Comparison of MHC class I risk haplotypes in Thai and Caucasian psoriatics shows locus heterogeneity at PSORS1

Variations in genetics, biology, and phenotype of cutaneous disorders in skin of color - Part I: Genetic, biologic, and structural differences in skin of color

Skin of color (SOC) populations include those who identify as Black/African, Hispanic/Latinx, Asian/Pacific Islander, American Indian/Native Alaskan, Indigenous Australian, Middle Eastern, biracial/multiracial, or non-White; this list is far from exhaustive and may vary between and within cultures. Recent genetic and immunological studies have suggested that cutaneous inflammatory disorders (atopic dermatitis, psoriasis, and hidradenitis suppurativa) and malignancies (melanoma, basal cell carcinoma, and cutaneous T-cell lymphoma) may have variations in their immunophenotype among SOC. Additionally, there is growing recognition of the substantial role social determinants of health play in driving health inequalities in SOC communities. It is critically important to understand that social determinants of health often play a larger role than biologic or genetic factors attributed to "race" in health care outcomes. Herein, we describe the structural, genetic, and immunological variations and the potential implications of these variations in populations with SOC. This article underscores the importance of increasing the number of large, robust genetic studies of cutaneous disorders in SOC to create more targeted, effective therapies for this often underserved and understudied population. Part II of this CME will highlight the clinical differences in the phenotypic presentation of and the health disparities associated with the aforementioned cutaneous disorders in SOC.

HLA-Cw1 and Psoriasis

Psoriasis is a chronic inflammatory skin condition with regional and ethnic differences in its prevalence and clinical manifestations. Human leukocyte antigen (HLA)-Cw6 is the disease allele conferring the greatest risk to psoriasis, but its prevalence is lower in Asian individuals. Recent studies have found associations between HLA-Cw1 and some Asian populations with psoriasis, especially Southern Chinese. HLA-Cw6 was associated with type I early-onset psoriasis, guttate psoriasis, Koebner phenomenon, and better response to methotrexate, interleukin (IL)-12/23, IL-17, and IL-23 targeting drugs. In contrast, HLA-Cw1 positivity has been associated with erythrodermic psoriasis, pustular psoriasis, and the axial type of psoriatic arthritis. Furthermore, HLA-Cw1 was more frequently associated with high-need patients who did not respond to conventional therapies. No known trigger factor nor autoantigen has been identified for HLA-Cw1 positivity. However, HLA-Cw1 has been linked to some viral agents. For example, cytotoxic T lymphocytes recognize multiple cytomegalovirus pp65-derived epitopes presented by HLA alleles, including HLA-C*01:02. In addition, cytomegalovirus can lead to severe exacerbation of psoriatic skin disease. The proposed interaction between viral infection, HLA-Cw1, and psoriasis is through the killer cell immunoglobulin-like receptors of natural killer cells. Given the diverse nature of psoriasis pathogenesis and the difference in HLA-Cw prevalence in different racial groups, more studies are needed to confirm the role of HLA-Cw1 in psoriasis.

Clinical Features and Genetic Polymorphism in Chinese Patients with Erythrodermic Psoriasis in a Single Dermatologic Clinic

BACKGROUND

Erythrodermic psoriasis (EP) is a rare variant of psoriasis that involves more complications and poorer biologic drug survival than plaque-type psoriasis vulgaris (PV). No prior study has explored human leukocyte antigen (HLA) or other genetic polymorphisms in patients with EP.

OBJECTIVES

Our objective was to describe the clinical features, comorbidities, and HLA polymorphisms among Chinese patients with EP.

METHODS

We enrolled consecutive patients with EP from our clinic, with EP defined as generalized confluent erythematous thin plaques covering at least 80% body surface area. Patients were categorized as having primary or secondary EP. Aggravating factors, comorbidities including psoriatic arthritis, family history of psoriasis, age of onset, and treatment history were also identified. Genetic studies were performed for HLA-C and HLA-DRB1, and the results were compared with those from a healthy population and patients with PV.

RESULTS

Of the 63 included patients, the male to female ratio was 2.71:1. Five (7.9%) patients had primary EP, and 58 (92.1%) had secondary EP. Genotyping of HLA-C and HLA-DRB1 was available in 61 and 58 subjects, respectively. HLA-C*0102 was the most frequent HLA-C allele (34.4%), followed by HLA-C*0702 (18.0%). The frequency of HLA-C*0602 allele (4.1%) was lower than in patients with plaque-type psoriasis (4.1 vs. 16.3%, corrected p value [P_c] = 0.02) and similar to that in the healthy population in Taiwan. The most frequent HLA-DRB1 allele was HLA-DRB1*0901 (20.7%), followed by HLA-DRB1*0803 (13.8%). An increased prevalence of psoriatic arthritis (61.9%) and higher male predominance were also noted in comparison with PV.

