Correlation of serum C-reactive protein and procalcitonin levels in infections of kidney transplant recipients

Abstract

Objectives. Procalcitonin is a propeptide of calcitonin and has been increasingly used as a biomarker of infection. The aim of this study was to evaluate correlation of serum C-reactive protein (CRP) and procalcitonin (PCT) levels of kidney transplant patients hospitalized due to infection. Methods. There were 121 patients who had kidney transplant in our center between September 2012 and February 2017 and patients with a diagnosis of infection or rejection were included in the study. Simultaneous 106 serum CRP and PCT levels at the beginning or during any time of treatment for post-transplant infection, cytomegalovirus (CMV) positivity, BK virem ia and rejection were evaluated. Results. Median and interquartile ranges of CRP and PCT serum levels were 40 mg/l [24.7-64.9] and 0.19 ng/ml [0.1-0.61], respectively. A significant positive correlation between serum CRP and PCT levels of the patients were observed (r=0.490, p <0.001). When serum CRP levels were grouped as <50 mg/l, 50-100 mg/l and >100 mg/l, correlations with serum PCT levels were as r=0.461 ( p <0.001), r=-0.52 ( p =0.860) and r=0.488 ( p =0.153), respectively . Serum levels of PCT did not increase in CMV and BK virus infections and rejection. Conclusions. Serum CRP and PCT levels were correlated as a whole in the study, whereas serum CRP levels of 50-100 mg/l and >100 mg/l did not show a statistically significant correlation. Stability of PCT levels in viral infections and rejections might be an advantage for the follow-up of solid organ transplants. We need prospective trials of PCT measurements for the evaluation of post-transplant infections.