Indeed, while C1q was positive in cases of class V membranous lupus nephritis (n = 2), it was found to be negative in cases of PLA2R1-associated MN (n = 6) and minimal change disease (n = 2) when conventional immunofluorescence was done on frozen sections of kidney biopsies without tissue preprocessing (Fig. 1e and Supplementary Fig. 5). This evidence concerns the gene PLA2R1 and lipoid nephrosis.