Immunobiologics in the treatment of psoriasis

From Traditional Medicine to Advanced Therapeutics: The Renaissance of Phyto-nano Interventions in Psoriasis

Psoriasis is an autoimmune systemic chronic inflammatory disease that exhibits characteristic detrimental effects on the skin, often leading to infections or comorbid conditions. The multifaceted nature of psoriasis has made it very challenging to treat, especially with current chemotherapy options. Therefore, it is essential to consider phytoconstituents as novel alternatives. However, despite demonstrating higher anti-inflammatory, anti-psoriasis, and immunomodulatory potential, their clinical usage is hindered due to their poor physicochemical properties. To address these drawbacks, nanoparticulate drug delivery systems have been developed, helping to achieve better permeation of phytoconstituents through topical administration. This has breathed new life into traditional systems of medicine, particularly in the context of treating psoriasis. In this current review, we present a detailed, comprehensive, and up-to-date analysis of the literature, which will contribute to affirming the clinical role of phyto-nano interventions against psoriasis.

FUT8 Remodeling of EGFR Regulates Epidermal Keratinocyte Proliferation during Psoriasis Development

α-(1,6)-fucosyltransferase 8 (FUT8) is implicated in the pathogenesis of several malignancies, but its role in psoriasis is poorly understood. In this study, we show that FUT8 remodeling of EGFR plays a critical role in the development of psoriasis phenotypes. Notably, elevated FUT8 expression was associated with disease severity in the lesional epidermis of a patient with psoriasis. FUT8 gain of function promoted HaCaT cell proliferation, whereas short hairpin FUT8 reduced cell proliferation and induced a longer S phase with downregulation of cyclin A1 expression. Furthermore, cell proliferation, which is controlled by the activation of EGFR, was shown to be regulated by FUT8 core fucosylation of EGFR. Short hairpin FUT8 significantly reduced EGFR/protein kinase B signaling and slowed EGF‒EGFR complex trafficking to the perinuclear region. Moreover, short hairpin FUT8 reduced ligand-induced EGFR dimerization. Overactivated EGFR was observed in the lesional epidermis of both human patient and psoriasis-like mouse model, whereas conditional knockout of FUT8 in an IL-23 psoriasis-like mouse model ameliorated disease phenotypes and reduced EGFR activation in the epidermis. These findings implied that elevated FUT8 expression in the lesional epidermis is implicated in the development of psoriasis phenotypes, being required for EGFR overactivation and leading to keratinocyte hyperproliferation.

Oral Squamous Cell Carcinoma Presenting in a Patient Receiving Adalimumab for Rheumatoid Arthritis

The efficacy of biologic agents in the treatment of inflammatory immune-mediated conditions has been clearly shown, but there also are numerous reports of adverse effects. Most reported adverse effects have been associated with tumor necrosis factor-α (TNF-α) inhibitors and include a possible increased risk of malignancy. There have been some reported cases of oral cancer developing in patients treated with TNF-α inhibitors. This case report describes a patient who was taking adalimumab for rheumatoid arthritis and who presented with a squamous cell carcinoma (SCC) in the mandible. Diagnosis was complicated because the clinical appearance was of a nonhealing extraction socket and the patient had a history of bisphosphonate therapy. An initial diagnosis of bisphosphonate-related osteonecrosis of the jaws was made, which delayed the commencement of appropriate treatment. This case highlights the importance of ruling out SCC in patients taking biological agents with unusual symptoms.

Infliximab treatment of psoriasis in supervised infusion centers: case management experience

Psoriasis is a systemic chronic inflammatory disease that affects 1-3% of the world's population. Knowledge of the pathogenesis of psoriasis, particularly in the understanding of the role of T cells and tumor necrosis factor α (TNFα), and advances in immunology have led to the development of biological agents, which, due to their great effectiveness, speed of response and good tolerability, have revolutionized patient management. One of these is infliximab, a human chimeric immunoglobulin G1 monoclonal antibody composed of human antibody constant regions and murine variable regions that was developed specifically to target TNFα. The six cases presented in this series highlight the feasibility, efficacy and safety of infliximab for psoriasis when administered in a variety of patients in several infusion centers across Spain. All six patients showed improvement in their psoriasis after the initiation of infliximab and no significant tolerability issues or injection site reactions were reported, despite the presence of several comorbid conditions or patient characteristics that traditionally reduce the efficacy of psoriasis treatments. This suggests that while the management of psoriasis patients with comorbid conditions and various unfavorable prognostic characteristics requires a multidisciplinary approach to ensure the patient obtains the best therapeutic response, infliximab is an effective and well tolerated treatment in these patients.

