Procalcitonin, cytokines and C-reactive protein in systemic inflammatory response

Background

Procalcitonin (PCT) is a biochemical marker with a high specificity for bacterial and mycotic etiology of inflammation. Its production is selectively induced by endotoxin-cytokines mechanism.

Aim of study

To verify differential diagnostic value of PCT in inflammation of different etiology and intensity and to test practical use of PCT estimation.

Methods

In a prospective pilot study, 14 patients with various main diagnoses admitted to a medical ward entered the study. Serum levels of PCT, interleukin 6 (IL-6), C-reactive protein (CRP), body temperature and APACHE-II score were estimated in 12 h intervals within 6 days. Results were statistically evaluated by linear correlation analysis.

Results

1. Patients with bacterial sepsis showed highest levels of PCT. Elevated levels of PCT were also present in patients with systemic autoimmune diseases. Patients with viral etiology of inflammatory process and those with no inflammatory process had normal levels of PCT.

2. Significant correlation was found between PCT and IL-6 (r² = 0.6568), and PCT and CRP (r² = 0.3714) in patients with bacterial sepsis. Correlation of CRP and IL-6 levels was less significant (r² = 0.1968).

3. No correlation between PCT and number of leukocytes, body temperature, lactate, and sedimentation of erythrocytes was observed neither in septic nor in non-septic individuals.

Discussion

Estimation of serum procalcitonin level in septic patients seems to be a reliable and easy-to-do test which corresponds with IL-6. As laboratory estimation of cytokines is relatively difficult and expensive, procalcitonin can be a good variant.