IgAVN patients are similar to IgAN patients in the presence of IgG autoantibodies against Gd-IgA1 in the serum, and the level is higher in the acute period of nephritis than in the resolution phase (37), and co-sedimentation of IgG and Gd-IgA1 immune complexes is seen in the kidney mesangial region by confocal microscopic analysis (25). Here, IGHA1 is linked to nephritis.