A single platform image cytometer for resource-poor settings to monitor disease progression in HIV infection.
BACKGROUND
For resource-poor countries, affordable methods are required for enumeration of CD4(+) T lymphocytes of HIV-positive patients. For infants, additional determination of CD4/CD8 ratio is needed.


METHODS
We determine the CD4(+) and CD8(+) T lymphocytes as the CD3(+)CD4(+) and CD3(+)CD8(+) population of blood cells. Target cells are CD3-immunomagnetically separated from the whole blood, and CD4-Phycoerythrin and CD8-PerCP immunofluorescently labeled. A point-of-care single platform image cytometer was developed to enumerate the target CD3(+)CD4(+) and CD3(+)CD8(+) populations. It has light-emitting diodes illumination, is fully computer-controlled, operates from a 12 V battery, and was designed to be cheap and easy-to-handle. Target cells are imaged on a CCD camera and enumerated by an image analysis algorithm. The cytometer outputs the absolute number of CD4(+) and CD8(+) T lymphocytes/microl and CD4/CD8 ratio.


RESULTS
The quality of the cell images obtained with the cytometer is sufficient for a reliable enumeration of target cells. The image cytometer achieves an accuracy of better than 10% in the range of 50-1700 cells/microl. Analysis of blood samples from HIV patients yields a good agreement with the TruCount method for CD4 and CD8 count and CD4/CD8 ratio.


CONCLUSIONS
The image cytometer is affordable (component costs $3,000), compact (25 x 25 x 20 cm(3)), and uses disposable test materials, making it a good candidate to monitor progression of immunodeficiency disease in resource-poor settings.
Ymeti
Aurel
A
Biophysical Engineering Group, MESA+ Institute for Nanotechnology and Biomedical Technology Institute, Faculty of Science and Technology, University of Twente, 7500 AE Enschede, The Netherlands. A.Ymeti@utwente.nl
Li
Xiao
X
Lunter
Björn
B
Breukers
Christian
C
Tibbe
Arjan G J
AG
Terstappen
Leon W M M
LW
Greve
Jan
J
D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D018450:Disease Progression; D015658:HIV Infections / Q000175:diagnosis*; D015497:HIV-1 / Q000276:immunology / Q000378:metabolism; D006801:Humans; D019044:Image Cytometry / Q000295:instrumentation* / Q000379:methods