WROCLAW, Poland — A trio of proteins can be used to differentiate patients with hidradenitis suppurativa from those with aggressive skin infections, boosting efforts to develop accurate biomarker tests for the chronic inflammatory skin disease.
Because hidradenitis suppurativa is relatively rare, most clinicians are not familiar with the disease, leading to delays in diagnosis, disease progression, and skin destruction, said Evangelos Giamarellos-Bourboulis, MD, PhD, from Athens University Medical School. Biomarker scores could provide a much-needed tool to hasten the diagnostic process.
“My vision is to use such scores to guide treatment,” Giamarellos-Bourboulis told Medscape Medical News.
“This could be encouragement for the general practitioner to quickly refer the patient to an expert outpatient clinic or dermatology center,” he explained here at the Conference of the European Hidradenitis Suppurativa Foundation 2019.
The study assessed four groups of adults: 50 healthy volunteers, 35 patients with inflammatory bowel disease, 115 patients with microbiologically confirmed staphylococcal acute bacterial skin and skin structure infections, and 196 patients with hidradenitis suppurativa.
Initially, levels of eight proteins were measured in the blood of the participants: IL (interleukin)-17, IL-20, IL-22, IL-23, cathelicidin (LL-37), s-E selectin, vascular endothelial growth factor (VEGF)-alpha, and human-beta defensing (HBD)-2. Protein levels were used to create a diagnostic algorithm.
A three-step process was used to exclude proteins that did not appear to signal hidradenitis suppurativa, which resulted in the exclusion of healthy patients and those with inflammatory bowel disease. The last step identified three proteins that, at different thresholds, helped distinguish between patients with skin infections that might present in a manner similar to hidradenitis suppurativa and patients with hidradenitis suppurativa.
Scores higher than 7 yielded both high specificity and a positive predictive value for hidradenitis suppurativa of 85.3%.
There are shortcomings that stem from biomarker screening that eliminates patients in a stepped process, Giamarellos-Bourboulis acknowledged in front of an audience of about 150 people.
“My philosophy behind this is that if we want to develop a perfect diagnostic in HS, sooner or later we have to understand our limits,” he said. “Biomarkers have limits.”
Additional research is still needed to add a metabolite or genetic marker and create an even more comprehensive composite biomarker score, he said.
Audience members offered mixed reactions to this biomarker concept and its potential clinical relevance.
Questioning Clinical Relevance
“The project represents a potentially important approach to addressing two of the largest unmet needs in HS, which are diagnostic accuracy and individualized therapy,” said Amit Garg, MD, from Northwell Health in New York.
“With some protocol refinement and external validation, the measure may represent a valuable contribution,” he told Medscape Medical News.
However, a diagnostic biomarker test would not necessarily help clinicians who are unfamiliar with hidradenitis suppurativa, said Hessel van der Zee, MD, PhD, from Erasmus University in Rotterdam, the Netherlands.
“If doctors are not familiar with this diagnosis,” it is unlikely that they will be familiar with the score, he told Medscape Medical News. “But if you know it, you probably also know about HS.”
A biomarker test that identifies the effectiveness of treatment in patients with hidradenitis suppurativa would probably be more useful than one for diagnosis, he suggested.
Giamarellos-Bourboulis is a consultant or received honoraria or grants from AbbVie, Biotest, Brahms GmbH, the Medicines Company, Astellas Greece, InflaRx GmbH Germany, and XBiotech. Garg is an advisor or has received grants from AbbVie, Amgen, UCB, Janssen, Pfizer, Merck, and NPF. van der Zee has disclosed no relevant financial relationships.
Conference of the European Hidradenitis Suppurativa Foundation (EHSF) 2019: Abstract 028 OS06-01. Presented February 7, 2019.