C3 and rapidly progressive glomerulonephritis: With the clinical suspect of an infection-triggered rapidly progressive glomerulonephritis (RPGN) superimposed on SRNS, we performed a second kidney biopsy which confirmed a proliferative GN with few crescents, as well as IgG and C3 deposition along the glomerular basement membrane (Figure 1e, Table 1, and Supplementary Figure S1C and D).