Genetic Susceptibility to Hidradenitis Suppurativa and Predisposition to Cardiometabolic Disease

Importance

Hidradenitis suppurativa (HS) is associated with an increased prevalence of cardiovascular diseases compared with the general population. Any association between polygenic risk for HS, risk of incident cardiometabolic outcomes, and the plasma proteome is unclear.

Objective

To investigate the genetic correlation between HS and cardiometabolic disease.

Design, Setting, and Participants

This cohort study used a polygenic risk score (PRS) for HS to examine the risks of coronary artery disease (CAD) and diabetes and identify changes in the plasma proteome in individuals of European ancestry from the UK Biobank. Participants were enrolled from January 1, 2006, to December 31, 2010. End of follow-up was January 1, 2023. Correlations were assessed between HS susceptibility and cardiometabolic traits using linkage disequilibrium score regression. Odds ratios were assessed in logistic regressions. The risk of incident CAD and diabetes was estimated in cause-specific survival models designed as time-to-event analyses.

Exposure

The PRS for HS.

Main Outcomes and Measures

Main outcomes were CAD and diabetes diagnosis measured by logistic regressions and incident disease measured by Cox proportional hazards regression models adjusted for sex, age, body mass index, and smoking status.

Results

The study included 391 481 individuals (median [IQR] age, 58 [51-64] years; 209 235 [53%] female). Genetic variants for HS correlated significantly with variants associated with CAD, diabetes, and plasma levels of high-density lipoprotein cholesterol, triglycerides, and C-reactive protein. Compared with the low-risk group, a high PRS for HS (≥75th percentile) conferred odds ratios of 1.09 (95% CI, 1.06-1.12; P < .001) for CAD and 1.13 (95% CI, 1.10-1.17; P < .001) for diabetes. Estimates remained consistent when examining only incident CAD and diabetes. The PRS for HS was significantly associated with altered expression of 58 plasma proteins. Integrating this proteomic profile and the PRS for HS in a machine learning model improved prediction of CAD and diabetes compared with a reference model based on sex, age, and body mass index.

Conclusions and Relevance

These findings suggest that a high genetic risk of HS is associated with increased risk of subsequent CAD and diabetes and altered composition of the plasma proteome. Additional investigation into the identified proteins and their potential roles as drug targets is warranted.

Effect of adalimumab treatment on inflammatory and hematological parameters in patients with Hidradenitis suppurativa

OBJECTIVE

Hidradenitis suppurativa (HS), a chronic inflammatory disease that typically manifests after puberty, is characterised by painful nodules, abscesses, draining sinus tracts, and scars in areas rich in apocrine glands such as the axillary and inguinal regions. In recent years, blood-based biomarkers such as the Neutrophil/Lymphocyte Ratio (NLR), Platelet/Lymphocyte Ratio (PLR), Monocyte/Lymphocyte Ratio (MLR), Mean Platelet Volume (MPV), Systemic Immune-Inflammation Index (SII) and Pan-Immune-Inflammation Value (PIV) have been used as significant indicators of systemic inflammation. While there are few studies evaluating these biomarkers in HS, the response of these markers to treatment has only been assessed in one study to date. Our study aims to investigate the effect of adalimumab treatment on blood-based systemic inflammation biomarkers in HS, where inflammation plays a significant role.

METHODS

The study included 42 adult patients who received adalimumab treatment at our dermatology and venereology clinic between January 2020 and January 2023. Medical records for complete blood count results of the patients were retrospectively reviewed. All systemic inflammation-based biomarkers were calculated from the absolute values of the complete blood count. The SII was calculated with the following formula: (neutrophil count × platelet count/lymphocyte count). The PIV was calculated as follows: (neutrophil count × platelet count × monocyte count/lymphocyte count). Values before the treatment and at the 12th week of treatment were compared.

