HIV tropism

HIV tropism refers to the

HIV can infect a variety of

Viruses that use only the CCR5 receptor are termed R5, those that only use CXCR4 are termed X4, and those that use both, X4R5. However, the use of a coreceptor alone does not explain viral tropism, as not all R5 viruses are able to use CCR5 on macrophages for a productive infection.[1]

Trofile assay

The Trofile assay is a blood test that identifies the tropism of a patient's HIV.^[3] A molecular assay, Trofile was developed by Monogram Biosciences for use in HIV treatment. The assay's purpose is to identify the tropism of an individual patient's HIV strain – R5, X4, or a combination of these known as dual/mixed (D/M). The results show whether the patient is infected with virus that enters cells using the R5 co-receptor, the X4 co-receptor, or both (dual/mixed). Patients with strains of HIV that prefer the R5 receptor tend to remain healthy longer than those with the strains that prefer X4. However, over the course of the disease, a patient's viral population may undergo a "tropism switch" from R5 to X4.

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