CONCLUSIONS

There are HLA differences in Chinese patients with EP compared with patients with PV. The incidence of psoriatic arthritis is also higher. The implications of the above findings await further investigation.

Psoriasis in the geriatric population: A retrospective study in Asians

There is a paucity of data focusing on geriatric psoriatic patients. The clinical features were different among those with early-onset psoriasis and elderly-onset psoriasis among the geriatric population. From 2014 to 2018, a total of 290 geriatric psoriatic patients were retrospectively enrolled in our study. They were subclassified into two groups, early-onset (aged <60 years, n = 154) and elderly-onset (aged ≥60 years, n = 136). The characteristics and treatment course of these two groups were reviewed. Psoriasis of the elderly-onset group was generally milder than the early-onset groups (P < 0.05). Less nail involvement and arthritis were noted among the elderly-onset group (P < 0.05). There were four cases of erythrodermic psoriasis in the early-onset group and three cases of palmoplantar psoriasis in the elderly-onset group. Oral medication and biologics for treatment of psoriasis appeared to be safe among the geriatric psoriatic patients. Elderly-onset psoriasis has features which are distinct from early-onset psoriasis and may be a particular subtype, which needs further evaluation.

HLA Correlations with Clinical Phenotypes and Risk of Metabolic Comorbidities in Singapore Chinese Psoriasis Patients

INTRODUCTION

Psoriasis is a systemic, chronic inflammatory disease that not only afflicts the skin but is also associated with cardiovascular disease and metabolic syndrome. The strongest susceptibility loci for the disease is within the human leukocyte antigen (HLA) complex, though specific HLA allelic associations vary between populations.

OBJECTIVE

Our objective was to investigate HLA associations with clinical phenotypes of psoriasis and metabolic syndrome in Chinese psoriasis cases.

METHODS

We conducted an observational case-control study in Singapore with a cohort of psoriasis cases consecutively recruited from an outpatient specialist dermatological center (n = 120) compared with 130 healthy controls.

RESULTS

Significant HLA associations with psoriasis were observed with HLA-A*02:07, B*46:01, C*01:02, and C*06:02. The three-locus haplotype of A*02:07-C*01:02-B*46:01 was also significant (odds ratio [OR] 3.07; p = 9.47 × 10^-5). We also observed an association between nail psoriasis and HLA-A*02:07 carriers (OR 4.50; p = 0.002), whereas C*06:02 carriers were less prone to have nail involvement (OR 0.16; p = 0.004). HLA-A*02:07 was also identified as a possible risk allele for hypertension (OR 2.90; p < 0.05), and C*01:02 was a possible risk allele for dyslipidemia (OR 3.36; p < 0.05), both known to be common comorbidities in patients with psoriasis.

CONCLUSION

Our results demonstrate the growing importance of discerning population-specific clinical phenotypes and their association with certain HLA alleles in psoriasis.

Psoriasis in Skin of Color: Insights into the Epidemiology, Clinical Presentation, Genetics, Quality-of-Life Impact, and Treatment of Psoriasis in Non-White Racial/Ethnic Groups

Psoriasis is a chronic inflammatory skin condition affecting diverse racial/ethnic groups throughout the world. Large population-based studies suggest that psoriasis occurs most often in individuals of European ancestry, followed by black and Hispanic individuals, although the true prevalence of psoriasis in non-white individuals is likely underestimated. Despite similarities in psoriasis between ethnic groups, there are notable differences in the presentation, quality-of-life impact, and treatment of psoriasis with important implications for the management of non-white individuals. Overall, heterogeneity in psoriasis susceptibility alleles, in combination with cultural and socioeconomic factors, may explain these differences. In this article, we review the epidemiology, clinical presentation, genetic polymorphisms, quality-of-life impact, and treatment nuances of psoriasis in patients with skin of color.

Limited clinical utility of HLA-Cw6 genotyping for outcome prediction in psoriasis patients under ustekinumab therapy: a monocentric, retrospective analysis

Purpose

Several studies have suggested that an HLA-Cw6+ allele can predict an improved outcome of treatment in psoriasis patients. The aim of the study was to assess whether the published association between HLA-Cw6 allele carriers and response to ustekinumab has the potential to impact treatment decisions.

Patients and methods

Differences in Psoriasis Activity and Severity Index 50, 75, and 90; Nail Psoriasis Severity Index; and Dermatology Life Quality Index at 16 weeks were evaluated between HLA-Cw6 allele carriers vs. non-carriers. Thirty patients with moderate-to-severe psoriasis under treatment with ustekinumab were included in our study.

