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Additional Resource

Viral Tropism

Viral Tropism


Creating a more complete HIV profile

  • HIV-1 uses a coreceptor on the surface of immune cells to enter them13
  • Viral tropism refers to the specific coreceptors that a particular HIV-1 virus uses to enter T-cells13
  • HIV-1 enters CD4+ T-cells via the CCR5 or CXCR4 coreceptor. Some strains of HIV-1 can utilize either coreceptor13


HIV uses R5, X4, or a combination of coreceptors to infect T-cells

X4, R5 and Dual HIV strains try to enter T-cell through CXCR4 and CCR5 coreceptors
Coreceptor13 Description13 Prevalence14*
R5
(CCR5-tropic)
R5 virus enters CD4+ T-cells only through the CCR5 coreceptor
66%-82% in treatment-naïve patients;

37% in highly treatment-experienced patients
X4
(CXCR4-tropic)
X4 virus enters CD4+ T-cells only through the CXCR4 coreceptor
0.3%-1.0% in treatment-naïve patients;

4% in highly treatment-experienced patients
Dual
(dual-tropic)
Dual-tropic virus enters CD4+ T-cells only through either the CCR5 or CXCR4 coreceptor
Data are only available for dual/mixed-tropic HIV-1
Mixed
(mixed-tropic)
Mixed virus populations contain a combination of R5 and/or X4 and/or dual-tropic viruses
18%-33% in treatment-naïve patients;

59% in highly treatment-experienced patients

Consider tropism testing to help you complete your patient’s HIV profile and guide individualized treatment


*Analysis is based on Trofile® ES. Trofile® ES is able to detect D/M or CXCR4-using variants when they are ≥0.3% of the total viral population.