Plasma lactoferrin content: differential effect of steroid administration and infective illnesses: lack of effect of ambient temperature at which specimens are collected.

The effect of parenteral hydrocortisone on plasma lactoferrin concentration, neutrophil count and lactoferrin:neutrophil ratio was assessed in 10 volunteer subjects. Administration of a single dose of corticosteroid was followed by a significant rise in the circulating neutrophil count, a significant but proportionately smaller rise in the plasma lactoferrin concentration and a significant fall in the lactoferrin:neutrophil ratio. Acute viral infections were found to be associated with a disproportionately low plasma lactoferrin concentration relative to the circulating neutrophil count. The relatively low lactoferrin concentrations in both these situations could be of significance in regard to the propensity to bacterial infection and superinfection which these 2 groups of subjects display. Compared to patients with viral infection, those suffering from Plasmodium falciparum malaria showed a significantly elevated lactoferrin:neutrophil ratio, although this ratio was not significantly different when malarial patients were compared to normal individuals. These findings suggest that the pathogenesis of relative neutropenia in viral and protozoal illnesses is fundamentally different. Finally, it was found that the temperature at which specimen collection takes place does not appear to be a significant variable determining the plasma lactoferrin concentration.