RESULTS

When the changes in the inflammatory parameters of the patients were examined, it was found that NLR (2.13 ± 0.87 vs 2.26 ± 1.12), PLR (111.01 ± 39.89 vs 99.43 ± 35.34), MLR (0.27 ± 0.11 vs 0.28 ± 0.12), MPV (9.59 ± 0.71 vs 9.70 ± 0.79), SII (680.79 ± 330.18 vs 687.89 ± 442.66), and PIV (552.02 ± 330.71 vs 605.05 ± 415.96) values did not change statistically significantly after treatment (p > 0.05). While there was a significant decrease in platelet count compared to before treatment, no statistically significant difference was found in the other evaluated blood cells.

CONCLUSION

Adalimumab treatment has not had a significant effect on systemic inflammation markers in HS, an inflammatory disease. More studies are needed to evaluate the effect of adalimumab on these markers in HS.

Relationship between circulating white blood cell count and inflammatory skin disease: a bidirectional mendelian randomization study

Observational studies have shown a strong association between circulating white blood cell counts (WBC) and inflammatory skin diseases such as acne and psoriasis. However, the causal nature of this relationship is unclear. We performed a two-way two-sample Mendelian randomization (MR) analysis to investigate potential causal relationships between leukocytes and inflammatory skin diseases. The circulating white blood cell count, basophil cell count, leukocyte cell count, lymphocyte cell count, eosinophil cell count, and neutrophil cell count data were obtained from the Blood Cell Consortium (BCX). The data for inflammatory skin disorders, including acne, atopic dermatitis (AD), hidradenitis suppurativa (HS), psoriasis, and seborrheic dermatitis (SD), were obtained from the FinnGen Consortium R10. The primary analysis utilized inverse variance weighting (IVW) along with additional methods such as MR-Egger, weighted mode, and weighted median estimator. To assess heterogeneity among instrument variables, Cochran's Q test was employed, while MR-Egger intercept and MR-PRESSO were used to test for horizontal pleiotropy. IVW demonstrated that an elevated monocyte count was significantly associated with a decreased risk of psoriasis (OR = 0.897, 95% CI: 0.841-0.957, P = 0.001, FDR = 0.016). Additionally, an increased eosinophil count was causally associated with a higher risk of AD (OR = 1.188, 95% CI: 1.093-1.293, P = 0.000, FDR = 0.002). No inverse causal relationship between inflammatory skin disease and circulating white blood cell count was found. In conclusion, this study provides evidence that increased monocyte count is associated with a reduced risk of psoriasis and that there is a causal relationship between increased eosinophil counts and an increased risk of AD. These findings help us understand the potential causal role of specific white blood cell counts in the development of inflammatory skin diseases.

Hematologic Abnormalities in Patients With Hidradenitis Suppurativa Receiving Adalimumab

This post hoc analysis of PIONEER I and II randomized clinical trials assesses whether receiving adalimumab is associated with decreased hematologic abnormalities and increased clinical improvement in patients with hidradenitis suppurativa.

Biomarkers of systemic inflammation are associated with disease severity and metabolic syndrome in patients with hidradenitis suppurativa

Background

Biomarkers associated with disease severity and comorbid metabolic syndrome (MetS) in patients with hidradenitis suppurativa (HS) are lacking.

Objective

To identify biomarkers associated with disease severity and comorbid MetS in patients with HS.

Methods

Data on hospital outpatients with HS were obtained through clinical examination and interviews. Indicators of systemic inflammation; C-reactive protein (CRP), erythrocyte sedimentation-rate (ESR), neutrophil/lymphocyte-ratio (NLR), platelet/lymphocyte-ratio (PLR), monocyte/lymphocyte-ratio (MLR), platelet/neutrophil-ratio (PNR), pan-immune-inflammation-value (PIV), and systemic-immune-inflammatory-index (SII), were calculated from blood samples.

