[Virological diagnosis and follow-up of HIV infection. State of the art and situation in Tunisia].

Human immunodeficiency virus (HIV) is a retrovirus infecting approximatively 40 million people worldwide. HIV is characterized by a great variability with epidemiological, diagnostic and therapeutic implications. The course of infection goes through three stages (acute infection, clinical latency and AIDS) with the evolution of virological markers (anti-HIV antibodies, p24 antigenemia, plasma RNA and proviral DNA). Direct virological diagnosis is mainly based on molecular tools allowing viral genome detection and amplification with specific primers and nucleic probes besides p24 antigenemia detection, and more rarely viral culture. Antigenic properties of viral proteins elicit in infected patients antibody synthesis, which is detected using serology (ELISA and Western blot tests). The follow-up of infected patients is carried out with plasma HIV-1 RNA quantitation and phenotypic or genotypic characterization of variant isolates. Virological tests are prescribed according to clinical presentation (screening, acute infection, newborn from HIV-infected mother). Most of these virological tools are available in Tunisia, allowing both diagnosis of HIV infection and monitoring of infected individuals. Regarding diagnostic tests indication and interpretation, multidisciplinary concertation is hopeful in order to optimize patient management.