HLA-Cw*0602 associates with a twofold higher prevalence of positive streptococcal throat swab at the onset of psoriasis: a case control study

Triggers for the onset and recurrence of psoriasis: a review and update

Psoriasis is an immune-mediated inflammatory skin disease, involving a complex interplay between genetic and environmental factors. Previous studies have demonstrated that genetic factors play a major role in the pathogenesis of psoriasis. However, non-genetic factors are also necessary to trigger the onset and recurrence of psoriasis in genetically predisposed individuals, which include infections, microbiota dysbiosis of the skin and gut, dysregulated lipid metabolism, dysregulated sex hormones, and mental illness. Psoriasis can also be induced by other environmental triggers, such as skin trauma, unhealthy lifestyles, and medications. Understanding how these triggers play a role in the onset and recurrence of psoriasis provides insights into psoriasis pathogenesis, as well as better clinical administration. In this review, we summarize the triggers for the onset and recurrence of psoriasis and update the current evidence on the underlying mechanism of how these factors elicit the disease. Video Abstract.

Childhood guttate psoriasis: an updated review

Background

Guttate psoriasis is common and affects 0.5-2% of individuals in the paediatric age group. This review aims to familiarize physicians with the clinical manifestations, evaluation, diagnosis and proper management of guttate psoriasis.

Methods

A search was conducted in July 2023 in PubMed Clinical Queries using the key term "guttate psoriasis". The search strategy included all observational studies, clinical trials and reviews published within the past 10 years. The information retrieved from the search was used in the compilation of the present article.

Results

Guttate psoriasis typically presents with an abrupt onset of numerous, small, scattered, tear-drop-shaped, scaly, erythematous, pruritic papules and plaques. Sites of predilection include the trunk and proximal extremities. There may be a history of preceding streptococcal infection. Koebner phenomenon is characteristic. Guttate psoriasis may spontaneously remit within 3-4 months with no residual scarring, may intermittently recur and, in 40-50% of cases, may persist and progress to chronic plaque psoriasis. Given the possibility for spontaneous remission within several months, active treatment may not be necessary except for cosmetic purposes or because of pruritus. On the other hand, given the high rates of persistence of guttate psoriasis and progression to chronic plaque psoriasis, some authors suggest active treatment of this condition.

Conclusion

Various treatment options are available for guttate psoriasis. Triggering and exacerbating factors should be avoided if possible. Topical corticosteroids alone or in combination with other topical agents (e.g. tazarotene and vitamin D analogues) are the most rapid and efficient treatment for guttate psoriasis and are therefore the first-line treatment for mild cases. Other topical therapies include vitamin D analogues, calcineurin inhibitors, anthralin, coal tar and tazarotene. Ultraviolet phototherapy is the first-line therapy for moderate-to-severe guttate psoriasis, as it is more practical than topical therapy when treating widespread or numerous small lesions. Systemic immunosuppressive and immunomodulatory therapies (e.g. methotrexate, cyclosporine, retinoids, fumaric acid esters and biologics) may be considered for patients with moderate-to-severe guttate psoriasis who fail to respond to phototherapy and topical therapies.

Group A Streptococcus induces CD1a-autoreactive T cells and promotes psoriatic inflammation

Group A Streptococcus (GAS) infection is associated with multiple clinical sequelae, including different subtypes of psoriasis. Such post-streptococcal disorders have been long known but are largely unexplained. CD1a is expressed at constitutively high levels by Langerhans cells and presents lipid antigens to T cells, but the potential relevance to GAS infection has not been studied. Here, we investigated whether GAS-responsive CD1a-restricted T cells contribute to the pathogenesis of psoriasis. Healthy individuals had high frequencies of circulating and cutaneous GAS-responsive CD4+ and CD8+ T cells with rapid effector functions, including the production of interleukin-22 (IL-22). Human skin and blood single-cell CITE-seq analyses of IL-22-producing T cells showed a type 17 signature with proliferative potential, whereas IFN-γ-producing T cells displayed cytotoxic T lymphocyte characteristics. Furthermore, individuals with psoriasis had significantly higher frequencies of circulating GAS-reactive T cells, enriched for markers of activation, cytolytic potential, and tissue association. In addition to responding to GAS, subsets of expanded GAS-reactive T cell clones/lines were found to be autoreactive, which included the recognition of the self-lipid antigen lysophosphatidylcholine. CD8+ T cell clones/lines produced cytolytic mediators and lysed infected CD1a-expressing cells. Furthermore, we established cutaneous models of GAS infection in a humanized CD1a transgenic mouse model and identified enhanced and prolonged local and systemic inflammation, with resolution through a psoriasis-like phenotype. Together, these findings link GAS infection to the CD1a pathway and show that GAS infection promotes the proliferation and activation of CD1a-autoreactive T cells, with relevance to post-streptococcal disease, including the pathogenesis and treatment of psoriasis.

