Different subsets of peripheral blood dendritic cells show distinct phenotypic and functional abnormalities in HIV-1 infection.

Objectives: To analyse the distribution, expression of chemokine receptors and ex vivo production of inflammatory cytokines by peripheral blood (PB) monocytes and DC in HIV-1+ individuals.
Design: Dendritic cells (DC) play an important role in the establishment and dissemination of HIV infection. DC interaction with HIV depends on expression of HIV receptors and co-receptors. Accumulating evidence supports the notion that DC functionality is impaired in HIV-1+ patients.
Methods: PB samples from 30 naive-treated HIV-1+ progressors were studied. Additionally, 10 adult healthy volunteers (AHV), seven Hepatitis C virus positive (HCV+)/HIV-1- patients and five long-term non-progressor HIV-1+ patients (HIV-1+LTNP) were included as controls. Flow cytometry immunophenotyping was used for the identification, enumeration and characterization of monocytes and DC.
Results: PB myeloid DC (mDC) and plasmacytoid DC (pDC) were significantly decreased in HIV-1+ progressors, while unaltered in HIV-1+LTNP. The expression of CXCR2 and CXCR4 and of CXCR4 and CCR5 were severely altered on PB mDC and pDC from HIV-1+ progressors, respectively. By contrast, both the expression of the chemokine receptors analysed and the numbers of CD16+ DC in HIV-1+ progressors were not different from AHV, while altered in HCV+/HIV-1- and HIV-1+LTNP. Furthermore, PB monocytes and DC from HIV-1+ progressors spontaneously produced inflammatory cytokines, in contrast with AHV.
Conclusions: These results support the existence of a selective interaction between HIV-1 and both mDC and pDC, associated with HCV co-infection-independent spontaneous production of inflammatory cytokines, reflecting the occurrence of in vivo activation of the immune system, which might further contribute to the impaired DC functionality.