In a Cell pre-preprint, members of the Deutsche COVID-19 OMICS Initiative report on results from an RNA sequencing-centered effort aimed at distinguishing individuals with mild or more severe SARS-CoV-2 respiratory infections. Using RNA-seq, single-cell RNA-seq, flow cytometry, mass cytometry, and other approaches, the team profiled transcriptomic and proteomic patterns in whole blood and cell-sorted blood immune cell samples from 242 mild COVID-19 cases and 109 individuals with severe SARS-CoV-2 infections. While mild cases tended to involve enhanced levels of certain inflammatory monocyte cells, for example, the authors saw a rise in neutrophil precursor cells and other myeloid lineage cells in cases classified as severe. "Our study provides detailed insights into the systemic immune responses to SARS-CoV-2 infection," they report, "and it reveals profound alterations in the myeloid cell compartments associated with severe COVID-19."
For a related pre-print, researchers from France, Singapore, and elsewhere share findings from their own analysis of blood myeloid cell alterations in individuals with SARS-CoV-2 infections. For that study, investigators relied on RT-PCR, flow cytometry-based cell sorting, antibody-based immune cell profiling, and single-cell RNA-seq to assess blood and other samples from up to 158 COVID-19 patients, uncovering shifts in monocyte cell representation and a jump in pro-inflammatory calprotectin release in participants with the most severe COVID-19 infections. The analysis also pointed to neutrophil and myeloid changes that extended to blood and lung samples, supporting a role for myelopoiesis in COVID-19. "Together," the team writes, "our study integrates frequencies of non-classical monocytes and immature neutrophils with calprotectin plasma level as robust biomarkers of COVID-19 severity, suggesting potential therapeutic strategies targeting calprotectin to alleviate severe COVID-19."
Finally, a VIB Center for Brain and Disease Research-, KU Leuven-, and University College London-led team shares findings from a spatial transcriptomic study of Alzheimer's disease in a mouse model, detecting gene co-expression network data that was supported by subsequent in situ sequencing analyses on samples from mouse and human brain samples. "We demonstrate early alterations in a gene co-expression network enriched for myelin and oligodendrocyte genes, whereas a multicellular gene co-expression network of plaque-induced genes involving the complement system, oxidative stress, lysosomes, and inflammation is prominent in the later phase of the disease," the researchers write.