SNP rs11652075 in the CARD14 gene as a risk factor for psoriasis (PSORS2) in a Spanish cohort

A recent genomic survey identified the association between a common single nucleotide polymorphism (SNP) at the CARD14 gene (SNP rs11652075; p.Arg820Trp) and psoriasis (Psor). Our aim was to replicate the association between this polymorphism and to determine whether other CARD14 variants could explain the association. A total of 400 Psor patients (mean age 47±15; 55% male) and 420 healthy controls (mean age 51±16; 56% male) all Caucasian were genotyped for rs11652075. The rs11652075 CC genotype was significantly associated with Psor in our population (p=0.003; odds ratios=1.59; 95% confidence intervals=1.16-2.19; statistical power >80). The sequencing of the whole CARD14 coding exons in a total of 15 patients did not identify other DNA variants that could explain this association. We did not find significant differences (allele/genotype frequencies) between the patients according to disease severity, presence of arthritis, onset of age, and family history of Psor. We confirmed the association between SNP rs11652075 at the CARD14 gene and Psor. The absence of other coding variants among our patients supported a direct role for this missense polymorphism on Psor risk.

Targeting IL-17 in psoriasis: from cutaneous immunobiology to clinical application

Psoriasis vulgaris is a chronic, immune-mediated inflammatory skin disease associated with complex genetic susceptibility. Although the hallmark of psoriasis is characterized by cutaneous inflammation and keratinocyte hyperproliferation, recent studies show that the pathologic features observed in psoriasis arises as a result of innate and adaptive immune activation in genetically prone individuals. Studies focused on the microenvironment in the skin of psoriasis lesions have revealed novel cellular and cytokine abnormalities of the immune system. One pathway important is the role of the T(H)17/IL-17 dysregulation. The recent development of biologics that target the IL-17 cytokine pathway has confirmed the importance of T(H)17 and IL-17 homeostasis in the skin and yielded potent therapies in the treatment of psoriasis, and potentially other autoimmune diseases.

Biological therapy of patients with severe psoriasis

Results of the clinical survey of 22 patients suffering from heavy forms of psoriasis have been submitted. The efficiency and safety of infliximab therapy has been evaluated during 48 weeks of patients’ survey.

Pathological crosstalk in vitro between T lymphocytes and lesional keratinocytes in psoriasis: necessity of direct cell-to-cell contact

Psoriasis, a chronic autoimmune-related skin disease, involves both immune and non-immune cells like T cells and keratinocytes. This study investigates the regulatory role of T cells-keratinocyte interactions during psoriasis on immune factors production. Cytokines and chemokines were evaluated by multiplex and ELISA assays in an in vitro model of co-culture of keratinocytes with T lymphocytes. Keratinocytes were from psoriatic skin lesions or healthy skin. T lymphocytes were from healthy volunteers. Psoriatic keratinocytes (PKs) alone generated concentrations of tumor necrosis factor (TNF)-α, interleukin (IL)-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-1β, IL-8, monocyte chemotactic protein (MCP)-1, interferon-γ-induced protein 10 kDa (IP-10) and vascular endothelial growth factor (VEGF) higher than those produced by healthy keratinocytes (HKs). In contrast, IL-1α and IL-Ra production was reduced in PKs. Normal T cells, which had no effect on HKs, increased the production of TNF-α, IL-6, GM-CSF, IL-8, MCP-1 and IP-10 by PKs, but did not influence PK production of IL-1β, IL-1α, IL-Ra and VEGF. The most striking effects were obtained with PK- and IL-2-stimulated T lymphocytes: most of the above cytokines and chemokines were greatly upregulated, except IL-1β and VEGF that were decreased or unchanged, respectively. In addition, fractalkine was overproduced in this latter condition only. Our results indicate (1) a functional interaction between keratinocytes and T lymphocytes that requires a direct cellular contact, and (2) a reciprocal influence that depends on cytokine and chemokine types. In conclusion, lesional keratinocytes from psoriasis vulgaris alter functions of normal T lymphocytes that conversely modulate these keratinocytes.

