Plasma IL-6 concentration correlates with clinical disease activity and serum C-reactive protein concentration in chronic urticaria patients

Background Our previous study was the first to demonstrate enhanced plasma IL-6 concentrations in chronic urticaria (CU). It is known that C-reactive protein (CRP) is a sensitive marker of an underlying systemic inflammation, triggered mainly as a response to IL-6. Objective To evaluate plasma IL-6 concentration in CU patients relating to the clinical disease activity and serum CRP concentration. Methods Serum CRP and plasma IL-6 concentrations were measured in 58 CU patients and 30 healthy subjects. Ten CU patients were evaluated twice, during the active period as well as upon the spontaneous clinical remission of the disease. CU activity was assessed with the use of the symptom scores recommended by EAACI/GALEN/EDF guidelines. Results IL-6 and CRP concentrations were significantly increased in CU patients as compared with the healthy subjects, whereas they decreased remarkably upon the spontaneous remission. IL-6 concentration was associated with weekly urticaria activity scores and also significant differences were found between patients showing different degrees of urticarial activity. Significant correlation was observed between IL-6 and CRP concentrations. Conclusions and Clinical Relevance This study reinforces evidence that, apart from a local cutaneous inflammation, CU is associated with a systemic inflammatory response. Such acute-phase response is manifested by increased circulating IL-6, which varies along with CRP changes and may be related to the urticarial activity.