PLA2R1 and nephrotic syndrome: The primary objective of the study is to compare the efficacy of a personalized treatment (stratifying the patients according to their epitope spreading status at month-0 and month-6 and treating them accordingly with either low or high dose rituximab) with the GEMRITUX therapeutic protocol (low dose rituximab after 6 months of symptomatic treatment) to induce clinical remission of the nephrotic syndrome at month-12 in patients with nephrotic iMN driven by anti-PLA2R1 antibodies.