Results

Seven hundred patients were included; of those 444 (63.4%) and 256 (36.6%) were female and male, respectively, with a median age of 38.3 years (IQR = 27.9-51.0). Increasing CRP, ESR, NLR, PIV, and SII (P < .001) were significantly associated with increasing Hurley-stage and international hidradenitis suppurativa severity score system 4 (IHS4)-score in adjusted analysis. A doubling in CRP (OR 1.59 (1.36-1.85), P < .001), ESR (OR 1.39 (1.17-1.66), P < .001) and PIV (OR 1.41 (1.12-1.77) P = .002) was associated with MetS in adjusted analysis. ESR was the best estimator for severe IHS4-score (AUC = 0.72 (0.66-0.77), P < .001) and Hurley III (AUC = 0.79 (0.73-0.85), P < .001) whereas CRP was best for MetS (AUC = 0.67 (0.62-0.72), P < .001).

Limitations

Patients in a hospital setting tend to have more severe disease.

Conclusion

Biomarkers like CRP, ESR, and PIV measuring systemic inflammation were associated with disease severity and comorbid MetS in patients with HS.

Exploring the role of systemic immune-inflammation index and neutrophil-lymphocyte ratio in cardiovascular risk stratification for patients with hidradenitis suppurativa: A cross-sectional study

Hidradenitis suppurativa (HS) is a chronic inflammatory disease of the hair follicle that has previously been associated with a higher cardiovascular risk (CVR). Although different methods have been described for CVR stratification in HS, there is little evidence about the role of hemogram indexes in CVR in HS. Given its potential convenience, the aim of this study was to assess the role of the hemogram indexes systemic immune-inflammation index (SII) and neutrophil-lymphocyte ratio (NLR) in CVR stratification for patients with HS. A cross-sectional study was performed to assess the role of SII and NLR in CVR stratification in patients with moderate to severe HS who were candidates for biologic therapy. SII, NLR, carotid intima-media thickness, and other clinical and biochemical CVR factors were assessed before the start of the treatment. Fifty patients were included. The male:female ratio was 3:2, and the mean International Hidradenitis Suppurativa Severity Score System score was 21.6. After multivariate analysis, SII correlated with higher values of systolic blood pressure, metabolic syndrome, and higher risk of insulin resistance (p < 0.05). NLR was associated with insulin resistance (p < 0.05). These associations were independent of age, sex, body mass index, severity of the disease, and tobacco consumption. The implementation of SII and NLR in daily practice may be of benefit for identifying patients with HS at higher risk of high blood pressure, insulin resistance, or metabolic syndrome. Since these indexes are simple to calculate, they could be used as a screening tool in HS-specific units.

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.

What's Race Got to Do With It? CRP Levels in Immune Mediated Skin Diseases: Considerations for Hidradenitis Suppurativa

Currently, there is a lack of racial/ethnic heterogeneity in research databases, exposing a systematic issue in studies exploring inflammation-mediated diseases, such as hidradenitis suppurativa (HS). HS is a chronic inflammatory skin condition that disrupts normal structure and functioning of terminal hair follicles, resulting in the formation of recurrent abscesses, nodules, and sinus tracts within intertriginous regions. Studies have described higher serum levels of inflammation-mediated C-reactive protein (CRP) in patients with HS, a disease that predominantly affects skin of color (SOC) populations. Herein, we explore the role of CRP levels in the context of HS disease presentation, management, and psychosocial implications in SOC patients to determine existing disparities in research studies.

Hidradenitis suppurativa: A folliculotropic disease of innate immune barrier dysfunction?

The innate immune system of human skin consists of a multi-layered barrier consisting of cells and soluble effector molecules charged with maintaining homeostasis and responding to insults and infections. It has become increasingly clear that these barrier layers become compromised in skin diseases, especially in disorders of an (auto)inflammatory nature. In the case of hidradenitis suppurativa, great strides have been made in recent years in characterizing the underlying breakdown in homeostatic innate immunity, including an increasing understanding of the central role of the hair follicle in this process. This breakdown appears to occur at multiple levels: the pilosebaceous unit, associated epithelium, the cutaneous microbiome, alteration of immune cell function and local molecular events such as complement activation. This review seeks to summarize, contextualize and analyse critically our current understanding of how these innate immune barriers become dysregulated in the early stage(s) of hidradenitis suppurativa, and to speculate on where potential hidradenitis suppurativa research could be most fruitful.

