title: Validation of a single-platform, volumetric, CD45-assisted PanLeucogating Auto40 flow cytometer to determine the absolute number and percentages of CD4 T cells in resource-constrained settings using Cameroonian patients' samples.
abstract: The study evaluated the single-platform, volumetric, CD45-assisted PanLeucogating Auto40 flow cytometer (Apogee Flow Systems Ltd., Hemel Hempstead, United Kingdom) for CD4 T cell numeration, compared to the reference FACSCalibur flow cytometer. Results of absolute counts and percentages of CD4 T cells by Auto40 and FACSCalibur of 234 tripotassium EDTA (K3-EDTA)-blood samples from 146 adults and 88 children (aged from 18 months to 5 years), living in Yaoundé, Cameroon, were highly correlated (r(2) = 0.97 and r(2) = 0.98, respectively). The mean absolute bias and relative bias between Apogee Auto40 and FACSCalibur absolute CD4 T cell counts were +9.6 cells/μl, with limits of agreement from -251 to 270 cells/μl, and +4.1%, with limits of agreement from -16.1 to 24.4%, respectively. The mean absolute bias and relative bias between Apogee Auto40 and FACSCalibur CD4 T cell results expressed as percentages were +0.05% CD4 (95% confidence interval [CI], -0.03 to 0.41), with limits of agreement from -6.0 to 5.9% CD4, and +1.0%, with limits of agreement from -32.3 to 34.4%, respectively. The Auto40 counting allowed identification of the majority of adults with CD4 T cell counts below 200 cells/μl (sensitivity, 87%; specificity, 98%) or below 350 cells/μl (sensitivity, 92%; specificity, 98%) and of children with CD4 T cell counts below 750 cells/μl (sensitivity, 82%; specificity, 98%) or below 25% CD4(+) (sensitivity, 96%; specificity, 99%). The Auto40 analyzer is a reliable alternative flow cytometer for CD4 T lymphocyte enumeration to be used in routine immunological monitoring according to the WHO recommendations for HIV-infected adults as well as children living in resource-constrained settings.
authors.affiliation: Laboratoire National de Santé Hygiène Mobile, Ministère de Santé Publique, Yaoundé, Cameroon, and Faculté de Médecine et des Sciences Biomédicales, Université de Yaoundé I, Yaoundé, Cameroon. fxmkeou@hotmail.com
authors.forename: François-Xavier
authors.initials: FX
authors.lastname: Mbopi-Kéou
authors.forename: Stefano
authors.initials: S
authors.lastname: Mion
authors.forename: Bertrand
authors.initials: B
authors.lastname: Sagnia
authors.forename: Laurent
authors.initials: L
authors.lastname: Bélec
mesh_terms: D000328:Adult; D018791:CD4 Lymphocyte Count / Q000379:methods; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002163:Cameroon; D002675:Child, Preschool; D019411:Clinical Laboratory Techniques / Q000379:methods*; D003906:Developing Countries; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D015658:HIV Infections / Q000276:immunology*; D006801:Humans; D007223:Infant; D017493:Leukocyte Common Antigens / Q000032:analysis*; D008297:Male; D012680:Sensitivity and Specificity
chemical_list: D017493:Leukocyte Common Antigens; C516769:PTPRC protein, human