Hidradenitis suppurativa: viewpoint on clinical phenotyping, pathogenesis and novel treatments

Innate Immune Sensors and Cell Death-Frontiers Coordinating Homeostasis, Immunity, and Inflammation in Skin

The skin provides a life-sustaining interface between the body and the external environment. A dynamic communication among immune and non-immune cells in the skin is essential to ensure body homeostasis. Dysregulated cellular communication can lead to the manifestation of inflammatory skin conditions. In this review, we will focus on the following two key frontiers in the skin: innate immune sensors and cell death, as well as their cellular crosstalk in the context of skin homeostasis and inflammation. This review will highlight the recent advancements and mechanisms of how these pathways integrate signals and orchestrate skin immunity, focusing on inflammatory skin diseases and skin infections in mice and humans.

Corneal Manifestations in Patients with Hidradenitis Suppurativa

PURPOSE

To report two cases of bilateral blepharokeratoconjunctivitis associated with hidradenitis suppurativa (HS).

METHODS

Case report and literature review. The clinical courses of two patients with HS, including ocular presentation and medical management, are described.

RESULTS

Two female patients aged 18 and 23-years-old with severe HS presented with bilateral blepharokeratoconjunctivitis. Shared slit lamp findings included bilateral corneal neovascularization and inferior corneal thinning. Systemic immunosuppression was needed in the first case, which resulted in improvement in the patient's ophthalmic and dermatological findings.

CONCLUSION

We report two cases of bilateral blepharokeratoconjunctivitis in two patients with severe HS. To our knowledge, this association has not previously been described in the literature. Clinicians should be aware of this association given its potentially visually devastating manifestations and the need for early therapeutic interventions.

Assessing the Role of Adalimumab in Treating Hidradenitis Suppurativa: Findings from a Retrospective Study at a Reference Center

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition characterized by inflammatory lesions, often leading to scarring. Managing HS can be difficult, requiring biological therapy, specifically adalimumab.

METHODS

A retrospective study was conducted on patients diagnosed with HS and treated with the TNF-α inhibitor adalimumab. Data from 21 patients were included in this study. International Hidradenitis Suppurativa Severity Score System (IHS4); Dermatology Life Quality Index (DLQI); pain intensity according to the Visual Analogue Scale (VAS); and number of nodules, abscesses, and fistulas were assessed.

RESULTS

Notably, 47.62% of patients achieved Hidradenitis Suppurativa Clinical Response. The mean number of inflamed nodules decreased from 5.62 ± 4.12 to 3 ± 3.46, abscesses decreased from 1.76 ± 2.63 to 0.81 ± 1.4, and fistulas decreased from 2.62 ± 1.86 to 2 ± 1.9 (p < 0.05). The IHS4 score decreased from 19 ± 10.78 to 12.62 ± 11.13 (p = 0.001), DLQI from 15.76 ± 7.73 to 7.43 ± 7.76 (p < 0.001), and VAS from 6.69 ± 1.56 to 3.64 ± 2.65 (p < 0.001). There was a significant difference in the baseline IHS4 scores between patients who had prior surgery with a mean score of 23.86 ± 9.4 versus non-surgical patients with a mean IHS4 score of 9.29 ± 5.53 (p = 0.001).

CONCLUSIONS

About half of HS patients responded positively to adalimumab treatment; the use of the drug reduces inflammatory lesions, and pain, and improves quality of life.

New insights on hidradenitis suppurativa phenotypes and treatment response: An exploratory automated analysis of the SUNSHINE and SUNRISE trials

BACKGROUND

Defining hidradenitis suppurativa (HS) subtypes was previously limited by small sample sizes and poor interrater reliability; no study has investigated subtype treatment responses. The objective of this analysis was to characterize HS clusters in adult patients with moderate to severe HS and evaluate secukinumab treatment responses between clusters.

METHODS

Clusters were identified via an unsupervised machine learning clustering analysis using baseline data from the randomized, placebo-controlled SUNSHINE (NCT03713619) and SUNRISE (NCT03713632) phase 3 trials. To assess treatment responses, patients received secukinumab every 2 (SECQ2W) or 4 weeks (SECQ4W) or placebo, for 16 weeks, after which, placebo patients randomly switched to SECQ2W/SECQ4W, and SECQ2W/SECQ4W patients maintained their original treatment, until week 52. Baseline outcomes included patient characteristics, disease characteristics and severity, HS-associated comorbidities and previous treatment exposures. Treatment response was assessed via the HS clinical response (HiSCR), abscess and inflammatory nodule (AN) count, flares and NRS30 (skin pain).

RESULTS

Based on baseline data, three clusters were identified from 1084 patients (Cluster 1: 54.1%, Cluster 2: 17.8%, Cluster 3: 28.1%). Cluster 1 was predominantly female (65.4%) and was characterized by milder HS. Cluster 2 had more patients from the Asia Pacific, Middle East and Africa region (58.5%) and was characterized by moderate HS. Cluster 3 had the highest rates of previous exposure to biologics (45.9%) and prior HS-related surgeries (47.5%) and was characterized by severe HS. SECQ2W and SECQ4W demonstrated efficacy versus placebo in all clusters at week 16; SECQ2W and SECQ4W efficacy was maintained to week 52. SECQ2W treatment showed a trend for greater efficacy versus SECQ4W in Cluster 3 through week 52.

CONCLUSIONS

Three HS clusters were identified. Secukinumab demonstrated benefit over placebo in all clusters. However, patients with more severe disease may take longer to respond and more frequent secukinumab dosing may be required for these patients.

TRIAL REGISTRATION

SUNSHINE (NCT03713619) and SUNRISE (NCT03713632).

[Hidradenitis suppurativa]

Hidradenitis suppurativa (HS) is a chronic inflammatory skin and systemic disease that is associated with considerable discomfort and a significant reduction in the quality of life. Despite a significantly increased understanding of the disease, the diagnosis is still delayed for many years. Delayed patient access to suitable treatment often leads to disease progression with increased surgical interventions and the occurrence of possible comorbidities. In recent years, there has been an improved understanding of the pathophysiology and, as a result the authorization of modern therapeutic agents for HS. The treatment of HS is based on three treatment pillars: surgery, antibiotics and biologics. Additionally, risk factors, such as smoking and obesity should be positively influenced. Knowledge of comorbidities and their interdisciplinary treatment is important for the individualized care of patients.

