Single-cell omics-based characterization of human basophils reveals two transcriptionally distinct populations

BackgroundBasophils are implicated in various diseases including allergies, but a comprehensive characterization of human basophils has yet to be performed at the single-cell level. ObjectiveWe aimed to generate a single-cell omics-based resource of circulating human basophils, to be made accessible to the research community. We also sought to investigate basophil heterogeneity at the transcriptional and surface epitope levels. MethodsCirculating basophils were analyzed using short- and long-read single-cell RNA-sequencing in combination with large-scale immunoprofiling of more than 100 cell surface markers. ResultsWe used a cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) based cell barcoding system to accurately track side scatterlow lineage- CCR3+ Fc{varepsilon}RI+ basophils through the single-cell omics analysis. The approach allowed for accurate transcriptional profiling of basophils among low-density peripheral blood leukocytes. The generation of an additional dataset with only basophils revealed two transcriptionally distinct populations. Single-cell transcriptomic analysis of samples from additional donors was performed and coupled with a large-scale immunoprofiling screen, producing a third CITE-seq dataset containing basophils. The analysis verified the existence of the two transcriptionally distinct populations and revealed that these populations have similar immunophenotypes with regard to the investigated surface markers. Long-read single-cell RNA-sequencing analysis provided further insights into the gene expression dynamics of the circulating basophils and confirmed the transcriptionally defined basophil states. ConclusionsThe single-cell omics analysis revealed two transcriptionally distinct basophil populations. Our single-cell omics resource constitutes a reference for charting human basophils at the cellular and molecular levels in health and disease. Capsule summaryShort- and long-read single-cell RNA-sequencing coupled with large-scale immunoprofiling characterize human basophils in peripheral blood and reveal two transcriptionally distinct populations.