Procalcitonin does not influence the surface expression of inflammatory receptors on whole blood leukocytes

The plasma levels of procalcitonin (PCT) are increased in patients with sev ere bacterial infections. Its cellular origin and potential pathophysiologi cal function in sepsis is, however, unclear. White blood cells have recentl y been described to express both PCT mRNA and protein. The aim of this stud y was to determine whether PCT has any influence on the surface expression of receptors, relevant in inflammation, on human whole blood leukocytes und er normal and septic conditions. Venous blood from healthy donors was incub ated with PCT (40 ng/ml or 1200 ng/ml) alone or in combination with lipopol ysaccharide (LPS, 10 ng/ml) or peptidoglycan (PepG, 10 mug/ml) for 6 h. The surface expression of CD14, CD54, CD64, CD80, CD86 and HLA-DR was determin ed by flow cytometry. We could not detect any influence of PCT on the expre ssion of these receptors. Further studies on potential effects on other cel l types during infection seem warranted.