title: HLA Cw*06 is not essential for streptococcal-induced psoriasis.
abstract: BACKGROUND
  Streptococcal throat infections and HLA Cw6 (Cw*06) have been implicated in the pathogenesis of psoriasis, particularly in the guttate form.
  
  
  OBJECTIVE
  To study 105 Irish patients with psoriasis to investigate the relationship between streptococcal infections and Cw*06.
  
  
  METHODS
  The patients were divided into two groups: those with guttate psoriasis or guttate flare (guttate group, GG, n=64) and those with chronic plaque psoriasis (chronic plaque group, CPG, n=41).
  
  
  RESULTS
  The incidence of Cw*06 was 86% in the GG and 73% in the CPG, which was not significantly different (P=0.1725) but the incidence in both groups was significantly higher than in an Irish control group (18%) (P<0.0001 vs. GG and P<0.0001 vs. CPG). Evidence for streptococcal infection was higher in the GG (56%) than in the CPG (32%) (P=0.0231). Of those patients with evidence of streptococcal infection, 30 of 36 GG (83%) and nine of 13 CPG (69%) patients possessed the Cw*06 genotype.
  
  
  CONCLUSIONS
  Thus, not all patients with streptococcal-related psoriasis carry Cw*06. The role of Cw*06 in psoriasis, if any, has yet to be determined.
authors.affiliation: Faculty of Medicine, Imperial College, London, UK, and The Skin Hospital, Dublin 2, Ireland.
authors.forename: L
authors.initials: L
authors.lastname: Fry
authors.forename: A V
authors.initials: AV
authors.lastname: Powles
authors.forename: S
authors.initials: S
authors.lastname: Corcoran
authors.forename: S
authors.initials: S
authors.lastname: Rogers
authors.forename: J
authors.initials: J
authors.lastname: Ward
authors.forename: D J
authors.initials: DJ
authors.lastname: Unsworth
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D005260:Female; D020022:Genetic Predisposition to Disease; D015236:HLA-C Antigens / Q000235:genetics*; D006801:Humans; D008297:Male; D010612:Pharyngitis / Q000150:complications / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods; D011565:Psoriasis / Q000235:genetics* / Q000382:microbiology*; D012008:Recurrence; D013290:Streptococcal Infections / Q000150:complications*
chemical_list: D015236:HLA-C Antigens; C528994:HLA-C*06 antigen