Immunocompetent cells in oral candidiasis of HIV-infected patients: an immunohistochemical and electron microscopical study.

OBJECTIVE

The purpose of this study was to elucidate the pathogenesis of oral candidiasis, a common cause of discomfort and social impairment among HIV-infected individuals.

STUDY DESIGN, MATERIALS AND

METHODS

The oral mucosal immune system cells were analysed by immunohistochemistry and electron microscopy in biopsies from five erythematous and four pseudomembranous candidiasis cases and were compared with those from seven HIV-positive and 10 HIV-negative controls without candidiasis.

RESULTS

The superficial lamina propria and basal epithelial layer was populated by CD1a+ Langerhans cells with infiltration of CD8+ lymphocytes. Within the submucosa are CD36+ dendritic macrophages and lymphocytes, although CD4+ subsets were absent from the infiltrate. The expression of human leukocyte antigen system, DR locus (HLA-DR) and leukocyte specific adhesion molecules was low in erythematous, yet more marked in pseudomembranous candidiasis. In the pseudomembranous form, CD14+ leukocytes were found in the basal epithelial layer. Langerhans cells were significantly more numerous and were richer in dendrites and Birbeck granules in erythematous than in pseudomembranous candidiasis.

CONCLUSIONS

Candidiasis is associated with alterations in the number and differentiation of lymphocytes and dendritic cells, being more severe in the pseudomembranous than erythematous form. We propose that these alterations play a role in the pathogenesis and evolution of the disease.