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 and 1-Carbon Metabolism: Role of Gut Microbiome, Matrix Metalloproteinases, and Hyperhomocysteinemia

Hidradenitis suppurativa (HS) is a chronic, inflammatory skin condition characterized by painful nodules which suppurate and later develop into scar tissues followed by the development of hypodermal tracts. Although the mechanisms behind HS are not fully understood, it is known that dietary factors play important roles in flare frequency and severity. We hypothesize that the high fat diet (HFD) causes dysbiosis, systemic inflammation, and hyperhomocysteinemia (HHcy) in susceptible individuals, which subsequently elevate inflammatory cytokines such as IL-1β, IL-6, IL-17, and tumor necrosis factor alpha (TNF-α). This increase in dysbiosis-led inflammation coupled with a dysregulation of the 1-carbon metabolism results in an increase in matrix metalloproteinases MMP-2, MMP-8, and MMP-9 along with tissue matrix remodeling in the development and maintenance of the lesions and tracts. This manuscript weaves together the potential roles played by the gut microbiome, HHcy, MMPs, and the 1-carbon metabolism toward HS disease causation in susceptible individuals.

Methotrexate shows benefit in a subset of patients with severe hidradenitis suppurativa

BACKGROUND

Methotrexate is an immunomodulatory therapy that may offer benefit to patients with hidradenitis suppurativa (HS). Despite its theoretical advantages, there is a paucity of available data regarding long-term methotrexate use in patients with HS.

OBJECTIVE

This study aimed to assess whether methotrexate treatment leads to improvement in HS disease severity.

METHODS

We conducted an institutional review board-approved, single-center, retrospective chart review of patients with HS who were treated with methotrexate between 2000 and 2018. Primary outcome measurements included the HS Physician's Global Assessment (HS PGA), Hurley staging, abscess count, fistula count, and inflammatory nodule count.

RESULTS

A total of 29 patients were identified; 14 were excluded for reasons including never starting methotrexate and missing follow-up data. For remaining patients (n = 15), the average cumulative dose of methotrexate was 520.1 mg (range, 30-1665 mg) and the average length of treatment was 11.7 months (range, 1-38 months). Patients taking methotrexate as a primary therapy had a higher cumulative dose and length of treatment (520.13 mg; 14.6 months) compared with those taking biologics concomitantly (468.44 mg; 9.1 months). Patients using methotrexate as primary therapy demonstrated nonsignificant reductions in HS PGA, inflammatory nodule count, and abscess count. Patients on concomitant biologic therapy failed to demonstrate any change in HS PGA, inflammatory nodule count, and abscess count.

LIMITATIONS

Limitations of the study include its retrospective nature, small sample size, length of time on methotrexate between groups, and homogeneity of the patient population.

CONCLUSION

Methotrexate may represent an effective treatment option in older patients with lower body mass indices but fails to offer benefit in patients taking concurrent biologic therapy.

Evaluation of Serum Adenosine Deaminase and Inflammatory Markers in Psoriatic Patients

Background:

Adenosine deaminase (ADA) is an enzyme involved in purine metabolism and it is a marker of nonspecific T-cell activation. Few studies have shown high levels of ADA in the epidermis and sera of psoriatic patients. Other inflammatory markers such as high-sensitive C-reactive protein (hsCRP), erythrocyte sedimentation rate (ESR), and serum uric acid (SUA) have shown correlations with psoriasis area severity index (PASI) score. The correlation between ADA and PASI score is still a matter of debate.

Aims:

The aim of this study was to evaluate serum ADA, hsCRP, SUA, and ESR in psoriatic patients and their correlation with PASI score.

Patients and Methods:

This study included 60 psoriatic patients divided according to PASI score into three groups (mild, moderate, and severe) each containing 20 patients. PASI score <10 was defined as mild, (10–20) moderate, and >20 severe. Twenty healthy subjects of matched age and sex were included as control. Serum ADA, hsCRP, SUA, and ESR were evaluated for patients and controls. Correlations of ADA, hsCRP, SUA, and ESR with PASI scores were done.

