Department of Biochemical Diagnostics, Medical University of Bialystok, Waszyngtona 15A St., 15-269 Bialystok, Poland.
Department of Infectious Diseases and Neuroinfections, Medical University of Bialystok, Zurawia 14 St., 15-540 Bialystok, Poland.
Int J Mol Sci. 2022 Sep 30;23(19):11589. doi: 10.3390/ijms231911589.
The aim of this study is to assess the synthesis of kappa (κ) and lambda (λ) free light chains (FLCs) in the serum of patients with COVID-19. All the 120 serum samples were collected from patients with COVID-19 and from healthy controls (vaccinated and non-vaccinated against SARS-CoV-2). FLCs, IgG total, IgG4, IgG anti-Nucleocapsid (N), anti-spike S1 receptor binding domain (S-RBD) antibodies and IL-6 were measured according to the manufacturers' instructions. The concentrations of anti-N IgG, IgG total, IgG4 and IL-6 were elevated in the COVID-19 group in comparison to the vaccinated and non-vaccinated controls. The levels of anti-S-RBD IgG and κFLC were increased in COVID-19 and healthy vaccinated patients when compared to non-vaccinated controls. λFLC concentration was higher in the COVID-19 group than in the non-vaccinated group. The κ:λ ratio was lower in both COVID-19 and non-vaccinated groups in comparison to vaccinated controls. κFLC correlated with all tested parameters (anti-S-RBD IgG, anti-N IgG, λFLC, κ:λ ratio, IgG total, IgG4 and IL-6) except CRP, whereas λFLC correlated with all examined parameters except IgG4. Elevated levels of FLCs in COVID-19 and healthy vaccinated against SARS-CoV-2 patients, as well as the correlation between free light chains with specific anti-SARS-CoV-2 antibodies and IL-6, reflect hyperactivation of the immune system after contact with coronavirus. Furthermore, it seems that serum levels of FLCs might be used as predictive markers of COVID-19. Our findings suggest that free light chains are involved in SARS-CoV-2 infection. However, understanding the exact mechanism requires further investigation.
本研究旨在评估 COVID-19 患者血清中 κ（κ）和 λ（λ）游离轻链（FLC）的合成。所有 120 份血清样本均来自 COVID-19 患者和健康对照者（接种和未接种 SARS-CoV-2 疫苗者）。根据制造商的说明测量 FLC、总 IgG、IgG4、抗核衣壳（N）、抗刺突 S1 受体结合域（S-RBD）抗体和 IL-6。与接种和未接种疫苗的对照组相比，COVID-19 组中抗-N IgG、总 IgG、IgG4 和 IL-6 的浓度升高。与未接种疫苗的对照组相比，COVID-19 和健康接种疫苗的患者中抗-S-RBD IgG 和 κFLC 的水平升高。与未接种疫苗组相比，COVID-19 组的 λFLC 浓度更高。与接种疫苗的对照组相比，COVID-19 和未接种疫苗组的 κ：λ 比值均较低。κFLC 与所有检测参数（抗-S-RBD IgG、抗-N IgG、λFLC、κ：λ 比值、总 IgG、IgG4 和 IL-6）相关，除 CRP 外，而 λFLC 与除 IgG4 外的所有检查参数相关。COVID-19 和健康接种 SARS-CoV-2 疫苗的患者中 FLC 水平升高，以及游离轻链与特定抗 SARS-CoV-2 抗体和 IL-6 之间的相关性，反映了接触冠状病毒后免疫系统的过度激活。此外，血清 FLC 水平似乎可用作 COVID-19 的预测标志物。我们的研究结果表明，游离轻链参与了 SARS-CoV-2 感染。然而，要了解确切的机制还需要进一步研究。
