Analysis of urinary macrophage migration inhibitory factor in systemic lupus erythematosus

Objective To characterise the clinical relevance of urinary macrophage migration inhibitory factor (uMIF) concentrations in patients with systemic lupus erythematosus (SLE). Methods MIF, adjusted for urine creatinine, was quantified by ELISA in urine samples from 64 prospectively recruited patients with SLE. Serum MIF and urinary monocyte chemoattractant protein 1 (uMCP-1) were quantified by ELISA in a subset of patients (n = 39). Disease activity was assessed using the SLE Disease Activity Index-2000 (SLEDAI-2K) score. Results uMIF was detectable in all patients with SLE. uMIF was positively correlated with overall SLEDAI-2K, was significantly higher in patients with SLE with high disease activity (SLEDAI-2K≥10) compared with those with inactive disease (SLEDAI-2K Conclusions These data suggest uMIF as a potential overall but not renal-specific SLE biomarker, whereas uMCP-1 is a renal-specific SLE biomarker.