AbstractThe outcome of infectious diseases may depend on the interaction between human and pathogen genomic variations. We explore this relationship in tuberculosis (TB) by conducting a genome-to-genome (g2g) study of paired genomes from humans and the infectious agent Mycobacterium tuberculosis (Mtb) in 1,556 Peruvian TB patients. We identified a significant association between a human variant in the FLOT1 gene and a unique Mtb Lineage 2 (L2) subclade. The host allele affects FLOT1 expression in multiple tissue and cell types including lung, the primary site of TB disease. Phylogenetic analysis shows that the Mtb subclade has expanded rapidly in Peru since its emergence in the 1950s. Unbiased phenotypic profiling demonstrates that strains from the interacting Mtb subclade display different redox metabolism from other L2 strains. This study presents clear evidence that human and bacterial genetic variation interact together to produce different clinical outcomes.