{
  "abstract": "Human immune responses remain poorly characterized across Indigenous South American (ISA) populations, limiting our understanding of human immune variation. Here, we generated a single-cell transcriptional atlas of 1.4 million peripheral blood mononuclear cells from 345 individuals representing 13 South American populations, profiled at baseline and following stimulation with lipopolysaccharide, influenza A virus, or Trypanosoma cruzi. Genetic ancestry was associated with the expression of a large fraction of the transcriptome, often only after stimulation, and explained more variation than age or sex. On average, cis-eQTLs accounted for one-quarter of these ancestry-associated differences. Thousands of regulatory variants were common in ISA populations but rare or absent in European reference datasets. Integrating eQTLs with GWAS revealed stimulation-specific disease-associated regulatory variants and an enrichment of ancestry-associated expression differences among genes with colocalizing signals. Our findings highlight the importance of studying diverse populations across immune contexts to understand the genetic architecture of human immune responses.",
  "abstract_shown": true,
  "affiliations": [
    "Section of Genetic Medicine, Department of Medicine, University of Chicago, Chicago, IL, USA"
  ],
  "article_type": "PUBLISHAHEADOFPRINT",
  "arxiv": null,
  "author_total": 39,
  "authors": [
    {
      "name": "C. Choy"
    },
    {
      "name": "L. Vicuna"
    },
    {
      "name": "M. Patino"
    },
    {
      "name": "D. S. Araujo"
    },
    {
      "name": "D. Obispo"
    },
    {
      "name": "M. L. Guevara-Fujita"
    },
    {
      "name": "S. Fonseca"
    },
    {
      "name": "D. Scariot"
    },
    {
      "name": "C. Araujo"
    },
    {
      "name": "J. R. Guerreiro"
    },
    {
      "name": "O. Acosta"
    },
    {
      "name": "C. Johnson"
    },
    {
      "name": "K. Meier"
    },
    {
      "name": "A. Dumaine"
    },
    {
      "name": "K. Williams"
    },
    {
      "name": "T. Lima"
    },
    {
      "name": "T. Rodrigues"
    },
    {
      "name": "A. Khayat"
    },
    {
      "name": "E. Wu"
    },
    {
      "name": "A. Gupta"
    },
    {
      "name": "R. Aguirre-Gamboa"
    },
    {
      "name": "B. Chak"
    },
    {
      "name": "J. Barroso-Batista"
    },
    {
      "name": "F. Capetillo"
    },
    {
      "name": "K. Marcelain"
    },
    {
      "name": "I. Fuentes"
    },
    {
      "name": "J. Gonzalez"
    },
    {
      "name": "P. Beltran"
    },
    {
      "name": "Y. Flores"
    },
    {
      "name": "T. Coronel"
    },
    {
      "name": "J. Latorre"
    },
    {
      "name": "J. Boutaud"
    },
    {
      "name": "C. K. Mickelson"
    },
    {
      "name": "R. Langlois"
    },
    {
      "name": "E. Scott"
    },
    {
      "name": "J. Guerreiro"
    },
    {
      "name": "T. Hünemeier"
    },
    {
      "name": "R. Fujita"
    },
    {
      "affs": [
        0
      ],
      "name": "L. B. Barreiro"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/d72m788pzjq4z.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.10.21.26365630",
  "fulltext_url": "https://www.medrxiv.org/content/10.64898/2026.10.21.26365630v1.full",
  "id": "d72m788pzjq4z",
  "issns": [],
  "landing_url": "https://www.medrxiv.org/content/10.64898/2026.10.21.26365630v1",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "medrxiv",
      "genetic and genomic medicine"
    ],
    [
      "openalex",
      "1311|Genetic Associations and Epidemiology"
    ]
  ],
  "openalex": "W7223140197",
  "pdf_url": "https://www.medrxiv.org/content/10.64898/2026.10.21.26365630v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-21",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/d72m788pzjq4z.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:27Z",
      "native_id": "10.64898/2026.10.21.26365630",
      "source": "medrxiv",
      "url": "https://www.medrxiv.org/content/10.64898/2026.10.21.26365630v1"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "medrxiv:genetic and genomic medicine",
      "subfield": "human-genetics"
    }
  ],
  "title": "Genetic ancestry shapes context-dependent immune regulation across Indigenous South American populations",
  "title_text": "Genetic ancestry shapes context-dependent immune regulation across Indigenous South American populations",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:27Z",
  "url": "https://research.draconitic.com/paper/d72m788pzjq4z",
  "venue": "medRxiv",
  "versions": []
}