Abstract
BackgroundCD4+ T-lymphocyte count (CD4 count) is a standard method used to monitor HIV-infected patients during anti-retroviral therapy (ART). The World Health Organization (WHO) has pointed out or recommended that a handheld, point-of-care, reliable, and affordable CD4 count platform is urgently needed in resource-scarce settings.MethodsHIV-infected patient blood samples were tested at the point-of-care using a portable and label-free microchip CD4 count platform that we have developed. A total of 130 HIV-infected patient samples were collected that included 16 de-identified left over blood samples from Brigham and Women's Hospital (BWH), and 114 left over samples from Muhimbili University of Health and Allied Sciences (MUHAS) enrolled in the HIV and AIDS care and treatment centers in the City of Dar es Salaam, Tanzania. The two data groups from BWH and MUHAS were analyzed and compared to the commonly accepted CD4 count reference method (FACSCalibur system).ResultsThe portable, battery operated and microscope-free microchip platform developed in our laboratory (BWH) showed significant correlation in CD4 counts compared with FACSCalibur system both at BWH (r = 0.94, p<0.01) and MUHAS (r = 0.49, p<0.01), which was supported by the Bland-Altman methods comparison analysis. The device rapidly produced CD4 count within 10 minutes using an in-house developed automated cell counting program.ConclusionsWe obtained CD4 counts of HIV-infected patients using a portable platform which is an inexpensive (<$1 material cost) and disposable microchip that uses whole blood sample (<10 µl) without any pre-processing. The system operates without the need for antibody-based fluorescent labeling and expensive fluorescent illumination and microscope setup. This portable CD4 count platform displays agreement with the FACSCalibur results and has the potential to expand access to HIV and AIDS monitoring using fingerprick volume of whole blood and helping people who suffer from HIV and AIDS in resource-limited settings.
Highlights
More than 30 million human immunodeficiency virus (HIV)infected people live in the sub Saharan Africa, yet it is estimated that only one in ten persons infected with HIV has been tested and knows their HIV status [1,2,3,4,5,6,7]
When the microchips were transported to Tanzania over 48 hours on dry ice in a plane setting, the correlation coefficient between the microchip and the FACSCalibur system counts were statistically significant, with a lower correlation coefficient for the measurements that were performed at Muhimbili University of Health and Allied Sciences (MUHAS) laboratory (Fig. 4b, correlation coefficient: 0.49, p,0.01)
The mean bias was +76 cells/mL of blood in microchip counts compared to fluorescent activated cell count and sorting systems (FACS) counts at Brigham and Women’s Hospital (BWH)
Summary
More than 30 million human immunodeficiency virus (HIV)infected people live in the sub Saharan Africa, yet it is estimated that only one in ten persons infected with HIV has been tested and knows their HIV status [1,2,3,4,5,6,7]. The current gold standard methodology for measuring CD4+ Tlymphocyte counts in whole blood is the fluorescent activated cell count and sorting systems (FACS) [3,10,13]. These systems face significant challenges in terms of scalability and applicability including high equipment cost, requirement for laboratory space, inadequate number of trained laboratory personnel, lack of reliable and regular preventive maintenance service and limited portability. The World Health Organization (WHO) has pointed out or recommended that a handheld, point-of-care, reliable, and affordable CD4 count platform is urgently needed in resource-scarce settings
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