HIV diagnosis and antiretroviral therapy

The laboratory diagnosis of HIV infection originally involved detection of HIV antibody using viral lysate-based assays. Over 20 years have passed since the introduction of these tests and many advances have been made including the incorporation of recombinant antigens, with or without synthetic peptide antigens, that have improved assay specificity and sensitivity; the combination of HIV antibody and p24 antigen as a single text; the development of automated platforms; HIV-1 RNA quantification assays that can be used in the diagnosis of a primary HIV infection as well as to monitor treatment response; rapid point-of-care tests that have made an impact on ease of access of tests; and using a detuned assay or avidity testing to estimate the incidence of HIV infection. Four classes of highly active antiretroviral therapy are available, namely the nucleoside/tide reverse transcriptase (RT) inhibitors, the non-nucleoside RT inhibitors, protease inhibitors and, more recently, the fusion inhibitor enfuvirtide. In addition, approval is expected for two new classes, the integrase inhibitor raltegravir, and the CCR 5 antagonist maraviroc. However, drug resistance remains a major limitation of antiviral efficacy; the incidence of resistance is estimated at around 30% after 6 years of first-line treatment.