Detection of podocyturia in patients with lupus nephritis

Abstract

INTRODUCTION: The podocyturia has been detected in glomerular diseases, such as lupus nephritis (LN), in which proteinuria is an important manifestation, and its occurrence seems to be limited to the active phase of the disease. OBJECTIVE: To evaluate podocyturia in LN patients, and the possible association with clinical disease activity. METHODS: We evaluated 56 patients with LN, that were classified in three groups according to the degree of clinical activity: Group B, no activity (n = 17), Group C with mild (n = 29) and Group D, moderate to severe activity (n = 10). The control group was composed by 29 healthy subjects (Group A). The podocyturia was studied by indirect immunofluorescence using primary antibodies to podocyte: anti-podocin, nephrin and synaptopodin, and a secondary antibody conjugated with FITC. We also evaluated serum creatinine levels, urinary protein/creatinine (P/C) ratio, hematuria and leucocituria. RESULTS: The podocyturia with anti-podocin and anti-sinaptopodin correlated statistically with the P/C ratio (p = 0.001 and p = 0.013, respectively). The podocyturia with anti-podocin, as well as the P/C ratio showed significant correlation (p < 0.001) with the degree of lupus disease activity, unlike the other two antibodies, anti-nephrin and anti-synaptopodin. CONCLUSION: Our findings show that podocyturia with anti-podocin could be useful in monitoring disease activity in LN patients.