Augmented release of human leucocyte lactoferrin (and elastase) during coagulation.

Lactoferrin, an iron binding protein, present in specific granules of neutrophils has been shown to be released concomitantly with elastase, when neutrophils are activated in vitro. Using enzyme-linked immunosorbent assay, lactoferrin release has been studied during blood coagulation, a more physiological system for studying the in vivo neutrophil activation in vitro. The assay has a lower detection limit of 1.0 ng/ml with intra and interassay coefficients of variation of 8 and 14% respectively. Median plasma and serum lactoferrin levels were 144 and 705 ng/ml respectively. The difference was statistically significant at p less than 0.0001. The median elastase proteinase inhibitor complex (EPIC) levels in plasma and serum were 85 and 176.5 ng/ml respectively. This difference was also highly significant at p less than 0.0001. There was no correlation between these parameters in the plasma samples. However, there was a statistically significant correlation between these measurements in sera at p less than 0.001 (Kendall's rank correlation). Release of lactoferrin and elastase-A1PIC during coagulation reflects the activation of neutrophils in vivo, especially during inflammation.