PLG and glomerulonephritis: Indeed, positive staining for NAPlr and plasmin activity has been used as a marker of IGRN in patients with various forms of glomerulonephritis, such as proliferative glomerulonephritis with monoclonal immunoglobulin G deposits [33] and eosinophilic proliferative glomerulonephritis [34], even if neither the pathogens nor the infection sites could be identified.