Clinical immunology
Immunomodulatory effect of recombinant human procalcitonin on mitogenic activity of lymphocytes

Procalcitonin (PCT) is an excellent inflammatory marker for early diagnosis of sepsis. However, little is known about its immunological functions.

Objective: The aim of our work was to determine the effect of recombinant human (rh) PCT on blastic transformation of lymphocytes.

Methods: Peripheral blood lymphocytes from 9 healthy volunteers were isolated on Ficoll-Metrizoat gradient and cultivated with polyclonal mitogens phytohemaglutinin (PHA), concanavalin A (Con A) and lipopolysaccharide (LPS) with or without rhPCT. RhPCT was added to the cultures in four different final concentrations.

Results: 1. RhPCT significantly inhibited the blastic transformation of PHA activated T-lymphocytes
(by 14-26%) as well as the simultaneous activation of T cells with rhPCT and PHA (21%). 2. RhPCT significantly decreased the ability of T cells stimulated by Con A either simultaneously (13-19%)
or subsequently (21-41%). 3. RhPCT increased the activity of unstimulated autologous lymphocytes.

Conclusion: Our preliminary results indicate that rhPCT suppressed the activity of both PHA and Con A stimulated T-cells, however it increased the activity of unstimulated lymphocytes. The results indicate that in vivo production of PCT in septic patients might contribute to a suppression of the hyperactivated specific cellular immunity.