Characterization of interleukin-33 and soluble ST2 in serum and their association with disease severity in patients with chronic kidney disease.

INTRODUCTION: This study aims to test the serum levels of interleukin-33 (IL-33) and soluble ST2 (sST2) in patients with chronic kidney disease (CKD) and to evaluate their association with disease severity. METHODS: Sixty-nine patients with CKD were enrolled, disease severity was assessed, and clinical data were collected. Twelve healthy volunteers served as healthy individuals. Serum IL-33 and sST2 were tested by enzyme-linked immunosorbent assay. RESULTS: The patients were classified into five categories based on their estimated glomerular filtration rate (eGFR). No difference was found as to the serum concentration of IL-33 between CKD patients and healthy individuals (p = 0.656), while a higher serum level of sST2 was found in CKD patients (p = 0.003). The correlation analysis revealed a significant correlation between the serum level of sST2 and disease severity (r = 0.586; p < 0.001). A higher level of sST2 was found in CKD patients with elevated parathyroid hormone (p = 0.001). Serum sST2 correlated with parathyroid hormone (r = 0.412; p < 0.001), serum phosphorus (r = 0.545; p < 0.001), and serum calcium (r = -0.494; p < 0.001). CONCLUSION: An elevated concentration of serum sST2 is found in CKD patients and correlates with disease severity. Serum sST2 may be also associated with parathyroid hormone disorder of CKD. The sST2 may have an important role in the development of CKD or as a marker of disease severity.