# human pancreatic islets

Cell proportions from bulk RNA sequencing are inferred through a single-cell reference, and that reference can change the conclusion drawn from them. In 981 PBMC donors the CD8 T-cell age association reversed in all 80 six-type references and the CD4 slope was inflated about 6.3-fold; in 48 islet donors a borderline alpha-cell association became significant in 54% to 100% of references. The error recurred across four estimator classes, its direction was set by the estimator, and fit accuracy did not flag it.

Cell proportions from bulk RNA sequencing are inferred through a single-cell reference, and that reference can change the conclusion drawn from them. In 981 PBMC donors the CD8 T-cell age association reversed in all 80 six-type references and the CD4 slope was inflated about 6.3-fold; in 48 islet donors a borderline alpha-cell association became significant in 54% to 100% of references. The error recurred across four estimator classes, its direction was set by the estimator, and fit accuracy did not flag it.

The authors developed multiplexed Deep Visual Proteomics (mxDVP), an end-to-end workflow combining high-plex imaging, automated computational analysis, and spatially guided ultra-sensitive mass spectrometry, powered by the open-source image analysis framework PIPΣX for whole-slide membrane-aware segmentation, annotation, and laser microdissection export, achieving more than 6,000 protein identifications from as few as 100 small islet cells; applied to human pancreatic islets it segmented over 860,000 cells and resolved twelve endocrine subtypes, including rare polyhormonal and intermediate-state populations showing spatial organization patterns, co-expression of INSM1 and SCG3, and hybrid α/β/δ signatures.

The authors developed multiplexed Deep Visual Proteomics (mxDVP), an end-to-end workflow combining high-plex imaging, automated computational analysis, and spatially guided ultra-sensitive mass spectrometry, powered by the open-source image analysis framework PIPΣX for whole-slide membrane-aware segmentation, annotation, and laser microdissection export, achieving more than 6,000 protein identifications from as few as 100 small islet cells; applied to human pancreatic islets it segmented over 860,000 cells and resolved twelve endocrine subtypes, including rare polyhormonal and intermediate-state populations showing spatial organization patterns, co-expression of INSM1 and SCG3, and hybrid α/β/δ signatures.