Objectives: The aim of the study was to qualitatively and semiquantitatively characterize the expression of the principal HIV co-receptors chemokine (C-C motif) receptor 5 (CCR5) and chemokine (C-X-C motif) receptor 4 (CXCR4) on susceptible CD4 T-helper cell, monocyte/macrophage and Langerhans dendritic cell populations within the cervical epithelia of asymptomatic women attending a genitourinary medicine clinic.
Methods: Of 77 asymptomatic women recruited, 35 were excluded: 21 because they were found to have bacterial vaginosis, eight because they were found to have candida and six for other reasons. Cervical cytobrush samples from 11 women with Chlamydia trachomatis infection and 31 women without any detectable genital infection were stained with fluorescently labelled antibodies specific for cell surface CCR5, CXCR4, CD4, CD3, CD1a and CD19 expression, then analysed by flow cytometry.
Results: CD4/CD3 T-helper cells (84%), CD1a Langerhans dendritic cells (75%) and CD4/CD14 monocytes/macrophages (59%) were detected in the samples. CCR5 and CXCR4 HIV co-receptor expression was observed on 46-86% of the above subsets. CD1a cells exhibited significantly higher CCR5 and CXCR4 positivity and median fluorescence than CD4 cells and higher CXCR4 positivity and median fluorescence than CD14 cells (P < 0.05 or less). Increased detection of CCR5 over CXCR4 was seen in CD14 cells (P < 0.05). No significant differences in CCR5 or CXCR4 expression were found in samples from asymptomatic women with or without chlamydial infection.
Conclusions: Co-receptor expression confirms the potential for CD1a Langerhans cells, monocytes/macrophages and T-helper cells in the cervix as primary targets for HIV infection. Previously observed selective transmission of CCR5-tropic isolates cannot be accounted for by a lack of CXCR4-expressing CD4 cervical immune cells. We were unable to identify any specific impact of chlamydial infection on co-receptor expression in this study.
© 2012 British HIV Association.