ARG1 and coinfection: HIV co-infection did not impact neutrophil subsets in the blood but was associated with a phenotypic change in the airways and a reduction in key neutrophil functional proteins cathelicidin and arginase 1.<h4>Discussion</h4>Active TB is associated with profound skewing of blood and airway neutrophils and suggests multiple mechanisms by which neutrophils may exacerbate the immunopathology of TB.