[Studies on the intraglomerular distribution of fibronectin in IgA nephropathy--in relation to clinical pictures and prognosis].

Forty-seven patients with IgA nephropathy were classified as having mesangial pattern (M: 29 cases) or mesangiocapillary pattern (C: 18 cases) according to an intraglomerular distribution of fibronectin (FN) observed by the immunofluorescence (IF) technique. The relationships between these IF patterns and the clinical pictures, and that between these IF patterns and prognosis of the disease were investigated. Significantly higher diastolic blood pressure, proteinuria, serum creatinine (Cr), total cholesterol and IgA, and lower total protein were noted in C pattern as compared with M pattern. beta-thromboglobulin, fibrinogen (Fib) and platelet factor 4 were found to be significantly higher in C pattern. Platelet aggregation (ADP 1 microM/ml) and FN tended to increase (p less than 0.1) as well. The distribution of FN in the glomeruli was similar to those of IgA and Fib, although perfect agreement was not observed. The picture in which FN might be infiltrated into the endothelial side of the glomerular basement membrane from the mesangium was observed in C pattern by the immunoelectron microscopic study. In the follow-up study, proteinuria showed a tendency to decrease in M pattern. On the other hand no marked change was observed in C pattern. C pattern showed high serum Cr levels throughout the course of the study as compared with M pattern. A significantly greater number of C pattern cases had serum Cr of 2 mg/dl or higher, C pattern showed a significant decrease of 1/Cr over time as compared with M pattern. Higher serum Fib and FN, platelet aggregation (ADP 1 microM/ml), antithrombin III and plasminogen were observed in C pattern as compared with M pattern. These results suggest that an involvement of tissue FN, especially the existence of FN in the capillary loop, may be an aggravating factor of IgA nephropathy, in addition to an augmented platelets-blood coagulation mechanisms. Therefore, it may be possible to evaluate the prognosis of IgA nephropathy by FN deposit patterns.