A genome-wide meta-analysis of palmoplantar pustulosis implicates TH2 responses and cigarette smoking in disease pathogenesis.

BACKGROUND: Palmoplantar pustulosis (PPP) is an inflammatory skin disorder that mostly affects smokers and manifests with painful pustular eruptions on the palms and soles. Although the disease can present with concurrent plaque psoriasis, TNF and IL-17/IL-23 inhibitors show limited efficacy. There is therefore a pressing need to uncover PPP disease drivers and therapeutic targets. OBJECTIVES: We sought to identify genetic determinants of PPP and investigate whether cigarette smoking contributes to disease pathogenesis. METHODS: We performed a genome-wide association meta-analysis of 3 North-European cohorts (n = 1,456 PPP cases and 402,050 controls). We then used the scGWAS program to investigate the cell-type specificity of the association signals. We also undertook genetic correlation analyses to examine the similarities between PPP and other immune-mediated diseases. Finally, we applied Mendelian randomization to analyze the causal relationship between cigarette smoking and PPP. RESULTS: We found that PPP is not associated with the main genetic determinants of plaque psoriasis. Conversely, we identified genome-wide significant associations with the FCGR3A/FCGR3B and CCHCR1 loci. We also observed 13 suggestive (P < 5 × 10-6) susceptibility regions, including the IL4/IL13 interval. Accordingly, we demonstrated a significant genetic correlation between PPP and TH2-mediated diseases such as atopic dermatitis and ulcerative colitis. We also found that genes mapping to PPP-associated intervals were preferentially expressed in dendritic cells and often implicated in T-cell activation pathways. Finally, we undertook a Mendelian randomization analysis, which supported a causal role of cigarette smoking in PPP. CONCLUSIONS: The first genome-wide association study of PPP points to a pathogenic role for deregulated TH2 responses and cigarette smoking.

Single-cell analysis implicates TH17-to-TH2 cell plasticity in the pathogenesis of palmoplantar pustulosis.

BACKGROUND: Palmoplantar pustulosis (PPP) is a severe inflammatory skin disorder characterized by eruptions of painful, neutrophil-filled pustules on the palms and soles. Although PPP has a profound effect on quality of life, it remains poorly understood and notoriously difficult to treat. OBJECTIVE: We sought to investigate the immune pathways that underlie the pathogenesis of PPP. METHODS: We applied bulk and single-cell RNA sequencing (RNA-Seq) methods to the analysis of skin biopsy samples and peripheral blood mononuclear cells. We validated our results by flow cytometry and immune fluorescence microscopy RESULTS: Bulk RNA-Seq of patient skin detected an unexpected signature of T-cell activation, with a significant overexpression of several TH2 genes typically upregulated in atopic dermatitis. To further explore these findings, we carried out single-cell RNA-Seq in peripheral blood mononuclear cells of healthy and affected individuals. Memory CD4+ T cells of PPP patients were skewed toward a TH17 phenotype, a phenomenon that was particularly significant among cutaneous lymphocyte-associated antigen-positive skin-homing cells. We also identified a subset of memory CD4+ T cells that expressed both TH17 (KLRB1/CD161) and TH2 (GATA3) markers, with pseudotime analysis suggesting that the population was the result of TH17 to TH2 plasticity. Interestingly, the GATA3+/CD161+ cells were overrepresented among the peripheral blood mononuclear cells of affected individuals, both in the single-cell RNA-Seq data set and in independent flow cytometry experiments. Dual-positive cells were also detected in patient skin by immune fluorescence microscopy. CONCLUSIONS: PPP is associated with complex T-cell activation patterns and may explain why biologic drugs that target individual T helper cell populations have shown limited therapeutic efficacy.

Diagnosing Omenn syndrome.

