CD1a-positive cells in odontogenic cysts.

Langerhans cells (LC) are bone marrow-derived cells that have a CD1a-positive immunophenotype and are an important portion of the cell-mediated immune response. The aim of this study was an immunohistochemical evaluation of CD1a positive cells in different types of oral cysts. Fifty-five cysts were studied: 18 odontogenic keratocysts (OKC), of which five were orthokeratotic and 13 parakeratotic; 19 radicular cysts; and 18 dentigerous cysts. Positive LC was 80% for orthokeratotic OKC, 33% for parakeratotic OKC, approximately 35% for radicular cysts, and approximately 20% for dentigerous cysts. The results show that OKC with well-differentiated epithelial linings presented a greater number of LC than the other cysts. However, when the cyst wall was inflamed there were no differences in LC expression in the different types of cysts. The data confirm that LC distribution seems to be associated with the degree of differentiation of the epithelia.