Méthodes d'analyse et de suivi de l'infection par les virus de l'immunodéficience humaine

The screening of HIV infection aims both to detect the presence of antibodies to HIV-I and HIV-2 in serum/plasma by ELISA, as well as, the presence of the viral antigen p24 by a combined ELISA of the fourth generation, or in some cases by fast screening tests (TDRs) on whole blood or serum/plasma. Analysis of positive serological screening must always be confirmed by a western-blot method. Infection by HIV-1 is established only when the result of the confirmation analysis is positive and when the same results are obtained for two different samples (HAS, 2008). The biological follow-up of the patients infected by HIV is based on the determination of the viral load in plasma (threshold of 40 copies/ml; therapeutic objectives < 50 copies/ml) and the levels of CD4+ lymphocytes in the peripheral blood (therapeutic objective CD4+ > 500/mm3). The performing of genotypic tests of resistance to anti-retrovirals drugs by RT-PCR and nucleotidic sequencing of certain parts of HIV genome is particularly recommended during the primary infection, before the initiation of the treatment, in case of therapeutic failure and in the follow-up and the treatment of infected pregnant women. The objective of these methods of analysis and follow-up of the HIV infection is to detect and treat the infected persons in order to decrease the morbi-mortality during this chronic viral infection.