Can C-reactive proteinbe used as a surrogate marker of IL-6 in a broad array of clinical entities?

Abstract

Background: C-reactive protein (CRP) is commonly performed, whereascytokine testing is limited to research. Aims: To determine CRP correlation to cytokinesIL-6, IL-1β and TNF-α. Results:Consecutive samples (n =307)were collected over 24 h. Ninety-six patients (31%) had acute infections, and 23 patients (7.5%) had autoimmune or inflammatory disease presentations. A strong correlation between CRP and two IL-6 assays (r=0.74 and r=0.71; p<0.001) was present. CRP did not correlate with IL-1β and TNF-α across the data set. Bacterial infection had a significantly higher CRP and IL-6 (p<0.001), while only CRP was elevated in inflammatory and autoimmune diseases (p<0.001). Discussion: CRP may be used as a surrogate marker of IL-6 levels in the routine diagnostic laboratories.