Serum transglutaminase 2 activity as a potential biomarker of disease severity and response to omalizumab in chronic spontaneous urticaria

Abstract

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No.2018R1A2B6009178) and Hallym University Research Fund 2017 (HURF-2017-76). Transglutaminase 2 (TG2) is expressed in mast cells and contributes to allergic asthma. We have previously reported that TG2 was associated with the pathogenesis of chronic spontaneous urticaria (CSU). The aim of this study is to investigate the clinical implication of serum TG2 levels in CSU. Patients with CSU (n=111), acute urticaria (AU, n=31), and normal controls (NC, n=45) were enrolled. TG2 activity in serum were measured by ELISA. Serum TG2 activity was serially measured in 9 patients with CSU in accordance with omalizumab treatment. Patients were divided by disease severity (mild, moderate, severe, very severe) which is defined by the treatment level from the guidelines for treatment of CSU. Student’s T-test and Wilcoxon signed-rank test were done for statistical analyses using SPSS, ver. 21 (SPSS Inc, Chicago, Illinois). TG2 activity was significantly higher in sera of CSU patients (132.8 ± 81.6 mU/mL) than AU (86.4 ± 57.8 mU/mL) and NC (70.0 ± 42.4 mU/mL). (P < 0.05, respectively), while Serum TG2 activity in AU was not significantly different from NC (P > 0.05). Serum TG2 activity in CSU patients was significantly increased according to disease severity (mild: 87.1 ± 66.3 mU/mL, moderate: 136.1 ± 64.0 mU/mL, severe: 159.7 ± 59.0 mU/mL, very severe: 222.1 ± 68.1 mU/mL, P < 0.0001). Initial TG2 activity was significantly decreased after omalizumab treatment (P < 0.05). Serum TG2 activity represents disease severity of CSU. Serum TG2 activity could be a useful marker of disease severity and treatment response of CSU.