Intraglomerular localization of platelet related antigens, platelet factor 4 and beta-thromboglobulin in glomerulonephritis.

We examined renal biopsies from 121 patients with various forms of glomerulonephritis, using antisera against platelet membrane antigens, platelet factor 4, beta-thromboglobulin and fibrinogen using the indirect immunofluorescent technique. Eight biopsies were also studied by electron microscopy for recognizable platelets. Thirty-six of sixty-four (56%) biopsies from patients with severe forms of glomerulonephritis showed some intraglomerular platelet antigen, extensive fluorescence in seventeen (25%). Of forty-six patient with milder, usually non-progressive forms of nephritis, twenty (44%) were positive, but only four (9%) showed extensive fluorescence. Platelets were identified by electron microscopy within the capillary lumina equally in those with positive and negative results for platelet-related antigens. There was no correlation between the presence of fibrin and platelet-related material in the glomeruli, nor between the presence or extent of intraglomerular platelet antigen and simultaneous measurements of intraplatelet serotonin in circulating platelets. However, there was a strong correlation between presence, extent and distribution of platelet-related antigen and platelet factor 4 fluorescence. These studies provide further evidence for the involvement of platelets in some forms of glomerular disease.