Pattanapanyasat Kovit, Thakar Madhuri R
Center of Excellence for Flow Cytometry, Office for Research & Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
Indian J Med Res. 2005 Apr;121(4):539-49.
The CD4+ T lymphocytes are the crucial cells in the orchestral events in forming immune response to the foreign antigen and it is also the primary target cells for human immunodeficiency virus (HIV). The progressive loss of these cells eventually results in the loss of an ability to mount desirable immune response to any pathogen and death of the patients in the terminal stage of HIV infection, i.e., acquired immune deficiency syndrome (AIDS). The longitudinal monitoring of CD4+ counts is used as a monitoring tool for disease progression and effectiveness of antiretroviral treatment. Various methods are being used for determination of absolute CD4+ T lymphocytes from the peripheral blood. To date, the flow cytometry is considered as the gold standard. Different modifications have been tried in the conventional flow cytometry to increase accuracy and cost-effectivity especially for adapting in resource-poor settings. Principles of the conventional and modified methodologies are discussed. The non-flow cytometric methodologies are also there that might be available soon widely. The choice of the methodology should depend upon the purpose of the assay, the age group of the patients, sample turnover and available resources. Importance of maintaining both internal and external quality control systems in every laboratory performing CD4 count estimation are discussed.
CD4+ T淋巴细胞是对外源抗原形成免疫应答的一系列协调事件中的关键细胞，也是人类免疫缺陷病毒（HIV）的主要靶细胞。这些细胞的逐渐丧失最终导致无法对任何病原体产生理想的免疫应答，并在HIV感染末期即获得性免疫缺陷综合征（AIDS）患者中导致死亡。CD4+细胞计数的纵向监测被用作疾病进展和抗逆转录病毒治疗效果的监测工具。目前有多种方法用于测定外周血中CD4+ T淋巴细胞的绝对数量。迄今为止，流式细胞术被认为是金标准。人们在传统流式细胞术中尝试了不同的改进方法，以提高准确性和成本效益，特别是为了适应资源匮乏的环境。文中讨论了传统方法和改进方法的原理。也存在一些非流式细胞术方法，可能很快会得到广泛应用。方法的选择应取决于检测目的、患者年龄组、样本周转情况和可用资源。文中还讨论了在每个进行CD4计数估计的实验室中维持内部和外部质量控制系统的重要性。
