Lack of association of HLA—C alleles with late-onset psoriasis in the northern Polish population

The association of HLA-C and ERAP1 polymorphisms in early and late onset psoriasis and psoriatic arthritis patients of Hungary

Introduction

Single nucleotide polymorphisms (SNPs) of the HLA-C and ERAP1 genes were recently determined to contribute to psoriasis susceptibility. However, data regarding the association of these genes with specific subgroups of psoriasis are scarce.

Aim

To examine the possible association of the HLA-C and ERAP-1 polymorphisms with early and late onset psoriasis and psoriatic arthritis.

Material and methods

Five ERAP1 SNPs and two HLA-C SNPs were genotyped in 105 psoriatic arthritis patients, 214 cutaneous psoriasis patients and 200 healthy individuals. Haplotypes were constructed for three ERAP1 SNPs (rs17482078, rs10050860, rs30187), and interaction between HLA-Cw*0602 and ERAP1 was also analysed.

Results

The HLA-Cw*0602 rs10484554 SNP was found to be a strong susceptibility factor for early onset cutaneous psoriasis and early onset psoriatic arthritis. ERAP1 SNPs (rs10050860, rs17482078, rs27525) appear to have a protective function for early onset psoriatic arthritis. The haplotype B was identified as a susceptibility factor for late onset psoriatic arthritis. In HLA-C positive individuals the rs27524 ERAP1 SNP was associated with a significantly increased risk of psoriatic arthritis development, whereas the rs27525 ERAP1 SNP had the opposite effect.

Conclusions

These results suggest that the HLA-C and ERAP1 genes contribute to the pathogenesis of psoriasis and psoriatic arthritis in an age-dependent manner.

A Large-Scale, Stratified Genetic Analysis of the Major Histocompatibility Complex Region in Early- and Late-Onset Psoriasis in China

Background

Psoriasis vulgaris is a chronic inflammatory skin disease which occur at any age. It can be clinically classified into two age-onset subtypes: early-onset psoriasis (EOP; <40 years) and late-onset psoriasis (LOP; ≥40 years). More evidence showed EOP and LOP have different genetic architecture, notably the risk allele human leukocyte antigen (HLA)-C^*06:02 located within the major histocompatibility complex (MHC) region, which was reported to be the outstanding variant associated with EOP. However, genetic structure of EOP and LOP have not been fully elucidated.

Objective

To investigated HLA genetic heterogeneity between EOP and LOP in China.

Methods

We first calculated the MHC-based heritability of EOP and LOP respectively. Then, we conducted a large-scale, stratified analysis including 7,097 EOP, 1,337 LOP patients, and 9,906 healthy controls by using MHC target sequencing data from a previous study.

Results

We observed that HLA alleles collectively explained a larger heritability of EOP (27.4%) than LOP (11.3%). Further association analysis identified three independent loci (HLA-C^*01:02, p=6.70×10⁻⁸; HLA-A amino acid position 9, p=3.27×10⁻¹⁷; and HLA-A amino acid position 161, p=5.75×10⁻¹⁰) that confer specific susceptibility to EOP. Our data also confirmed HLA-C^*06:02 as an independent psoriasis-associated variant, contributing a higher degree of risk to EOP than LOP. Moreover, case-case analysis confirmed that HLA-C^*06:02-positive psoriasis patients have earlier onset.

Conclusion

Our analysis indicating that different genetic background underlie the EOP and LOP. We believe these findings will serve to predict psoriasis risk in the future and facilitate clinical decision.

The association between 38 previously reported polymorphisms and psoriasis in a Polish population: High predicative accuracy of a genetic risk score combining 16 loci

Objectives

To confirm the association of previously discovered psoriasis (Ps) risk loci with the disease in a Polish population and to create predictive models based on the combination of these single nucleotide polymorphisms (SNPs).

