title: HLA-Cw6 homozygosity in plaque psoriasis is associated with streptococcal throat infections and pronounced improvement after tonsillectomy: A prospective case series.
abstract: BACKGROUND
  Carriage of the HLA-Cw*0602 allele is associated with a particular set of clinical features and treatment responses in psoriasis. Tonsillectomy can improve psoriasis.
  
  
  OBJECTIVE
  We sought to evaluate whether HLA-Cw*0602 predicts a favorable outcome after tonsillectomy of patients with psoriasis.
  
  
  METHODS
  This prospective case series followed up 28 tonsillectomized patients with plaque psoriasis for 24 months. The Psoriasis Area and Severity Index, Psoriasis Disability Index, and Psoriasis Life Stress Inventory were used for assessment. Tonsils were swabbed for bacteria and patients genotyped for HLA-Cw*0602.
  
  
  RESULTS
  After tonsillectomy, HLA-Cw*0602 homozygotes showed significantly more improvement, compared with heterozygous and HLA-Cw*0602-negative patients. Thus, Psoriasis Area and Severity Index score was reduced by 82% in the homozygous patients compared with 42% and 31%, respectively (P < .001), Psoriasis Disability Index score improved by 87% compared with 38% and 41%, respectively (P < .001), and Psoriasis Life Stress Inventory score was 82% reduced compared with 60% and 54%, respectively (P < .001). The homozygotes more often had psoriasis onset associated with a throat infection (P = .007) and an increased frequency of streptococcal throat infections per lifetime (P = .038).
  
  
  CONCLUSIONS
  Few patients were included and some data were retrospective.
  
  
  CONCLUSIONS
  Homozygous HLA-Cw*0602 carriage in plaque psoriasis may predict a favorable outcome after tonsillectomy.
authors: Section of Dermatology, Faculty of Medicine, University of Iceland, Reykjavik, Iceland; Department of Immunology, Landspitali-National University Hospital of Iceland, Reykjavik, Iceland; Department of Dermatology, Akademiska University Hospital, Uppsala, Sweden. Electronic address: ragnahlin@gmail.com.
authors: Ragna H
authors: RH
authors: Thorleifsdottir
authors: Department of Immunology, Landspitali-National University Hospital of Iceland, Reykjavik, Iceland.
authors: Sigrun L
authors: SL
authors: Sigurdardottir
authors: Section of Dermatology, Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
authors: Bardur
authors: B
authors: Sigurgeirsson
authors: Section of Dermatology, Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
authors: Jon H
authors: JH
authors: Olafsson
authors: Department of Otolaryngology-Head and Neck Surgery, Landspitali-National University Hospital of Iceland, Reykjavik, Iceland.
authors: Hannes
authors: H
authors: Petersen
authors: Department of Anesthesiology and Critical Care, Landspitali-National University Hospital of Iceland, Reykjavik, Iceland.
authors: Martin I
authors: MI
authors: Sigurdsson
authors: Department of Dermatology, University of Michigan Medical School, Ann Arbor, Michigan.
authors: Johann E
authors: JE
authors: Gudjonsson
authors: Department of Dermatology, University of Michigan Medical School, Ann Arbor, Michigan.
authors: Andrew
authors: A
authors: Johnston
authors: Department of Immunology, Landspitali-National University Hospital of Iceland, Reykjavik, Iceland.
authors: Helgi
authors: H
authors: Valdimarsson
mesh_terms: D000328:Adult; D017668:Age of Onset; D000483:Alleles; D005260:Female; D005500:Follow-Up Studies; D015236:HLA-C Antigens / Q000235:genetics*; D006801:Humans; D008297:Male; D010612:Pharyngitis / Q000150:complications / Q000235:genetics* / Q000382:microbiology; D011379:Prognosis; D011446:Prospective Studies; D011565:Psoriasis / Q000209:etiology / Q000235:genetics*; D012720:Severity of Illness Index; D013290:Streptococcal Infections / Q000150:complications / Q000235:genetics*; D014068:Tonsillectomy; D014069:Tonsillitis / Q000150:complications / Q000235:genetics* / Q000382:microbiology / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015236:HLA-C Antigens; C528994:HLA-C*06 antigen
keywords: HLA-Cw*0602; Psoriasis Disability Index; Psoriasis Life Stress Inventory; chronic plaque psoriasis; sore throat; streptococcal throat infection; tonsillectomy