Efficacy of systemic therapies for moderate-to-severe psoriasis: a systematic review and meta-analysis of long-term treatment

BACKGROUND

Despite the chronicity of psoriasis, most systematic reviews focus on short-term treatment.

METHODS

The systematic search strategy and results from the German Psoriasis Guidelines were adapted. To update the data a literature search in Medline, Embase and the Cochrane Library was conducted. The proportion of participants achieving ≥75% decrease in Psoriasis Area and Severity Index (PASI) as well as Dermatology Life Quality Index (DLQI) reduction at different time points were assessed. Trials were summarized with respect to time periods and study designs. Suitable trials were included in a meta-analysis. Particular attention was paid to statistical approaches of handling dropouts.

RESULTS

A total of 33 articles including 27 trials totaling 6575 patients with active treatment were included in the systematic review. Seven randomized controlled trials were eligible for the meta-analysis. Over a 24 week treatment period infliximab [risk difference (RD) 78%, 95% confidence interval (CI) 72-83%] and ustekinumab 90 mg every 12 weeks (RD 77%, 95% CI 71-83%) were the most efficacious treatments. Adalimumab (RD: 60%, 95% CI 45-74%) showed results within the range of different etanercept dosages (etanercept 50 mg once weekly: RD 62%, 95% CI, 52-72%), (etanercept 25 mg twice weekly: RD 45%, 95% CI 34-56%), (etanercept 50 mg twice weekly: RD 56%, 95% CI 49-62%) and (etanercept 50 mg twice weekly until week 12, then 25 mg twice weekly: RD 50%, 95% CI 42-57%). After 24 weeks a decrease in efficacy for inflximab, adalimumab and etanercept was observed.

CONCLUSIONS

More sufficient data is required to draw reliable conclusions in extended long-term treatment and head-to-head comparisons are necessary.

Infliximab for the treatment of plaque psoriasis

Infliximab is a monoclonal antibody that targets tumor necrosis factor-α (TNFα). It is used in the treatment of a number of inflammatory disorders including severe plaque psoriasis. TNFα is thought to have a major role in psoriasis by promoting an inflammatory infiltrate into the skin and inducing keratinocyte proliferation and preventing keratinocyte apoptosis, which directly contributes to the characteristic plaque skin lesions. Based on four randomized, placebo-controlled, double-blind clinical trials and nine open-label uncontrolled trials of the use of infliximab in plaque psoriasis, it was found that infliximab is a highly efficacious, rapid, sustainable, and relatively safe therapy. Yet as with any biologic, caution is recommended in its use as infusion reactions, lupus-like syndromes, infections, malignancies including lymphomas, as well as other rare events have been reported.

Costimulatory signals potently modulate the T cell inhibitory capacity of the therapeutic CD11a antibody Efalizumab

The therapeutic CD11a antibody Efalizumab interferes with psoriasis pathogenesis by blocking T cell activation and migration. We have performed a detailed analysis on its effects during the activation of human T cells and found that the capability of Efalizumab to inhibit proliferation and cytokine production of T cells critically depends on the quality and quantity of costimulatory signals. Efalizumab potently inhibited the proliferation and cytokine production of human T cells costimulated via ICOS, OX40, CD27 or 4-1BB, but did not significantly inhibit T cells that received stimuli via CD2 or CD28. The capacity of CD2 and CD28 signals to interfere with the T cell inhibitory effects of Efalizumab was also observed upon stimulation of T cells with allogeneic DC. Furthermore, studies with T cells from psoriasis patients indicated that Efalizumab therapy induces inhibition of T cell responses that can be reverted by CD2 or CD28 signals.

The role of etanercept on the expression of markers of T helper 17 cells and their precursors in skin lesions of patients with psoriasis vulgaris