Phage therapy for hidradenitis suppurativa: a unique challenge and possible opportunity for personalized treatment of a complex, inflammatory disease

Phage therapy is an emerging antimicrobial treatment for critical multidrug-resistant pathogens. In this review, the specific potential and challenges of phage therapy for patients with hidradenitis suppurativa (HS) are discussed. This represents a unique challenge as HS is a chronic inflammatory disease, but presenting with acute exacerbations, which have an enormous negative impact on patient's quality of life. The therapeutic arsenal for HS has expanded in the past decade, for example, with adalimumab and several other biologicals that are currently under investigation. However, treatment of HS remains challenging for dermatologists because there are individuals who do not respond to any classes of the current treatment options when used for a first or second time. Furthermore, after several courses of treatment, a patient may lose their response to therapy, meaning long-term use is not always an option. Culturing studies and 16S ribosomal RNA profiling highlight the complex polymicrobial nature of HS lesions. Despite the detection of various bacterial species in lesion samples, several key pathogens, including Staphylococcus, Corynebacterium and Streptococcus, may be potential targets for phage therapy. Using phage therapy for the treatment of a chronic inflammatory disease could potentially provide new insights into the role of bacteria and the immune system in HS development. In addition, it is possible more details on the immunomodulatory effects of phages may come to light.

Hidradenitis Suppurativa: An Interdisciplinary Problem in Dermatology, Gynecology, and Surgery-Pathogenesis, Comorbidities, and Current Treatments

Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic inflammatory disease that manifests as painful nodules, abscesses, draining dermal tunnels, and scarring in intertriginous areas such as the axillae, groin, and breasts. The nature of the disease and its chronicity have a destructive impact on mental health and quality of life. HS has an estimated global prevalence of 0.00033-4.1% and it disproportionately affects females compared to males. HS involving the female anogenital regions is reported rarely in the gynecological literature, and it can often be mistaken for other vulvar diseases. The distinct phenotypes and HS rarity cause delayed diagnosis and the implementation of effective treatment. Acne inversa is associated with several comorbidities, including metabolic disease, diabetes mellitus, inflammatory bowel diseases, and spondyloarthropathies. Although HS etiology and pathogenesis remain unclear, studies have shown that lifestyle, immunological processes, genetics, and hormonal predispositions may promote follicular hyperkeratosis, dilatation, and rupture, leading to the development of chronic tissue inflammation. This article provides updated information on HS pathogenesis, comorbidities, and treatment methods. Furthermore, we share our experience in the surgical treatment of the disease, which often proves most effective, and highlight that an interdisciplinary management approach ensures optimal outcomes.

New Insight into the Molecular Pathomechanism and Immunomodulatory Treatments of Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is an immune-mediated inflammatory disorder characterized by deep-seated nodules, abscesses, sinus tracts and scars localized in the intertriginous areas. It is accompanied by pain, malodourous secretion and a dramatically decreased quality of life. Although the pathogenesis has not been entirely elucidated, the primary event is follicular hyperkeratosis of the pilosebaceous apocrine unit. Since the registration of the tumor necrosis factor-alpha inhibitor Adalimumab in 2015, several cytokines have been implicated in the pathomechanism of HS and the research of novel therapeutic targets has been intensified. We provide an update on the inflammatory cytokines with a central role in HS pathogenesis and the most promising target molecules of future HS management.

Friction-Aggravated Skin Disorders-A Review of Mechanism and Related Diseases

ABSTRACT

Skin is subject to frequent friction injury. Friction affects different structures of the skin, including keratinocytes, melanocytes, fibroblasts, and follicular units. Friction can also stimulate cytokine production. Friction is sensed by the mechanoreceptors, resulting in signal transduction to the nucleus, activating transcription factors and mechanoresponsive genes. Numerous friction-aggravated diseases have been identified, including inflammatory, depositional, follicular, genetic, infectious, and vesiculobullous disorders. Friction, as a potential modifiable aggravator, should be considered when skin diseases are located at friction-prone areas.

Long-term risk of death in patients with hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is associated with substantial morbidity. Few studies have addressed the natural history and mortality rates associated with HS. A higher risk of cardiovascular death in patients with HS has been reported. We investigated whether patients with HS have an increased overall risk of death compared with age- and gender-matched referents.

METHODS

We performed a retrospective cohort study of residents of Olmsted County, Minnesota, with incident HS between January 1, 1980, and December 31, 2008, and age- and gender-matched referents. The main outcomes and measures were the overall and cause-specific risks of death.

RESULTS

We identified 226 incident cases of HS and 678 age- and gender-matched referents among Olmsted County residents during the study period. Compared to referents, patients with HS had a significantly higher risk of all-cause death (hazard ratio [HR, 2.48; 95% CI, 1.53-4.03, P < 0.001) and cardiovascular- or cerebrovascular-related death (HR, 2.85; 95% CI, 1.10-7.40, P = 0.03). However, these risks were attenuated by adjusting for smoking history: all-cause HR, 1.65 (95% CI, 0.97-2.82, P = 0.07) and cardiovascular- or cerebrovascular-related HR, 2.03 (95% CI, 0.71-5.81, P = 0.18). The 71% of patients were former or current smokers at the time of HS diagnosis.

CONCLUSIONS

Hidradenitis suppurativa patients have a substantially increased risk of death from any cause, including cardiovascular or cerebrovascular causes; the risk is especially dependent on smoking history.

Top 100 most-cited publications in hidradenitis suppurativa: An updated bibliometric analysis

Background

Over the last several decades, our understanding of hidradenitis suppurativa (HS) has improved considerably, thereby enhancing our ability to clinically diagnose and treat the disease.

Objective

The purpose of this study was to identify and analyze the top 100 most-cited publications related to HS to update bibliometric information on HS.

Materials and methods

We used the Web of Science database to identify reports on hidradenitis suppurativa. Data from the 100 most-cited publications were extracted and analyzed.

Results

The citation number of the top 100 most-cited articles was 89-532 (mean, 153.51), with the most productive periods being from years 2007 to 2016. Most publications originated from the British Journal of Dermatology and the Journal of the American Academy of Dermatology. The 100 articles originated from 18 countries, with Denmark being the most productive country, followed by the United States (17), England (14), and Germany (12). Jemec GB, from the University of Copenhagen, had 32 citations and was the most frequently identified author. The 100 articles encompassed several fields of research as follows: pathogenesis (18%), pathophysiology (7%), epidemiology (14%), clinical diagnosis and features (16%), treatment (25%), comorbidity (10%), and others (10%). In total, 11 reviews, three guidelines, and 86 original articles (nine randomized clinical trials) were included.

Conclusion

Through this bibliometric analysis, we aimed to indicate a series of intellectual landmark publications that offer us critical reviews, guidelines, and original articles, which highlight the immense level of progress achieved in the field of HS.

