title: Human leukocyte antigen polymorphism in chronic and aggressive periodontitis among Caucasians: a meta-analysis.
abstract: OBJECTIVE
  Multiple studies have reported associations between periodontitis and particular human leukocyte antigens (HLA). Because associations are inconsistent, we conducted a systematic literature review and a meta-analysis focusing on Caucasian case-control studies.
  
  
  METHODS
  A literature search reporting on the distribution of HLA class I and II phenotypes in Caucasian patients with chronic periodontitis (CP) and aggressive periodontitis (AP) was performed. Data sources included electronic databases and bibliographies of published articles. Screening and data abstraction were conducted independently by different reviewers.
  
  
  RESULTS
  Out of 174 publications, 12 studies were considered to be suitable for meta-analysis. In patients with CP, no significant HLA associations were found. Patients with AP showed a positive association with HLA-A9 [odds ratio=2.59 (95% confidence interval 1.36-4.83), p=0.004] and HLA-B15 [1.90 (1.15-3.16), p=0.01] as well as a negative association with HLA-A2 [0.72 (0.56-0.94), p=0.01] and -B5 [0.49 (0.30-0.79), p=0.004]. On grouping all patients into one periodontitis group (AP+CP), the same deviations were confirmed with higher statistical significance. For HLA-A9 and -B15, significant heterogeneity was found between the studies. No significant associations were found with HLA class II antigens.
  
  
  CONCLUSIONS
  HLA-A9 and -B15 seem to represent susceptibility factors for AP whereas HLA-A2 and -B5 are potential protective factors against periodontitis among Caucasians.
authors.affiliation: Department of Operative Dentistry, Periodontology and Preventive Dentistry, University Hospital (RWTH), Aachen, Germany. JStein@ukaachen.de
authors.forename: Jamal M
authors.initials: JM
authors.lastname: Stein
authors.forename: Helmut K G
authors.initials: HK
authors.lastname: Machulla
authors.forename: Ralf
authors.initials: R
authors.lastname: Smeets
authors.forename: Friedrich
authors.initials: F
authors.lastname: Lampert
authors.forename: Stefan
authors.initials: S
authors.lastname: Reichert
mesh_terms: D002908:Chronic Disease; D018740:Genetic Heterogeneity; D005819:Genetic Markers / Q000235:genetics; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D006801:Humans; D010518:Periodontitis / Q000208:ethnology / Q000235:genetics*; D010641:Phenotype; D011110:Polymorphism, Genetic / Q000235:genetics*; D044465:White People / Q000235:genetics
chemical_list: D005819:Genetic Markers; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II