Quantitation of lactoferrin in odontogenic cyst fluids.

A competitive enzyme linked immunosorbent assay (ELISA) method was used to measure the concentration of lactoferrin in fluids from 36 odontogenic keratocysts, 15 dentigerous cysts, and 30 radicular/residual cysts. Keratocyst fluids contained significantly higher concentrations of lactoferrin than fluids from the other two types of cyst (p less than 0.001); but the range of values obtained within each group was large. Although lactoferrin represents a larger proportion of the total protein in keratocyst fluids than in dentigerous or radicular cyst fluids, lactoferrin concentration is not an absolute diagnostic marker for keratocysts. Lactoferrin concentration correlated strongly with the numbers of neutrophils present in keratocyst fluids (p less than 0.001), less so for dentigerous cyst fluids (p less than 0.05, and not at all in the case of radicular cyst fluids. It is suggested that neutrophils are the source of lactoferrin in the three categories of cyst studied but that the relatively impermeable nature of the keratocyst lining probably accounts for the particularly high concentrations of lactoferrin found in their fluids. Given that most keratocysts were asymptomatic, acute inflammation itself does not explain the reason for the high numbers of neutrophils in many of the fluids.