Serum inflammatory markers and leukocyte profiles accurately describe hidradenitis suppurativa disease severity

BACKGROUND

Inflammatory markers and leukocyte profiles have not been longitudinally evaluated as objective signs of hidradenitis suppurativa (HS) severity. We sought to assess C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), interleukin-6 (IL-6), and leukocyte profiles as reliable indicators of HS severity.

METHODS

Retrospective cohort study of 404 patients seen at the Einstein/Montefiore HS Center, Bronx, New York, between March 2019 and November 2020. Associations of disease severity (HS-Physician Global Assessment) with inflammatory markers and leukocyte profiles were assessed by odds ratios (OR) and 95% confidence intervals (95% CI) incorporating up to four visits per patient, adjusting for baseline gender, age, BMI, and smoking status.

RESULTS

Patients with severe disease had elevated CRP (OR 1.87; 95% CI 1.49, 2.34), ESR (OR 1.04; 95% CI 1.03, 1.04), IL-6 (OR 1.08; 95% CI 1.00, 1.16), leukocytes (OR 1.22; 95% CI 1.14, 1.31), neutrophils (OR 1.31; 95% CI 1.20, 1.42), eosinophils (OR 14.40; 95% CI 2.97, 69.74), basophils (OR 2.53; 95% CI 1.09, 5.85), monocytes (OR 5.36; 95% CI 2.49, 11.53), and neutrophil-lymphocyte ratios (OR 1.63; 95% CI 1.35, 1.96) but decreased lymphocytes (OR 0.86; 95% CI 0.68, 1.10).

CONCLUSIONS

This novel longitudinal study of inflammatory markers and leukocyte profiles offers critical laboratory measures to confirm clinically determined disease severity over time.

Hidradenitis Suppurativa: Host-Microbe and Immune Pathogenesis Underlie Important Future Directions

Hidradenitis suppurativa (HS) is an inflammatory disease of the skin with a chronic, relapsing-remitting course. The pathogenesis of the disease is poorly understood and involves multiple factors, including genetics, environment, host-microbe interactions, and immune dysregulation. In particular, the composition of the cutaneous microbiome shifts as the disease progresses, although it is unclear whether this is a primary or secondary process. Trials with immunomodulatory therapy elucidate the role of specific immune pathways and cytokine signaling in disease mechanism, such as TNF-α, IL-1β, IL-12, IL-17, IL-23, and complement. Future studies should continue examining the causes of and contributing factors to microbial changes and immune dysregulation in HS pathogenesis.

Paradoxical hidradenitis suppurativa in Crohn's disease patients receiving infliximab: a case report and review of literature

The introduction of TNF blockers in the therapeutic armamentarium of inflammatory bowel diseases (IBD) has largely advanced the way by which clinicians manage these disorders. However, some patients develop de novo immune-mediated diseases during the treatment. We here present the case of paradoxical hidradenitis suppurativa, a chronic inflammatory skin disease characterized by the development of recurrent nodules and abscesses in intertriginous areas, in a 20-year-old, nonsmoker, normal-weight women, with no family history of hidradenitis suppurativa or IBD, diagnosed with nonstricturing nonpenetrating ileocolonic Crohn's disease in 2013, during treatment with infliximab. Infliximab discontinuation was followed by a significant improvement of skin lesions. We also discuss 22 additional cases of paradoxical hidradenitis suppurativa in IBD patients on TNF antagonists reported in the literature with the aim to identify potential risk factors for the development of such a complication. All the patients had Crohn's disease, and the majority of them were women (19/23; 82.6%). All cases occurred during therapy with anti-TNF agents [14/23 (61%) patients were treated with adalimumab and 9/23 (39%) patients were treated with infliximab]. The therapeutic approach directed at maintaining/holding the undergoing biologic therapy is still uncertain. Further studies are needed to determine the most appropriate treatment choice toward ongoing biologic therapy.

Hyperhidrosis treatments in hidradenitis suppurativa: A systematic review

Hyperhidrosis impairs quality of life (QOL) in hidradenitis suppurativa (HS) patients and may exacerbate HS. However, there is limited literature on whether hyperhidrosis treatments improve HS disease. To systematically review literature on efficacy and tolerability of hyperhidrosis treatments in HS patients. In May 2021, MEDLINE and EMBASE databases were systematically searched by two reviewers per PRISMA guidelines for articles on hyperhidrosis and HS. Sixteen articles met inclusion criteria (2 randomized controlled trials [RCTs], one case-control study, three cross-sectional studies, 10 case-studies/series), encompassing 252 HS patients across studies. They examined botulinum toxin A (BTX-A) (n = 6) and B (BTX-B) (n = 1), suction-curettage (n = 1), diode laser (n = 1), and microwave-based energy device (MED) (n = 3). Overall, BTX treatments improve HS severity, QOL, hyperhidrosis, and were well-tolerated. Suction-curettage did not improve disease. One HS patient tolerated diode laser well, with improvement in sweating and HS. One RCT studying MED was discontinued due to adverse events. Two studies reported MED-induced HS. BTX was overall helpful in HS patients, including in patients without concomitant hyperhidrosis. However, more prospective studies are needed to examine its utility in HS. There is potential harm of MEDs in HS. Most studies examining hyperhidrosis treatments in HS patients are low level of evidence. Larger RCTs should examine the efficacy and tolerability of hyperhidrosis treatments in HS.

Use of thermal imaging and a dedicated wound imaging smartphone app as an adjunct to staging hidradenitis suppurativa

Hidradenitis suppurativa (HS) presents with painful nodules, draining tunnels, abscesses, ulcers, and fistula formation¹ . Grading systems, (e.g. Hurley Staging System, International Hidradenitis Suppurativa Severity Score System (IHS4), Severity Assessment of Hidradenitis Suppurativa Score (HS-PGA score), and Hidradenitis Suppurativa Area and Severity Index (HASI)) assess disease severity in terms of lesion count, extension and morphology.

Insights into the Pathogenesis of HS and Therapeutical Approaches

Hidradenitis suppurativa (HS) is a debilitating, chronic, (auto)inflammatory disease primarily affecting apocrine gland-rich areas of the body. Although pathogenic mechanisms responsible for HS have not yet been fully elucidated, it is a multifactorial process whose main target is the terminal follicle. The role of the inflammatory process (and consequently of cytokine milieu) and of several other factors (genetics, lifestyle, hormonal status, microbiome, innate and adaptive immune systems) involved in HS pathogenesis has been investigated (and often defined) over the years with a view to transferring research results from bench to bedside and describing a unique and universally accepted pathogenetic model. This review will update readers on recent advances in our understanding of HS pathogenesis and novel (potential) medical therapies for patients with moderate-to-severe HS.

