The effect of altitude on the expression of immune-related genes in Peruvian rural indigenous

Background: Some genes associated with immune response have been elucidated in some Andean populations, which may explain part of the immune system adaptation and pathogen response in high-altitude residents. We performed differential expression analysis and mainly focused on genes with high fold-change between groups and those genes with differential expression related to the immune system. Methods: We performed a transcriptome analysis of Peruvian individuals, primarily from rural areas, with high genetic backgrounds from ancient indigenous people, exposed to different living altitudes (high vs low). We collected peripheral blood mononuclear cells (PBMC) from 62 volunteers and exposed them to bacterial lipopolysaccharide (LPS), Pam3CSK4 (a synthetic triacylated lipopeptide responsible for bacterial components), and R848 (an imidazoquinoline compound related to viral nucleic acids). Results: Differential expression analysis results and data integration analysis with immune system pathway data exhibit a set of 17 genes associated with the immune system, nine down-regulated genes (ITGAX, CCL22, CSF1, CXCL8, IL12A, MMP9, CSF2, PTGS2, ENSG00000138685.17), and eight up-regulated genes (HLA-DPB1, FN1, CD36, MMP2, HLA-DRB1, FCGR1A, CCL17, HLA-DRB5). These genes are notably enriched in antigen-presenting cells, such as dendritic cells and macrophages. Conclusion: The differential expression of immune system genes in native inhabitants with a prominent Andean genetic background highlights the active involvement of both the innate and adaptive immune systems. Remarkably, our study revealed a distinct gene expression signature in our population, setting it apart from other transcriptomic studies conducted thus far. ### Competing Interest Statement The authors have declared no competing interest.