ABSTRACT

Coronavirus disease (COVID-19) is challenging many health, economic, and social systems. RT-PCR assays are diagnosis gold standard; however, they can lead to false-negative results. Therefore, anti-SARS-CoV-2 IgG, IgM, and IgA investigation can play a complementary role in assessing the individuals immune status. Majority of serological tests focus on IgM and IgG although IgA are the main immunoglobulins involved in mucosal immunity. It has been reported that digestive symptoms may occur in the absence of any typical respiratory symptom. Thus, a complete screening, comprising IgA, IgM, and IgG detection could be more consistent and useful in patients with atypical symptoms or in paucisymptomatic cases. Current literature describes over 200 immunoassays available worldwide, pointing out a great results variability, depending on methodology or antigens’ nature. In our study we evaluated anti-SARS-CoV-2 IgA, IgM, and IgG trend on a control group and on two COVID-19 patient groups (early and late infection time) with a lateral-flow combined immunoassay (LFIA) and an enzyme-linked immunosorbent assay (ELISA). Dissimilar antibodies time kinetics have been described in COVID-19 (decreasing IgM concentration with IgA/IgG persistence for a longer time; as well as persistent IgA, IgG, and IgM concentration); our results confirmed both of them depending on the methodology; therefore, it is difficult to compare different studies outcomes, suggesting the importance of a serological tests international standardization. Nevertheless, we propose a flowchart with combined anti-SARS-CoV-2 IgG/IgM/IgA detection as a screening on general population, where serological positivity should be considered as an “alert,” to avoid and contain possible new outbreaks.

摘要

冠状病毒病 (COVID-19) 正在挑战许多健康、经济和社会系统。RT-PCR 检测是诊断金标准；然而，它们可能会导致假阴性结果。因此，抗SARS-CoV-2 IgG、IgM和IgA检测可以在评估个体免疫状态方面发挥补充作用。尽管 IgA 是参与粘膜免疫的主要免疫球蛋白，但大多数血清学检测集中于 IgM 和 IgG。据报道，在没有任何典型呼吸道症状的情况下也可能出现消化系统症状。因此，包括 IgA、IgM 和 IgG 检测在内的完整筛查对于症状不典型或症状较少的患者可能更加一致和有用。目前的文献描述了全球范围内可用的 200 多种免疫测定法，并指出了结果的巨大差异，具体取决于方法或抗原的性质。在我们的研究中，我们使用侧流联合免疫分析 (LFIA) 和酶联免疫吸附测定（ELISA）。COVID-19 中描述了不同抗体的时间动力学（随着 IgA/IgG 持续时间的延长，IgM 浓度降低；以及持续的 IgA、IgG 和 IgM 浓度）；我们的结果证实了这两者，具体取决于方法；因此，很难比较不同的研究结果，这表明血清学测试国际标准化的重要性。尽管如此，我们提出了一个结合抗 SARS-CoV-2 IgG/IgM/IgA 检测的流程图，作为对一般人群的筛查，其中血清学阳性应被视为“警报”，以避免和遏制可能的新疫情爆发。