IMMUNE CELL INFILTRATION IN PERIODONTAL LESIONS OF HIV-INFECTED SUBJECTS - ANTIGENIC AND ULTRASTRUCTURAL FEATURES

The presence and morphological and antigenic differentiation of immune cells are prerequisites for efficient local immune responses. In this research, these issues were investigated in gingival biopsies from se ven HIV-infected patients with periodontal disease. The inflammatory, non-necrotic edge of the lesions was analysed. In all cases, the epith elium-lamina propria border was infiltrated by CD8+ lymphocytes, close ly associated with CD1a+ dendritic cells DCs with electron microscop ic features of cells of Langerhans lineage. This infiltrate suggested the existence of a local, cell mediated immune reaction, but was diffe rent in some crucial respects from that of most immune-mediated inflam matory disease occurring in the skin and oral mucosa of HIV-negative s ubjects. Firstly, it was characterized by almost complete absence of C D4+ T-lymphocytes. Moreover, CD1a+ DCs were restricted to the epitheli um-lamina propria border and were closely associated with CD8+ T-cells . Conversely, CD36+ perivascular dendritic macrophages showed rare and scanty contact with CD8+ cells, which are their usual co-actors in re gulatory immune responses. Also, lymphocytes and dendritic cells showe d a weak expression of functionally meaningful molecules (HLA-DR, LFA- 1 and ICAM-1) as compared with that observed in most immune-mediated d isorders of the skin and oral mucosa. These features are suggestive of aberrancy and low efficiency of local cell-mediated immune responses, which may be relevant to the pathogenesis and clinical course of peri odontal lesions in HIV-infected patients.