Omenn syndrome is a rare combined immunodeficiency mostly associated with RAG1 and RAG2 mutations; the clinical manifestations are well-described and include neonatal erythroderma. Mortality due to opportunistic infections is a serious risk, and a timely diagnosis with a skin biopsy is an important part of the diagnostic workup. We wish to highlight key clinical features of Omenn syndrome and discuss the relevance of a skin biopsy.

Neonatal urticaria: Could it be CAPS?

A neonatal boy presented with a persistent urticarial rash. Initial investigations showed raised inflammatory markers and evidence of systemic inflammation. A working diagnosis of cryopyrin-associated periodic syndrome (CAPS) was made, and the patient responded extremely well to Anakinra. Molecular genetic testing revealed a somatic mutation (affecting 12.5% of cells) in the NLRP3 gene, accounting for the persistent inflammatory state but milder phenotype as seen in our patient.

Assessing the validity and response distribution of the simplified psoriasis index in patients receiving phototherapy.

BACKGROUND/OBJECTIVES: The simplified psoriasis index (SPI) is a three-part multidimensional tool incorporating disease severity, psychosocial impact and historical course completed by the health-care professional (professional SPI, [proSPI]) or the patient (self-assessment SPI, [saSPI]). We aimed to assess the validity and response distribution of proSPI and saSPI in patients with psoriasis undergoing phototherapy. METHODS: The validity and response distribution of SPI was assessed by recording saSPI and proSPI in patients with psoriasis before and after a course of phototherapy. Recruitment ended once 100 complete data sets were available for analysis. RESULTS: Altogether 52 of the 100 patients evaluated were male and most (93) underwent narrowband UVB phototherapy. There was a close correlation between the proSPI-current severity score (proSPI-s) with the psoriasis area and severity index (PASI) score (r = 0.76, r = 0.86) before and after treatment, respectively. Although pretreatment correlation between the saSPI-current severity score (saSPI-s) and PASI was weak (r = 0.39), a more close correlation was noted at the end of treatment (r = 0.50). A moderate correlation was observed between the SPI-psychosocial impact score (SPI-p) and the dermatology life quality index (DLQI), both before and after phototherapy (r = 0.64, r = 0.73). The SPI had wide response distributions in all three domains. CONCLUSIONS: Both versions of SPI demonstrated wide response distributions and the proSPI-s in particular was shown to have good validity with PASI.

Use of Phototherapy in Children.

BACKGROUND: Phototherapy is a well-recognized treatment in adults and children. Previous articles have reported success in treating recalcitrant skin disorders such as atopic dermatitis (AD), psoriasis, pityriasis lichenoides chronica, and vitiligo in children. METHODS: This was a retrospective review over an 18-month period from June 2012 to December 2013 of all children receiving phototherapy in a tertiary pediatric dermatology center. RESULTS: Seventy-five patients 3 to 17 years of age (mean 10.6 years; 35 male, 40 female) were included. Forty-eight (64%) patients had AD and 21 (28%) had psoriasis. Seventy received narrowband ultraviolet B (NBUVB) treatment and five received hand and foot psoralen and ultraviolet A (PUVA) treatment. All patients with AD were treated with NBUVB and four (8.3%) were also treated with hand PUVA. After phototherapy, 76% had documented clear to almost clear skin. At the 12-month follow-up, 52% of the patients with AD remained clear. All 21 patients with psoriasis underwent NBUVB phototherapy. The clearance rate after phototherapy was 86%. At the 12-month follow-up, 43% of the patients with psoriasis remained clear. CONCLUSION: Phototherapy can reduce disease burden in individuals with severe AD and psoriasis and should be considered as a second-line therapy if standard topical regimens are unsuccessful.

Case Report of Lichen Planopilaris Occurring in a Pediatric Patient Receiving a Tumor Necrosis Factor α Inhibitor and a Review of the Literature.