[Clinical, pathology-associated and molecular biomarkers of hidradenitis suppurativa/acne inversa]

Hidradenitis suppurativa/acne inversa is a scarring disease of the intertrigines that is now intensively researched. Improved pathogenetic understanding has led to the introduction of tumor necrosis factor alpha (TNF‑α) inhibition, which represents a major advance over traditional broad immunosuppression and antibiotic administration. In addition, a wide range of newer and promising treatments is or is about to be clinically evaluated. These include various specific antibodies against cytokines and the complement system and small molecules. Successful use of the individual drugs depends on the stratification of suitable patient groups with the help of clinically relevant biomarkers. While molecular investigations have shown a number of possible biomarkers and/or therapeutic target molecules, the detection of robust predictive biomarkers is still in its initial phase. In summary, the therapeutic options for hidradenitis suppurativa/acne inversa are improving through the introduction of new drugs, possibly in combination with surgical interventions, whereby the possibilities for predictive therapeutic decisions through the discovery of biomarkers would revolutionize the chances of therapeutic success.

Long-Term Follow-Up after Radiotherapy of Hidradenitis Suppurativa

BACKGROUND

Patients with hidradenitis suppurativa (HS) are still often disappointed with the current treatments offered and there is a clear demand for more effective options. Since the late 1990s there has been a revival in the use of radiotherapy (RT) for different benign diseases, including HS. During the past 20 years one case series and some scattered case reports have described promising results of RT.

OBJECTIVES

To evaluate the long-term efficacy of RT in early-stage HS.

METHODS

A postal survey-based long-term follow-up with simple factual questions of partly retrospective and partly contemporary characteristics was performed. Sixty-four patients (96 axillae), diagnosed with mild to moderate HS were irradiated with a orthovoltage unit with 100 kV, 3 mm Al or 200 kV, 0.5 Cu filtering, respectively. Four to six biweekly fractional doses ranging from 0.75 to 1 Gy up to a total dose of 6 Gy in one series, and in chronic cases followed by four daily fractions of 2 Gy up to a total dose of 14 Gy, were given. Late treatment toxicity and the rate of remission of the disease were evaluated.

RESULTS

The overall response rate of the survey was 64.1% with 40.6% (26/64) valid, complete questionnaires. In total, 40 axillae were irradiated in these 26 patients. After a median follow-up of 40 years (range 32-52) complete remission of the lesions occurred in 34 of the 40 sites (85%). None of the 26 patients with 40 irradiated sites reported adverse effects at the time of the survey.

CONCLUSIONS

RT appears to be an effective treatment for early and mild HS in the majority of patients. In this case series, no side effects were reported after a median follow-up period of 40 years.

Differential Diagnosis Between Perianal Crohn's Disease and Hidradenitis Suppurativa: A Challenging Teamwork

Hidradenitis suppurativa (HS) is a rare, debilitating skin disease characterized by the presence of recurrent tender subcutaneous nodules that develop into abscesses and fistulae. Isolated perineal Crohn's disease (CD) is unusual, diagnosis can be difficult, and distinction from HS is a challenge for the gastroenterologist. The aim of this work was to determine the criteria that distinguish perineal CD from perineal HS. Four patients with isolated perineal CD and three with perineal HS were included. Rectal or skin biopsies of all CD patients showed granulomas. No granulomas were found for HS. Fistulae were present in 4/4 CD, extended to the anal canal. All patients with HS had gluteal abscesses. They were bilateral in all cases, superficial. Perineal lesions management should involve a multidisciplinary approach in order to make an accurate diagnosis and ultimately to give the best and most effective treatment.

Epidemiology of hidradenitis suppurativa in Taiwan: A 14-year nationwide population-based study

Hidradenitis suppurativa (HS), also called acne inversa, is an inflammatory skin disease, which causes HS patients to suffer from recurrent symptoms and severe comorbidities. The aim of this article was to provide evidence on the epidemiology of HS in Taiwan through a retrospective population-based cohort study. The patients with International Classification of Diseases, Ninth Revision, Clinical Modification code 705.83 and Anatomical Therapeutic Chemical codes for HS treatments from 2000 to 2013 in the National Health Insurance Research Database, which covers 99.9% Taiwanese residents, were enrolled in this 14-year nationwide population-based cohort study. The age- and sex-standardized prevalence, incidence, and the prescription pattern for HS were analyzed. The annual percent change (APC) was used to estimate the trend of prevalence and incidence of HS from 2000 to 2013. During 2000-2013 in Taiwan, the 14-year period prevalence rate was 185.6/100 000 (95% confidence interval [CI], 177.3-194.3) with an APC of -2.96% (95% CI, -1.73 to -4.17) and the mean annual adjusted incidence rate from 2001 to 2013 was 11.8/100 000 (95% CI, 11.2-12.5) with an APC of -4.65% (95% CI, -3.32 to -5.95). Female : male ratio was 0.92 and the most common onset age was 15-24 years. Major treatments were systemic corticosteroids, systemic antihistamines, systemic antibiotics, and topical antibiotics. An increasing tendency of using systemic antibiotics was noted. In Taiwan, decreasing incidence and prevalence of HS was shown during 2000-2013. Relatively lower incidence and prevalence were noted compared to Western countries. Male predominance was revealed, and the use of systemic antibiotics became the mainstream in treatment for HS.

Evaluation of the laboratory parameters in hidradenitis suppurativa: Can we use new inflammatory biomarkers?

Hidradenitis suppurativa (HS) is a chronic, recurrent, and debilitating skin disease. Recent studies showed that inflammatory biomarkers, such as neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), Lymphocyte/HDL ratio (LHR), Neutrophil/HDL ratio (NHR), and Monocyte/HDL ratio (MHR) are an indicator of inflammatory diseases and may be associated with disease severity and disease activity. To investigate NLR, PLR, LHR, NHR, and MHR in HS patients. In addition, to compare erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complete blood count, leukocyte profile, and biochemical parameters between the control and the patient group. Clinical and biochemical data of patients and healthy subjects were collected from medical records, retrospectively. In total, 166 patients with HS and 124 control subjects were included. We found no significant difference in NLR (P = .207) and PLR (P = .257). LHR (P < .001), NHR (P < .001), and MHR (P < .001) were significantly higher in the patient group. No positive correlation was found between any of these markers and disease severity according to Hurley staging system. However, MCV (Mean corpuscular volume), RDW (Red cell distribution width), and CRP showed a significant positive correlation with disease severity. Among these markers, only MHR was positively correlated with disease duration. Our study shows that CRP still maintains its value for HS patients compared to new inflammation markers. Unlike the studies in other inflammatory diseases, no significant relationship was found with most of these inflammatory parameters. MHR may be more useful in patients with HS as an indicator of inflammation compared to other parameters.

