title: Differential expression of antimicrobial peptides in psoriasis and psoriatic arthritis as a novel contributory mechanism for skin and joint disease heterogeneity.
abstract: OBJECTIVE
  This study tested the hypothesis that a differential innate immune antimicrobial peptide (AMP) profile was evident between the skin and joints in psoriasis and psoriatic arthritis (PsA) and that PsA synovitis may have a distinct AMP pattern compared to other arthropathies.
  
  
  METHODS
  Twenty-two cases had knee biopsies [10 PsA, eight rheumatoid arthritis (RA), and four osteoarthritis (OA)]. Lesional and non-lesional skin biopsies in psoriasis and control tissue were also obtained (n = 4 each). Immunohistochemistry with semi-quantitative scoring of both synovium and skin was performed using the following panel of AMPs: S100 A8, S100 A9, human neutrophil peptides 1-3 (HNP1-3), human β-defensins 2 and 3 (hBD-2 and hBD-3), cathelicidin LL-37, psoriasin (S100 A7), and ribonuclease 7 (RNase 7).
  
  
  RESULTS
  Similar expression of S100 A8, S100 A9, and HNP1-3 was detectable in PsA and RA synovium but only in the synovium sublining layer (SSL). No expression of psoriasin, RNase 7, hBD-2, and hBD-3 could be detected in the synovial tissue of PsA, RA, or OA. All psoriasis skin samples exhibited broad expression of all investigated AMPs, with strong keratinocyte expression.
  
  
  CONCLUSIONS
  Given that some AMPs, especially hBD-2, are genetically linked to psoriasis and are only expressed in the skin, these findings show how differential AMP expression in innate immune responses may contribute to disease heterogeneity between PsA and psoriasis and provides a genetic basis for the non-progression of psoriasis subgroups to PsA.
authors.affiliation: a Department of Dermatology , University Hospital of Schleswig-Holstein , Kiel , Germany.
authors.forename: H
authors.initials: H
authors.lastname: Bierkarre
authors.affiliation: a Department of Dermatology , University Hospital of Schleswig-Holstein , Kiel , Germany.
authors.forename: J
authors.initials: J
authors.lastname: Harder
authors.affiliation: b Leeds Institute of Rheumatic and Musculoskeletal Medicine , University of Leeds , Leeds , United Kingdom.
authors.forename: R
authors.initials: R
authors.lastname: Cuthbert
authors.affiliation: b Leeds Institute of Rheumatic and Musculoskeletal Medicine , University of Leeds , Leeds , United Kingdom.
authors.forename: P
authors.initials: P
authors.lastname: Emery
authors.affiliation: c Department of Paediatric Pathology , University Hospital of Schleswig-Holstein , Kiel , Germany.
authors.forename: I
authors.initials: I
authors.lastname: Leuschner
authors.affiliation: a Department of Dermatology , University Hospital of Schleswig-Holstein , Kiel , Germany.
authors.forename: U
authors.initials: U
authors.lastname: Mrowietz
authors.affiliation: d Department of Medical Informatics and Statistics , University Hospital of Schleswig-Holstein , Kiel , Germany.
authors.forename: J
authors.initials: J
authors.lastname: Hedderich
authors.affiliation: b Leeds Institute of Rheumatic and Musculoskeletal Medicine , University of Leeds , Leeds , United Kingdom.
authors.forename: D
authors.initials: D
authors.lastname: McGonagle
authors.affiliation: a Department of Dermatology , University Hospital of Schleswig-Holstein , Kiel , Germany.
authors.forename: R
authors.initials: R
authors.lastname: Gläser
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D023181:Antimicrobial Cationic Peptides / Q000378:metabolism*; D015535:Arthritis, Psoriatic / Q000378:metabolism*; D001172:Arthritis, Rheumatoid / Q000378:metabolism; D001182:Arthroscopy; D040501:Calgranulin A / Q000378:metabolism; D040502:Calgranulin B / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007719:Knee Joint / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000378:metabolism; D011565:Psoriasis / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism; D000075023:S100 Calcium Binding Protein A7; D009418:S100 Proteins / Q000378:metabolism; D012867:Skin / Q000378:metabolism*; D013583:Synovial Membrane / Q000378:metabolism*; D055815:Young Adult; D023084:alpha-Defensins / Q000378:metabolism; D023083:beta-Defensins / Q000378:metabolism; D054804:Cathelicidins
chemical_list: D023181:Antimicrobial Cationic Peptides; D040501:Calgranulin A; D040502:Calgranulin B; C422950:DEFB103A protein, human; C106641:DEFB4A protein, human; D000075023:S100 Calcium Binding Protein A7; D009418:S100 Proteins; C089242:S100A7 protein, human; D023084:alpha-Defensins; D023083:beta-Defensins; C406413:human neutrophil peptide 1; C406416:human neutrophil peptide 2; C406427:human neutrophil peptide 3; D012260:Ribonucleases; C470000:Ribonuclease 7; D054804:Cathelicidins