The ultrastructural morphology of the mesangial cell in IgA nephropathy.

By means of electron microscopy, three types of mesangial cell change were identified in IgA nephropathy. They represented proliferative, phagocytic and resting mesangial cells. The proliferative mesangial cells were characterised by the presence of centrioles, numerous free ribosomes, well developed Golgi apparatus and SER. They were found in the proliferative forms of IgA nephropathy. Phagocytic mesangial cells had numerous spinous cytoplasmic processes, better differentiated RER and numerous dense bodies and lipid inclusions. They were found in all histological forms of IgA nephropathy. The resting mesangial cells were unusual and were occasionally present in cases with normal numbers of mesangial cells.