Direct detection of HIV-1 rna in epidermal langerhans cells of hiv-infected patients

Human Langerhans cells (LC) are bone marrow-derived, HLA-DR⁺, CDla⁺, and CD4⁺ dendritic antigen-presenting cells found in stratified squamous epithelia. As other members of the dendritic leukocyte family, to which they belong, LC have been reported as targets for HIV-1 infection. The aim of the present study was to investigate whether HIV-1 RNA is expressed in epidermal LC of HIV-1-infected patients. Bulk epidermal cell (EC) suspensions were prepared from skin of nine recently deceased AIDS patients and 11 seronegative controls. Purified LC (94 ±4% HLA-DR⁺ cells with no CD3⁺cells, as assessed by flow microfluorimetry analysis) and LC-depleted EC were obtained by immunomagnetic separation using an anti-CDla monoclonal antibody. Samples were analyzed for the presence of HIV-1 RNA by reverse transcription of a spliced mRNA region of the tat gene, followed by polymerase chain reaction amplification. HIV-l-spliced RNA was detected in LC from 6 of 9 patients examined, whereas LC-depleted EC fractions from the same patients were all negative. The results indicate that epidermal LC from HIV-seropositive patients actively transcribe HIV-1 proviral DNA, further supporting the hypothesis that HIV productively infected LC could serve as a reservoir of the virus in the epidermis and as a source for the infection of T lymphocytes.