title: Palmoplantar pustular psoriasis (PPPP) is characterized by activation of the IL-17A pathway.
abstract: BACKGROUND
  Palmoplantar pustular psoriasis (PPPP) is a variant of psoriasis, which has significant negative impact on quality of life. The cellular and molecular inflammatory pathways involved in PPPP have not been well studied.
  
  
  OBJECTIVE
  Study the expression of cytokines and chemokines involved in the IL-17/IL-23 axis in palmoplantar pustular psoriasis and other difficult to treat psoriasis areas (palms, scalp, elbows and lower legs).
  
  
  METHODS
  Skin biopsies were performed on a total of 80 patients with PPPP, non-pustular palmoplantar psoriasis (NPPPP), or psoriasis located on elbows, knees and scalp as well as 10 healthy subjects. RT-PCR, immunohistochemistry and flow cytometry on cells extracted from skin biopsies were used to compare PPPP to other forms of psoriasis.
  
  
  RESULTS
  There was a significant (p<0.05) increase in the expression of IL-1β, IL-6, LL-37, IL-19, IL-17A, CXCL1 and CXCL2 in PPPP as compared to NPPPP. However, there was no significant difference in expression of IL-23 in PPPP as compared to NPPPP and other forms of psoriasis. The proportion of IL-22+but not IL-17A+mast cells was higher in PPPP as compared to NPPPP (p<0.05).
  
  
  CONCLUSIONS
  These results suggest that the IL-17A pathway may play a more important role in PPPP than in NPPPP.
authors.affiliation: Innovaderm Research, 1851 Sherbrooke St. East, Suite 502, Montreal, Quebec, H2K 4L5, Canada. Electronic address: Rbissonnette@innovaderm.ca.
authors.forename: Robert
authors.initials: R
authors.lastname: Bissonnette
authors.affiliation: Laboratory of Investigative Dermatology, The Rockefeller University, 1230 York Avenue, New York, NY, 10065 USA.
authors.forename: Judilyn
authors.initials: J
authors.lastname: Fuentes-Duculan
authors.affiliation: Immunoregulation Laboratory, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint-Denis Street, Montreal, Quebec, H2X 0A9, Canada.
authors.forename: Shunya
authors.initials: S
authors.lastname: Mashiko
authors.affiliation: Laboratory of Investigative Dermatology, The Rockefeller University, 1230 York Avenue, New York, NY, 10065 USA.
authors.forename: Xuan
authors.initials: X
authors.lastname: Li
authors.affiliation: Laboratory of Investigative Dermatology, The Rockefeller University, 1230 York Avenue, New York, NY, 10065 USA.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Bonifacio
authors.affiliation: Laboratory of Investigative Dermatology, The Rockefeller University, 1230 York Avenue, New York, NY, 10065 USA.
authors.forename: Inna
authors.initials: I
authors.lastname: Cueto
authors.affiliation: Dept. of Population Health Science and Policy, Dept. of Genetics and Genomics Science and Dept. of Dermatology, Icahn School of Medicine at Mount Sinai, 1425 Madison Ave, L2-70C, Box 1077, New York, NY, 10029, USA.
authors.forename: Mayte
authors.initials: M
authors.lastname: Suárez-Fariñas
authors.affiliation: Innovaderm Research, 1851 Sherbrooke St. East, Suite 502, Montreal, Quebec, H2K 4L5, Canada.
authors.forename: Catherine
authors.initials: C
authors.lastname: Maari
authors.affiliation: Innovaderm Research, 1851 Sherbrooke St. East, Suite 502, Montreal, Quebec, H2K 4L5, Canada.
authors.forename: Chantal
authors.initials: C
authors.lastname: Bolduc
authors.affiliation: Innovaderm Research, 1851 Sherbrooke St. East, Suite 502, Montreal, Quebec, H2K 4L5, Canada.
authors.forename: Simon
authors.initials: S
authors.lastname: Nigen
authors.affiliation: Immunoregulation Laboratory, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint-Denis Street, Montreal, Quebec, H2X 0A9, Canada.
authors.forename: Marika
authors.initials: M
authors.lastname: Sarfati
authors.affiliation: Laboratory of Investigative Dermatology, The Rockefeller University, 1230 York Avenue, New York, NY, 10065 USA.
authors.forename: James G
authors.initials: JG
authors.lastname: Krueger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D016207:Cytokines / Q000378:metabolism*; D004550:Elbow; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D020381:Interleukin-17 / Q000378:metabolism*; D053760:Interleukin-23 Subunit p19 / Q000378:metabolism*; D007866:Leg; D008297:Male; D008407:Mast Cells / Q000378:metabolism; D008875:Middle Aged; D010457:Peptidoglycan; D011565:Psoriasis / Q000378:metabolism*; D011788:Quality of Life; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012535:Scalp; D015398:Signal Transduction; D012867:Skin / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D060726:Torso; D055815:Young Adult
chemical_list: D016207:Cytokines; C508717:IL17A protein, human; C508840:IL23A protein, human; D020381:Interleukin-17; D053760:Interleukin-23 Subunit p19; D010457:Peptidoglycan; C029323:pneumococcal purpura-producing principle
keywords: IL-17; IL-23; Palmoplantar psoriasis; Palmoplantar pustular psoriasis; Psoriasis; Skin biopsies