Hidradenitis suppurativa - The role of interleukin-17, the aryl hydrocarbon receptor and the link to a possible fungal aetiology

Hidradenitis Suppurativa (HS) is a chronic, recurrent, debilitating skin disease of the hair follicle that usually presents after puberty with painful, deep-seated, inflamed lesions in the apocrine gland bearing areas of the body, most commonly the axillae, inguinal and anogenital regions. The pathophysiology of the disease remains elusive, with newer therapies targeting various aspects of the dysregulated immune system. This presents a useful opportunity to look at the cytokine profile in HS and other inflammatory conditions that share similar patterns with the aim of teasing out less considered explanations for HS pathogenesis. It has been observed that IL-17 appears to be the most common denominator linking HS with other immune mediated diseases like Crohn, ulcerative colitis, multiple sclerosis and psoriasis. Given that IL-17 plays an important role in antifungal immunity, evidenced by the cytokine pattern in fungal disease and the bulk of data citing their potential involvement in Crohn, ulcerative colitis, multiple sclerosis and psoriasis; it is fair to suggest the need to explore the role that fungi play in the setting of HS going forward. The aryl hydrocarbon receptor (ahr) is a ubiquitous and largely conserved entity that is gaining interest in inflammatory conditions such as psoriasis and atopic dermatitis. It is well known to modulate autoimmune states. Its activation by both exogenous and endogenous agents result in secretion of IL-17 by Th17 cells. One of such agents is the tryptophan metabolite 6-formylindolo [3,2-b] carbazole (FICZ)-which can be produced by microorganisms such as fungi. It will be interesting to explore its usefulness in HS pathogenesis.

Histologic progression of acne inversa/hidradenitis suppurativa: Implications for future investigations and therapeutic intervention

Since first recognized in 1839, the pathogenesis of acne inversa (AI) has undergone repeated revisions. Although there is agreement that AI involves occlusion of hair follicles with subsequent inflammation and the formation of tracts, the histologic progression of this disease still requires refinement. The objective of this study was to examine the histologic progression of AI based on the examination of a large cohort of punch biopsies and excisional samples that were examined first by hematoxylin and eosin staining. The most informative of these samples were step‐sectioned and stained by immunohistochemistry for epithelial and inflammatory markers. Based on this examination, the following observations were made: 1) AI arises from the epithelium of the infundibulum of terminal and vellus hairs; 2) These form cysts and epithelial tendrils that extend into soft tissue; 3) Immunohistochemical staining demonstrates the epithelium of AI is disordered with infundibular and isthmic differentiation and de novo expression of stem cell markers; 4) The inflammatory response in AI is heterogeneous and largely due to cyst rupture. The conclusions of this investigation were that AI is an epithelial‐driven disease caused by infiltrative, cyst forming tendrils and most of the inflammation is due to cyst rupture and release of cornified debris and bacteria. Cyst rupture often occurs below the depths of punch biopsy samples indicating their use for analysis may give an incomplete picture of the disease. Finally, our data suggest that unless therapies inhibit tendril development, it is unlikely they will cause prolonged treatment‐induced remission in AI.

[CME Dermatology 23: Hidradenitis suppurativa]

CME Dermatology 23: Hidradenitis suppurativa Abstract. Hidradenitis suppurativa (Acne inversa) is a chronic skin disease characterized by recurrent inflammatory nodules, abscesses, and scarring mainly in the intertriginous areas. The prevalence is estimated to be 0.05 to 4.1 % worldwide, with women being more commonly affected. The exact pathogenesis remains unknown, but hair follicle occlusion and inflammation seem to be the initiating events. Several epidemiological correlations with smoking and obesity as well as mutations in gamma secretase genes were described. The therapy depends on the extension of the disorder and should respect the current guidelines. Topical clindamycin is suitable for mild forms of the disease whereas moderate to severe disease requires systemic anti-inflammatory treatment. Surgical intervention is currently the only definitive treatment for hidradenitis suppurativa.

Prevalence of Neuropathic Pain and Related Characteristics in Hidradenitis Suppurativa: A Cross-Sectional Study

BACKGROUND

Pain is a core symptom of hidradenitis suppurativa (HS) and is of complex, multifactorial origin. HS patients frequently report typical neuropathic pain qualities, but its prevalence has been poorly described.

METHODS

In this cross-sectional study, we examine the prevalence of neuropathic pain (NP) component and related pain-characteristics of a hospital-based cohort of patients with symptomatic HS. We administered the pain-DETECT tool (PDQ), a validated screening tool for NP, collecting clinical and patient-reported data on pain, pruritus and pain-management. We obtained 110 complete datasets from symptomatic HS patients (49.1% females; Hurley I (27.3%])-II (45.5%)-III (27.3%)). According to the PDQ tool, 30% of patients were classified with a high probability (>90%) of neuropathic pain (LNP). LNP status was significantly associated with increased pain severity, disease activity, pruritus intensity and use of pain medication. Regression analysis showed a significant impact of the PDQ score on patient-reported outcomes, including pain severity and the dimensions of activity and affective pain interference. HS patients may present a mixed chronic pain phenotype with a neuropathic component, thus requiring additional pain-assessments. A multi-modal approach to pain management, in combination with disease-specific treatment, should be implemented in future interventional studies.

Serum Concentration and Skin Expression of S100A7 (Psoriasin) in Patients Suffering from Hidradenitis Suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease. An important role of innate immune dysregulation in the pathogenesis of HS has been highlighted. S100A7 (psoriasin) is an innate, antimicrobial protein that exerts proinflammatory and chemotactic action.

OBJECTIVES

The objective of the study was to investigate serum concentrations of S100A7 in individuals with HS as compared to healthy controls. Further, we evaluated the expression of S100A7 in lesional HS skin as compared to perilesional (clinically uninvolved) HS skin and normal skin.

METHODS

Serum concentrations of S100A7 were evaluated with a commercially available ELISA kit. The expression of S100A7 in the skin was assessed using qRT-PCR and immunofluorescence staining.

RESULTS

We found increased expression of S100A7 in lesional HS skin as compared to perilesional HS skin (p = 0.0017). The expression of S100A7 in lesional HS skin was positively associated with serum C-reactive protein concentration and the severity of disease according to Hurley staging. The serum concentration of S100A7 in individuals with HS was decreased as compared to healthy controls and patients with psoriasis.

