCR-RFLP method.

RESULTS

TNFα -238A allele was 5 times commoner in PsV patients than in the control group (P = 4.1 × 10^-7 ; odds ratio [OR] = 6.5 [0.95 CI: 2.9-14.6]). Distribution of the genotypes in the two groups showed statistically significant difference in dominant genetic model (P = 2.3 × 10^-7 ) and not in recessive genetic model (P = 2.5 × 10^-1 ). Odds ratio for the occurrence of -238A genotype in PsV patients was 8.8 (0.95 CI: 3.5-20.2). The association showed no major difference when PsV patients were subgrouped into type I and type II categories and tested separately. Subgroup analysis on the basis of disease severity showed higher association with the moderate-severe subgroup (P = 2.4 × 10^-9 , OR 15.4 [0.95 CI: 5.8-41.0]) than with mild subgroup (P = 1.3 × 10^-2 , OR 3.8 [0.95 CI: 1.3-10.9]).

CONCLUSIONS

Our results indicate that TNFα gene -238G/A polymorphism increases the risk of developing psoriasis vulgaris among Indians. Also, the data show that severity and not the type affects the strength of association in this population.

Is there any increased risk of hypertension, diabetes and cardiac diseases in psoriatic patients with TNF-α G238A and G308A polymorphism?

Introduction

Psoriasis is regarded as a complex autoimmune disease with strong genetic background. Psoriatic patients suffer from many comorbidities including hypertension, diabetes and cardiovascular diseases. Cytokines such as tumor necrosis factor α (TNF-α) may be a key player that triggers psoriasis and diabetes, hypertension and cardiac disease at the same time.

Aim

To evaluate genetic variations in the TNF-α region and its association with psoriasis and related comorbidities.

Material and methods

The study covered 129 psoriasis patients with three main subgroups with coronary artery disease (n = 41), hypertension (n = 35), and diabetes (n = 21). DNA samples were genotyped for TNF-α G308A and G238A polymorphisms by real-time polymerase chain reaction melting-curve analysis and results were compared statistically.

Results

Psoriatic patients with both TNF-α-298 and TNF-α-308 polymorphisms showed no statistically significant increase in the risk of hypertension (OR = 0.425, χ² = 1.76, p = 0.18 and OR = 1.87, χ² = 1.33, p = 0.25), coronary artery disease (OR = 1.97, χ² = 1.91, p = 0.17 and OR = 2.63, χ² = 1.35, p = 0.25), or diabetes (OR = 1.35, χ² = 0.24, p = 0.62 and OR = 1.53, χ² = 0.24, p = 0.62).

Conclusions

The current preliminary results suggested that there was no correlation between TNF-α promoter polymorphism and diabetes, hypertension and cardiac disease among psoriatic patients in the Turkish population.

