Serum human epididymis protein 4 is a predictor for developing nephritis in patients with systemic lupus...

It has been demonstrated that serum human epididymis protein 4 (HE4) is a useful biomarker for differentiating lupus nephritis (LN) from systemic lupus erythematosus (SLE). However, it remains unclear whether HE4 can be used to predict the development of LN.

A total of 74 SLE patients without LN were recruited between August 2008 and September 2013. Serum HE4 concentrations were measured by enzyme-linked immunosorbent assay. These patients were followed up from the date of SLE diagnosis to LN development or the end of the study. The receiver operating characteristics (ROC) curve was drawn to assess the predictive value of HE4 for the incidence of LN. In addition, Kaplan-Meier and Cox regression analyses were used to determine the prognostic factors for the incidence of LN.

Serum HE4 levels significantly increased in patients who are positive for anti-dsDNA antibody, low C3 and the incidence LN (P < 0.05), and these were closely correlated with age, erythrocyte sedimentation rate (ESR) and the SLE disease activity index (SLEDAI) (P < 0.05). During the follow-up, 44 patients developed LN. The ROC curve revealed that for HE4 levels, the predictive performance for LN with 64.8 pM as an optimal cutoff yielded an AUC of 0.714, with a 95% confidence interval of 0.597-0.831, and a sensitivity and specificity of 81.8% and 53.3%, respectively. The Kaplan-Meier analysis revealed that LN occurred in 72% of high-HE4 patients and 33.3% of low-HE4 patients (P = 0.036). The univariate analysis revealed that anti-dsDNA antibody, low C3, SLEDAI and HE4 were significantly associated with the incidence of LN (P < 0.05). Multivariate Cox regression revealed that only SLEDAI and HE4 were independently associated with the incidence of LN.

Elevated serum HE4 is significantly associated with a higher risk of incidence for LN, and may be a useful predictor for developing LN.