Improving The Sensitivity And Predictability Of Testing

提高测试的灵敏度和可预测性

• 批准号: 7007131
• 负责人: Dori R Germolec
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7007131
• 关键词: dosage; environmental toxicology; enzyme linked immunosorbent assay; flow cytometry; histopathology; immunosuppressive; immunotoxicity; laboratory mouse; lymphatic tissue; toxicant screening

The accuracy of extended histopathology to detect immunotoxic chemicals in female B6C3F1 mice was evaluated under the auspices of the National Toxicology Program (NTP). A workgroup was formed consisting of four pathologists that conducted extended histopathological evaluation of lymphoid tissues obtained from a subset of NTP toxicology studies, in which previously detailed immunotoxicity assessment was performed. In addition, a positive control data set of three known immunosuppressive agents, one negative control data set, and an additional negative control group composed of the vehicle only treated groups were included. Data obtained from extended histopathology evaluations were compared to more traditional immune test results (both functional and non-functional) from previously conducted immunotoxicity assessments. Analyses of the data indicated that the ability to identify immunotoxic chemicals using histological endpoints decreased linearly as the level of stringency used to determine significant histopathological changes increased. A relatively high (80 %) accuracy level was achieved when histological changes were considered in toto (i.e., any histological abnormality in the 3 tissues examined), using minimal or mild criteria for scoring. When minimal or mild histological changes were considered significant for a specific tissue, a 60% level of accuracy in identifying immunotoxic chemicals was obtained as compared to a 90% accuracy level that was achieved with this data set using the antibody plaque forming cell response, considered to represent the most predictive functional test. A minimal classification was obtained in the analyses of the negative control groups, suggesting that use of the minimal classification for hazard identification is inappropriate as it will likely result in a high incidence of false positives. This was not the case when mild classifications were used as an indicator of significance, which in most instances allowed the successful identification of negatives. When moderate to marked histopathological changes were used to identify immunotoxic chemicals, the level of accuracy that could be achieved was poor. A considerably higher level of accuracy was obtained for the positive control data set than the test chemical data set suggesting that the ability to detect an immunotoxic agent histologically is proportional to the potency of the immunotoxic agent. Comparison of immune function test results and histopathological results obtained from the high-dose treatment groups and the lower-dose treatment group did not reveal any significant differences between the two endpoints to predict immunotoxicity as a function of dose. Of the three lymphoid organs examined, (i.e., lymph node, thymus and spleen), the most consistent and discernible histological lesions were observed in the thymus cortical region. These lesions correlated with thymus: body weight ratios and to a slightly lesser extent, the antibody plaque forming cell response. Addition of general toxicological endpoints such as body weight and leukocyte counts did not significantly improve the sensitivity of extended histopathology for this data set. Taken together, these data suggest that, while not as sensitive as functional analyses, extended histopathology may provide a reasonable level of accuracy as a screening test to identify immunotoxic chemicals, provided the level of stringency used to score histological lesions are carefully considered to allow for detection of immunotoxic agents while limiting false positives

在国家毒理学计划（NTP）的主持下，评价了扩展组织病理学检测雌性B6C3F1小鼠中免疫毒性化学物质的准确性。成立了一个由四名病理学家组成的工作组，对从NTP毒理学研究子集中获得的淋巴组织进行扩展的组织病理学评价，其中进行了之前详细的免疫毒性评估。此外，还包括3种已知免疫抑制剂的阳性对照数据集、1个阴性对照数据集和由仅溶剂处理组组成的额外阴性对照组。将从扩展组织病理学评价中获得的数据与先前进行的免疫毒性评估中获得的更传统的免疫试验结果（功能性和非功能性）进行比较。数据分析表明，使用组织学终点识别免疫毒性化学物质的能力随着用于确定显著组织病理学变化的严格程度的增加而线性下降。当全部考虑组织学变化时（即，检查的3种组织中的任何组织学异常），使用最小或轻度标准进行评分。当最小或轻度的组织学变化被认为对特定组织有意义时，与使用抗体空斑形成细胞反应（被认为是最具预测性的功能试验）的该数据集达到的90%准确度水平相比，获得了60%的免疫毒性化学品鉴定准确度水平。在阴性对照组的分析中获得了最小分类，这表明使用最小分类进行危害识别是不适当的，因为它可能会导致假阳性的发生率很高。当使用轻度分类作为显著性指标时，情况并非如此，在大多数情况下，这允许成功识别阴性。当使用中度到显著的组织病理学变化来识别免疫毒性化学品时，可以达到的准确性水平很差。阳性对照数据集获得的准确度水平显著高于供试化学品数据集，表明组织学检测免疫毒性剂的能力与免疫毒性剂的效价成比例。从高剂量治疗组和低剂量治疗组获得的免疫功能试验结果和组织病理学结果的比较未显示两个终点之间的任何显著差异，以预测作为剂量函数的免疫毒性。在检查的三个淋巴器官中，（即，淋巴结、胸腺和脾脏），在胸腺皮质区观察到最一致和可辨别的组织学病变。这些病变与胸腺：体重比相关，在较小程度上与抗体空斑形成细胞反应相关。添加一般毒理学终点（如体重和白细胞计数）并未显著改善该数据集扩展组织病理学的灵敏度。综上所述，这些数据表明，虽然不如功能分析敏感，但扩展的组织病理学可以提供合理水平的准确性，作为识别免疫毒性化学物质的筛选试验，前提是仔细考虑用于评分组织学病变的严格程度，以允许检测免疫毒性剂，同时限制假阳性