Candidate gene polymorphisms and risk of psoriasis: A pilot study

Psoriasis is a complex genetic disease, which has previously been associated with numerous single nucleotide polymorphisms (SNPs) that are implicated in various processes, including skin barrier functions and in the regulation of inflammatory and immune responses. The present study aimed to investigate the genotypic and allelic frequencies of 32 SNPs at 24 genetic loci, and their association with psoriasis in a Mexican population. These SNPs, which were associated with psoriasis in previous studies, included the following genes: Major histocompatibility complex class I-C (HLA-C), interleukin (IL)-12B, IL-23R, IL-23A, IL-28RA, tumor necrosis factor (TNF)-α, ring finger protein-114 (RNF114), cyclin-dependent kinase 5 regulatory subunit-associated protein 1-like 1, late cornified envelope 3B/3C, signal transducer and activator of transcription 4, LINC01185, interferon induced with helicase C domain 1, IL-13, TNF-α-induced protein 3 (TNFAIP3), TNFAIP3 interacting protein 1, endoplasmic reticulum aminopeptidase 1, TNF receptor-associated factor interacting protein 2, Leptin, nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor-alpha, F-box and leucine-rich repeat protein 19, nitric oxide synthase 2, cluster of differentiation 40, nuclear receptor coactivator 5, and ADAM metallopeptidase domain 33. A total of 32 male and 14 female subjects with a clinical diagnosis of chronic plaque psoriasis, as well as 103 control subjects, were analyzed. Molecular analyses were performed using TaqMan® assays in a TaqMan® OpenArray® Genotyping system. Results were analyzed using the Golden Helix SNP and Variation Suite 7 program. Of the 32 SNPs, six were associated with an increased risk of developing psoriasis, including: HLA-C rs10484554 [allele T: odds ratio (OR) 3.51], IL-12B rs3212227 (allele T: OR 1.88), IL-12B rs3213094 (allele C: OR 1.94), HLA complex group 27 rs1265181 (allele C: OR 2.83), annexin A6 rs17728338 (allele A: OR 2.41), and RNF114 rs6125829 (allele G: OR 1.98). Fisher's exact test detected statistical significance; however, following false discovery rate and Bonferroni correction, this association was no longer significant (threshold for genome-wide significance, P<1.56×10⁻³). SNPs that were associated with an increased risk of psoriasis in the present study have previously been associated with psoriasis in European, American, and Asian populations. In order to establish genome-wide significance, future studies must analyze a greater sample size. To the best of our knowledge, the present pilot study is the first to investigate the association between these 32 SNPs and psoriasis in a Mexican Mestizo population.

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.

HLA-C*12:02 is a susceptibility factor in late-onset type of psoriasis in Japanese

Psoriasis is thought to be a multifactorial disease triggered by both genetic and environmental factors. The HLA-C locus on chromosome 6p21.33 remains the strongest susceptibility candidate locus in psoriasis. The strong association between psoriasis and the HLA-Cw6 allele has been well documented in various races. It is known that psoriatic patients with early onset are more likely to be familial and associated with HLA-Cw6. Familial occurrence of Japanese psoriasis is smaller than other populations. Furthermore, males are predominant over females in Japanese psoriasis. We investigated the relation between HLA-C alleles and age of onset, and in each gender for Japanese psoriasis, and discuss male predominance in the incidence of psoriasis in Japan. Four hundred forty six unrelated Japanese patients with psoriasis vulgaris and 557 sex- and age-matched unrelated Japanese healthy controls were investigated by genotyping. We confirmed the association between early-onset type of psoriasis with HLA-C*06:02 allele in Japanese. In addition, we detected the association between the late-onset type of psoriasis and the HLA-C*12:02 allele in Japanese. No significant differences in allele frequency were observed between females and males. Our results suggest that there is no genetic factor effect on male predominance in Japanese. In contract, the effect of environmental risk factors on the onset of Japanese psoriatic patients is stronger in males than in females. As a result, male predominant in psoriasis may occur in Japan.

TNF, IL12B, and IFNG Gene Polymorphisms in Serbian Patients with Psoriasis

Background

Psoriasis is a common chronic inflammatory skin disease with a strong genetic basis. Cytokines such as tumor necrosis factor alpha (TNF-α), interleukins (ILs) such are IL-12 and IL-23, and interferon gamma (IFN-γ) are released from various inflammatory and resident cells, and have been implicated in the initiation/maintenance of inflammation. Certain alleles of the aforementioned cytokines may be associated with disease susceptibility/severity.

Objective

To investigate the association of three common functional gene polymorphisms, namely TNF -308 G/A (rs1800629), IL12B (encoding the p40 subunit of IL-12/23) +1188 A/C (rs3212227), and IFNG +874 T/A (rs2430561) with psoriasis development and severity in Serbian patients.

Methods

We genotyped 130 patients with psoriasis (26 of whom also had psoriatic arthritis) and 259 controls; rs1800629 and rs3212227, and rs2430561, by real-time PCR assay.

