title: Expression of the IL-23/Th17 pathway in lesions of hidradenitis suppurativa.
abstract: BACKGROUND
  Hidradenitis suppurativa is a debilitating chronic disease primarily affecting intertriginous skin of the axillae, perineum, and inframammary regions. The pathogenesis of this inflammatory disease is still poorly understood. Recently, increased attention has been paid to the role of the immune system.
  
  
  OBJECTIVE
  Since the interleukin 12 (IL-12)/T helper 1 (Th1) and the IL-23/Th17 pathways are believed to be crucially involved in the pathogenesis of multiple chronic inflammatory diseases, we investigated the expression and cellular source of IL-12, IL-23, and IL-17 in hidradenitis suppurativa.
  
  
  METHODS
  Ten patients with hidradenitis suppurativa were included in the study. Tissue samples were obtained from lesional skin and compared with healthy skin as a control. Expression of IL-12, IL-23, and IL-17 was analyzed by semiquantitative real-time polymerase chain reaction and immunohistochemistry, and the cellular source of these cytokines was determined by double immunofluorescence.
  
  
  RESULTS
  IL-12 and IL-23 were found to be abundantly expressed by macrophages infiltrating papillary and reticular dermis of lesional skin. In accordance with the high expression of IL-23 and its important role in the development of T helper 17 (Th17) cells, IL-17-producing T helper cells were found to distinctly infiltrate lesional dermis.
  
  
  CONCLUSIONS
  The sample size was small.
  
  
  CONCLUSIONS
  Our findings suggest that the IL-23/Th17 pathway is expressed in hidradenitis suppurativa and further support involvement of the immune system. Moreover, targeting the IL-12/IL-23-common subunit p40 with novel monoclonal antibodies may represent a new option for the treatment of this recalcitrant disease.
authors.affiliation: Department of Dermatology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schlapbach
authors.affiliation: Department of Dermatology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Tanja
authors.initials: T
authors.lastname: Hänni
authors.affiliation: Department of Dermatology, Inselspital, University of Bern, Bern, Switzerland.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Yawalkar
authors.affiliation: Department of Dermatology, Inselspital, University of Bern, Bern, Switzerland. Electronic address: robert.hunger@insel.ch.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Hunger
mesh_terms: D000328:Adult; D005260:Female; D017497:Hidradenitis Suppurativa / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D018664:Interleukin-12 / Q000096:biosynthesis*; D020381:Interleukin-17 / Q000096:biosynthesis*; D053759:Interleukin-23 / Q000096:biosynthesis*; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D006377:T-Lymphocytes, Helper-Inducer / Q000378:metabolism
chemical_list: D020381:Interleukin-17; D053759:Interleukin-23; D012333:RNA, Messenger; D018664:Interleukin-12