Roles of Infection in Psoriasis

Psoriasis is a chronic, immune-mediated disorder with cutaneous and systemic manifestations. Genetic predisposition, environmental factors, and immune dysfunction all contribute to the pathogenesis of psoriasis with host-microbe interaction governing the progression of this disease. Emerging evidence has indicated that infection is an environmental trigger for psoriasis and plays multiple roles in its maintenance as evidenced by the frequent association between guttate psoriasis onset and acute streptococcal infection. Different infectious factors act on immune cells to produce inflammatory cytokines that can induce or aggravate psoriasis. In addition to bacterial infections, viral and fungal infections have also been shown to be strongly associated with the onset or exacerbation of psoriasis. Intervention of skin microbiota to treat psoriasis has become a hot research topic. In this review, we summarize the effects of different infectious factors (bacteria, viruses, and fungi) on psoriasis, thereby providing insights into the manipulation of pathogens to allow for the identification of improved therapeutic options for the treatment of this condition.

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.

The Psoriasis Risk Allele HLA-C*06:02 Shows Evidence of Association with Chronic or Recurrent Streptococcal Tonsillitis

Pharyngeal tonsillitis is one of the most common upper respiratory tract infections, and group A streptococcus is the most important bacterial pathogen causing it. While most patients experience tonsillitis only rarely, a subset of patients suffers from recurrent or chronic tonsillitis or pharyngitis. The predisposing factors for recurring or chronic forms of this disease are not yet fully understood, but genetic predisposition has been suggested. A genetic association study using Illumina's Immunochip single-nucleotide polymorphism (SNP) array was performed to search for new genetic biomarkers in pharyngeal tonsillitis. More than 100,000 SNPs relevant to immune-mediated diseases were analyzed in a cohort of 95 patients subjected to tonsillectomy due to recurrent/chronic tonsillitis and 504 controls. Genetic association between the cases and controls showed strongest association with two peaks in the HLA locus (odds ratio [OR], 3.7 to 4.7; P = 4.9 × 10^-6 to 5.7 × 10^-6). Further analysis with imputed classical HLA alleles suggested the known psoriasis risk allele HLA-C*06:02 as a risk factor for tonsillitis (P = 4.8 × 10^-4; OR, 2.3). In addition, the imputed HLA haplotype HLA-C*06:02/HLA-B*57:01, a reported risk haplotype in psoriasis, had the strongest risk for tonsillitis (P = 3.2 × 10^-4; OR, 6.5). These findings further support the previously reported link between streptococcal throat infections and psoriasis.

CLA+ T Cell Response to Microbes in Psoriasis

Streptococcus pyogenes throat infection is a clinically relevant trigger of both guttate and chronic plaque psoriasis, and it provides an ideal context in which to study the pathogenesis of these diseases using an antigen-dependent approach. Circulating cutaneous lymphocyte-associated antigen (CLA) positive (+) memory T cells are a subset of peripheral lymphocytes whose phenotype and function are related to immunological mechanisms in the skin. These cells are considered peripheral biomarkers of T-cell-mediated skin diseases. The coculture of autologous epidermal cells with CLA⁺ T cells from psoriasis patients activated by S. pyogenes allows the reproduction of the ex vivo initial molecular events that occur during psoriatic lesion formation. With cooperation of autologous epidermal cells, S. pyogenes selectively activates CLA⁺ T cells both in guttate and plaque psoriasis, inducing key mediators, including an IL-17 response. Here, we explore potential new mechanisms of psoriasis development including the influence of HLA-Cw6 on S. pyogenes CLA⁺ T cell activation in guttate psoriasis, the relevance of IL-9 on microbe induced IL-17 response in guttate and plaque psoriasis, and novel effector functions of Candida albicans. This review will summarize recent knowledge of psoriatic mechanisms elicited by microbes that have been studied through an innovative translational perspective based on CLA⁺ T cell-mediated cutaneous immune response.

