title: Intradermal antigen tests and the Koebner phenomenon in psoriasis.
abstract: BACKGROUND
  Psoriasis is one of several dermatologic conditions in which nonspecific irritation may elicit the disease where it was not previously present. In this study we aimed to assess the cutaneous cellular immune reaction with intradermal antigen tests and the relation between Koebner's phenomenon and intradermal antigens.
  
  
  METHODS
  Thirty psoriasis patients and 20 control subjects were tested with 0.1 mL intradermal injections of purified protein derivative (PPD), Candida (C), mumps (M), mixed respiratory vaccine (MRV), and saline control solutions. Koebner status was also determined in the psoriatic patients. Injection sites were evaluated at 72 h and on the eighth, 12th, 16th, and 20th days for erythema, induration, and local development of psoriasis.
  
  
  RESULTS
  Two patients were Koebner positive and developed psoriasis at all five injection sites. However, local psoriasis development was observed at one or more injection sites in five Koebner-negative patients. In addition, intensity of delayed hypersensitivity reaction and resolution times demonstrate no significant difference between psoriatic and nonpsoriatic subjects statistically (P > 0.05).
  
  
  CONCLUSIONS
  These findings may indicate that intradermal antigens used in this study were more effective in inducing the Koebner phenomenon than injury alone. Furthermore, we observed that there is no meaningful difference between psoriatic and nonpsoriatic subjects in developing cutaneous cellular immune reactions.
authors.affiliation: Department of Dermatology, GATA Haydarpasa Teaching Hospital, Istanbul, Turkey.
authors.forename: B
authors.initials: B
authors.lastname: Dogan
authors.forename: Y
authors.initials: Y
authors.lastname: Harmanyeri
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007111:Immunity, Cellular / Q000276:immunology; D007428:Intradermal Tests; D008297:Male; D011565:Psoriasis / Q000209:etiology / Q000276:immunology*; D013997:Time Factors