Results

The TNF GG genotype was detected at a higher frequency in patients with psoriasis compared to control subjects (OR, 1.420; 95% CI, 0.870~2.403) without statistical significance (p=0.191). Lack of the TNF G allele was associated with lower psoriasis severity (p=0.007). The IL12B AC genotype was underrepresented in the patients with psoriatic arthritis compared to healthy subjects (OR, 0.308; 95% CI, 0.090~1.057; p=0.049). The distribution of the rs2430561 allele and genotype frequencies was similar between patients with psoriasis and controls.

Conclusion

Our study demonstrates an effect of the rs1800629 on psoriasis severity, and a marginal impact of the rs3212227 on susceptibility to psoriatic arthritis. Collectively, our results obtained in a Serbian cohort expand current knowledge regarding individual predisposition to psoriatic disease.

Genetic and epigenetic basis of psoriasis pathogenesis

Psoriasis is a chronic inflammatory skin disease whose prevalence varies among different populations worldwide. It is a complex multi-factorial disease and the exact etiology is largely unknown. Family based studies have indicated a genetic predisposition; however they cannot fully explain the disease pathogenesis. In addition to genetic susceptibility, environmental as well as gender and age related factors were also been found to be associated. Recently, imbalances in epigenetic networks are indicated to be causative elements in psoriasis. The present knowledge of epigenetic involvement, mainly the DNA methylation, chromatin modifications and miRNA deregulation is surveyed here. An integrated approach considering genetic and epigenetic anomalies in the light of immunological network may explore the pathogenesis of psoriasis.

A possible relationship of human leucocyte antigens with psoriasis vulgaris and geographic tongue

BACKGROUND

Geographic tongue (GT) is the most frequent oral lesion in psoriatic patients (PP), and genetic involvement in these conditions has been described. The association of psoriasis with GT is still not clear, and the study of human leucocyte antigen (HLA) may help clarify this relation.

OBJECTIVE

The aim of this study was to investigate the association of HLA alleles with psoriasis vulgaris and GT.

METHODS

Fifty-eight Brazilian PP, 29 GT patients and 125 healthy controls individuals were selected. Information on demographic and clinical characteristics was collected. All patients underwent an oral examination and blood collection for HLA typing.

RESULTS

HLA-A did not show significant differences in frequencies among the groups. HLA-B*57 allele was more frequently found in PP and was not found in GT. HLA-B*58 allele was more frequently found in GT. HLA-C*06 and -C*18 alleles were associated with psoriasis. No significant differences in HLA-DRB1 and HLA-DQB1 were observed.

CONCLUSION

HLA-B*58 was associated with GT and HLA-B*57 was possibly associated with psoriasis. This suggested that some GT cases may represent true oral psoriasis and some may represent only GT. Therefore, it is necessary to make this distinction and increase our sample size to improve the correct diagnosis and treatment of these conditions.

Associations between tumor necrosis factor-α polymorphisms and risk of psoriasis: a meta-analysis

Background

Tumor necrosis factor-α (TNF-α) may play an important role in the recalcitrant inflammatory and hyperproliferative dermatosis of psoriasis, and there may be a relationship between TNF-α polymorphisms and psoriasis risk.

Methods

We performed a meta-analysis to evaluate the associations between TNF-α polymorphisms and psoriasis. Electronic searches of Pubmed, Embase, and Web of Science were performed for all publications on the associations between TNF-α polymorphisms and psoriasis through September 26, 2012. The pooled odds ratios (ORs) with their 95% confidence interval (95%CIs) were calculated to assess the associations.

