Department of Molecular Medicine, School of Medical Sciences, College of Health Sciences, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana.
BMC Infect Dis. 2012 Jun 7;12:128. doi: 10.1186/1471-2334-12-128.
CD4 testing is the recognized gold standard used to stage HIV/AIDS, guide treatment decisions for HIV-infected persons and evaluate effectiveness of therapy. The need for a less expensive surrogate marker that can be used in resource-limited setting is however necessary. The study sought to assess the suitability of Total lymphocyte count (TLC) as a surrogate marker for CD4 count in resource-limited localities in Ghana.
This observational study was conducted at the Central Regional Hospital, which has one of the established antiretroviral therapy centres in Ghana. A total of one hundred and eighty-four (184) confirmed HIV I seropositive subjects were included in the study. Blood samples were taken from all the subjects for estimation of CD4 and total lymphocyte counts. The study subjects were further categorised into three (3) groups according to the Centers for Disease Control and Prevention (CDC) classification criteria as follows: CD4 counts (1) ≥ 500 cells/mm3 (2) 200-499 cells/mm3 and (3) <200 cells/mm3. Positive predictive value (PPV), negative predictive value (NPV), sensitivity and specificity of various TLC cut-offs were computed for three groups. Correlation and Receiver Operator Characteristic analysis was performed for the various CD4 counts and their corresponding Total Lymphocyte count obtained.
The sensitivity, specificity, positive and negative predictive values of TLC 1200 cells/ mm3 to predict CD4 count were <200 cells/mm3 72.2%, 100%, 100% and 95.7% respectively. A TLC of 1500 cells/ mm3 was found to have maximal sensitivity (96.67%), specificity (100%), PPV (100%) and NPV (75.0%) for predicting a CD4 cell count of 200-499 cell/mm3. A TLC of 1900 cells/mm3 was also found to have a maximal sensitivity (98.45%), specificity (100%), PPV (100%) and NPV (100%) for predicting CD4 count ≥500 cells/mm3. A positive correlation was noted between 184 paired CD4 and TLC counts (r = 0.5728).
Total Lymphocyte count can therefore adequately serve as a surrogate marker for CD4 count in HIV patients who are naïve for antiretroviral therapy in resource-limited areas.
CD4 检测是用于分期 HIV/AIDS、指导 HIV 感染者治疗决策以及评估治疗效果的公认金标准。然而，在资源有限的地区，需要一种更经济的替代标志物。本研究旨在评估总淋巴细胞计数（TLC）作为资源有限地区 CD4 计数替代标志物的适用性。
本观察性研究在加纳的一个已建立的抗逆转录病毒治疗中心之一的中央地区医院进行。共有 184 名确认为 HIV I 血清阳性的受试者纳入本研究。从所有受试者中抽取血液样本，用于估计 CD4 和总淋巴细胞计数。根据疾病控制和预防中心（CDC）分类标准，将研究对象进一步分为三组：（1）CD4 计数≥500 个细胞/mm3；（2）200-499 个细胞/mm3；（3）<200 个细胞/mm3。计算了各种 TLC 截断值在三组中的阳性预测值（PPV）、阴性预测值（NPV）、灵敏度和特异性。对各种 CD4 计数及其对应的总淋巴细胞计数进行了相关性和接收者操作特征分析。
TLC<1200 个细胞/mm3 预测 CD4 计数<200 个细胞/mm3 的灵敏度、特异性、阳性预测值和阴性预测值分别为 72.2%、100%、100%和 95.7%。TLC 为 1500 个细胞/mm3 时，预测 CD4 计数为 200-499 个细胞/mm3 的灵敏度（96.67%）、特异性（100%）、PPV（100%）和 NPV（75.0%）最高。TLC 为 1900 个细胞/mm3 时，预测 CD4 计数≥500 个细胞/mm3 的灵敏度（98.45%）、特异性（100%）、PPV（100%）和 NPV（100%）最高。184 对 CD4 和 TLC 计数之间存在正相关（r=0.5728）。
因此，在资源有限的地区，对于未接受抗逆转录病毒治疗的 HIV 患者，总淋巴细胞计数可作为 CD4 计数的替代标志物。
