Clinical Relevance of Plasma miR‐21 in New‐Onset Systemic Lupus Erythematosus Patients

Background Plasma miR‐21 is widely investigated as biomarker in many diseases. Recent studies show that miR‐21 participates in the development of systemic lupus erythematosus (SLE). The aim of this study was to evaluate the expression profile of miR‐21 in the plasma of SLE patients. Methods Relative quantities of plasma miR‐21 both in SLE patients and healthy controls were determined by relative qRT‐PCR under endogenous and exogenous controls. The diagnostic value of plasma miR‐21 was evaluated in SLE patients. Data of some SLE‐associated clinical parameters were collected. Results Eighty participants from Central China were recruited. Forty‐four participants were new‐onset SLE patients and the others were healthy controls. Plasma miR‐21 level in SLE patients was higher than that of healthy controls ( P = 0.031). Receiver operating characteristic analysis of plasma miR‐21 revealed an Area Under Curve (AUC) of 0.64 ± 0.06 (95% CI: 0.51–0.76, P = 0.03854) when differentiating SLE from healthy controls. The level of plasma miR‐21 was not associated with the level of white blood cells ( P = 0.4284), red blood cells ( P = 0.4079), and platelets ( P = 0.4961), but significantly correlated with the level of plasma complement C3 ( r = −0.5297, P = 0.0004), C4 ( r = −0.4732, P = 0.0020), and serum uric acid ( r = 0.3932, P = 0.0121) in SLE patients. Conclusions Plasma miR‐21 in SLE patients from Central China is overexpressed. Since circulating miR‐21 is aberrantly expressed in many diseases, the applying of it as a disease biomarker should be considered carefully.