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.

HLA-Cw6 homozygosity in plaque psoriasis is associated with streptococcal throat infections and pronounced improvement after tonsillectomy: A prospective case series

BACKGROUND

Carriage of the HLA-Cw*0602 allele is associated with a particular set of clinical features and treatment responses in psoriasis. Tonsillectomy can improve psoriasis.

OBJECTIVES

We sought to evaluate whether HLA-Cw*0602 predicts a favorable outcome after tonsillectomy of patients with psoriasis.

METHODS

This prospective case series followed up 28 tonsillectomized patients with plaque psoriasis for 24 months. The Psoriasis Area and Severity Index, Psoriasis Disability Index, and Psoriasis Life Stress Inventory were used for assessment. Tonsils were swabbed for bacteria and patients genotyped for HLA-Cw*0602.

RESULTS

After tonsillectomy, HLA-Cw*0602 homozygotes showed significantly more improvement, compared with heterozygous and HLA-Cw*0602-negative patients. Thus, Psoriasis Area and Severity Index score was reduced by 82% in the homozygous patients compared with 42% and 31%, respectively (P < .001), Psoriasis Disability Index score improved by 87% compared with 38% and 41%, respectively (P < .001), and Psoriasis Life Stress Inventory score was 82% reduced compared with 60% and 54%, respectively (P < .001). The homozygotes more often had psoriasis onset associated with a throat infection (P = .007) and an increased frequency of streptococcal throat infections per lifetime (P = .038).

LIMITATIONS

Few patients were included and some data were retrospective.

CONCLUSIONS

Homozygous HLA-Cw*0602 carriage in plaque psoriasis may predict a favorable outcome after tonsillectomy.

Streptococcus pyogenes-induced cutaneous lymphocyte antigen-positive T cell-dependent epidermal cell activation triggers TH17 responses in patients with guttate psoriasis

BACKGROUND

Guttate psoriasis (GP) is characterized by acute onset of small, rounded psoriatic lesions. Although this particular phenotype of psoriasis is usually associated with streptococcal throat infections and mainly occurs in HLA-Cw6(+) patients, the specific immunologic response to this innate stimulus that causes these skin lesions is poorly understood.

OBJECTIVE

This study aims to elucidate how key cellular elements of patients with GP respond to Streptococcus pyogenes and whether this initial immune response is favored by the genetic and environmental background of these patients.

METHODS

Circulating memory T cells and autologous epidermal cells from samples from either patients with GP (n = 14) or healthy control subjects (n = 6) were cocultured ex vivo in the presence of an S pyogenes extract. Levels of the psoriasis-associated cytokines IL-17A, IL-17F, IFN-γ, TNF-α, IL-6, and IL-8 were determined. The expression of several genes with increased (DEFB4, S100A7, LCN2, IL36G, IL8, CXCL9, CXCL10, and CXCL11) or decreased (FLG and LOR) transcripts in psoriatic lesions was examined in keratinocytes treated with coculture supernatants.

RESULTS

When skin-homing effector memory cutaneous lymphocyte antigen-positive T cells were used in cocultures, a TH17-dominant response was observed, as reflected by the higher amounts of IL-17A and IL-17F than IFN-γ. Moreover, a higher TH17 response was observed in cells isolated from patients with flares associated with a streptococcal tonsillitis and with the HLA-Cw6 allele (cohort 1). In addition, in normal keratinocytes the supernatants from these cocultures induced an increase in IL-17-associated genes, such as DEFB4, S100A7, LCN2, IL36G, and IL8 but a decrease in FLG and LOR, thereby confirming the role of activated TH17 cells.

CONCLUSION

This study reveals a dominant TH17 response of cutaneous lymphocyte antigen-positive T cells activated by epidermal cells and S pyogenes in patients with GP.

Frequency of streptococcal upper respiratory tract infections and HLA-Cw*06 allele in 70 patients with guttate psoriasis from northern Poland

Introduction

The association of guttate psoriasis with a streptococcal throat infection and HLA-Cw*06 allele is well established in different populations. Nevertheless, only few studies on this form of disease have been performed in the Polish population.

