Proteinuria selectivity index predicts response to rituximab in adults with minimal change disease and focal segmental glomerulosclerosis
Marco Allinovi, Giorgio Trivioli, Gianmarco Lugli, Maurizio Villanti, Iacopo Gianassi, Giulia Antognoli, Paola Romagnani, Augusto Vaglio, Leonardo Caroti, Calogero Lino Cirami
Abstract
The B-cell-depleting antibody rituximab is frequently used in patients with minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS), but there are no predictors of response [1]. These are particularly needed in adult patients, given the substantial incidence of ‘secondary’ forms in this population and the extremely variable outcome after rituximab [2–6]. The proteinuria selectivity index (PSI), i.e. the ratio between the urinary clearance of immunoglobulin G and that of transferrin, predicts response to steroids in children and adults with idiopathic nephrotic syndrome (NS) [7, 8]. A PSI ≤ 0.20, indicating a predominant loss of medium molecular-weight rather than high molecular-weight proteins, was associated with steroid-induced remission in MCD and FSGS [9]. Herein, we explored whether the PSI predicts response to rituximab in adult-onset idiopathic NS. Patients ≥18 years diagnosed with MCD or FSGS who received rituximab at our centre and...