Procalcitonin is released by human monocytes

Introduction

Procalcitonin (PCT), the precursor of calcitonin, was recently forwarded as a diagnostic marker of systemic bacterial infection and sepsis. Previously we have demonstrated that PCT is expressed in human peripheral blood mononuclear cells (PBMC). Aim of this study was to estimate wether PCT could be released by monocytes in culture medium.

Methods

PBMC were prepared from heparinized venous blood samples from healthy volunteers and septic patients (according to ACCP/SCCM consensus conference criteria) by density gradient centrifugation. Monocytes were obtained by differential adhesion to plastic surface and cultivated for 12 h with or without 10 μg/ml lipopolysaccharide E. coli B4. Supernatants were analyzed for PCT content by commercially available Lumitest^® kit (B.R.A.H.M.S, Berlin).

Results

In contrast to monocytes from septic patients, monocytes from healthy volunteers did not release PCT at detectable levels (<0.1 ng/ml) under control conditions. LPS-stimulation lead to readily detectable levels of PCT both in the supernatants of healthy and septic patient monocyte cultures. In comparison to monocytes from healty volunteers monocytes from septic patients released significantly more PCT after LPS stimulation.

Conclusion

Our data demonstrate for the first time that PCT can be released by human monocytes. Furthermore LPS, a key mediator of septic sequelae, can significantly increase the PCT release.