Aim

To analyze the frequencies of streptococcal-induced guttate psoriasis and HLA-Cw*06 allele in 70 patients with guttate psoriasis originating from northern Poland.

Material and methods

Seventy patients with guttate psoriasis and 24 healthy volunteers were enrolled into the study. Both groups were sex- and age-matched. The evidence of streptococcal infection was based on the positive throat swabs and/or elevated ASO titers. The modified method, including PCR-SSP and PCR-RFLP, was applied to HLA-Cw*06 genotyping.

Results

HLA-Cw*06 allele was confirmed in 49 (70%) out of 70 patients, which is significantly higher than in the control population (30%) (p = 0.001). Evidence for streptococcal infection was found in 34 (48.5%) subjects with psoriasis. Twenty-seven of them (79%) carried HLA-Cw*06 allele. In 36 individuals in whom no evidence of streptococcal infection was found, 14 (39%) did not carry HLA-Cw*06 allele.

Conclusions

Our data confirm that HLA-Cw*06 is a major, but not imperative, genetic determinant for guttate psoriasis.

Guttate Psoriasis Following Streptococcal Vulvovaginitis in a Five-year-old Girl

BACKGROUND

Guttate psoriasis is frequently associated with a preceding pharyngeal or perianal streptococcal infection in children. Despite Group A beta-hemolytic streptococci (GABHS) being the most common cause of specific bacterial vulvovaginitis in prepubertal girls, there are no reports of streptococcal vulvovaginitis triggering guttate psoriasis.

CASE

A five-year-old girl presented with guttate psoriasis following an episode of Streptococcal pyogenes vulvovaginitis. Following antibiotic treatment and bacterial eradication she developed vulvar psoriasis that resolved with high potency topical steroids.

SUMMARY AND CONCLUSION

Identification of an antecedent streptoccocal infection can help predict the long term prognosis in children with guttate psoriasis. The vulvovaginal area should be considered as a source of GABHS infection in young girls with guttate psoriasis, and cultures should be considered if symptoms are present.

Molecular and genetic studies of the predisposition to the development of psoriasis among the population of the Russian Federation: a study of polymorphisms of TNFAIP3, TNIP1, TYK2 and REL genes

Goal. To study the role of polymorphic variants of genes encoding proteins of the signaling pathway of the nuclear transcription factor kappa-B, NF-kB (TNFAIP3 (rs610604), TNIP1 (rs17728338), TYK2 (rs12720356) and REL (rs702873)) in the predisposition to psoriasis among the Caucasian population of the Russian Federation. Materials and methods. The authors studied markers of the predisposition to the development of psoriasis such as TNFAIP3 (rs610604), TNIP1 (rs17728338), TYK2 (rs12720356) and REL (rs702873) using Real-Time PCR methods and allele-specific oligonucleotide probes and PFLP (Restriction Fragment Length Polymorphism) assay in whole blood samples taken from psoriatic patients (n = 301). To compare the frequency of genotypes, the authors used data obtained as a result of the genotyping of DNAs taken from healthy volunteers (n = 109). Results. The authors analyzed particular features of the distribution of polymorphic variants of TNFAIP3 (rs610604), TNIP1 (rs17728338), TYK2 (rs1272035) и REL (rs702873) genes in a sample of 301 psoriatic patients and 109 healthy volunteers from the Russian Federation. They revealed reliable differences in the frequency of registration of genotypes of these genes. The authors also determined genotypes considered as risk factors with regard to the development of psoriasis (TNFAIP3-A/C, TNIP1-A/G, TNIP1-A/A and TYK2-T/T) as well as protector genotypes (TNFAIP3-A/Ä, REL-A/A and TYK2-T/G)

Association of polymorphisms in TNFAIP3 and TNIPI genes with predisposition to the development of psoriasis in the Russian population

