CD4 and CD8 enumeration for HIV monitoring in resource‐constrained settings

Background: We developed a volumetric single platform image cytometer (SP ICM) that is dedicated to count CD4+ and CD8+ T lymphocytes for HIV monitoring in resource‐constrained settings. The instrument was designed to be low‐cost, yet reliable, easy‐to‐use, and robust. Methods: Whole blood is incubated with CD3‐magnetic nanoparticles, CD4‐phycoerythrin (PE), and CD8‐peridinin‐chlorophyll‐protein complex (PerCP). The CD3 cells are immunomagnetically attracted to an analysis surface, where fluorescence images of CD4+ and CD8+ T lymphocytes are recorded and analyzed, respectively. We compared CD4, CD8 counts, and CD4/CD8 ratio obtained by the SP ICM with those from a SP flow cytometer (FCM) tetraCXP method on blood samples from 145 patients. Results: Good correlations were obtained (R: 0.96–0.99) between the SP ICM and the SP FCM. There was ∼10% CD8 undercount in the SP ICM, which could be partly caused by CD8+dim T lymphocytes that were not detected by the instrument or not counted by the image analysis due to the cross‐talk from the CD4‐PE signal in the CD8‐PerCP image. Conclusions: The SP ICM is a good candidate for HIV monitoring in point‐of‐care settings of resource‐constrained countries. © 2008 Clinical Cytometry Society