Field evaluation in Chad of community usage of CD4 T lymphocyte counting by alternative single-platform flow cytometry.

BACKGROUND: Field and community evaluation of the routine usage of CD4 T counting platforms is essential in resource-poor countries for efficient and cost-effective monitoring of HIV-infected adults and children attending health care centers. METHODS: We herein addressed the principal issues raised by the implementation of the single-platform, volumetric Auto40 flow cytometer (Apogee Flow Systems Ltd, Hemel Hempstead, UK) in 8 community HIV monitoring laboratories of different levels throughout Chad. This is a country with particularly difficult conditions, both in terms of climate and vast geographical territory, making the decentralization of the therapeutic management of HIV-infected patients challenging. RESULTS: The routine usage of the Auto40 flow cytometers for a period of 5 years (2008-2013) confirms the reliability and robustness of the analyzer for community-based CD4 T cell enumeration in terms of both absolute numbers and percentages to enable accurate monitoring of HIV-infected adults and children. However, our observations suggest that the Auto40 mini flow cytometer is not suitable for all laboratories as it is oversized and ultimately very expensive. CONCLUSION: The Chad experience with the Auto40 flow cytometer suggests that its usage in resource-limited settings should be mainly reserved to reference (level 1) or district (level 2) laboratories, rather than to laboratories of health care centres (level 3).

Single-platform, volumetric, CD45-assisted pan-leucogating flow cytometry for CD4 T lymphocytes monitoring of HIV infection according to the WHO recommendations for resource-constrained settings.

BACKGROUND: Validation of new affordable CD4 T cell measurement technologies is crucial specifically in resource-poor countries for antiretroviral treatment eligibility and immunologic CD4 monitoring of HIV-infected patients. METHODS: The absolute and percentage CD4 T cell counts of 258 HIV-1-infected blood samples (182 adults and 76 children), living in N'Djamena, Chad, were performed by single-platform, volumetric, CD45-assisted pan-leucogating Auto40 flow cytometer (Apogee Flow Systems Ltd, Hemel Hempstead, UK) comparing to the FACSCalibur flow cytometer as a reference method. RESULTS: Absolute and percentage CD4 T cell counts obtained by Auto40 and FACSCalibur of 258 HIV-1-infected blood samples were highly correlated (r = 0.99 and r = 0.96, respectively). The mean absolute bias and percent bias between Apogee Auto40 and FACSCalibur absolute CD4 T cell counts, were -9.4 cells/µl with limits of agreement from -15 to 93 cells/µl, and +2.0% with limits of agreement from -0.9 to 4.9%, respectively. The mean of absolute bias and percent bias between Apogee Auto40 and FACSCalibur of CD4 percentage results were +0.4% (95% CI: -0.02 - 0.86) with limits of agreement from -2.4 to 0.3%, and +3.0% with limits of agreement from -6.6 to 0.6%, respectively. The Auto40 counting allowed to identify the majority of adults with CD4 T cells below 200 cells/µl (sensitivity: 89%; specificity: 99%) or below 350 cells/µl (sensitivity: 94%; specificity:98%); and of children below 750 cells/µl (sensitivity: 99%; specificity: 96%) or below 25% CD4+ (sensitivity: 94%; specificity: 98%). CONCLUSION: The Auto40 analyzer is an alternative flow cytometer for CD4 T lymphocyte enumeration to be used in routine for immunological monitoring according to the current WHO recommendations in HIV-infected adults as well as children living in resource-constrained settings like Chad.

High frequency of antiretroviral drug resistance among HIV-infected adults receiving first-line highly active antiretroviral therapy in N'Djamena, Chad.

Antiretroviral drug resistance was evaluated in 88 adults infected with human immunodeficiency virus, most with subtype CRF11_cpx, who had received a first-line antiretroviral regimen for 6 months, in N'Djamena, Chad. A total of 47 patients (53%) had detectable viral load at month 6, and 56 (64%) had at least 1 antiretroviral resistance mutation observed.