Epigenetic immunophenotyping in monitoring of SARS-CoV2 vaccine response and COVID-19 disease course

Abstract The objective was to explore whether epigenetic immune cell counting can advance efficiency and quality of diagnostic and immune monitoring related to COVID-19. Application areas were monitoring disease course, therapeutic clinical development, and measurements of SARS-CoV2 vaccine responses. Immune cell type specific epigenetic assays have been developed over the last decade. They are primarily used in therapeutic clinical research in oncology and autoimmune disease. Due to the high sample stability and low amount requirements for epigenetic measurements and available assay portfolio for key immune cell populations relevant in COVID-19, the method promised to be useful and practical in the pandemic setting. Epigenetic immunophenotyping using whole blood of hospitalized Covid19 patients was applied and CD3, CD4, CD8 and regulatory T cell populations, NK cells, naïve and memory B cells were quantified, and measurement results show to predict mild or severe COVID-19 disease courses. Furthermore, nasopharyngeal swab and saliva samples were applied demonstrating that epigenetic immune monitoring can measure immune cell content in such non-invasive sample types. Due to the low sample volume and handling requirements and availability of 35 assays for relevant immune cell populations, epigenetic immune monitoring is suitable for therapeutic COVID-19 clinical trials. Another possibility for sample collection is single drops of capillary blood deposited on filter paper (dried blood spots), which have been collected pre and post SARS-CoV2 booster vaccinations in healthy subjects. Such measurements revealed vaccine response for example in changes of cell populations epigenetically active in the markers CCR7 and TIGIT.