Low-cost enumeration of CD4+ T cells using a density-based negative selection method (RosetteSep) for the monitoring of HIV-infected individuals in non-OECD countries.

The CD4 count is the best surrogate marker for monitoring HIV. The reference method for assessing CD4 counts (flow cytometry, FCM), as expensive technique, is not widely used in non-OECD countries. To make HIV-monitoring available to more patients in these countries, we modified a commercially available density-based negative selection assay (RosetteSep) to make it applicable for low-cost cell enumeration.