A 12-year-old girl with extended oligoarthritis treated with adalimumab presented with a short history of a progressive cutaneous eruption involving the legs and scalp. Physical examination and histologic results were consistent with lichen planopilaris. The adalimumab was discontinued. She received treatment with topical clobetasol propionate and the majority of the lesions resolved. Residual lesions and the extended oligoarthritis were then treated with sulfasalazine. Adalimumab is a tumor necrosis factor α (TNF-α) inhibitor used for the treatment of a variety of immunologically mediated conditions, including lichen planus and lichen planopilaris. TNF-α antagonists have been associated with paradoxical psoriasiform, lichenoid, eczematous, granulomatous, and acneiform eruptions. We detail this case and review the literature of lichenoid reactions secondary to TNF-α inhibitors.

Differences in Clinical Features and Comorbid Burden between HLA-C∗06:02 Carrier Groups in >9,000 People with Psoriasis.

The identification of robust endotypes-disease subgroups of clinical relevance-is fundamental to stratified medicine. We hypothesized that HLA-C∗06:02 status, the major genetic determinant of psoriasis, defines a psoriasis endotype of clinical relevance. Using two United Kingdom-based cross-sectional datasets-an observational severe-psoriasis study (Biomarkers of Systemic Treatment Outcomes in Psoriasis; n = 3,767) and a large population-based bioresource (UK Biobank, including n = 5,519 individuals with psoriasis)-we compared demographic, environmental, and clinical variables of interest in HLA-C∗06:02-positive (one or two copies of the HLA-C∗06:02 allele) with those in HLA-C∗06:02‒negative (no copies) individuals of European ancestry. We used multivariable regression analyses to account for mediation effects established a priori. We confirm previous observations that HLA-C∗06:02-positive status is associated with earlier age of psoriasis onset and extend findings to reveal an association with disease expressivity in females (Biomarkers of Systemic Treatment Outcomes in Psoriasis: P = 2.7 × 10-14, UK Biobank: P = 1.0 × 10-8). We also show HLA-C∗06:02-negative status to be associated with characteristic clinical features (large plaque disease, OR for HLA-C∗06:02 = 0.73, P = 7.4 × 10-4; nail involvement, OR = 0.70, P = 2.4 × 10-6); higher central adiposity (Biomarkers of Systemic Treatment Outcomes in Psoriasis: waist circumference difference of 2.0 cm, P = 8.4 × 10-4; UK Biobank: waist circumference difference of 1.4 cm, P = 1.5 × 10-4), especially in women; and a higher prevalence of other cardiometabolic comorbidities. These findings extend the clinical phenotype delineated by HLA-C∗06:02 and highlight its potential as an important biomarker to consider in future multimarker stratified medicine approaches.

A 3-month-old with a blistering plaque.

Cutaneous Mastocytosis is not an uncommon condition in the pediatric setting. The eruption can have multiple clinical presentations. We present a case of a 3-month-old child with a solitary mastocytoma who was initially diagnosed with recurrent bullous impetigo. Solitary mastocytoma can present as a blister. Although bullous impetigo is a common diagnosis in children and it would be tempting to make that diagnosis in the presence of a positive skin swab culture, clinicians always have to be mindful of secondary impetiginization of another primary skin disease process.

Association of Clinical and Demographic Factors With the Severity of Palmoplantar Pustulosis.