Goal. To study polymorphisms in TNFAIP3 (rs610604) and TNIPI (rs17728338) genes in a sample of psoriasis patients and healthy volunteers from the Russian Federation. Materials and methods. By using allele specific hybridization methods in the form of real-time PCR and RFLP assay (Restriction Fragment Length Polymorphism), single-nucleotide polymorphisms of fragments of the following genes associated with predisposition to the development of psoriasis were studied in whole blood samples taken from psoriasis patients (n = 286) and healthy volunteers (n = 89): TNFAIP3 (rs610604) and TNIPI (rs17728338). Results. Psoriasis patients had a reliable increase in the frequency of the A/C heterozygous genotype of rs610604 polymorphism of the TNFAIP3 gene and A allele of rs17728338 polymorphism of the TNIP1 gene (A/G and A/A genotypes), which makes it possible to treat carriers of these genotypes as people with predisposition to the development of psoriasis, and to treat A/C genotypes of rs610604 polymorphism and A/G and A/A genotypes of rs17728338 polymorphism as predictors of the development of psoriasis in the Russian population. Conclusion. these data broaden the perception of genetic factors associated with the development of psoriasis in persons from the Russian population.

Psoriatic arthritis: recent progress in pathophysiology and drug development

Psoriatic arthritis (PsA) is the second most common inflammatory arthropathy, after rheumatoid arthritis diagnosis, in early arthritis clinics. Most patients have established psoriasis, often for years, prior to the onset of joint pain and swelling; in addition, associated features of nail disease, dactylitis, enthesitis, spondylitis or uveitis may be present. Psoriasis may not be immediately apparent, as small or patchy lesions may occur in the scalp or perineum. PsA presents as a symmetrical polyarthritis, similar to rheumatoid arthritis, or an asymmetrical oligoarthritis with a predilection for the distal interphalangeal joints. Spinal involvement is similar, although not identical, to ankylosing spondylitis. Joint damage occurs early; up to 50% of PsA patients have an 11% annual erosion rate in the first 2 years of disease duration, suggesting it is not a benign condition. There have been significant advances in our understanding of PsA pathogenesis in recent years, in the areas of genetics and molecular biology, implicating both the innate and the adaptive immune systems. This has lead to the introduction of evidence-based targeted therapy, primarily with tumour necrosis factor inhibitor (TNFi) agents. Therapy with disease-modifying anti-rheumatic drugs, such as methotrexate and leflunomide, remains the first-choice therapeutic intervention, even though there are few randomised controlled trials with these agents. In contrast, a number of successful studies of TNFi agents demonstrate excellent efficacy, in combination with methotrexate, and several novel agents are currently in development for the treatment of PsA.

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.

Improvement of psoriasis after tonsillectomy is associated with a decrease in the frequency of circulating T cells that recognize streptococcal determinants and homologous skin determinants

Exacerbation of chronic psoriasis can be associated with streptococcal throat infections, and T cells that respond to peptide sequences common to streptococcal M proteins and skin keratins have been detected in patients' blood. To our knowledge, we have conducted the first blinded, prospective study to assess the impact of tonsillectomy on psoriasis. Twenty-nine patients with chronic psoriasis and history of exacerbation after sore throat were randomly assigned to tonsillectomy (n = 15) or control (n = 14) groups and monitored for 2 y clinically and by enumeration of circulating skin homing T cells that respond to short homologous M protein or keratin peptides. Thirteen patients (86%) showed sustained improvement after tonsillectomy ranging from 30 to 90% reduction in disease severity. Furthermore, there was a close correlation between the degree of clinical improvement in individual patients and reduction in the frequency of peptide-reactive skin-homing T cells in their circulation. No corresponding clinical or immunologic changes were observed among the controls. These findings indicate that tonsillectomy may have a beneficial effect on chronic psoriasis because the palatine tonsils generate effector T cells that recognize keratin determinants in the skin.

Clinical comparison of psoriasis in Korean adults and children: correlation with serum anti-streptolysin O titers

Psoriasis is a relatively common disorder in children and can be triggered by an upper respiratory tract infection. The aim of this study was to compare the clinical features of psoriasis in children and adult. In addition, we evaluated the relationship between anti-streptolysin O (ASO) titers and the clinical features of psoriasis. A total of 30 childhood psoriasis patients and 30 adult psoriasis patients were evaluated. Childhood psoriasis had a facial predominance when compared with the adult psoriasis. The childhood psoriasis patients with high ASO titers had guttate psoriasis more frequently than patients with normal ASO titers. In children with plaque-type psoriasis, psoriasis area and severity index score was increased in the high ASO titer group than normal ASO titer group. In conclusion, if the children with psoriasis show increased ASO titer, the physician should pay attention to the worsening of the psoriasis. Furthermore, early treatment of streptococcal infections might be beneficial in childhood psoriasis.