Intrarenal Localisation Of Platelet Related Antigens, PF4, β-TG, Fibrin And Factor VIII In Patients With Glomerulonephritis
In vivo platelet activation is common in glomerular disease. A strone correlation between platelet serotonin depletion and the factors in the serum which affect platelet aggregation in vitro suggests that platelet activation predominantly occurs in the peripheral circulation. However, platelet activation could occur in the renal microvasculature resulting in the deposition of platelet related antigens at this site. We studied 88 biopsies by immunofluorescence microscopy for the presence of platelet membrane antigen(s), PF4, β-TG, fibrin and factor VIII. β-TG was not observed in any of the biopsies studied. Most biopsies (92%) showed positive endothelial fluorescence for factor VIII antigen, but were otherwise negative. Biopsies from patients with usually benign forms of glomerular disease (minimal change, focal and mesangial proliferative glomerulonephritis) were mostly negative; only 8% showing weakly positive fluorescence for platelet membrane antigens and PF4. Biopsies from patients with usually progressive forms of glomerulonephritis (MCGN, membranous nephropathy, PAN, SLE) were mostly positive (85%) for platelet membrane antigen(s) and PF4. A notable exception was biopsies from patients with FSGS; only two out of 11 biopsies (18%) were positive in this group of patients. The presence of platelet related antigens in glomerulonephritis suggests platelet activation and trapping at this site as well as in the peripheral circulation.