While high-throughput single cell technologies enable in depth examination of specific cell subsets, these experiments lack the context of these subsets in other cell types and diseases. We compared novel dendritic and monocyte signatures from single cell RNAseq with bulk transcriptome of immune cells to show that the gene signatures for the novel cell subsets are also up-regulated in functionally related but non-parental cell populations. We extended utility of these signatures by demonstrating their consistent down-regulation in cancers, up-regulation in autoimmune diseases, and signature-specific effects in infections. We encourage other researchers to similarly complement their experiments and analyses using existing, publicly available datasets.