Importance: Although palmoplantar pustulosis (PPP) can significantly impact quality of life, the factors underlying disease severity have not been studied. Objective: To examine the factors associated with PPP severity. Design, Setting, and Participants: An observational, cross-sectional study of 2 cohorts was conducted. A UK data set including 203 patients was obtained through the Anakinra in Pustular Psoriasis, Response in a Controlled Trial (2016-2019) and its sister research study Pustular Psoriasis, Elucidating Underlying Mechanisms (2016-2020). A Northern European cohort including 193 patients was independently ascertained by the European Rare and Severe Psoriasis Expert Network (2014-2017). Patients had been recruited in secondary or tertiary dermatology referral centers. All patients were of European descent. The PPP diagnosis was established by dermatologists, based on clinical examination and/or published consensus criteria. The present study was conducted from October 1, 2014, to March 15, 2020. Main Outcomes and Measures: Demographic characteristics, comorbidities, smoking status, Palmoplantar Pustulosis Psoriasis Area Severity Index (PPPASI), measuring severity from 0 (no sign of disease) to 72 (very severe disease), or Physician Global Assessment (PGA), measuring severity as 0 (clear), 1 (almost clear), 2 (mild), 3 (moderate), and 4 (severe). Results: Among the 203 UK patients (43 men [21%], 160 women [79%]; median age at onset, 48 [interquartile range (IQR), 38-59] years), the PPPASI was inversely correlated with age of onset (r = -0.18, P = .01). Similarly, in the 159 Northern European patients who were eligible for inclusion in this analysis (25 men [16%], 134 women [84%]; median age at onset, 45 [IQR, 34-53.3] years), the median age at onset was lower in individuals with a moderate to severe PGA score (41 years [IQR, 30.5-52 years]) compared with those with a clear to mild PGA score (46.5 years [IQR, 35-55 years]) (P = .04). In the UK sample, the median PPPASI score was higher in women (9.6 [IQR, 3.0-16.2]) vs men (4.0 [IQR, 1.0-11.7]) (P = .01). Likewise, moderate to severe PPP was more prevalent among Northern European women (57 of 134 [43%]) compared with men (5 of 25 [20%]) (P = .03). In the UK cohort, the median PPPASI score was increased in current smokers (10.7 [IQR, 4.2-17.5]) compared with former smokers (7 [IQR, 2.0-14.4]) and nonsmokers (2.2 [IQR, 1-6]) (P = .003). Comparable differences were observed in the Northern European data set, as the prevalence of moderate to severe PPP was higher in former and current smokers (51 of 130 [39%]) compared with nonsmokers (6 of 24 [25%]) (P = .14). Conclusions and Relevance: The findings of this study suggest that PPP severity is associated with early-onset disease, female sex, and smoking status. Thus, smoking cessation intervention might be beneficial.

Successful treatment of central nervous system juvenile xanthogranulomatosis with cladribine.

Juvenile xanthogranulomatosis (JXG) is an uncommon histiocytic disease that is usually limited to the skin. Here we describe an infant with systemic JXG including a central nervous system (CNS) lesion. He was initially treated with prednisolone and vinblastine but developed an idiosyncratic reaction to prednisolone that was discontinued. The lesion then failed to respond to vinblastine monotherapy. Treatment with cladribine (2-chlorodeoxyadenosine) was subsequently successful with radiological resolution of the CNS lesion.

A Framework for Multi-Omic Prediction of Treatment Response to Biologic Therapy for Psoriasis.

Biologic therapies have shown high efficacy in psoriasis, but individual response varies and is poorly understood. To inform biomarker discovery in the Psoriasis Stratification to Optimise Relevant Therapy (i.e., PSORT) study, we evaluated a comprehensive array of omics platforms across three time points and multiple tissues in a pilot investigation of 10 patients with severe psoriasis, treated with the tumor necrosis factor (TNF) inhibitor, etanercept. We used RNA sequencing to analyze mRNA and small RNA transcriptome in blood, lesional and nonlesional skin, and the SOMAscan platform to investigate the serum proteome. Using an integrative systems biology approach, we identified signals of treatment response in genes and pathways associated with TNF signaling, psoriasis pathology, and the major histocompatibility complex region. We found association between clinical response and TNF-regulated genes in blood and skin. Using a combination of differential expression testing, upstream regulator analysis, clustering techniques, and predictive modeling, we show that baseline samples are indicative of patient response to biologic therapies, including signals in blood, which have traditionally been considered unreliable for inference in dermatology. In conclusion, our pilot study provides both an analytical framework and empirical basis to estimate power for larger studies, specifically the ongoing PSORT study, which we show as powered for biomarker discovery and patient stratification.

Quantitative Evaluation of Biologic Therapy Options for Psoriasis: A Systematic Review and Network Meta-Analysis.

