Department of Biochemistry and Molecular Biology and Research Institute Hospital 12 de Octubre (Imas12), Universidad Complutense de Madrid, Madrid, Spain.
Faculty of Health Sciences, Rey Juan Carlos University, Alcorcón, Spain.
Front Cell Infect Microbiol. 2022 Sep 2;12:934321. doi: 10.3389/fcimb.2022.934321. eCollection 2022.
Assessment of serological -specific antibodies in highly endemic areas provides valuable information about malaria status and parasite exposure in the population. Although serological evidence of exposure is commonly determined by -specific immunoglobulin G (IgG) levels; IgM and IgA are likely markers of malaria status that remain relatively unexplored. Previous studies on IgM and IgA responses have been based on their affinity for single antigens with shortage of immune responses analysis against the whole proteome. Here, we provide evidence of how infection triggers the production of specific IgM and IgA in plasma and its relationship with parasite density and changes in hematological parameters. A total of 201 individuals attending a hospital in Breman Asikuma, Ghana, were recruited into this study. Total and -specific IgM, IgA, and IgG were assessed by ELISA and examined in relation to age (0-5, 14-49, and ≥50 age ranges); infection (submicroscopic vs. microscopic malaria); pregnancy and hematological parameters. Well-known IgG response was used as baseline control. -specific IgM and IgA levels increased in the population with the age, similarly to IgG. These data confirm that acquired humoral immunity develops by repeated infections through the years endorsing IgM and IgA as exposure markers in endemic malaria regions. High levels of specific IgA and IgM in children were associated with microscopic malaria and worse prognosis, because most of them showed severe anemia. This new finding shows that IgM and IgA may be used as diagnostic markers in this age group. We also found an extremely high prevalence of submicroscopic malaria (46.27% on average) accompanied by IgM and IgA levels indistinguishable from those of uninfected individuals. These data, together with the observed lack of sensitivity of rapid diagnostic tests (RDTs) compared to PCR, invoke the urgent need to implement diagnostic markers for submicroscopic malaria. Overall, this study opens the potential use of -specific IgM and IgA as new serological markers to predict malaria status in children and parasite exposure in endemic populations. The difficulties in finding markers of submicroscopic malaria are highlighted, emphasizing the need to explore this field in depth.
在高流行地区评估血清特异性抗体,可为人群中的疟疾状况和寄生虫暴露提供有价值的信息。虽然寄生虫暴露的血清学证据通常通过特异性免疫球蛋白 G(IgG)水平来确定;但 IgM 和 IgA 可能是疟疾状况的标志物,但其相关研究相对较少。以前关于 IgM 和 IgA 反应的研究基于它们对单个抗原的亲和力,而针对整个蛋白质组的免疫反应分析则相对较少。在这里,我们提供了证据表明疟原虫感染如何触发血浆中特异性 IgM 和 IgA 的产生,以及其与寄生虫密度和血液学参数变化的关系。总共招募了 201 名来自加纳 Breman Asikuma 医院的个体参与这项研究。通过 ELISA 评估总 IgM、IgA 和 IgG 以及与年龄(0-5、14-49 和≥50 年龄范围)、感染(亚微观与微观疟疾)、妊娠和血液学参数的关系。使用众所周知的 IgG 反应作为基线对照。随着年龄的增长,人群中的 -特异性 IgM 和 IgA 水平也会增加,这与 IgG 相似。这些数据证实,通过多年的反复感染,获得性体液免疫得以发展,这表明 IgM 和 IgA 是地方性疟疾地区的寄生虫暴露标志物。儿童中高水平的特异性 IgA 和 IgM 与微观疟疾和更差的预后相关,因为他们中的大多数人都有严重的贫血。这一新发现表明,IgM 和 IgA 可能在该年龄组中用作诊断标志物。我们还发现亚微观疟疾的患病率极高(平均为 46.27%),同时 IgM 和 IgA 水平与未感染者无法区分。这些数据,加上与 PCR 相比快速诊断测试(RDT)的观察到的低灵敏度,迫切需要实施亚微观疟疾的诊断标志物。总的来说,这项研究为使用 -特异性 IgM 和 IgA 作为新的血清学标志物来预测儿童中的疟疾状况和地方性人群中的寄生虫暴露开辟了潜力。突出了在亚微观疟疾标志物方面存在的困难,强调需要深入探索这一领域。