CONCLUSIONS

Upregulated in lesional HS skin, S100A7 may enhance the inflammatory process and contribute to the HS pathogenesis.

Cytokine Pathways and Investigational Target Therapies in Hidradenitis Suppurativa

Background: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease affecting areas with a high density of apocrine glands and characterized by subcutaneous nodules that may evolve into fistulas with pus secretion. Methods: The aim of this review is to investigate all current knowledge on cytokine regulation in the pathogenesis of HS. A systematic literature research using the words “cytokine”, “interleukin”, “pathway”, and “hidradenitis suppurativa” was performed in PubMed/Medline and Scopus/Embase databases. A search of the clinicaltrials.gov website for interventional recruiting and completed trials including the term “hidradenitis suppurativa” was also performed up to August 2020. We will discuss the pathogenetic role of various cytokines in HS and potential therapeutic targets for this debilitating disease. Results: The pathophysiology underlying this complex condition has not been clearly defined. An upregulation of various cytokines, such as tumor necrosis factor alpha (TNF-α), interleukin (IL)-1, IL-17, IL-23, and other molecules seems to be related to this inflammatory condition. Various cells, such as lymphocytes T Helper 1 and 17 and keratinocytes seem to be involved in the genesis of this condition. Conclusions: Several future studies and clinical trials are necessary in order to have new knowledge about HS and to properly treat this complex condition.

PASH, PAPASH, PsAPASH, and PASS: The autoinflammatory syndromes of hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory disease usually involving the major skin folds characterized by a multifactorial pathogenesis and a wide spectrum of clinical manifestations. It can also rarely present in association with other diseases as complex clinical syndromes, causing additional diagnostic and therapeutic challenges. Different etiopathologic factors contribute to follicular inflammation and suppurative lesions of syndromic HS, including follicular hyperkeratinization and plugging, as well as activation of autoinflammatory pathways. Patients with syndromic HS frequently have a severe disease course, presenting with atypical skin involvement, signs of systemic inflammation, and resistance to conventional treatments. Systematic classification of syndromic HS is based on clinical, pathogenetic, and genetic factors, but it is constantly evolving due to increased disease awareness. Treatment of syndromic HS is difficult and should be personalized on a case-by-case basis. Investigating syndromic HS can lead to useful insights on genetics and pathogenesis, translating into new clinical approaches for sporadic hidradenitis. We review the classification, clinical presentation, disease associations, and therapeutic management of syndromic HS, focusing mainly on its autoinflammatory syndromes PASH, PAPASH, PsAPASH, and PASS.

Metabolic, pharmacokinetic, and toxicological issues of biologic therapies currently used in the treatment of hidradenitis suppurativa

INTRODUCTION

Hidradenitis suppurativa is a chronic, relapsing, debilitating inflammatory dermatologic disease of the terminal hair follicles at intertriginous sites clinically characterized by painful inflammatory nodules, abscesses, draining sinus tracts, and dermal fibrosis. The management of hidradenitis suppurativa is a challenge and usually consists of both medical and surgical approaches, which must often be combined for best outcome. The introduction of biological therapies, specifically TNFα-inhibitors such as adalimumab, has profoundly changed the therapeutic armamentarium of the disease.

AREAS COVERED

The PubMed database was searched using combinations of the following keywords: hidradentis suppurativa, biologic therapy, TNF-α inhibitors, adalimumab, etanercept, infliximab, certolizumab pegol, golimumab, adverse effects, pharmacodynamics, pharmacology, adverse events, pharmacokinetics, drug interaction. This article reviews and updates the chemistry, pharmacokinetics, mechanism of action, adverse effects, drug interactions of on-label and off-label use of TNF-α inhibitors in HS.

EXPERT OPINION

Biologic agents, particularly adalimumab, exhibit clinical efficacy in patients with hidradenitis suppurativa. Careful patient selection and close monitoring during treatment are mandatory to provide safe and effective use of the TNF-α inhibitor. Familiarity with biologic agents is crucial because these agents could become a consolidated treatment option in the clinician's therapeutic approaches.

Baseline Characteristics from UNITE: An Observational, International, Multicentre Registry to Evaluate Hidradenitis Suppurativa (Acne Inversa) in Clinical Practice

Background

Hidradenitis suppurativa (HS), also known as acne inversa, is a recurring, painful, chronic, and sometimes disfiguring inflammatory skin disease.

Objectives

Our objective was to report the baseline clinical characteristics, natural history, and associated outcomes of patients with HS from the ongoing, prospective, non-interventional UNITE registry that is collecting data regarding the natural history and associated outcomes of HS.

Methods

Patients with inflammatory HS lesions were enrolled, including adolescents (aged 12 to < 18 years) and adults (aged ≥ 18 years). None had participated in previous or current originator-adalimumab studies/registries. Patients received treatment consistent with site-specific, routine clinical practice. HS disease status was assessed by HS lesions and disease flare; treatment and outcomes data were collected at enrolment and every 6 months for ≤ 4 years.

Results

Enrolment (N = 594; 89.1% adults; 10.9% adolescents) occurred from 29 October 2013 to 29 December 2015 at 73 sites in 12 countries. At baseline, the majority were female (69.7%) and White (81.2%), had moderate-to-severe disease (Hurley stage II or III; 93.3%), and had undergone prior procedures/surgery for HS (68.7%). In total, 61.6% of adults and 49.2% of adolescents were obese; 40.2% of patients reported current tobacco use. Scarring due to lesions occurred in 91.2% of patients. The prevalence of comorbidities of interest was as follows: depression (13.3%), other psychiatric disorders (9.6%), inflammatory bowel disease (2.7%), diabetes (9.1%), and polycystic ovary syndrome (5.2%).

Conclusions

In this population from the UNITE HS registry, obesity and smoking were common, and disease burden was high, manifesting as multiple lesions, scarring, surgical history, and considerable comorbidities.

Electronic supplementary material

The online version of this article (10.1007/s40257-020-00504-4) contains supplementary material, which is available to authorized users.

The Hidradenitis Suppurativa Quality of Life (HiSQOL) score: development and validation of a measure for clinical trials

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic, inflammatory condition that can have a large negative impact on health-related quality of life (HRQOL). A reliable and validated measure of HS-specific HRQOL in clinical studies is needed.

OBJECTIVES

To develop and validate the Hidradenitis Suppurativa Quality Of Life (HiSQOL©) scale, for clinical trial measurement of HS-specific HRQOL.

