Biomarkers of disease activity in patients with chronic spontaneous urticaria

Introduction
Previous studies have examined biomarkers of coagulation, inflammation and immunity in chronic spontaneous urticaria (CSU), but no recommended biomarkers for disease activity have been established yet.

Aim
To find the relationship between certain laboratory parameters and disease activity in patients with CSU.

Material and methods
Serum concentrations of D-dimer, C-reactive protein (CRP), C3, C4, and prothrombin time (PT), activated partial thromboplastin time (aPTT) values were measured in 44 CSU patients and compared with 33 healthy controls. Correlation between biomarkers and urticaria activity score during 7 consecutive days (UAS7) was calculated.

Results
Our study included 44 CSU patients (38 females and 6 males), mean age of 50.4 years and the average disease duration of 3.1 years. Based on UAS7, 23 (52.3%) CSU patients had mild urticaria, 8 (18.2%) well-controlled, 7 (15.9%) moderate and 6 (13.6%) severe urticaria. Fourteen (31.8%) patients had elevated CRP, 21 (47.7%) had elevated D-dimer and 14 (13.6%) CSU patients had elevated C4 levels. Patients with CSU had statistically significant elevated D-dimer, CRP and PT as compared with controls (p = 0.007, p = 0.005 and p = 0.029, respectively). There was no correlation between PT, aPTT, D-dimer, CRP, C3 and disease activity. Statistically significant differences in C4 levels between patients with severe and well-controlled, mild, moderate urticaria were determined (p = 0.003).

Conclusions
CRP, D-dimer, and PT may be considered as biomarkers for distinguishing patients with CSU from controls. The C4 levels correlate with disease activity and may be useful as a potential biomarker of disease activity.