Introduction

1. POLYMORPHISMS IN THE IL-1 GENE CLUSTER INFLUENCE THE PERIODONTAL MICROFLORA M.L. Laine1, M.A. Farré2, M.A. García-González2, E.G. Winkel3, J.B.A. Crusius2, J.P. Vandenbroucke4, A.J. van Winkelhoff1 and A.S. Peña2 1Academic Centre for Dentistry Amsterdam (ACTA),2Laboratory of Immunogenetics, VUMC, 3Clinic of Periodontology Amsterdam and 4Department of Clinical Epidemiology, Leiden University, The Netherlands 135 114 bp Allele 220-320 kb 40-110 kb 3 IL-1A IL-1B IL-1RN 1 400 300 1 ( ) 2 200 100 M 1.1 2.2 1.2 1.3 2.3 1.4 The present study was supported by the Netherlands Institute for Dental Sciences and Academic Centre for Dentistry Amsterdam. #3278 Introduction Material and Methods Results Periodontitis is a multi-factorial infectious disease. Bacteria are essential to initiate and establish inflammatory processes in periodontitis but bacteria alone are not enough to cause disease. Interleukin (IL)-1, IL-1 and their natural specific inhibitor IL-1ra play a key role in the regulation of the inflammatory response in periodontal tissues. Polymorphisms in IL-1 gene cluster have been associated with severe adult periodontitis. No significant differences were found in prevalence of periodontal pathogens in distinct IL-1A, IL-1B and IL-1RN genotypes. Carriers of allele 2 of IL-1B, and IL-1A+IL-1B had significantly higher levels of Porphyromonas gingivalis and lower levels of Prevotella intermedia in comparison to non-carriers. The study included 105 patients with severe adult periodontitis. Mouthwash samples were collected and genotyped for bi-allelic polymorphisms IL-1A-889, IL-1B+3953 and a penta-allelic 86 bp variable number of tandem repeat IL-1RN gene polymorphisms using PCR technique. Table 1. Levels (%) of periodontal pathogens in association with carriage of IL-1B +3953 allele 2 and carriage of IL-1A-889 and IL- 1B+3953 allele 2 in comparison to non-carriers. bp Allele 400 300 2 (249) 4 200 100 M 1.2 2.2 1.1 Figure 1. Organization of IL-1 gene cluster on chromosome 2. Figure 3. IL-1RN genotypes. Figure 2. IL-1B genotypes. Presence and levels of putative periodontal pathogens were established by anaerobic culture techniques. Aim We aimed to investigate the composition of subgingival microflora in association with the IL-1 gene cluster polymorphisms in periodontitis. Conclusion Our results provide evidence that polymorphisms in IL-1 gene clustermay influence bacterial growth. This might be explained by impaired host defence response,and by the host response that contributes to define the habitatfor the growth of P. gingivalis and P. intermedia. #Mann-Whitney U Test.