Urinary MCP-1 as diagnostic and prognostic marker in patients with lupus nephritis flare

Abstract

This study aimed to assess correlation of urinary monocytic chemoattractant protein-1 (UMCP-1) with severity of lupus nephritis and its role as predictor of outcome. Twenty patients with lupus nephritis flare were included in the study. Ten patients in each group of stable systemic lupus erythematosus and non-renal flare were taken as controls. Biopsy was done to define lupus nephritis stage. UMCP-1 levels were measured in all patients at the time of entry and at four and eight weeks of follow-up. Mild, moderate and severe lupus nephritis flare was noted in one, five and 15 patients, respectively. UMCP-1 levels were high in patients with severe lupus nephritis flare (2.74 ± 0.95 ng/mg creatinine) as compared to patients with moderate (1.43 ± 0.46 ng/mg creatinine) and mild lupus nephritis flare (0.76 ± 0.57 ng/mg creatinine) (P = 0.0093). Baseline mean UMCP-1 levels in lupus nephritis flare, non-renal flare and stable SLE patients were 2.32 ± 1.06, 0.171 ± 0.03 and 0.213 ± 0.026 ng/mg creatinine, respectively. The difference among the three groups was very significant (P < 0.001). Also, mean UMCP-1 levels correlated significantly with severity of lupus nephritis class (P = 0.0358). During follow-up, 15 patients achieved complete or partial remission, and in these patients mean UMCP-1 levels had significant decline at eight weeks (P < 0.0001). However, mean UMCP-1 levels in the remaining five non-responders did not show significant changes at four and eight weeks (P = 0.4858). Mean UMCP-1 levels were significantly higher in the lupus nephritis flare group as compared to non-renal flare and stable patients. Baseline mean UMCP-1 levels significantly correlated with both lupus nephritis class and severity of lupus nephritis flare, hence UMCP-1 could be used as a non-invasive marker for the judgement of lupus flare and lupus nephritis class.