Target cell populations of human immunodeficiency virus type 1 in peripheral blood lymphocytes with different chemokine receptors at various stages of disease progression

We studied the distribution of human immunodeficiency virus type 1 (HIV-1) DNA in CCR5-positive and -negative peripheral blood lymphocyte populations in HIV-l-infected individuals. While HIV-1 DNA in the CCR5-positive population showed no correlation with CD4 count, the increase of total HIV-1 DNA with lower CD4 count was mainly contributed by the increase of HIV-1 DNA in the CCR5-negative population. This might indicate the change in coreceptor usage from CCR5 to CXCR4 in later stages of disease progression, However, some of the samples with a high viral DNA load in the CCR5-negative population did not have any characteristic of the V3 loop sequence that is compatible with CXCR4 usage or the syncytium inducing (SI) phenotype. We also did not find any known characteristic change predictive of the SI phenotype in V1 and V2 sequences. Our findings showed that there might be a shift in target cell populations during disease progression, and this shift was not necessarily associated with the genetic changes characteristic of CXCR4 usage.