Flowcytomeric analysis on neutrophil intracellular enzyme activity in patients on hemodialysis and continuous ambulatory peritoneal dialysis

: To elucidate the mechanism of neutrophil dysfunction in patients with maintenance hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD), intracellular enzyme activity such as oxidative burst, elastase, cathepsin, and collagenase, was investigated. Response of enzyme activity to in vitro addition of TNF-alpha, which is known to have a powerful priming effect on neutrophils, was also evaluated. Peripheral blood from 15 HD and 15 CAPD patients was washed and incubated with Cell Probe, an indicator for intracellular enzyme activity. Mean fluorescent intensity of neutrophils, which represents neutrophil enzyme activity, was measured by flowcytometry. In HD group, unstimulated enzyme activity was similar to that of control, but activity after addition of TNF-alpha was significantly lower than the control. In the group of CAPD, enzyme activity without stimulation was not different from that of control, and in TNF-alpha stimulated neutrophils, only elastase activity was lower than control. Many of the enzyme activities after stimulation were lower in HD than in CAPD. Response to in vitro addition of TNF-alpha was diminished in both dialysis groups, but more prominent in HD neutrophils. Duration of dialysis, serum concentration of beta 2-microglobulin (beta 2-MG) and parathyroid hormone (PTH) was significantly related inversely to intracellular enzyme activity in HD patients. To the contrary, in CAPD group, although beta 2-MG and PTH showed similar negative correlation, duration of dialysis was not related to enzyme activity. These results indicate that neutrophils in patients with maintenance dialysis have diminished intracellular oxidative burst, elastase, and cathepsin activity. Especially, impaired response to TNF-alpha closely related to neutrophil dysfunction in dialysis patients.