[Diagnosis of HIV-1 non-B subtypes and HIV-2]

The high genetic diversity of human immunodeficiency virus (HIV) poses a significant challenge to the diagnosis and microbiological characterization of HIV infection. Because of the continual emergence of new variants and the global spread of HIV groups, subtypes and recombinant forms, accurate diagnostic tools are of prime importance. The present review analyzes the problems posed by HIV assays for antibody screening, nucleic acid testing and patient monitoring in HIV-1 non-B subtypes, as well as the utility of some recently introduced genetic algorithms, such as those proposed for the characterization of viral tropism. Overall, the reliability of serological and molecular tests for HIV-1 strains is high, except for the more genetically diverse HIV variants (HIV-1 group O, N, and HIV-2). In contrast, genetic algorithms show acceptable accuracy for HIV-1 subtype B, but are less accurate for non-B subtypes. In conclusion, the ongoing evolution of HIV requires constant monitoring of the performance of screening tests and provides a stimulus to the development of molecular assays to detect all spreading and emerging HIV variants. The availability of both in vitro and clinical data from studies of HIV-1 non-B subtypes will improve the performance of bioinformatics tools.