METHODS

In stage 1, qualitative concept elicitation interviews were conducted with patients with HS in Denmark (n = 21) and the U.S.A. (n = 21). In stage 2, cognitive debriefing interviews were performed with U.S. (n = 30) and Danish patients with HS (n = 30). In stage 3 an observational study of 222 patients with HS in the U.S.A. was conducted for item reduction, measure validation and assessment of psychometric properties. In stage 4, an observational study of 215 patients with HS in Denmark was conducted to confirm the psychometric structure derived in stage 3. In both studies the Dermatology Life Quality Index, Hospital Anxiety and Depression Scale and numerical rating scale for pain were also included.

RESULTS

In concept elicitation, 99 items were generated, which were reduced to 41 after removing duplicates. In cognitive debriefing, two items were added and one item removed. A 42-item instrument was psychometrically assessed. Based on psychometric analyses and patient input, the instrument was reduced to 17 items that had strong psychometric properties in both the U.S. and Danish samples.

CONCLUSIONS

The HiSQOL is a reliable and valid instrument to measure HS-specific HRQOL in clinical trials.

Bacterial biofilm is associated with higher levels of regulatory T cells in unaffected hidradenitis suppurativa skin

BACKGROUND

The role of bacterial biofilm in hidradenitis suppurativa (HS) is highly debated. Less biofilm is found in clinically unaffected axillary perilesional skin of HS patients compared with healthy controls.

OBJECTIVE

To study the correlation between biofilm and the phenotypical characterization of the preclinical inflammatory infiltrate.

MATERIALS AND METHODS

An exploratory comparative study of punch biopsies from unaffected axillary HS skin compared to similarly biopsies from healthy controls underwent standard staining procedures for CD4, CD8, CD25, FoxP3 and IL17. Standard-sized inflammatory histological hotspots were identified manually. Slides were scanned into Leica Biosystems' Digital Image Hub. Number of stained cells per slide and hotspot was found using an algorithm.

RESULTS

12.5% of HS had biofilm compared to 85% of controls. For full slides, HS patients had more CD4+ cells than controls; HS patients with biofilm had higher CD4+ cell number than controls with or without biofilm and HS patients without biofilm. For hotspots, HS patients with biofilm had higher number of CD4+FoxP3+ cells than HS patients without biofilm and controls with biofilm.

CONCLUSION

The association between biofilm and the number of regulatory T cells in HS patients supports the concept of dysbiosis as a factor in the preclinical HS lesions.

Hidradenitis Suppurativa Recurrence in a Caesarean Scar

Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic, relapsing inflammatory skin condition characterised by the presence of painful nodules, abscesses, and sinus tracts or scarring. Affecting up to 4% of the population, it is not uncommon and is seen predominantly in females at a ratio of 3 : 1. HS carries a substantial burden for those who suffer from it, from the significant psychosocial impact, to the cost of the multitude of topical and systemic treatments which often do not successfully control its symptoms. In this case report, we discuss a 33-year-old female known to our clinic, who presented with a recurrence of her HS in a caesarean scar, with otherwise silent disease. From our review of the literature, this appears to be only the second case of recurrence of HS in a caesarean scar reported to date. With a predilection for females of reproductive ages, involvement of sensitive areas, and an average of greater than seven years from onset of symptoms until diagnosis, the ability to recognise HS and ensure referral for specialist management is essential for all who are regularly involved in the management of this patient group.

The Use of TNFα Inhibitors in Treating Pediatric Skin Disorders

Tumor necrosis factor alpha (TNF) inhibitors have had a significant impact in medicine since the approval of the first drug of its class by the US FDA in 1998. New clinical data and indications have emerged for TNF inhibitors in recent years. Currently, four TNF inhibitors have been approved by the US FDA for dermatology, two of which include US FDA-approved pediatric use. In particular, growing evidence supports the use of etanercept and adalimumab as attractive therapies for pediatric psoriasis. Data for use of etanercept in treating toxic epidermal necrolysis and either etanercept or infliximab for Kawasaki disease is expanding. In addition, there have been clinical reports on the use of TNF inhibitors to treat a variety of other pediatric dermatologic conditions. To help clinicians keep pace with the new data provided by many pediatric dermatology studies involving TNF inhibitors, this review provides an overview of the use of TNF inhibitors in the treatment of pediatric plaque psoriasis, hidradenitis suppurativa, atopic dermatitis, pyoderma gangrenosum, toxic epidermal necrolysis, and Kawasaki disease. For TNF inhibitors with little data in the pediatric population, data on adult use is discussed. Furthermore, the review summarizes available clinical data on efficacy, safety, and tolerability of agents currently available.

Weekly adalimumab treatment decreased disease flare in hidradenitis suppurativa over 36 weeks: integrated results from the phase 3 PIONEER trials

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic skin disease characterized by inflammatory lesions that flare unpredictably. The impact of weekly adalimumab (ADAew) on HS flare is not well-characterized.

OBJECTIVE

To evaluate the impact of disease flare on health-related quality of life (HRQOL) in moderate-to-severe HS patients and to determine the effect of ADAew on disease flare using integrated data from two phase 3 trials over 36 weeks.

METHODS

In period A (12 weeks), Dermatology Life Quality Index (DLQI) score change from baseline was compared in patients who flared and those who did not, regardless of treatment. The proportion of patients experiencing flare, duration of flare and time to flare was evaluated for ADAew vs. placebo (PBO). In period B (24 weeks), proportion of patients experiencing flare who received continuous ADAew treatment through 36 weeks was assessed.

RESULTS

HRQOL was markedly improved among those who did not experience flare. In period A, the proportion of patients who experienced flare was significantly lower with ADAew vs. PBO (12.3% vs. 35.3%, P < 0.001). ADAew patients also had longer time to first flare (101 days vs. 57 days; P < 0.001) and shorter flare duration (18.9 days vs. 32.0 days, respectively; P = 0.001) vs. PBO. Through 36 weeks of treatment, 20.2% of ADAew patients flared, and for those who achieved at least a partial clinical response to ADAew at 12 weeks, only 5.7% flared.

CONCLUSIONS

Flare reduction is an important measure in HS that correlates with clinically meaningful improvement in HRQOL. ADAew reduces HS flare through 12 and subsequent 36 weeks of treatment.

Emerging medical treatments for hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a chronic inflammatory disease affecting intertriginous skin areas, and it is characterized by recurrent painful episodes of inflammatory drainage. Although the pathophysiology of HS is not fully understood, recent research points to an imbalance of cytokines as a contributing factor to the associated symptoms of purulent drainage and sinus tract formation. HS lesions are often characterized by a superimposed pathogenic/commensal bacterial infection that can improve with targeted antibiotic therapy. New medical treatments have emerged in recent years, many of which specifically work against a variety of proinflammatory mediators associated with HS. These newer, specified treatment options, in conjunction with surgery and lasers, are thought to provide positive outcomes and an overall improvement in quality of life in patients with HS.

