Sex-specific metabolic programming in human neutrophil subsets.

While sex differences in neutrophil metabolism have been documented, whether this metabolic dimorphism extends to specific neutrophil subsets remains unknown. Low-density neutrophils (LDNs) are characterized by their lower buoyant density compared with normal-density neutrophils (NDNs), are present in low numbers in healthy individuals, and are often associated with disease severity and immune dysregulation. LDNs and NDNs from healthy human donors were isolated, whereafter cellular metabolism, specifically oxidative phosphorylation and glycolysis, alongside flow cytometry for maturity markers (CD16hi/lo), was assessed. Male LDNs exhibited significantly higher basal oxygen consumption rate (OCR) and adenosine triphosphate production than female LDNs, while no sex differences were observed in NDNs. Strikingly, male LDNs also had higher OCR and glycolysis than their matched NDNs, whereas female LDNs exhibited a lower OCR than their NDNs. Our study reveals subset-specific sexual metabolic reprogramming in LDNs, whereby male LDNs exhibit a hypermetabolic phenotype. These findings provide a metabolic basis for sex-biased immune responses and highlight the need for sex-stratified approaches in neutrophil-targeted therapies.