Tapia-Rojas Salyoc, Murillo Carrasco Alexis Germán, Pons Maria J, Ugarte-Gil Manuel, Mayanga-Herrera Ana
Cancer and Stem Cells Research Group, Universidad Cientifica del Sur, Lima, Peru.
Laboratorio de Cultivo Celular e Inmunologia, Universidad Cientifica del Sur, Lima, Peru.
PeerJ. 2025 Aug 22;13:e19771. doi: 10.7717/peerj.19771. eCollection 2025.
The COVID-19 pandemic exposed vulnerabilities in health systems and revealed variations in immune responses across populations worldwide. This study examined the kinetics of IgG and IgM antibodies against S1 and receptor-binding domain (RBD) proteins in hospitalized Peruvian patients prior to vaccination.
A total of 157 serological samples were collected from 44 hospitalized COVID-19 patients during Peru's first wave (August-October 2020) and stored at -80 °C. Anti-SARS-CoV-2 IgG and IgM antibodies were quantified using an in-house ELISA with recombinant Spike S1 and RBD proteins. Statistical analyses-including linear regression, Kaplan-Meier curves, and receiver operating characteristic (ROC) curves-were conducted to evaluate antibody kinetics, clinical correlations, and predictive accuracy.
IgG levels stabilized between days 10 and 15 of hospitalization, while IgM levels declined after day 10, with greater variability observed in severe acute respiratory distress syndrome (ARDS) cases. A significant positive correlation was found between IgG levels and lymphocyte counts ( = 0.37, < 0.001), and a negative correlation with neutrophil counts ( = - 0.33, < 0.01), particularly in severe ARDS non-ICU patients ( = - 0.34, < 0.01). Severe ARDS cases also exhibited elevated neutrophil-to-lymphocyte ratios and increased inflammatory biomarkers, such as C-reactive protein and D-dimer, indicating an exacerbated inflammatory response associated with poorer prognosis. Risk factors, including sex and obesity, were linked to higher mortality and increased need for mechanical ventilation. This study contributes to a better understanding of the immune response in COVID-19 and supports the development of predictive models based on immunological and hematological biomarkers.
新冠疫情暴露了卫生系统的脆弱性，并揭示了全球不同人群免疫反应的差异。本研究检测了秘鲁住院患者在接种疫苗前针对S1和受体结合域（RBD）蛋白的IgG和IgM抗体的动力学变化。
在秘鲁第一波疫情期间（2020年8月至10月），从44名住院的新冠患者中收集了157份血清样本，并储存在-80°C。使用含有重组刺突S1和RBD蛋白的内部ELISA法对新冠病毒-2 IgG和IgM抗体进行定量。进行了包括线性回归、Kaplan-Meier曲线和受试者工作特征（ROC）曲线在内的统计分析，以评估抗体动力学、临床相关性和预测准确性。
IgG水平在住院第10天至15天之间稳定，而IgM水平在第10天后下降，在严重急性呼吸窘迫综合征（ARDS）病例中观察到更大的变异性。IgG水平与淋巴细胞计数之间存在显著正相关（r = 0.37，p < 0.001），与中性粒细胞计数呈负相关（r = -0.33，p < 0.01），特别是在严重ARDS非ICU患者中（r = -0.34，p < 0.01）。严重ARDS病例还表现出中性粒细胞与淋巴细胞比值升高以及炎症生物标志物如C反应蛋白和D-二聚体增加，表明炎症反应加剧与预后较差相关。包括性别和肥胖在内的风险因素与更高的死亡率和机械通气需求增加有关。本研究有助于更好地理解新冠病毒感染中的免疫反应，并支持基于免疫和血液生物标志物的预测模型的开发。
