What is the role of CCR5 trophism testing in the management of HIV infection?

Updated: Jun 23, 2020
  • Author: Philip A Chan, MD, MS; Chief Editor: John Bartlett, MD  more...
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Answer

CCR5 trophism testing

HIV requires an additional co-receptor for cell entry in addition to CD4. The co-receptor that HIV uses depends on the cell type: for CD4 cells, it is CXCR4; for macrophages, it is CCR5. Early in infection, HIV almost exclusively uses the CCR5 co-receptor, but, in many individuals, there is a shift to using alternative receptors such as CXCR4. This shift has important implications for choosing antiretroviral regimens. Maraviroc is a fusion inhibitor that blocks binding to the CCR5 co-receptor. Prior to starting therapy with maraviroc, viral tropism testing should be performed to confirm that CXCR4-trophic or dual-trophic strains are not present, as these would be quickly selected for, rendering treatment useless. In contrast, the fusion inhibitor enfuvirtide acts on the gp41 viral protein. This drug is active against CCR5, CXCR4, and dual-trophic strains of HIV-1. [37]


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