Lymphocyte receptor pattern heightens susceptibility of GI mucosa to HIV
A preponderance of T lymphocytes in the gastrointestinal mucosa express both CCR5 and CXCR4 chemokine receptors, the major coreceptors for HIV-1. This creates a “favoured target” for HIV-1 infection, according to a report in the September Journal of Virology.
Dr. Michael A. Poles and colleagues from UCLA School of Medicine in Los Angeles, California, conducted in vitro experiments with mononuclear cells derived from rectosigmoid biopsy specimens and from peripheral blood, to investigate the known susceptibility of gastrointestinal mucosa to HIV-1 infection.
Significantly more mucosal mononuclear cells (2.6%) than peripheral blood mononuclear cells (0.74%) became infected in vitro with an R5-tropic HIV, the authors report. Infection rates with an X4-tropic HIV strain were similar at 1.7% versus 0.96%, respectively.
Mucosal lymphocytes also supported about 10 times the number of HIV replications per infected cell than did peripheral blood mononuclear cells, the researchers report.
They also found that 70% of mucosal mononuclear cells coexpress CCR5 and CXCR4, compared with fewer than 14% of peripheral blood mononuclear cells. Moreover, both R5- and X4-tropic HIV-1 predominantly infected CCR5+ CXCR4+ cells in both mucosal and peripheral blood compartments.
“Given the enhanced infection of mucosal lymphoid cells by HIV, ” Dr. Poles and colleagues suggest, “perhaps therapies should be directed specifically toward this important compartment.”
Poles MA et al. A preponderance of CCR5(+) CXCR4(+) mononuclear cells enhances gastrointestinal mucosal susceptibility to human immunodeficiency virus type 1 infection. J Virol 2001 Sep;75(18):8390-9.
Source: Reuters Health