Schönbacher Marlies, Banfi Chiara, Berghold Andrea, Matzhold Eva Maria, Wagner Thomas, Mayr Wolfgang R, Körmöczi Günther F
Department of Blood Group Serology and Transfusion Medicine, Medical University of Vienna, Vienna, Austria.
Statistics and Documentation, Institute for Medical Informatics, Medical University of Graz, Graz, Austria.
Transfus Med Hemother. 2022 Nov 29;50(4):294-302. doi: 10.1159/000527233. eCollection 2023 Aug.
The coronavirus disease (COVID-19) pandemic gave rise to studies investigating the association of ABO blood group with COVID-19 susceptibility. It is hypothesized that ABO antibodies might play a role in neutralizing SARS-CoV-2. However, ABO antibodies were exclusively analyzed in blood samples. Investigation of ABO antibodies in saliva, an easy-to-obtain surrogate for respiratory secretions, may provide novel insights into mucosal immunity crucial in early defense against respiratory pathogens.
In this study, saliva and serum samples from healthy individuals with known blood groups were investigated using a flow cytometric method for separate anti-A/anti-B IgA, IgM, and IgG class antibody detection. Saliva samples were additionally tested using hemagglutination-based neutral and indirect anti-human globulin test gel cards. This method comparison was complemented by dilution experiments with a high-titer anti-A/anti-B WHO standard.
In saliva, IgA was the most abundant ABO antibody class, followed by IgM; IgG was detected only in low levels in all non-AB blood types. In serum, IgM was the predominant ABO antibody class in all non-AB blood types, followed by IgA and IgG, the latter mainly detected in group O individuals. Saliva and serum samples of group O individuals yielded the highest variability of ABO-specific antibody levels. Regardless of sample material and blood type, major interindividual differences in ABO antibody reactivities were recorded. Antibody levels correlated moderately between these two body fluids. There were no significant sex and age-group differences in ABO antibody levels in both serum and saliva. WHO standard dilution experiments yielded technique-specific limits of detection, illustrating the inherent differences of immunofluorescence versus agglutination.
For the first time, salivary ABO antibodies were investigated by separate detection of the three most relevant antibody classes IgA, IgM, and IgG in a healthy cohort. This study opens new perspectives regarding mucosal ABO antibody class profiles and their potential influence on respiratory infections.
冠状病毒病（COVID-19）大流行引发了对ABO血型与COVID-19易感性之间关联的研究。据推测，ABO抗体可能在中和严重急性呼吸综合征冠状病毒2（SARS-CoV-2）中发挥作用。然而，此前仅对血液样本中的ABO抗体进行了分析。对唾液（一种易于获取的呼吸道分泌物替代物）中的ABO抗体进行研究，可能会为早期抵御呼吸道病原体至关重要的黏膜免疫提供新的见解。
在本研究中，使用流式细胞术对已知血型的健康个体的唾液和血清样本进行检测，以分别检测抗A/抗B IgA、IgM和IgG类抗体。此外，还使用基于血凝的中和及间接抗人球蛋白试验凝胶卡对唾液样本进行检测。通过使用高滴度抗A/抗B世界卫生组织标准进行稀释实验，对该方法比较进行了补充。
在唾液中，IgA是最丰富的ABO抗体类别，其次是IgM；在所有非AB血型中，IgG仅以低水平被检测到。在血清中，IgM是所有非AB血型中主要的ABO抗体类别，其次是IgA和IgG，后者主要在O型血个体中被检测到。O型血个体的唾液和血清样本中ABO特异性抗体水平的变异性最高。无论样本材料和血型如何，均记录到ABO抗体反应性存在较大的个体间差异。这两种体液中的抗体水平呈中度相关。血清和唾液中的ABO抗体水平在性别和年龄组之间均无显著差异。世界卫生组织标准稀释实验得出了特定技术的检测限，说明了免疫荧光与凝集的固有差异。
本研究首次在健康队列中通过分别检测三种最相关的抗体类别IgA、IgM和IgG来研究唾液ABO抗体。这项研究为黏膜ABO抗体类别谱及其对呼吸道感染的潜在影响开辟了新的视角。
