Immunofluorescence microscopy showing mesangial immunoglobulin A (IgA) deposits

Immunofluorescence microscopy demonstrating large, globular mesangial IgA deposits that are diagnostic of IgA nephropathy or IgA vasculitis (Henoch-Schönlein purpura). Note that the capillary walls are not outlined since the deposits are primarily limited to the mesangium.