用于定量评估 IgG 同种型的干血斑，及其与 HIV 暴露未感染（HEU）婴儿血清样本的相关性。

Dried blood spots for the quantitative evaluation of IgG isotypes and correlation with serum samples in HIV-exposed uninfected (HEU) infants.

机构信息

National Center for Global Health, Istituto Superiore di Sanità, Rome, Italy.

出版信息

J Immunol Methods. 2021 Jun;493:113019. doi: 10.1016/j.jim.2021.113019. Epub 2021 Mar 8.

DOI:10.1016/j.jim.2021.113019

PMID:33705735

Abstract

BACKGROUND

The determination of IgG levels and their subclasses can provide clinically relevant information on the status of the immune system. Here we determined the sensitivity and reproducibility of the quantification of IgG subclasses from Dried Blood Spots (DBS) in Malawian uninfected infants exposed to HIV (HEU).

METHODS

Sixty paired samples of serum and DBS from HEU infants were used. Samples were collected from 1, 6, and 24-month old infants. IgGs concentrations from both serum and DBS were analyzed by BN ProSpec Siemens assay, using a different setting for sample dilutions. The reproducibility of the DBS method was tested on 10 samples run twice, starting from the DBS extraction process. To assess the systematic, proportional, and random differences, we computed the Passing-Bablok regression, and the Bland-Altman analysis to estimate the total mean bias between the two tests.

RESULTS

The IgG isotypes concentrations from serum and DBS showed significant differences in all the comparisons. Generally, the DBS method underestimated IgG subclasses' values showing a recovery range between 51.2% and 77.6%. Passing Bablok regression on age-based groups showed agreement for IgG, IgG1, and IgG2, but not for IgG3 and IgG4. The mean bias obtained with the Bland Altman test varied largely depending on IgG isotypes (-0.02-2.21 g/l) Coefficient of variation <7.0% was found in the repeated tests for IgG, IgG1, IgG3, and IgG4, while it was 12.4% for IgG2.

CONCLUSIONS

Varying degrees of differences were seen in the IgGs measurement in the two different matrices. In IgGs analysis, the DBS method offers promise for population-based research, but the results should be carefully evaluated and considered as a relative value since they are not equivalent to the serum concentrations.

摘要

背景

IgG 水平及其亚类的测定可提供有关免疫系统状态的临床相关信息。在这里，我们确定了从暴露于 HIV（HEU）的马拉维未感染婴儿的干血斑（DBS）中定量 IgG 亚类的敏感性和重现性。

方法

使用来自 HEU 婴儿的 60 对血清和 DBS 样本。从 1、6 和 24 月龄的婴儿中采集样本。使用不同的样品稀释设置，通过 BN ProSpec Siemens 分析来分析血清和 DBS 中的 IgGs 浓度。在 10 个样本上进行了两次重复运行，从 DBS 提取过程开始，测试 DBS 方法的重现性。为了评估系统、比例和随机差异，我们计算了通过 Bablok 回归，以及 Bland-Altman 分析来估计两种测试之间的总平均偏差。

结果

血清和 DBS 中的 IgG 同种型浓度在所有比较中均存在显着差异。通常，DBS 方法低估了 IgG 亚类的值，其回收率在 51.2%至 77.6%之间。基于年龄的分组的通过 Bablok 回归显示 IgG、IgG1 和 IgG2 具有一致性，但 IgG3 和 IgG4 没有。Bland Altman 测试获得的平均偏差差异很大，取决于 IgG 同种型（-0.02-2.21 g/l），在 IgG、IgG1、IgG3 和 IgG4 的重复测试中发现变异系数<7.0%，而 IgG2 为 12.4%。