Response to adalimumab in Caucasian and Asian patients with hidradenitis suppurativa: A retrospective cohort study of an Australian cohort stratified by patient-reported ethnicity.

BACKGROUND/OBJECTIVES: Caucasian and Asian patients with hidradenitis suppurativa demonstrate significant differences with regard to age, gender and body mass index. Demographic characteristics are known to influence the efficacy and drug survival of hidradenitis suppurativa therapeutics including biologic therapies. What remains unknown is the impact of ethnicity upon the efficacy of therapeutics once demographic and disease characteristics have been taken into account. This is an important question given the expansion of biologic therapies for HS into the global patient community. METHODS: We assessed 170 patients from a single HS specialist centre in Australia stratified by patient-identified ethnicity including those identifying as either Caucasian or Asian. RESULTS: Asian patients demonstrated lower BMI, higher rates of smoking and greater odds of Hurley stage 3 disease with tunnels than Caucasian patients in line with the reported literature. There was no significant difference between percentage of individuals achieving HiSCR50 or IHS4-55 at Week 16. Significant differences were seen in median time to secondary loss of response, and Kaplan-Meier curve analysis showed a significant difference between curves when stratified by patient-reported ethnicity. Cox regression analysis demonstrated after accounting for age, gender, BMI, smoking and Hurley stage, the significance of ethnicity in influencing time to secondary loss of response disappears. CONCLUSIONS: Caucasian or Asian ethnicity does not influence response to adalimumab treatment on patients with hidradenitis suppurativa.

Alterations to the Hidradenitis Suppurativa Serum Proteome with Spleen Tyrosine Kinase Antagonism: Proteomic Results from a Phase 2 Clinical Trial.

Hidradenitis suppurativa is a disease in great need of novel therapies. Given the heterogeneous nature of the disease and the variable response to therapies, biomarkers are essential to predict response to therapies and increase our understanding of disease pathogenesis. Our recent phase 2 clinical trial of spleen tyrosine kinase antagonism using fostamatinib in hidradenitis suppurativa demonstrated a 75% clinical response, with the greatest benefit in individuals with elevated serum inflammation and IgG. In this study, we present results of an in-depth serum proteomic analysis in this patient cohort identifying downregulation of IL-12B as well as B-cell-associated proteins CCL19 and CCL20 and IFN-γ-mediated proteins CXCL10 and CX3CL1. Clinical responders demonstrated greater reduction in serum IL-17A, IL-6, IL-8, and CX3CL1 compared with clinical nonresponders. Baseline levels of CCL28 were associated with clinical response to fostamatinib therapy at week 12. Overall, this suggests that fostamatinib, by targeting B-cell receptor and Fc receptor activity in B cells, monocytes, and macrophages, has a significant molecular impact on the inflammatory serum proteome of hidradenitis suppurativa. In addition, potential therapeutic biomarkers may aid in patient selection for targeted therapy.

Human dermal fibroblast subpopulations and epithelial mesenchymal transition signals in hidradenitis suppurativa tunnels are normalized by spleen tyrosine kinase antagonism in vivo.

Hidradenitis Suppurativa is a chronic inflammatory disease of which the pathogenesis is incompletely understood. Dermal fibroblasts have been previously identified as a major source of inflammatory cytokines, however information pertaining to the characteristics of subpopulations of fibroblasts in HS remains unexplored. Using in silico-deconvolution of whole-tissue RNAseq, Nanostring gene expression panels and confirmatory immunohistochemistry we identified fibroblast subpopulations in HS tissue and their relationship to disease severity and lesion morphology. Gene signatures of SFRP2+ fibroblast subsets were increased in lesional tissue, with gene signatures of SFRP1+ fibroblast subsets decreased. SFRP2+ and CXCL12+ fibroblast numbers, measured by IHC, were increased in HS tissue, with greater numbers associated with epithelialized tunnels and Hurley Stage 3 disease. Pro-inflammatory CXCL12+ fibroblasts were also increased, with reductions in SFRP1+ fibroblasts compared to healthy controls. Evidence of Epithelial Mesenchymal Transition was seen via altered gene expression of SNAI2 and altered protein expression of ZEB1, TWIST1, Snail/Slug, E-Cadherin and N-Cadherin in HS lesional tissue. The greatest dysregulation of EMT associated proteins was seen in biopsies containing epithelialized tunnels. The use of the oral Spleen tyrosine Kinase inhibitor Fostamatinib significantly reduced expression of genes associated with chronic inflammation, fibroblast proliferation and migration suggesting a potential role for targeting fibroblast activity in HS.

A proof-of-concept open-label clinical trial of spleen tyrosine kinase antagonism using fostamatinib in moderate-to-severe hidradenitis suppurativa.

