The diversity of human immunodeficiency virus type 1 (HIV-1)
has given rise to multiple subtypes and recombinant strains.
The majority of research into antiretroviral agents and drug
resistance has been performed on subtype B viruses, yet nonsubtype
B strains are responsible for 90% of global infections.
Although it seems that combination antiretroviral regimens are
effective against all HIV-1 subtypes, there is emerging evidence
of subtype differences in drug resistance, relevant to
antiretroviral strategies in different parts of the world. For this
purpose, extensive sampling of HIV genetic diversity, curation
and analyses are required to inform antiretroviral strategies in
different parts of the world.
Summary of main concepts:
- HIV-1 diversity has given rise to numerous subtypes and recombinant forms.
- New subtyping tools (e.g. Rega HIV-1 Subtyping Tool version 3, SCUEL and COMET) can accurately identify the most important HIV-1 variants.
- National and international public drug resistance databases are useful resources to trace the evolution of drug resistance in different subtypes.
- HIV-1 subtype genetic variation can influence the development of drug resistance and the susceptibility to certain antiretroviral drugs.
- K65R is an example of a clinically relevant mutation that emerges more frequently and more rapidly in subtype C viruses compared to subtype B; this has been shown to be related to the different template nucleotide sequence.
- Evidence from recent clinical trials and cohort studies suggests that response to combination antiretroviral regimens does not differ substantially by HIV-1 subtype.
- Appreciation of subtype differences is important in the development of new drugs and in the formulation of antiretroviral strategies.