Very recently, it has been demonstrated that CD161, retinoic acid-related orphan receptor gamma-t (RORgamma-t) and CC-chemokin receptor 6 (CCR6) can be considered good surface markers to detect T helper 17 cells and their precursors, T cell populations that are considered to play an important role in the pathogenesis of psoriasis. In the present study, we evaluate the clinical involvement by calculating the PASI score and the number of CD4+, CD161+, RORgammat+ and CCR6+ cells before and after a 12-week course with etanercept or acitretin in patients with moderate-to-severe, plaque-type psoriasis vulgaris. Ten patients were given etanercept 50 mg twice weekly and 10 patients acitretin 0.4 mg/kg per day, both for 12 weeks. At the baseline and at the end of the treatment PASI was calculated, and skin biopsies were taken to evaluate the expression of CD4, CD161, RORgammat and CCR6 by immunohistochemistry. As controls, 10 patients with atopic dermatitis (AD) were included in the study. After 12 weeks, PASI was significantly lower than at the baseline for both groups. However, etanercept-treated patients showed lower PASI than acitretin-treated ones. While CD4+ cell numbers were similar in both diseases, all the other markers, that are considered more specific for Th17 cells and their precursors, were more expressed in psoriasis than in AD. Furthermore, only etanercept, but not acitretin, was able to significantly reduce CD161+, RORgammat+ and CCR6+ cells in skin lesions of patients with psoriasis. Our study provides further evidence of the role of Th17 pathway in the pathogenesis of psoriasis. Furthermore, our findings suggest that etanercept is able to downregulate the expression of the recently recognized markers of Th17 cells and their precursors CD161, RORgammat and CCR6, while acitretin is not. This activity on the Th17 lineage may contribute to the efficacy of etanercept in the treatment of psoriasis.

Tranilast could has potential therapeutic value in the treatment of psoriasis

Psoriasis is a common chronic skin disease characterized by recurrent erythromatous skin plaques that exhibit epidermal hyperplasia, variable inflammatory cell infiltrate, and abnormalities of the dermal vascularization. The involvement of angiogenic growth factors such as vascular endothelial growth factor (VEGF), matrix metalloproteinases (MMPs) and inflammatory cytokines such as IFNγ, IL-1, IL-2, TNFα, TGFα and β, IL-6, IL-8, amphiregulin and monocyte chemoattractant protein 1 (MCP-1) have been known to play pathogenic roles in traumatic psoriatic skin. However, anti-angiogenic and anti-inflammatory cytokines regimens might favorably affect the psoriasis disease process. Tranilast is an anti-allergic drug now emerging as anti-angiogenesis and anti-inflammatory effects. In vitro and in vivo experiments have also been strongly showed that tranilast would treat skin psoriasis by inhibition of involving factors. Herein, we hypothesize that local administration of tranilast may be potentially clinically useful in psoriasis.

Interleukin-21 as a new therapeutic target for immune-mediated diseases

Cytokines have a decisive role in initiating and shaping pathologic responses in patients with various immune-inflammatory diseases. Recent studies indicate that interleukin (IL)-21, a cytokine produced mostly by activated CD4+ T cells, participates in the tissue damage in various tissues, owing to its ability to regulate the function of immune and non-immune cells. For instance, IL-21 controls the differentiation and functional activity of T cells, B cells and NK cells, limits the differentiation of inducible regulatory T cells (Tregs), and makes T cells resistant to the Treg-mediated immunesuppression. It also stimulates epithelial cells and fibroblasts to produce inflammatory mediators. Here, we focus on data supporting the pathogenic role of IL-21 in human inflammatory diseases and discuss pre-clinical studies that suggest that neutralization of IL-21 in vivo could be a new biological therapy to combat immune-mediated pathologies, such as inflammatory bowel diseases, diabetes, rheumatoid arthritis and systemic lupus erythematosus.

Amelioration of psoriasis by anti-TNF-alpha RNAi in the xenograft transplantation model

Tumor necrosis factor-alpha (TNF-alpha) is upregulated in psoriatic skin and represents a prominent target in psoriasis treatment. The level of TNF-alpha-encoding mRNA, however, is not increased in psoriatic skin, and it remains unclear whether intervention strategies based on RNA interference (RNAi) are therapeutically relevant. To test this hypothesis the present study describes first the in vitro functional screening of a panel of short hairpin RNAs (shRNAs) targeting human TNF-alpha mRNA and, next, the transfer of the most potent TNF-alpha shRNA variant, as assessed in vitro, to human skin in the psoriasis xenograft transplantation model by the use of lentiviral vectors. TNF-alpha shRNA treatment leads to amelioration of the psoriasis phentotype in the model, as documented by reduced epidermal thickness, normalization of the skin morphology, and reduced levels of TNF-alpha mRNA as detected in skin biopsies 3 weeks after a single vector injection of lentiviral vectors encoding TNF-alpha shRNA. Our data show efficient lentiviral gene delivery to psoriatic skin and therapeutic applicability of anti-TNF-alpha shRNAs in human skin. These findings validate TNF-alpha mRNA as a target molecule for a potential persistent RNA-based treatment of psoriasis and establish the use of small RNA effectors as a novel platform for target validation in psoriasis and other skin disorders.

