On the role of Interleukin 6 and Soluble Interleukin-6 receptor as potential biomarkers for Crohn’s Disease

Background: The aim of the study was to determine whether IL-6, sIL-6R and sgp130 were suitable as biomarkers in Crohn’s disease. To date, the published data on this topic originates from studies with small cohorts and the results are contradictory. I evaluated the levels of IL-6, sIL-6R and sgp130 as markers for disease activity in a large cohort of Crohn’s disease patients recruited from an outpatient clinic. Methods: A total of 815 measurements from 212 patients with confirmed Crohn’s disease were included. General, clinical and laboratory parameters were collected and monitored, including the patients’ disease activity status. The data used as controls were obtained from 100 age-matched, healthy blood donors. Results: The majority of the measurements showed IL-6 serum levels below the detection limit. However, a small cohort had IL-6 levels which were significantly elevated in active versus inactive disease, and also in comparison to the healthy controls. The positive associations with thrombocytes, leukocytes and C-reactive protein serum levels know from previous research, were confirmed in this study. The serum concentrations of sIL-6R and sgp130 were only slightly elevated and showed no statistical significance. Moreover, a negative association was found between IL-6 levels and serum alanine transaminase (ALT) and aspartate transaminase (AST) while SIL-6 and sgp130 were positively associated with ALT and AST. Conclusions: Only a small proportion of patients with Crohn’s disease show elevated IL-6 levels in their blood samples. However, in these patients, the IL-6 is strongly associated with the disease activity and can be used as a biomarker. According to these results, sIL-6R and sgp130 do not appear to play a role in clinical practice