Lutwama Fred, Serwadda Ronnie, Mayanja-Kizza Harriet, Shihab Hasan M, Ronald Allan, Kamya Moses R, Thomas David, Johnson Elizabeth, Quinn Thomas C, Moore Richard D, Spacek Lisa A
Academic Alliance for AIDS Care and Prevention and the Infectious Diseases Institute, Kampala, Uganda.
J Acquir Immune Defic Syndr. 2008 Jul 1;48(3):297-303. doi: 10.1097/QAI.0b013e31817bbc3a.
Laboratory-based monitoring of antiretroviral therapy is essential but adds a significant cost to HIV care. The World Health Organization 2006 guidelines support the use of CD4 lymphocyte count (CD4) to define treatment failure in resource-limited settings.
We compared CD4 obtained on replicate samples from 497 HIV-positive Ugandans (before and during ART) followed for 18 months by 2 manual bead-based assays, Dynabeads (Dynal Biotech), and Cytospheres (Beckman Coulter) with those generated by flow cytometry at the Infectious Diseases Institute in Kampala, Uganda.
We tested 1671 samples (123 before ART) with Dynabeads and 1444 samples (91 before ART) with Cytospheres. Mean CD4 was 231 cells/mm (SD, 139) and 239 cells/mm (SD, 140) by Dynabeads and flow cytometry, respectively. Mean CD4 was 186 cells/mm (SD, 101) and 242 cells/mm (SD, 136) by Cytospheres and flow cytometry, respectively. The mean difference in CD4 count by flow cytometry versus Dynabeads were 8.8 cells/mm (SD, 76.0) and versus Cytospheres were 56.8 cells/mm (SD, 85.8). The limits of agreement were -140.9 to 158.4 cells/mm for Dynabeads and -112.2 to 225.8 cells/mm for Cytospheres. Linear regression analysis showed higher correlation between flow cytometry and Dynabeads (r=0.85, r=0.73, slope=0.85, intercept=28) compared with the correlation between flow cytometry and Cytospheres (r=0.78, r=0.60, slope=0.58, intercept=45). Area under the receiver operating characteristics curve to predict CD4<200 cells/mm was 0.928 for Dynabeads and 0.886 for Cytospheres.
Although Dynabeads and Cytospheres both underestimated CD4 lymphocyte count compared with flow cytometry, in resource-limited settings with low daily throughput, manual bead-based assays may provide a less expensive alternative to flow cytometry.
基于实验室的抗逆转录病毒治疗监测至关重要，但会给艾滋病护理增加显著成本。世界卫生组织2006年指南支持在资源有限的环境中使用CD4淋巴细胞计数（CD4）来定义治疗失败。
我们比较了497名乌干达艾滋病毒阳性患者（接受抗逆转录病毒治疗之前和期间）重复样本中通过两种基于磁珠的手工检测方法（Dynabeads，Dynal Biotech公司；Cytospheres，贝克曼库尔特公司）获得的CD4结果，以及在乌干达坎帕拉传染病研究所通过流式细胞术获得的结果。这些患者随访了18个月。
我们用Dynabeads检测了1671个样本（123个在抗逆转录病毒治疗前），用Cytospheres检测了1444个样本（91个在抗逆转录病毒治疗前）。通过Dynabeads和流式细胞术测得的平均CD4分别为231个细胞/mm³（标准差，139）和239个细胞/mm³（标准差，140）。通过Cytospheres和流式细胞术测得的平均CD4分别为186个细胞/mm³（标准差，101）和242个细胞/mm³（标准差，136）。流式细胞术与Dynabeads测得的CD4计数平均差值为8.8个细胞/mm³（标准差，76.0），与Cytospheres测得的平均差值为56.8个细胞/mm³（标准差，85.8）。Dynabeads的一致性界限为-140.9至158.4个细胞/mm³，Cytospheres的一致性界限为-112.2至225.8个细胞/mm³。线性回归分析显示，与流式细胞术和Cytospheres之间的相关性（r = 0.78，r = 0.60，斜率 = 0.58，截距 = 45）相比，流式细胞术与Dynabeads之间的相关性更高（r = 0.85，r = 0.73，斜率 = 0.85，截距 = 28）。预测CD4<200个细胞/mm³的受试者工作特征曲线下面积，Dynabeads为0.928，Cytospheres为0.886。
虽然与流式细胞术相比，Dynabeads和Cytospheres都低估了CD4淋巴细胞计数，但在每日通量较低的资源有限环境中，基于磁珠的手工检测方法可能为流式细胞术提供一种成本较低的替代方案。