Results:

While ADA, hsCRP, SUA, and ESR showed a significant increase in psoriatic patients compared with that of the controls (P<001), they showed no significant difference between different psoriatic groups (P>0.05) and no correlations with PASI score (P>0.05). The frequency of joint affection increased with increasing severity of psoriasis (5%, 10%, and 25% in mild, moderate, and severe psoriasis, respectively).

Conclusion:

Serum ADA, hsCRP, SUA, and ESR showed higher levels among psoriatic patients than in controls. The increased ADA in psoriatic patients supports the role of T-cell activation and proliferative disorder in the pathogenesis of psoriasis. No significant correlations were found between these biomarkers and PASI score. Further studies are needed to validate these biomarkers as diagnostic and prognostic factors in psoriasis.

Investigational drugs in clinical trials for Hidradenitis Suppurativa

INTRODUCTION

Hidradenitis suppurativa is a chronic skin disease with a significant unmet need for treatment options. Randomized controlled trials are few and only a single drug (adalimumab) has Hidradenitis as a registered indication.

AREAS COVERED

The clinicaltrials.gov and the EudraCT clinical trials register for reported trials on Hidradenitis Suppurativa was searched on the 22-06-2017. Trials for upcoming new drugs for HS are reported focusing on drugs in phase I and II trials.The clinicaltrials.gov and the EudraCT clinical trials register for reported trials on Hidradenitis Suppurativa was searched on the 22-06-2017. Trials for upcoming new drugs for HS are reported focusing on drugs in phase I and II trials.

EXPERT OPINION

Currently, MABp1, Secukinumab, CJM112, Apremilast and IFX-1 are being investigated in Phase I and II trials and offer theoretical and promising new treatment options. A trial with the drug MEDI8968 has been terminated with disappointing results. Metformin, Botulinum Toxin B, Provodine, Benzoyl Peroxide and intralesional triamcinolone are being tested as well. Treatment of Hidradenitis remains a challenge and quality RTCs are needed. Studies indicates a range of potential targets for therapy such as interleukin-1 and interleukin-17, but 'broad-spectrum' immunosuppressants like phosphodiesterase-4 inhibitors are being examined as well. A range of outcomes, including Physician Global Assessment, Sartorius scores and hidradenitis suppurativa clinical response are used in these trials, making future meta-analysis of the data difficult.

Moderate to severe hidradenitis suppurativa patients do not have an altered bacterial composition in peripheral blood compared to healthy controls

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease defined by recurrent nodules, tunnels and scarring involving the intertriginous skin. Patients with HS often report an array of systemic symptoms such as fatigue and malaise. The aetiology of these symptoms remains unclear. Previously, various bacteria have been associated with mature HS lesions, and bacteraemia has been reported in patients with HS using traditional culturing methods. Thus, we hypothesized that a low-grade bacteraemia contributes to the symptomatology in patients with HS.

OBJECTIVE

To explore the potential presence of bacteraemia in patients with HS and healthy controls.

METHOD

A case-control study. Compositions of bacteria in the blood of 27 moderate to severe HS patients and 26 healthy controls were investigated using next-generation 16S ribosomal RNA gene sequencing (NGS) and routine anaerobic and aerobic blood culturing. None of the participants received any antibiotics (systemic or topical therapy) within 1 month prior to the study. HS patients with a recent flare were randomly selected by consecutive recruitment of eligible patients from the Department of Dermatology, Zealand University Hospital, Denmark. Healthy controls were recruited from the University of Copenhagen as well as from the healthcare staff.

RESULTS

The different bacterial compositions were investigated using NGS and traditional anaerobic and aerobic blood culturing. Our NGS analysis provided a previously unreported characterization of the bacterial composition in peripheral blood from patients with HS and healthy controls. Overall, our data demonstrated that patients with HS do not have a different bacterial composition in their peripheral blood than healthy controls.

CONCLUSION

The study suggests that the self-reported symptoms in HS such as malaise and fatigue may not be linked to bacteraemia.