Correlation between circulating stromal cell-derived factor 1 levels and CD4 super(+) cell count in human immunodeficiency virus type 1-infected individuals

Stromal cell-derived factor 1 (SDF-1) is the natural ligand that recognizes CXCR4, which also serves as a coreceptor for some strains of HIV-1. In this study, we explored SDF-1 blood levels among HIV-1-infected individuals exhibiting a wide range of CD4 super(+) cell counts. Plasma or serum concentrations of SDF-1 protein were measured by ELISA in samples from 31 HIV-1-seronegative individuals and 79 HIV-1-infected subjects. Although SDF-1 protein levels were stable for months among seronegative individuals (mean intrasubject variation, 17%), the absolute values varied widely (0.28 to 106.5 ng/ml; mean, 25.6 ng/ml). In HIV-1-infected subjects, there was a direct correlation between SDF-1 level and CD4 super(+) cell count. Subjects with fewer than 50 CD4 super(+) cells per cubic microliter of blood had significantly lower mean SDF-1 levels ( plus or minus SD) than did either HIV-1-infected subjects with higher CD4 super(+) cell counts or uninfected controls: CD4 super(+) cell count