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

AIM OF THE STUDY: 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.
METHOD: 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.
RESULTS: 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).
CONCLUSION: 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.