A ceramide-1-phosphate analogue, PCERA-1, simultaneously suppresses tumour necrosis factor-alpha and induces interleukin-10 production in activated macrophages

Tight regulation of the production of the key pro-inflammatory cytokine tumour necrosis factor-alpha (TNF-alpha) is essential for the prevention of chronic inflammatory diseases. In vivo administration of a synthetic phospholipid, named hereafter phospho-ceramide analogue-1 (PCERA-1), was previously found to suppress lipopolysaccharide (LPS)-induced TNF-alpha blood levels. We therefore investigated the in vitro anti-inflammatory effects of PCERA-1. Here, we show that extracellular PCERA-1 potently suppresses production of the pro-inflammatory cytokine TNF-alpha in RAW264.7 macrophages, and in addition, independently and reciprocally regulates the production of the anti-inflammatory cytokine interleukin-10 (IL-10). Specificity is demonstrated by the inability of the phospholipids ceramide-1-phosphate (C1P), sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) to perform these activities. Similar TNF-alpha suppression and IL-10 induction by PCERA-1 were observed in macrophages when activated by Toll-like receptor 4 (TLR4), TLR2 and TLR7 agonists. Regulation of cytokine production is demonstrated at the mRNA and protein levels. Finally, we show that, while PCERA-1 does not block activation of nuclear factor (NF)-kappaB and mitogen-activated protein kinases by LPS, it elevates the intracellular cAMP level. In conclusion, the anti-inflammatory activity of PCERA-1 seems to be mediated by a cell membrane receptor, upstream of cAMP production, and eventually TNF-alpha suppression and IL-10 induction. Thus, identification of the PCERA-1 receptor may provide new pharmacological means to block inflammation.

In-situ-topoproteome analysis of cutaneous lymphomas: perspectives of assistance for dermatohistologic diagnostics by Multi Epitope Ligand Cartography (MELC)

BACKGROUND

Immunophenotyping is essential for diagnostics of cutaneous lymphomas. In this regard we present a skin tissue-adapted application platform of MELC technology.

PATIENTS AND METHODS

This topoproteome analysis allows the subcellular colocalization of at least n = 100 epitopes in situ. For this purpose the specimen is processed by a Toponome Imaging Cycler for a n-fold repetition of the following cycle: 1) staining with a fluorophore-labeld antibody, 2) fluorescence-imaging, and 3) photobleaching. Overlay and binarization of fluorescence images lead to combinatorial molecular phenotypes (CMP), which relate to a pixel or microtopographic unit (450 x 450 nm2, 20x objective). Skin biopsies were derived from patients with mycosis fungoides (patch/plaque lesions), psoriasis, atopic eczema and from healthy skin donors.

RESULTS

In orientation to the WHO-EORTC-classification of cutaneous lymphomas a MELC-library of 23 markers was established. According to an inaugurative detailed procedure the CMP frequency was determined in a normalization to 100 microm horizontal skin width. By a TopoMiner strategy mycosis fungoides could be separated from the other states with a maximum of significance (p < or = 0.03) by at least 10-fold overexpression of the following tumor cell-representative CMP-motif: CD3+/CD4+/CD1a-/CD7-/CD8-/CD45R0+/CD45RA-/CD11a+.

CONCLUSIONS

The skin tissue-adapted MELC-application-platform extends substantially conventional lymphoma diagnostics by an unprecedented dimension of in-situ-analysis of marker combinatorics including its exact quantification and visualization.

Serum levels of IL-17 and IL-22 are reduced by etanercept, but not by acitretin, in patients with psoriasis: a randomized-controlled trial

INTRODUCTION

There are no controlled trials comparing etanercept and acitretin efficacy and therapeutic mechanisms in psoriasis.

MATERIALS AND METHODS

In the present study, 30 patients were given etanercept 50 mg twice weekly and 30 patients acitretin 0.4 mg/kg per day, both for 12 weeks. Before and after treatment, psoriasis area and severity index was calculated, and serum levels of interleukin (IL)-17, IL-22, and IL-23 were investigated.