Pathogenetic Characteristics of Mesenchymal Stem Cells in Hidradenitis Suppurativa

Importance

Hidradenitis suppurativa (HS) is a disease of the terminal hair follicle in apocrine gland-enriched skin areas, where immunobiology dysregulation of mesenchymal stem cells (MSCs) may have a key role.

Objective

To investigate the MSC profile in patients with HS and in healthy controls.

Design, Setting, and Participants

In this prospective case-control study, patients with HS were recruited from the Dermatological Clinic at the Department of Clinical and Molecular Sciences, Università Politecnica delle Marche, Ancona, Italy. Biopsy specimens were analyzed at the Histology Section of the Department of Clinical and Molecular Sciences. Participants included 11 patients with HS and 9 healthy controls, who were recruited into the study between January 20, 2015, and September 20, 2016, and underwent punch biopsy from axillary skin. None of the participants had received any antibiotics (systemic or topical therapy) within almost 12 weeks before the study.

Main Outcomes and Measures

The immunophenotypic profile of MSCs was characterized following the minimal criteria established by the International Society for Cellular Therapy for the identification of MSCs. Levels of 12 cytokines belonging to helper T-cell subtypes 1, 2, and 17 pathways were examined on the secretome of isolated cells by enzyme-linked immunoabsorbent assay.

Results

Skin MSCs were characterized in 11 patients with HS (8 women and 3 men; mean [SD] age, 35.8 [7.9] years) and 9 healthy controls (7 women and 2 men; mean [SD] age, 36.7 [6.9] years). The healthy controls were matched with patients with HS for body mass index. Mesenchymal stem cells isolated from patients with HS (HS-MSCs) and from healthy controls (C-MSCs) met the International Society for Cellular Therapy minimal criteria. Compared with C-MSCs, cytokine analyses of HS-MSCs revealed statistically significant overexpression of interleukin (IL) 6 (median [interquartile range {IQR}], 8765.00 [7659.00-9123.00] vs 2849.00 [2609.00-3001.00] pg/mL; P = .008), IL-10 (median [IQR], 29.46 [26.35-35.79] vs 21.36 [19.89-23.33] pg/mL; P = .004), IL-12 (median [IQR], 15.25 [13.27-16.25] vs 11.89 [10.73-12.33] pg/mL; P = .03), IL-17A (median [IQR], 15.24 [13.23-17.24] vs 11.24 [10.28-11.95] pg/mL; P = .008), tumor necrosis factor (median [IQR], 42.54 [42.20-43.94] vs 32.55 [31.78-33.28] pg/mL; P = .004), transforming growth factor β1 (median [IQR], 1728.00 [1535.00-1979.00] vs 500.80 [465.00-634.50] pg/mL; P = .004), and interferon γ (median [IQR], 11.49 [10.71-12.35] vs 9.45 [9.29-10.01] pg/mL; P = .005).

Conclusions and Relevance

Mesenchymal stem cells isolated from the skin of patients with HS seem to be activated toward an inflammatory status. The imbalance between proinflammatory and anti-inflammatory activities of MSCs favors the hypothesis of their pathogenic involvement in HS.

Should Patients with Hidradenitis Suppurativa Undergo LASIK?

Hidradenitis suppurativa (HS) is a relatively common chronic inflammatory disease with immune dysregulation. While eye manifestations of HS are rare, a dilemma arises when these patients seek treatment for refractive errors. Although excimer laser surgery can be safely performed in patients with autoimmune and immune-mediated inflammatory disease, there are caveats. Aside from the routine laser-assisted in situ keratomileusis (LASIK) screening tests, in some instances, we recommend additional screening tests in patients with HS, such as dry eye tests, consultation with specialists regarding HS diagnosis and treatment, careful assessment of the eyelids and periorbital structures, and thorough history of past and current lesions and treatments. After these patients undergo LASIK, careful, frequent, and long-term follow-up is necessary. Any adverse event or complication should be managed immediately. FUNDING: Research to Prevent Blindness funded the study. Hoopes Vision funded the Rapid Service Fees.

A new T helper 17 cytokine in hidradenitis suppurativa: antimicrobial and proinflammatory role of interleukin-26

BACKGROUND

Interleukin (IL)-26 is a signature T helper 17 cytokine described as a proinflammatory and antimicrobial mediator. So far, IL-26 has been reported in several immune-mediated inflammatory diseases, but its involvement in inflammatory skin disorders is poorly known.

OBJECTIVES

To investigate the role of IL-26 in hidradenitis suppurativa (HS), through its involvement in antimicrobial activity.

METHODS

IL-26 was assessed in patients with HS through gene expression and protein analysis at skin and circulating levels. Ex vivo HS organ skin cultures, together with IL-26 antibody treatment, were performed to determine the IL-26 activity. Peripheral blood mononuclear cells (PBMCs) from patients with HS and healthy controls were either silenced or not with IL-26 small interfering (si)RNA in order to measure its antimicrobial, cytotoxic and phagocytic activities against Staphylococcus aureus.

RESULTS

Firstly, we observed that IL-26 is able to modulate the proinflammatory response at the immune cell level. IL-26 was increased in the plasma of patients with HS compared with healthy controls. Subsequently, we explored the bactericidal, cytotoxic and phagocytic activities of PBMCs against S. aureus in patients with HS and healthy controls. These activities were lower in patients with HS than in controls. Remarkably, the killing activities were reduced when healthy control PBMCs were transfected with IL-26 siRNA. However, the transfection did not affect the killing activity of HS PBMCs, supporting the idea that IL-26 lacks efficacy in HS.

CONCLUSIONS

Our findings suggest that infection susceptibility in HS might be related to IL-26. Although the role of bacteria remains controversial in HS, this paper supports that there is a defect of antimicrobial response in these patients. What's already known about this topic? Interleukin (IL)-26 is a T helper 17 cytokine described as an antimicrobial and proinflammatory mediator. IL-26 has been reported in immune-mediated inflammatory diseases, but its involvement in inflammatory skin disorders remains unclear. Hidradenitis suppurativa (HS) is a chronic inflammatory skin disorder characterized by deficiency of IL-20 and IL-22 (a close homologue of IL-26), which causes antimicrobial peptide pauperization leading to severe and recurrent skin infections. What does this study add? IL-26 plasma levels are higher in patients with HS than in healthy control individuals. The antimicrobial activity of IL-26 might be ineffective in patients with HS. What is the translational message? Cutaneous antimicrobial incompetence in HS could be related to IL-26.