Effects of nicotine- and tar-free smoke extracts from combustible cigarettes and heated tobacco products on the function of neutrophil-like HL-60 cells

Impaired neutrophil function is thought to increase infection risk associated with smoking. We examined the effects of nicotine- and tar-free cigarette smoke extracts (CSEs) from combustible cigarettes (CCs) and heated tobacco products (HTPs) on neutrophil-like HL-60 cells. HTP-derived CSEs exhibited lower cytotoxicity and milder impairment of neutrophil functions, including chemotaxis, reactive oxygen species production, phagocytosis, and neutrophil extracellular trap formation, than those of CC-derived CSEs. However, at higher concentrations, HTP-derived CSEs markedly impaired the cell viability and function. These results indicate that HTP emissions impair neutrophil functions at high concentrations, highlighting the need for cautious health risk evaluation.