Material and methods

Thirty-eight SNPs were genotyped in 480 Ps patients and 490 controls. Alleles distributions were compared between patients and controls, as well as between different Ps sub-phenotypes. The genetic risk score (GRS) was calculated to assess the cumulative risk conferred by multiple loci.

Results

We confirmed associations of several loci with Ps: HLA-C, REL, IL12B, TRIM39/RPP21, POU5F1, MICA. The analysis of ROC curves showed that GRS combining 16 SNPs at least nominally (uncorrected P<0.05) associated with Ps (GRS-N) had significantly better discriminative power than GRS combining SNPs associated with Ps after the Bonferroni correction (AUC 0.776 vs. 0.750, P = 1 x 10⁻⁴) or HLA-C (AUC 0.776 vs. 0.694, P<1 x 10⁻⁵). On the other hand, adding additional SNPs to the model did not improve its discriminatory ability (AUC 0.782 for GRS combining all SNPs, P>0.05). In order to assess the total risk conferred by GRS-N, we calculated ORs according to GRS-N quartile ˗ the Ps OR for top vs. bottom GRS-N quartiles was 12.29 (P<1 x 10⁻⁶). The analysis of different Ps sub-phenotypes showed an association of GRS-N with age of onset and family history of Ps.

Conclusions

We confirmed the association of Ps with several previously identified genetic risk factors in a Polish population. We found that a GRS combining 16 SNPs at least nominally associated with Ps had a significantly better discriminatory ability than HLA-C or GRS combining SNPs associated with Ps after the Bonferroni correction. In contrast, adding additional SNPs to GRS did not increase significantly the discriminative power.

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.

Clinical differences between early- and late-onset psoriasis in Thai patients

OBJECTIVES

There is a paucity of data regarding clinical differences between early-onset psoriasis (EOP) and late-onset psoriasis (LOP) in Asian populations. This study aimed to investigate clinical differences between EOP (onset at the age of <40 years) and LOP (onset at the age of ≥40 years) in Thai patients.

METHODS

From 2002 until 2008, staff and residents in the Department of Dermatology, Siriraj Hospital, were asked to complete a questionnaire detailing the age of onset, family history of psoriasis, comorbid diseases, clinical features, nail and joint involvement, and severity of psoriasis in all psoriasis patients. Data were analyzed using descriptive statistics and chi-squared tests.

RESULTS

A total of 1017 patients were enrolled. Of these, 663 (65.2%) patients had EOP and 354 (34.8%) had LOP. The mean ± standard deviation age of onset was 24.8 ± 8.7 years in the EOP group and 51.6 ± 9.6 years in the LOP group. The two most common comorbid diseases were hypertension and diabetes mellitus in both groups. Patients with EOP had a significantly higher likelihood of both a family history of disease and guttate psoriasis. Palmoplantar psoriasis was more commonly found in LOP patients. Nail and joint involvement and disease severity were not associated significantly with age of onset.

CONCLUSIONS

The present study supports the hypothesis that there are clinical differences between EOP and LOP in Asian populations.

Genetic variations associated with psoriasis and psoriatic arthritis found by genome-wide association

Psoriasis and psoriatic arthritis are immune disorders with a complex polygenic basis. HLA-Cw6, which lies in the major histocompatibility region on chromosome 6, is considered the major genetic determinant of psoriasis. Recent genome-wide association studies have identified new variants outside of the MHC with relevance to the immunology of psoriasis. Variants in or near genes that encode subunits of cytokines (IL12B, IL23A) or cytokine receptors (IL23R) are interesting given that the gene product of IL12B, p40, is the target of a recently approved monoclonal antibody therapy for psoriasis (ustekinumab). Association with psoriasis and psoriatic arthritis has been found in TNFAIP3 and TNFIP1, ubiquitin ligases in the NF-kappaB pathway, and IL13, a Th2 cytokine. Copy number variation of human beta-defensin and late cornified envelope genes also associate with psoriasis. Many of these genetic variations also associate with immune disorders considered psoriatic co-morbidities, including Crohn's disease and diabetes.