Results

Sixteen case-control studies with a total of 2,253 psoriasis cases and 1,947 controls on TNF-α 308 G/A polymorphism and fourteen studies on TNF-α 238 G/A polymorphism with 2,104 cases and 1,838 controls were finally included into the meta-analysis. Overall, TNF-α 308 G/A polymorphism was significantly associated with decreased risk of psoriasis under three genetic comparison models (for A versus G: fixed-effects OR 0.71, 95%CI 0.62-0.82, P < 0.001; for AG versus GG: fixed-effects OR 0.67, 95%CI 0.57-0.78, P < 0.001; for AA/AG versus GG: fixed-effects OR 0.67, 95%CI 0.58-0.78, P < 0.001). In addition, TNF-α 238 G/A polymorphism was associated with increased risk of psoriasis under three genetic models (for A versus G: fixed-effects OR 2.46, 95%CI 2.04-2.96, P < 0.001; for AG versus GG: fixed-effects OR 2.69, 95%CI 2.20-3.28, P < 0.001; for AA/AG versus GG: fixed-effects OR 2.68, 95%CI 2.20-3.26, P < 0.001). Subgroup analysis by ethnicity identified a significant association between TNF-α 308 G/A polymorphism and decreased risk of psoriasis in both Caucasians and Asians and a significant association between TNF-α 238 G/A polymorphism and increased risk of psoriasis in Caucasians.

Conclusions

The meta-analysis suggests that TNF-α 308 G/A polymorphism is associated with decreased risk of psoriasis, while TNF-α 238 G/A is associated with increased risk of psoriasis.

Single nucleotide polymorphisms in the tumor necrosis factor-alpha gene promoter region alter the risk of psoriasis vulgaris and psoriatic arthritis: a meta-analysis

BACKGROUND

It has been confirmed that tumor necrosis factor-alpha (TNFα), a macrophage-derived pro-inflammatory cytokine, plays an important role in the pathogenesis of psoriasis vulgaris and psoriatic arthritis (PsV&PsA). In contrast, the reported association of TNFα gene promoter region single nucleotide polymorphisms (SNPs) and PsV&PsA has remained controversial. Accordingly, we performed a meta-analysis to provide new evidence that SNPs in the TNFα gene promoter region alter not only the risk of psoriasis vulgaris (PsV) or psoriatic arthritis (PsA) but also of PsV&PsA.

METHODS

Interrelated literature dated to October 2012 was acquired from the PubMed, ScienceDirect, and SpringerLink databases. The number of the genotypes and/or alleles for the TNFα promoter in the PsV and PsA and control subjects was obtained. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to calculate the risk of PsV and/or PsA with TNFα promoter SNPs.

RESULTS

A total of 26 papers of 2159 for PsV (2129 normal controls) and 2360 for PsA (2997 normal controls) were included in our meta-analysis. The results showed that the variant genotype and allele of TNFα -308A/G was protective in pooled groups of patients with PsV&PsA (OR = 0.682, 0.750; 95% CI, 0.596-0.779, 0.653-0.861). However, the variant genotypes and alleles of TNFα -238A/G and -857T/C had an increased risk of PsV&PsA (OR = 2.493, 2.228, 1.536, 1.486, 95% CI, 1.777-3.498, 1.628-3.049, 1.336-1.767, 1.309-1.685). Moreover, the meta-analysis revealed a significant association between TNFα -238A/G and -857T/C polymorphism and PsA susceptibility (OR = 2.242, 2.052, 1.419, 1.465; 95% CI, 1.710-2.941, 1.614-2.610, 1.214-1.658, 1.277-1.681). In contrast, the variant genotypes and alleles of TNFα -308A/G proved to be protective against PsV (OR = 0.574, 0.650, 95% CI, 0.478-0.690, 0.556-0.759), whereas TNFα -238A/G was found to have a risk association (OR = 2.636, 2.223, 95% CI, 1.523-4.561, 1.317-3.751).

CONCLUSIONS

SNPs in the TNFα gene promoter region alter the risk of PsV and/or PsA.

Investigation of 20 non-HLA (human leucocyte antigen) psoriasis susceptibility loci in Chinese patients with psoriatic arthritis and psoriasis vulgaris

BACKGROUND

Recently, a number of non-HLA (human leucocyte antigen) psoriasis genetic susceptibility loci have been identified through genome-wide association studies, but data on their association with psoriatic arthritis (PsA) are lacking.

OBJECTIVES

To investigate recently identified psoriasis susceptibility loci in a cohort of Chinese patients with PsA, psoriasis vulgaris (PsV) and healthy controls.

