What is the pathophysiology of HIV infection?

Updated: Sep 19, 2018
  • Author: David J Cennimo, MD, FAAP, FACP, AAHIVS; Chief Editor: Michael Stuart Bronze, MD  more...
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Human immunodeficiency virus (HIV)–1 is a member of the Retroviridae family. It is an enveloped virus with two copies of single-stranded RNA, which have capacity to recombine. The genome contains 3 major genes that encode structural proteins: gag, pol, and env. [8, 9] The gag gene encodes for p24, p17, and p7, among others. The env gene encodes for glycoprotein (gp) 120 and gp 41. The pol gene encodes the enzymes reverse transcriptase, integrase, and protease. HIV-1 also has regulatory genes (tat and rev) and genes that encode for accessory proteins (vpu, vpr, vif, and nef) that are important in viral replication and interaction with the host. HIV-2 shares the same genes with HIV-1 with the exception of vpu.

HIV-1 is divided into several groups [10] based on phylogenetic analysis: M (main), O (outlier), N (not M and not O), and the most recently identified P group, [11] named according to nomenclature guidelines. [12] Group M comprises several clades: A to D, F to H, J, K, and several circulating recombinant forms (CRFs). Subtype B is the most common clade in the United States. Although there is a difference in transmission rates, disease progression, response to antiretroviral therapy, and emergence of resistance to therapy among HIV groups and clades, [13, 14, 15] the most recent enzyme immunoassays are able to detect non-B subtypes. [16]

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