title: HLA antigens and pANCA define ulcerative colitis as a genetically heterogeneous disorder.
abstract: BACKGROUND
  Several genetic and subclinical markers have been associated with ulcerative colitis.
  
  
  OBJECTIVE
  To determine whether a significant association with HLA class I and II antigens was present in Italian ulcerative colitis patients considered as a whole population or stratified according to their anti-neutrophil cytoplasmatic antibodies.
  
  
  METHODS
  HLA class I and II antigens were studied by serological typing techniques and related to the presence of anti-neutrophil cytoplasmatic antibodies detected by means of indirect immunofluorescence.
  
  
  RESULTS
  Patients with ulcerative colitis (n = 45) had a significantly increased frequency of DQ6 (p = 0.04) and DQ7 (p = 0.003) and a decreased frequency of DQ5 (p = 0.03) and DQ8 (p = 0.02) when compared with ethnically matched healthy controls (n = 252 for HLA class I and 173 for HLA class II). No significant difference in HLA I- and DR-antigens was observed. Anti-neutrophil cytoplasmatic antibodies were found in 27/45 (60%) ulcerative colitis patients and in 0/252 controls (p < 0.001). After stratifying ulcerative colitis patients according to their anti-neutrophil cytoplasmatic antibodies status, anti-neutrophil cytoplasmatic antibodies +ve patients had an increased frequency of A19 (p = 0.007), DR2 (p = 0.03), and DR15 (p = 0.006), and a decreased frequency of A1 (p = 0.004) compared with anti-neutrophil cytoplasmatic antibodies -ve ones.
  
  
  CONCLUSIONS
  We suggest that specific HLA-class II loci play an important role in the susceptibility to ulcerative colitis in Italy. A subset of ulcerative colitis patients is characterised by the presence of a specific subclinical marker (anti-neutrophil cytoplasmatic antibodies) which seems to be genetically determined as shown by the increased frequencies of HLA-A19 and DR2 observed in anti-neutrophil cytoplasmatic antibodies +ve ulcerative colitis.
authors.affiliation: Division of Gastroenterologiy, Casa Sollievo della Sofferenza Hospital, IRCCS, San Giovanni Rotondo, FG, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Perri
authors.forename: V
authors.initials: V
authors.lastname: Annese
authors.forename: A
authors.initials: A
authors.lastname: Piepoli
authors.forename: G
authors.initials: G
authors.lastname: Napolitano
authors.forename: G
authors.initials: G
authors.lastname: Lombardi
authors.forename: G
authors.initials: G
authors.lastname: Ciavarella
authors.forename: G
authors.initials: G
authors.lastname: Di Giorgio
authors.forename: A
authors.initials: A
authors.lastname: Andriulli
mesh_terms: D000328:Adult; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000276:immunology*; D003093:Colitis, Ulcerative / Q000453:epidemiology / Q000235:genetics* / Q000276:immunology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006579:Heterozygote; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D006650:Histocompatibility Testing; D006801:Humans; D007558:Italy / Q000453:epidemiology; D015810:Linkage Disequilibrium; D008297:Male; D009504:Neutrophils / Q000276:immunology; D015995:Prevalence
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II