title: A case-control study on the association of human leukocyte antigen-A*9 and -B*15 alleles with generalized aggressive periodontitis in an Indian population.
abstract: BACKGROUND
  The genes encoding the human leukocyte antigens (HLAs; major histocompatibility complex [MHC]) have been considered candidate markers for periodontitis because they are involved in regulating immune responses. Several studies have examined this association, and despite the inconclusive results, the antigens HLA-A9 and HLA-B15 have been found to be consistently associated with the destructive forms of periodontitis in many populations. Ethnic factors are considered to be a major variable for evaluating the predisposition to the disease. The purpose of the present study was to: 1) assess the association of HLA-A*9 and HLA-B*15 with generalized aggressive periodontitis (GAgP) and 2) evaluate the role of these genetic risk factors in influencing the severity of GAgP in a South Indian population.
  
  
  METHODS
  Forty GAgP patients (cases) and 80 periodontally and systemically healthy subjects (controls) participated in this study. HLA-A*9 and HLA-B*15 typing was carried out using the polymerase chain reaction with sequence specific primers (PCR-SSP)-based molecular method.
  
  
  RESULTS
  HLA-B*15 was a significant risk factor for GAgP and was positively correlated with the disease severity, whereas HLA-A*9 had no association with the disease. The haplotype of HLA-A*9:B*15 did not impart any additional risk for GAgP compared to that imparted by HLA-B*15 alone.
  
  
  CONCLUSIONS
  To our knowledge, this is the first report on HLA-B*15 association with GAgP in an Indian population. The finding of HLA-B*15 as a risk factor may have potential use in the future management of GAgP. The precise disease-causing mechanism of this HLA disease association and whether this association is "causal" or "casual" need to be evaluated further.
authors.affiliation: Department of Periodontics, Seema Dental College and Hospital, Rishikesh, Uttaranchal, India. roshna_t@yahoo.com
authors.forename: T
authors.initials: T
authors.lastname: Roshna
authors.forename: Rasmi
authors.initials: R
authors.lastname: Thomas
authors.forename: K
authors.initials: K
authors.lastname: Nandakumar
authors.forename: Moinak
authors.initials: M
authors.lastname: Banerjee
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D015234:HLA-A Antigens / Q000235:genetics*; D015235:HLA-B Antigens / Q000235:genetics*; D059910:HLA-B15 Antigen; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D009911:Oral Hygiene Index; D017622:Periodontal Attachment Loss / Q000209:etiology; D010518:Periodontitis / Q000150:complications / Q000208:ethnology / Q000235:genetics* / Q000276:immunology; D011110:Polymorphism, Genetic; D012016:Reference Values; D012720:Severity of Illness Index; D012737:Sex Factors; D044465:White People
chemical_list: D015234:HLA-A Antigens; C037709:HLA-A9 antigen; D015235:HLA-B Antigens; D059910:HLA-B15 Antigen