Changes in Neutrophil Membranes Induced by Plasma from Newborns with Infection

This study aimed to identify neutrophil membrane characteristics that could serve as clinical biomarkers for the development of infectious complications in newborns. Materials and Methods . Neutrophils isolated from healthy donors were used as a model system. The cells were incubated with plasma samples (S) isolated from blood of newborns categorized into three groups: apparently healthy (normal) (NS) (N=6), with localized infection (LIS) (N=7), and with generalized infection (GIS) (N=8). We assessed cellular morphology and membrane roughness before and after stimulation with phorbol 12-myristate 13-acetate (PMA) using fluorescence and atomic force microscopy. We quantified nuclear and membrane surface areas, the intensity of neutrophil extracellular trap (NET) formation, and membrane arithmetic average roughness (Ra). Results. A standardized protocol for neutrophil preparation and evaluation was developed. Optimal incubation conditions were established; 1% bovine serum albumin (BSA) yielded minimal background activation. Dose-dependent activation of neutrophils by PMA was observed in the presence of 1% plasma. PMA stimulation significantly increased nuclear area (P0.001), membrane area (P0.001), and Ra (P0.001), regardless of plasma sample group. The most significant changes occurred in neutrophils incubated with plasma from the GIS group. Generalized infection was associated with enhanced NET activation, which may contribute to the pathogenesis of thrombotic complications in neonatal sepsis. Conclusion. Microscopy-based neutrophil characteristics are promising biomarkers for evaluating infection including sepsis in newborns.