SLC11A1 and tuberculosis: Our data show associations of both MARCO variants and M. tuberculosis lineage with TB susceptibility suggesting potential for host–pathogen co-evolution, as reported previously with TLR2, NRAMP1 and EREG. 15, 27, 28 Our associated SNPs may be markers of non-synonymous structural variants of MARCO that effects ability to bind ligands from Beijing lineage strains, reducing phagocytosis and increasing susceptibility to TB.