Capturing systemic inflammation in a nonhuman primate using a new leukocyte activity assessment system

We developed an optical system that simultaneously monitors leukocytes producing the reactive oxygen species (ROS) superoxide and hypochlorite ions using only a few microliters of whole blood. Here, we report the first use of this system to measure circulating blood from a nonhuman primate. This observational pilot study involved rhesus monkeys recruited for a different purpose, brain positron emission tomography in the conscious state. The results indicated that (1) surgical inflammation influences the total ROS produced by leukocytes per unit of time; (2) blood analysis of a septic rhesus monkey exhibited a characteristic pattern of leukocyte ROS production; and (3) a strong positive correlation was observed between leukocyte ROS production and neutrophil counts at normal C-reactive protein (CRP) levels, which decreased under abnormal CRP levels. These findings suggest that the system can capture systemic inflammation in non-human primates and highlight the importance of monitoring leukocyte ROS production to understand inflammatory status. The difficulty of identifying subjective symptoms in veterinary medicine highlights the importance of technologies for easily and objectively monitor animals' physical conditions. Further analyses, including studies with larger animal populations and comparisons with conventional biomarkers, are needed to determine the specific inflammatory status reflected in leukocyte ROS production.