Multiple biologic treatments are licensed for psoriasis. The lack of head-to-head randomized controlled trials makes choosing between them difficult for patients, clinicians, and guideline developers. To establish their relative efficacy and tolerability, we searched MEDLINE, PubMed, Embase, and Cochrane for randomized controlled trials of licensed biologic treatments for skin psoriasis. We performed a network meta-analysis to identify direct and indirect evidence comparing biologics with one another, methotrexate, or placebo. We combined this with hierarchical cluster analysis to consider multiple outcomes related to efficacy and tolerability in combination for each treatment. Study quality, heterogeneity, and inconsistency were evaluated. Direct comparisons from 41 randomized controlled trials (20,561 participants) were included. All included biologics were efficacious compared with placebo or methotrexate at 3-4 months. Overall, cluster analysis showed adalimumab, secukinumab, and ustekinumab were comparable in terms of high efficacy and tolerability. Ixekizumab and infliximab were differentiated by very high efficacy but poorer tolerability. The lack of longer term controlled data limited our analysis to short-term outcomes. Trial performance may not equate to real-world performance, and so results need to be considered alongside real-world, long-term safety and effectiveness data. These data suggest that it is possible to discriminate between biologics to inform clinical practice and decision making (PROSPERO 2015:CRD42015017538).

Risk of Serious Infections in Patients with Psoriasis on Biologic Therapies: A Systematic Review and Meta-Analysis.

A comprehensive evaluation of the risk of serious infections in biologic therapies for psoriasis is lacking. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) and prospective cohort studies reporting serious infections in people taking any licensed biologic therapy for psoriasis compared with those taking placebo, nonbiologic therapy, or other biologic therapies. The quality of the studies was assessed using Grading of Recommendations Assessment, Development and Evaluation criteria. No significant heterogeneity was detected in data from 32 RCTs (n = 13,359 participants) and one cohort study (n = 4,993 participants). In adults, low- to very-low-quality RCT data showed no significant difference between any biologic therapy and placebo at weeks 12-16 (overall pooled Peto odds ratio = 0.71, 95% confidence interval = 0.36-1.41) and weeks 20-30 (odds ratio = 2.27, 95% confidence interval = 0.45-11.49). No significant differences were found in any of the other comparisons in underpowered RCT data. Prospective cohort study data of low quality suggests that only adalimumab (adjusted hazard ratio [adjHR] = 2.52, 95% confidence interval = 1.47-4.32) was associated with a significantly higher risk of serious infection compared with retinoid and/or phototherapy in adults. No association between biologic therapies and serious infections in patients with psoriasis who were eligible for RCTs was detected. Further observational studies are needed to inform the uncertainty around this risk in the real world.

Efficacy and local safety of a calcipotriol/ betamethasone dipropionate ointment in elderly patients with psoriasis vulgaris.

The proportion of elderly patients with psoriasis vulgaris is set to increase in the future due to an ageing population. This descriptive analysis assessed the efficacy and safety of a new ointment containing calcipotriol and betamethasone dipropionate (Daivobet/Dovobet in a pooled analysis of patients aged 60 years and over. A total of 1534 patients, including 357 aged > or = 60 years, with psoriasis vulgaris received the two-compound ointment once-daily in four randomised, double-blind, studies. After 4 weeks treatment the mean reduction in PASI was 67.8% in patients < 60 years compared with 72.6% in patients > or = 60 years. "Controlled disease" (i.e. a global assessment of "absence of disease" or "very mild disease"), according to the investigators, was achieved by 52.1% of patients < 60 years and 58.2% of patients > or = 60 years. Patients in both age groups reported a similar number of lesional/perilesional adverse drug reactions; 6.4% in patients < 60 years vs 5.0% in patients > or = 60 years. Thus, the new two-compound ointment is effective and well-tolerated in the treatment of psoriasis vulgaris, regardless of age group.