Paxton H, Pins M, Denton G, McGonigle A D, Meisner P S, Phair J P
Department of Flow Cytometry, Maryland Medical Metpath, Baltimore.
Clin Diagn Lab Immunol. 1995 Jan;2(1):104-14. doi: 10.1128/cdli.2.1.104-114.1995.
Measurement of CD4 T-lymphocyte levels is clinically useful in monitoring immune status in a number of conditions, including human immunodeficiency virus (HIV) infection, in which the absolute CD4 count is used to guide therapy. The absolute CD4 count is obtained by multiplying the results of the leukocyte count and the differential with a hematology cell counter and the percentage of CD4+ T lymphocytes determined by flow cytometry. These techniques require expensive, complex instrumentation, and interlaboratory results are difficult to standardize and reproduce. The rapid growth of HIV infection worldwide has increased the need for more-reproducible and cost-effective methods for CD4 T-cell monitoring. The TRAx CD4 test kit is based on a novel adaptation of conventional enzyme-linked immunosorbent assay (ELISA) and permits the simple quantitation of total CD4 protein from whole-blood lysates. In this study, the relationship between total CD4 protein measured in units per milliliter (TRAx) and in cells per microliter (flow cytometry and hematology) was defined in a multisite clinical study using linear regression analysis. Data from 230 HIV-seronegative and 321 HIV-seropositive specimens were used to calibrate the TRAx assay recombinant CD4 standards and controls in equivalent CD4 T lymphocytes per microliter (cells per microliter). The calibration of the TRAx CD4 assay in cells per microliter was validated with a second group of specimens from 17 healthy volunteers and 20 HIV-seropositive patients which were collected and tested under strictly controlled conditions intended to minimize the effects of specimen aging on the results of the reference method. These data were also used to estimate the variability of absolute CD4 count by cytometric methods as well as the precision of the TRAx CD4 result after it was calibrated in cells per microliter. Overall, correlations between the two methods ranged from 0.87 to 0.95. Additional studies demonstrated that the contribution of CD4 protein from monocytes and any soluble CD4 in sera are negligible in the TRAx assay and do not significantly affect results. This new method represents a promising alternative to absolute CD4 T-cell enumeration by flow cytometry and hematology.
在包括人类免疫缺陷病毒（HIV）感染在内的多种病症中，测量CD4 T淋巴细胞水平对于监测免疫状态具有临床实用价值，在HIV感染中，CD4绝对计数用于指导治疗。CD4绝对计数是通过用血液学细胞计数器将白细胞计数结果和分类计数结果相乘，并通过流式细胞术确定CD4 + T淋巴细胞的百分比而获得的。这些技术需要昂贵、复杂的仪器，而且实验室间的结果难以标准化和重现。全球HIV感染的快速增长增加了对更具可重复性和成本效益的CD4 T细胞监测方法的需求。TRAx CD4检测试剂盒基于对传统酶联免疫吸附测定（ELISA）的一种新型改良，可对全血裂解物中的总CD4蛋白进行简单定量。在本研究中，通过线性回归分析在一项多中心临床研究中确定了以每毫升单位（TRAx）测量的总CD4蛋白与每微升细胞数（流式细胞术和血液学方法）之间的关系。来自230份HIV血清阴性和321份HIV血清阳性标本的数据用于校准TRAx检测的重组CD4标准品和对照品，使其等同于每微升CD4 T淋巴细胞数（每微升细胞数）。用来自17名健康志愿者和20名HIV血清阳性患者的第二组标本对TRAx CD4检测以每微升细胞数进行校准，这些标本是在严格控制的条件下收集和检测的，目的是尽量减少标本老化对参考方法结果的影响。这些数据还用于估计通过细胞计数法测定的CD4绝对计数的变异性以及TRAx CD4结果在以每微升细胞数校准后的精密度。总体而言，两种方法之间的相关性范围为0.87至0.95。其他研究表明，在TRAx检测中，单核细胞的CD4蛋白以及血清中任何可溶性CD4的贡献可忽略不计，并且不会显著影响结果。这种新方法是通过流式细胞术和血液学方法进行CD4 T细胞绝对计数的一种有前景的替代方法。
