PracticeUpdate Conference Series: IID 2018

Cutaneous Bacterial Presence May Provoke Activated Immune Response in Hidradenitis Suppurativa Cutaneous bacterial presence may provoke an activated immune response in hidradenitis suppurativa, and these organisms may become resistant to antibiotics, results of a genomic and proteomic study show.

M ichelle A. Lowes, MD, PhD, of Rockefeller University, and Lauren K. Hoffman, BA, of Albert Einstein College of Medicine in Bronx, New York, set out to determine the skin and blood transcriptomeof patientswithhidradenitis suppurativa. She analyzed patient data from two 2016 studies by Blok et al. The female-to-male ratio was 13:4 and age range 20–53 years. A total of 13 patients suffered from Hurley stage II, and 4 from stage III disease. Data of these patients were compared with that of 10 healthy volunteers. The reanalysis employed a mixed effect model with random intercept to determine: ƒ ƒ Differentially expressed genes and fold change >2.0 and false discovery rate <0.05 ƒ ƒ Differentially expressed proteins as fold change >1.5 and false discovery rate <0.05 In the hidradenitis suppurativa skin transcriptome (lesional vs nonlesional skin), an abundance of immunoglobulins, antimicrobial peptides, and an interferon signature were observed. CIBERSORT analysis of the hidradenitis suppu- rativa skin transcriptome revealed a significantly increased proportion of plasma cells in lesional skin. Gene sets related Notch signaling and interferon pathways were activated differentially in hidrade- nitis suppurativa lesional skin vs nonlesional skin. In the hidradenitis suppurativa skin and blood tran- scriptome and blood proteome, gene sets related to the complement system changed significantly (false discovery rate <0.05), with dysregulation of complement-specific differentially expressed genes and differentially expressed proteins. Ms. Hoffman concluded that the data pointed to an activated immune response that may be respond- ing to a cutaneous bacterial presence. The results raised the possibility that this activated immune response may drive hidradenitis suppurativa dis- ease progression.

Dr. Michelle A. Lowes

Bacteriamay become resistant to antibiotics used for hidradenitis suppurativa H eather Ma, BS, of the University of California in San Francisco, explained that long courses of antibiotics are commonly used to treat hidradenitis suppurativa. These prolonged courses raise concern about antibiotic resistance. Ms. Ma, Joslyn Sciacca Kirby, MD, and Paul Leiphart, BA, of the Penn State College of Medicine in Hershey, and Haley B. Naik, MD, of the University of California in San Francisco, set out to examine the effect of antiseptic washes on the frequency of antibiotic resistance in hidradenitis suppurativa lesions. Dr. Naik told Elsevier’s PracticeUpdate , “High- quality evidence to support therapeutic interventions for hidradenitis suppurativa is lacking, partly due to a poor understanding of the patho- genesis of the disorder. More effective, targeted therapies for hidradenitis suppurativa are needed.” She continued, “Antimicrobial therapy and antisep- tic washes have been a mainstay of hidradenitis suppurativa management for decades, owing to the purulent and malodorous nature of lesions and the presence of bacteria identified by con- ventional culture methods in approximately 50% of

Dr. Lauren K. Hoffman

Ms. Heather Ma

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PRACTICEUPDATE CONFERENCE SERIES • IID 2018