Hypersensitivity to abacavir, a nucleoside reverse-transcriptase inhibitor commonly used for anti-AIDS treatment, has been reported to be associated with an HLA-B allele (HLA-B*5701) and a haplo-typic Hsp70-Hom variant in the HLA region (Mallal et al. 2002; Martin et al. 2004). This evidence concerns the gene HLA-B and AIDS.