Low serum uromodulin levels and their association with lupus flares.

BackgroundOnly two previous studies in systemic lupus erythematosus (SLE) patients have identified that the blood concentrations of uromodulin are lower in nephritis. However, none of them had evaluated whether a low serum uromodulin adjusted by the glomerular filtration rate (sUromod/eGFR index) contributed to identify patients in risk of lupus nephritis (LN) using multivariable models.AimTherefore, this study aimed two objectives to evaluate the association between low serum uromodulin levels and low sUromod adjusted by eGFR with renal flares in SLE excluding effects of potential confounders in multivariable analyses; and to identify the value of low sUmod and low sUmod/eGFR index as a potential diagnostic marker of LN.Patients and methodsDesign: Cross-sectional study. SLE patients (n = 114) were investigated for lupus flare with renal SLEDAI. Two groups: a) SLE with renal flare (renal-SLEDAI≥4, n = 41) and b) SLE non-renal flare (renal SLEDAIResultsLow serum uromodulin and low sUromod/eGFR index correlated to high scores of renal-SLEDAI, SLICC-renal and proteinuria. SLE patients with a renal flare had lower uromodulin levels compared to SLE patients without renal flare (p = 0.004). After adjusting by potential confounders, the low sUromod/eGFR index (ConclusionsWe propose the low sUromod/eGFR index as a potential new marker of renal disease activity in SLE.