RESULTS

After treatment, psoriasis area and severity index was significantly lower for both groups. However, etanercept-treated patients showed lower psoriasis area and severity index than acitretin-treated ones. Psoriasis patients showed higher IL-17 and IL-22 levels than controls, while no IL-23 was found in any serum. Furthermore, a correlation between IL-17 levels and psoriasis severity was found. Only etanercept was able to reduce IL-17 and IL-22 levels.

CONCLUSIONS

Our findings suggest that etanercept is more effective than acitretin in the treatment of psoriasis and that it is able to affect Th17 system.

Psoríase na infância e na adolescência

A psoríase é doença inflamatória crônica, imunologicamente mediada, recorrente e de caráter universal. Aproximadamente um terço dos adultos acometidos refere início da doença antes dos 16 anos de idade. Quanto mais precoce, mais grave tende a ser a evolução do quadro. Em crianças, as lesões podem ser fisicamente desfigurantes, causando prejuízos psicológicos e evidente comprometimento da qualidade de vida. As medicações sistêmicas utilizadas na psoríase, bem como a fototerapia, têm indicação limitada na infância, devido aos efeitos cumulativos das drogas, à baixa aceitação e ao risco de teratogenicidade. Nesta seção, discutiremos as principais manifestações clínicas da psoríase na infância e na adolescência, bem como os diagnósticos diferenciais, opções terapêuticas e prognóstico.

Long-term prognosis in patients with psoriasis

Psoriasis is a chronic, inflammatory, immune-mediated skin disease associated with substantial comorbidity. Traditional comorbid conditions include psychological/psychiatric disorders, psoriatic arthritis and inflammatory bowel disease. Increasingly, an association with metabolic dysfunction, including obesity and the metabolic syndrome, and cardiovascular disease, with consequent effects on morbidity and mortality, has been recognized in psoriasis. The underlying inflammatory mechanisms of both psoriasis and psoriasis-associated comorbidities involve mediation by proinflammatory T-helper type 1 cytokines. For effective management of psoriasis and related comorbidities, an integrated approach targeting both cutaneous and systemic inflammation may be beneficial, and strategies to improve overall management of the patient should be encouraged to reduce the disease burden. This paper discusses the emerging role of biological agents in this approach, and offers an appreciation of the role of existing anti-psoriasis and adjunctive therapies.

T cells in psoriatic arthritis

Psoriatic arthritis is characterized by chronic inflammation of the skin and synovial joint. T cells are abundant in the inflamed joint and skin. Disease susceptibility is associated with major histocompatibility complex, which presents antigens to T cells. T cells in the synovial joints have an activated phenotype and demonstrate selective T-cell receptor usage suggestive of oligoclonal expansions. Taken together, these facts suggest that psoriatic arthritis is driven by antigen or autoantigen-driven T-cell activation. The therapeutic benefit of anti-T-cell agents further supports an important pathogenic role for T cells in persistent synovial inflammation and joint damage in psoriatic arthritis.

Distribution of the CTLA-4 single nucleotide polymorphisms CT60G>A and +49A>G in psoriasis vulgaris patients and control individuals from a Polish Caucasian population

Psoriasis vulgaris is a multifactorial disease with an autoimmune component, and T lymphocytes seem to be involved in its aetiology. CTLA-4 molecule is an important down-regulator of T-lymphocyte activation, and several polymorphisms of the CTLA-4 gene were found to be associated with some autoimmune diseases. We examined whether single nucleotide polymorphisms (SNPs) in the CTLA-4 gene, CT60A>G and +49A>G, are associated with psoriasis vulgaris. Alleles of these two SNPs were determined by the polymerase chain reaction-restriction fragment length polymorphism method. Both the CT60G>A and the +49A>G alleles and genotypes were distributed similarly in patients and controls. Although the two SNPs studied here in Poles were in linkage disequilibrium, all four possible two-locus haplotypes were found, one of them rare; of the remaining three, the haplotype +49G, CT60G was significantly (P = 0.019, OR = 0.58, 95%CI = 0.37-0.91) less frequent in the patient group with disease onset between the ages of 21 and 40 years than in controls and the other patient groups, whereas the frequencies of the other haplotypes were similar in patients and controls. To the authors' knowledge, this is the first study on CTLA-4 CT60 allele frequencies in psoriasis.