Christophe Benoist, Barbara Stranger, Philip De Jager and colleagues conducted expression quantitative trait locus (eQTL) profiling of CD4+ T cells and monocytes purified from the blood cells of 461 healthy volunteers from a multi-ancestry cohort (Science 344, 519–523, 2014). They identified cis-eQTLs in each cell type in individuals of African, European and East Asian ancestry within this cohort, finding that over 90% of these loci were shared across ancestry groups. They identified cell type–specific cis-eQTLs, including 39% specific to monocytes, 8% specific to T cells and 62% shared by both cell types. They also identified 482 trans-eQTL associations involving 55 genes specific to monocytes, 31 specific to T cells and 4 shared by both cell types. They examined the overlap of eQTLs with SNPs associated with disease in the US National Institutes of Health (NIH) catalog of published genome-wide association studies (GWAS) and used a regulatory trait concordance score to identify those suggested to tag the same functional variant. They found an enrichment of cis-eQTLs in SNPs associated with autoimmune disorders. Some diseases showed marked cell type specificity: SNPs associated with multiple sclerosis, rheumatoid arthritis or type 1 diabetes were enriched for T cell–specific cis-eQTLs, whereas SNPs associated with Alzheimer's disease, Parkinson's disease or type 2 diabetes were enriched for monocyte-specific cis-eQTLs.