Time between seroconversion (SC) and AIDS among participants in the Amsterdam Cohort Studies on HIV infection and AIDS with or without CXCR4-using variants detected prior to AIDS diagnosis. All homosexual and drug-user participants with AIDS diagnosis according to the 1993 CDC definition prior to initiation of effective antiretroviral therapy were included in the analysis. Participants were divided into 2 groups based on the presence (X4, closed circles) or absence (R5, open circles) of CXCR4-using HIV-1 variants as detected by the MT-2 assay prior to AIDS diagnosis. Time between SC and AIDS was categorized in 12-monthly intervals. The graph shows the proportion of participants per category as a percentage of the total number of participants in the group.