Results

There was no difference between the two groups with respect to Psoriasis Activity and Severity Index 50, 75, and 90 or in terms of change in Nail Psoriasis Severity Index or Dermatology Life Quality Index.

Conclusion

In our retrospectively analyzed cohort, we could not detect the previously reported better response in HLA-Cw6+ vs. HLA-Cw6- patients.

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.

Mining emerging biomedical literature for understanding disease associations in drug discovery

Systematically evaluating the exponentially growing body of scientific literature has become a critical task that every drug discovery organization must engage in in order to understand emerging trends for scientific investment and strategy development. Developing trends analysis uses the number of publications within a 3-year window to determine concepts derived from well-established disease and gene ontologies to aid in recognizing and predicting emerging areas of scientific discoveries relevant to that space. In this chapter, we describe such a method and use obesity and psoriasis as use-case examples by analyzing the frequency of disease-related MeSH terms in PubMed abstracts over time. We share how our system can be used to predict emerging trends at a relatively early stage and we analyze the literature-identified genes for genetic associations, druggability, and biological pathways to explore any potential biological connections between the two diseases that could be utilized for drug discovery.

What can the genetics of psoriasis teach us about alopecia areata?

Previous genetic epidemiological studies of psoriasis and alopecia areata demonstrated strong heritability in first-degree relatives and in twins. In recent years, these two conditions have emerged as two skin diseases that are starting to yield their secrets through genome-wide association studies. Both diseases manifest prominent human leukocyte antigen (HLA) associations, psoriasis primarily with major histocompatibility complex (MHC) Class 1, specifically HLA-Cw6, and alopecia areata primarily with MHC Class II. Despite these differences in HLA associations, both diseases have in common a prominent role for CD8+ lymphocytes. The purpose of this brief review is to present the recent developments in the genetics of psoriasis.

Genetic associations of psoriasis in a Pakistani population

BACKGROUND

Genetic predisposition to psoriasis, an inflammatory skin disease affecting 0·2-4% of the world population, is well established. Thus far, 41 psoriasis susceptibility loci reach genome-wide significance (P ≤ 5 × 10(-8) ). Identification of genetic susceptibility loci in diverse populations will help understand the underlying biology of psoriasis susceptibility.

OBJECTIVES

The primary objective of this study was to examine psoriasis susceptibility associations previously reported in Chinese and caucasian populations in a Pakistani cohort.

METHODS

Blood samples and phenotype data were collected from psoriasis cases and controls in Islamabad, Pakistan. DNA was isolated and genotypes of selected susceptibility markers were determined. The data were analysed using χ(2) tests or logistic regression for psoriasis association.

RESULTS

HLA-Cw6 showed the strongest association [odds ratio (OR) 2·43, P = 2·3 × 10(-12) ]. HLA-Cw1 showed marginally significant association (OR 1·66, P = 0·049), suggesting that the HLA-Cw1-B46 risk haplotype may be present in the Pakistani population. Three other loci (IL4/IL13, NOS2, TRAF3IP2) showed nominally significant association (P < 0·05).

CONCLUSIONS

HLA-Cw6 is strongly associated with psoriasis susceptibility in the Pakistani population, as has been found in every other population studied. In addition, HLA-Cw1 showed marginal association, reflecting the relative geographical proximity and thus likely genetic relatedness to other populations in which the HLA-Cw1-B46 haplotype is known to be associated. A larger cohort and a denser marker set will be required for further analysis of psoriasis associations in the South Asian population.

Etanercept use for psoriasis in Taiwan: a case series study

BACKGROUND

The reported efficacy and safety of some biologic agents for psoriasis vary between Caucasians and Asians. Few reports of etanercept exist in psoriasis patients within the Asia-Pacific region.

OBJECTIVES

The study aims to report our clinical experience of etanercept in the treatment of patients with moderate-to-severe psoriasis in Taiwan.

METHODS

A retrospective analysis of 59 patients with moderate-to-severe psoriasis who received etanercept was conducted in a tertiary referral center.

RESULTS

Etanercept therapy resulted in a reduction of mean Psoriasis Area and Severity Index (PASI) of 47% at week 12 and 61% at week 24. After 12 weeks of treatment, 48%, 26%, and 3.4% of the patients achieved at least PASI50, 75 and 90 response, respectively. At week 24, the proportion of patients achieving at least PASI50, 75 and 90 response was 59%, 37%, and 14%, respectively. Etanercept efficacy in achieving PASI75 improvement was, however, lower than that reported in previous pivotal placebo-controlled trials. No cases of active tuberculosis, viral hepatitis or malignancies were observed during the observation period.

CONCLUSION

Our case series demonstrated the efficacy and safety of etanercept for the management of moderate-to-severe psoriasis in Taiwan.