BACKGROUND: Hidradenitis suppurativa (HS) is an autoinflammatory disorder of keratinization with a prominence of B cells and plasma cells. Fostamatinib is a spleen tyrosine kinase inhibitor targeting B cells and plasma cells. OBJECTIVES: To assess the safety, tolerability, and clinical response at week 4 and week 12 of fostamatinib in moderate-to-severe HS. METHODS: Twenty participants were administered fostamatinib 100 mg twice a day for 4 weeks, escalating to 150 mg twice a day thereafter until week 12. Participants were assessed for adverse events and clinical response assessed by HiSCR (Hidradenitis Suppurativa Clinical Response Score) and IHS4 (International Hidradenitis Suppurativa Severity Score) as well as other outcomes including DLQI (Dermatology Life Quality Index), visual analog scale, and physician global assessment. RESULTS: All 20 participants completed the week 4 and week 12 endpoints. Fostamatinib was well tolerated in this cohort with no grade 2/3 adverse events reported. A total of 85% achieved HiSCR at week 4 and 85% at week 12. The greatest reduction in disease activity was seen at weeks 4/5 with worsening in a proportion of patients thereafter. Significant improvements were seen in pain, itch, and quality of life. CONCLUSIONS: Fostamatinib was well tolerated in this HS cohort with no serious adverse events and improvement in clinical outcomes. Targeting B cells/plasma cells may be a viable therapeutic strategy in HS and requires further exploration.

The impact of psoriasis biologic therapy on HIV viral load and CD4+ cell counts in HIV-positive individuals: A real-world cohort study.

BACKGROUND: Psoriasis is a chronic immune-mediated inflammatory disorder that also occurs in the setting of human immunodeficiency virus (HIV). Biological therapy has transformed the treatment landscape for psoriasis; however, individuals with HIV are excluded from clinical trials. The impact of biological therapy on blood parameters in HIV is unclear and is only observed in small case series. OBJECTIVE: The aim of this study was to assess the effect of biological therapy in psoriasis vulgaris in individuals with well-controlled HIV on CD4+ cell counts, CD4+ proportion and HIV viral load over 12 months. METHODS: This retrospective cohort study was conducted at a tertiary referral centre in Sydney, Australia and included 36 HIV-positive individuals with psoriasis treated with biological therapy, compared with 144 age-, gender- and HAART-matched individuals without psoriasis seen between 2010 and 2022. Outcomes of interest included HIV viral load, CD4+ cell count and incidence of infections. RESULTS: No statistically significant difference was seen in baseline HIV viral load and CD4+ count between individuals with and without psoriasis. No significant change in CD4+ count or HIV viral load was seen over the 12-month period of analysis in the HIV cohort without psoriasis. The HIV cohort treated with biological therapy for psoriasis also did not demonstrate any significant change in HIV viral load and CD4+ counts over the 12-month period examined. Stratification by type of biological therapy used did not identify any significant changes in these parameters. Rates of infections and adverse events were also not significantly different between cohorts. It is possible that minor blips seen in the biologics cohort may be a risk factor for future virological failure, and future prospective longitudinal studies are required. CONCLUSIONS: In individuals with well-controlled HIV, the use of biological therapy for psoriasis does not significantly impact HIV viral load, CD4+ cell count, CD4+ proportion and rates of infection over the first 12 months of therapy.

Pyoderma gangrenosum: A systematic review of the molecular characteristics of disease.

Pyoderma gangrenosum is a painful recurrent ulcerative neutrophilic dermatosis in which the pathogenesis is incompletely defined. Current evidence suggests that PG is associated with dysregulation of components of both the innate and adaptive immune system with dysregulation of neutrophil function and contribution of the Th17 immune axis. PG can be present in numerous heterogeneous clinical presentations and be associated with multiple inflammatory conditions including rheumatoid arthritis, inflammatory bowel disease and hidradenitis suppurativa. However, no critical evaluation of the observed molecular characteristics in PG studies in association with their clinical findings has been assessed. Additionally, emerging evidence suggests a potential role for other cell types and immune pathways including B cells, macrophages, autoantibodies and the complement system in PG, although these have not yet been integrated into the pathogenesis of disease. This systematic review aims to critically evaluate the current molecular observations regarding the pathogenesis of PG and discuss associations with clinical characteristics as well as the evidence supporting novel cell types and immune pathways in PG.

Netherton's Syndrome: A Case of Two Male Siblings Diagnosed in Adulthood.

Netherton's syndrome (NS) is a rare autosomal recessive genetic disease caused by a germline mutation in the SPINK5 gene. It is most commonly diagnosed in neonates due to the presence of congenital ichthyosiform erythroderma. Affected individuals will typically also develop a hair shaft abnormality known as trichorrhexis invaginata, severe atopy, and a migratory rash known as ichythyosis linearis circumflexa. The chronicity and severity of NS adversely affects a patient's quality of life to a large extent. It Is therefore important that this condition is identified early, and treatment to reduce cutaneous inflammation is initiated in a timely fashion. However, due to this condition being relatively rare, a lack of awareness may lead clinicians to misdiagnose it as atopic dermatitis or undifferentiated psoriasis. Clinicians should therefore be aware of the peripheral stigmata that this disease may present as in adulthood, so that a correct diagnosis can be made if it was previously missed. Here we present a case of two male siblings from Jordon who were misdiagnosed since childhood as having erythrodermic psoriasis. Clinical examination of one of the siblings, as an adult, revealed multiple peripheral features associated with NS. Genetic analysis through sanger sequencing was also able to identify a mutation in the SPINK5 gene, confirming the diagnosis.