Laminin in the interstitium indicates prognosis in patients with IgA nephropathy

Laminin is implicated in cell migration, remodelling of the extracellular m atrix and basement membrane. Therefore, laminin deposition could be of conc ern in the progression of some renal diseases. In the present study, immuno histochemical and in situ hybridization studies were performed for laminin in IgA nephropathy (IgAN) specimens in order to reveal the importance of la minin deposition for their prognosis. Fifteen patients were used as the sta ble group who maintained stable renal function for more than 10 years after biopsy. Thirteen patients formed the progressive group who reached end-sta ge renal failure within 10 years after biopsy. Immunohistochemically, lamin in was specifically deposited in damaged glomeruli and strong immunoreactiv ity was particularly shown in the expanded interstitial area containing inf iltrating mononuclear cells. Although the staining score in glomeruli was n ot significantly different between these two groups (P=0.181), deposition i n the expanded interstitium was extensive and significantly greater in the progressive group (P<0.01). In situ hybridization revealed that most of the interstitial cells and some of the tubular cells expressed laminin messeng er ribonucleic acid. In conclusion, the extent of interstitial laminin depo sition was an important prediction of adverse renal outcome, This laminin c ould be produced by interstitial cells and/or tubular cells.