Background: Lupus nephritis was established as the major cause of morbidity and mortality in systemic lupus erythematosus (SLE) patients. This severity could be monitored by laboratory prognosis with accuracy and specificity for the disease. Recently, various SLE laboratory investigations still have had improper prognosis and also possibly causing tissue injury in the patients. The present study thus aimed to systematically explore a novel urinary protein for further development into a prognosis biomarker in patients.
Methods: Several urinary proteins that previously were reported with abnormal expression in SLE patients between 2014 - 2019 were comprehensively collected. These proteins were also analyzed for functional category and sites of expression using STIRNG, FUNRICH, and Uniport database. Thereafter, the level of altered protein candidate was then validated by western blotting, correlation analysis, and diagnostic performance.
Results: Vascular cell adhesion molecule-1 (VCAM1) protein was found in higher levels and also specific in SLE patients with nephritis. Moreover, VCAM1 has a role in immune response, inflammation, is expressed on plasma membrane of renal cells, and has the ability to secret into urine. The level of VCAM1 in urine of SLE patients was significantly higher than in healthy controls. The area under ROC curve (AUC) was also 0.891. Furthermore, the level of VCAM1 was dramatically associated with the severity of renal insufficiency (r = 0.738).
Conclusions: VCAM1 may be a novel urinary biomarker for reliable prognosis of nephritis severity in SLE patients.