title: Role of HLA-DR Alleles to Increase Genetic Susceptibility to Onychomycosis in Nail Psoriasis.
abstract: BACKGROUND
  Patients with nail psoriasis have an increased risk of onychomycosis. Previous studies suggest it may be due to structural changes of the nails. However, a genetic predisposition seems to be also at play.
  
  
  OBJECTIVE
  To determine a genetic susceptibility for onychomycosis in nails with changes of psoriasis.
  
  
  METHODS
  This is a prospective case-control study of patients with suggestive changes of nail psoriasis with onychomycosis (cases) and without onychomycosis (controls) confirmed by mycological tests. HLA typing was performed in all of them by sequence-specific primers.
  
  
  RESULTS
  Twenty-five patients and 20 controls with a mean age of 50 years (range 37-72 years) were studied. HLA-DRB1*08 was found in 12 cases (48%) and only 3 controls (15%) [p < 0.033, odds ratio (OR) = 3.8, 95% confidence interval (CI): 0.9-19]. HLA-DR1 was found in 9 cases (36%) and only 1 control (5%) (p < 0.023, OR = 8.5, 95% CI: 1-188).
  
  
  CONCLUSIONS
  HLA-DR*08 and HLA-DR*01 probably increase the susceptibility to fungal infection in psoriasis-affected nails, but larger studies are required to confirm this observation.
authors.affiliation: Department of Dermatology, 'Dr. Manuel Gea González' General Hospital, Mexico City, Mexico.
authors.forename: Hilda
authors.initials: H
authors.lastname: Carrillo-Meléndrez
authors.affiliation: Department of Transplantation, Inmunogenetics Division, Instituto Nacional de Ciencias Médicas y Nutrición 'Salvador Zubirán', Mexico City, Mexico.
authors.forename: Esteban
authors.initials: E
authors.lastname: Ortega-Hernández
authors.affiliation: Department of Transplantation, Inmunogenetics Division, Instituto Nacional de Ciencias Médicas y Nutrición 'Salvador Zubirán', Mexico City, Mexico.
authors.forename: Julio
authors.initials: J
authors.lastname: Granados
authors.affiliation: Department of Molecular Biology and Histocompatibility, 'Dr. Manuel Gea González' General Hospital, Mexico City, Mexico.
authors.forename: Sara
authors.initials: S
authors.lastname: Arroyo
authors.affiliation: Department of Molecular Biology Department, Escuela Nacional de Antropología e Historia, Mexico City, Mexico.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Barquera
authors.affiliation: Department of Dermatology, 'Dr. Manuel Gea González' General Hospital, Mexico City, Mexico.
authors.forename: Roberto
authors.initials: R
authors.lastname: Arenas
keywords: Genetic predisposition; HLA class II allele; Nail fungus; Nail psoriasis; Onychomycosis; Psoriasis