Microfibrils in glomerulopathies of children: an ultrastructural study.

Extracellular microfibrils were found in 47 per cent. of 360 renal biopsies performed in children with a variety of nephropathies. They were observed in the mesangial matrix and basal lamina. They are 17 to 35 nm in diameter and a few show cross-striations with a periodicity of about 10 nm. They are different from fibrin or interstitial collagen. Their close association with thinner filaments in the mesangial matrix and basal lamina suggests that they are derived from such filaments.