['Children have a lower incidence of postinjury multiple organ failure (MOF) compared with adults with equivalent injury severity. Because MOF appears to be the end result of systemic hyperinflammation, children may have either an attenuated proinflammatory response or an augmented antiinflammatory response compared with adults. The purpose of this study was to determine the lipopolysaccharide (LPS)-induced pro- and antiinflammatory cytokine response of pediatric versus adult peritoneal macrophages (PM). The authors hypothesized that pediatric PMs would have an enhanced antiinflammatory response compared with adults.', 'Human PMs were collected during elective laparoscopic procedures and stimulated with LPS. (Pediatric cohort: n = 9 [mean, 5.4 years], adult cohort: n = 8 [mean, 41.6 years]). P less than.05 was accepted as significant.', 'LPS-induced a 50-fold increase in interleukin-10 (IL-10) antiinflammatory cytokine production in pediatric versus adult PMs. LPS-induced tumor necrosis factor-alpha (TNF-alpha) production was also increased in pediatric versus adult PMs. The anti-proinflammatory cytokine ratio (IL-10 to TNF-alpha) was 20-fold higher in pediatric versus adult PMs.'] Does endotoxin induce an exaggerated interleukin-10 response in peritoneal macrophages of children compared with adults?