An investigation of the role of oral epithelial cells and Langerhans cells as possible HIV viral reservoirs.

Background: The role of the oral mucosa as a target of human immunodeficiency virus (HIV-1) infection and persistence is unclear. HIV-1 has been reported in oral epithelial cells, but this has not been confirmed. Cellular reservoirs may impede antiretroviral therapies and should be identified. This study was performed to determine the presence of HIV-1 in oral epithelial and Langerhans cells (LCs) of HIV-1-positive antiretroviral naïve patients. Non-invasive brush biopsy technique for future in vivo HIV research was also evaluated.

Methods: Oral mucosal cells were harvested from the buccal mucosae, dorsal tongue and the gingiva of the mandibular teeth of 35 HIV-1-positive patients using a Cytobrush Plus cell collector. Epithelial cells were purified from the samples by flow cytometric cell sorting using cytokeratin stains after which the epithelial cell samples were further purified and divided into superficial and deep epithelial cells by laser microdissection on Pap stained cytospin smears. LCs were picked up individually by laser microdissection from CD1a stained cytospin smears. Purified epithelial and LC samples were tested for the presence of HIV-1 DNA by polymerase chain reaction analysis.

Results: Ten of the patients had HIV-1 DNA in one or more of the sampled anatomical locations. No HIV-1 DNA could be demonstrated in any of the purified superficial or deep epithelial or LC samples.

Conclusions: HIV-DNA can be found using non-invasive oral brush biopsies and should be investigated further as an experimental model for in vivo oral HIV research. Better ways to purify the different cell types should be investigated.