EXPRESSION OF HLA CLASS-II ANTIGENS IN MARGINAL PERIODONTITIS OF PATIENTS WITH DOWNS-SYNDROME

The expression of HLA Class II antigens on the surfaces of immunocompe tent cells and the presence of CD1a(+) cells (Langerhans cells) are im portant components of antigen presentation. Quantitative variations in HLA class II expression on antigen-presenting cells play a role in im mune regulation. An indirect immunofluorescent technique was used on c ryostat sections to reveal such differences qualitatively or quantitat ively between chronic marginal periodontitis (CMP) in patients with Do wn's syndrome (DS) and in otherwise normal patients (NP). We found inc reased frequency of HLA Class II (HLA-expression on inflammatory cells and on keratinocytes of the oral gingival epithelium) in CMP of DS pa tients compared to sections from NP. The expression of HLA-DR was more frequent on the keratinocytes of the pocket epithelium in NP than in DS. There were significantly higher numbers of CD1a+ cells and ratios of HLA-DR+/CD1a(+) cells and HLA-DP+/CD1a(+) cells in the DS group com pared to the NP group. Our conclusion is that there is a more pronounc ed inflammatory process in the gingival sites with CMP of DS patients compared to CMP in NP. The findings also indicate that there is a high ly activated immune response in CMP of DS patients.