METHODS

Twenty single-nucleotide polymorphisms (SNPs) from 20 loci were selected for genotyping in 379 patients with PsA, 595 patients with PsV and 1181 healthy controls using the MassARRAY platform (Sequenom, San Diego, CA, U.S.A.). Data handling, quality control and association were performed using PLINK software, v. 1.07. The Cochran-Armitage trend test was used to test the genotype-phenotype association.

RESULTS

PsA showed a significant association with markers at TNIP1 (rs17728338, P = 2.20 × 10(-8)), IL28RA (rs4649203, P = 5.04 × 10(-6)), IL12B (rs2082412, P = 3.82 × 10(-5)), ERAP1 (rs27524, P = 1.25 × 10(-3)), PTTG1 (rs2431697, P = 1.22 × 10(-3)) and GJB2 (rs3751385, P = 1.48 × 10(-3)) when compared with the control group. In PsV a significant association was found for IL28RA (rs4649203, P = 9.53 × 10(-7)), TNIP1 (rs17728338, P = 1.21 × 10(-4)) and ERAP1 (rs27524, P = 1.17 × 10(-3)). The allele frequencies were not statistically different between PsA and PsV except for SNPs at IL12B and ZNF816A with a nominal P-value of 0.04 and 0·01, respectively.

CONCLUSIONS

This study provides evidence for the involvement of ERAP1, IL28RA, GJB2 and PTTG1 loci in PsA susceptibility and confirmed the previously reported association with PsA and PsV. These results support the hypothesis that genetic aetiology of psoriasis is the same in both PsA and PsV and also support the higher genetic component of PsA than PsV.

Tumor necrosis factor-alpha and the cytokine network in psoriasis

New molecular methods of research have greatly expanded the knowledge about the role of cytokines in several diseases, including psoriasis. The work orchestrated by these peptides is essential for the communication between resident inflammatory cells (keratinocytes and endothelial cells) and infiltrating cells (neutrophils, lymphocytes, Langerhans cells). This is a complex network due to redundancy, synergism and, sometimes, the antagonism of cytokines, which prevents full understanding of the pathogenesis of the disease. Currently, it seems premature to try to establish a main actor, but TNFalpha participates in all stages of psoriatic plaque development, as we shall see.

Study of the genetic factors predisposing to the development of psoriasis

Background papers on psoriasis epidemiology, pathogenesis and genetics are presented. Special attention is given to genetic factors of the aptitude to psoriasis development. Were analysed researches, dedicated to the genome-wide screening of associations of polymorphic genetic locus with psoriasis development. Obtained results allow to reveal pathogenic psoriasis mechanisms, to forecast the character of the clinical course of the disease, as well as the efficiency of therapy and forecast the risk of psoriasis origination at patient’s relatives.

[Study of genetic polymorphisms in the tumor necrosis factor α promoter region in Spanish patients with psoriasis]

BACKGROUND

Several studies have reported an association between tumor necrosis factor α (TNF-α) polymorphisms and inflammatory diseases such as psoriasis vulgaris and psoriatic arthritis, although the results vary according to the population studied. No studies have been performed in the Spanish population.

OBJECTIVE

To analyze the polymorphisms of the promoter region of the TNF-α gene in patients with moderate to severe psorasis and to identify potential differences in genotype compared to a group of healthy volunteers.

MATERIAL AND METHODS

Eighty-nine patients with moderate to severe psoriasis and 76 healthy controls with no personal or family history of psoriasis were selected. Polymorphisms of the TNF-α promoter region of both groups were genotyped.

RESULTS

We observed a higher prevalence of the genotype with both wild-type alleles at positions -238 (GG genotype, 86.5% vs 70.4%, respectively) and -1031 (TT genotype, 80.2% vs 45.8%, respectively) in patients compared to the healthy control group. The differences at positions -308 and -857 were not significant.

CONCLUSION

There are differences in polymorphisms at positions -238 and -1031 in patients with moderate to severe psoriasis compared to healthy volunteers. This observation provides further support for the importance of the part that TNF-α plays in the pathophysiology of this disease.