Heparin causes partial removal of glomerular antigen deposits by a mechanism independent of its anticoagulant properties.

We have previously reported that heparin can enhance the removal of antigen from the glomeruli of rats with chronic serum sickness glomerulonephritis. We have performed two studies to investigate the relevance of anticoagulation to this effect. The first experiment was essentially a repeat of those described before, but instead of using heparin, anticoagulation was achieved using Ancrod, which causes depletion of fibrinogen. The amount of antigen in the glomeruli of these rats at the end of the experiment did not differ from controls. In the second experiment, both kidneys were excised from rats with glomerulonephritis induced by a radiolabelled cationic antigen. Of each pair of kidneys, one was perfused for 30 min at 5 ml/min with Hank's balanced salt solution (HBSS) at 37 degrees C. The other was perfused with HBSS to which a total of 4500 units of heparin had been added. The antigen content of isolated glomeruli was subsequently measured. In every case, the kidney perfused with heparin had less antigen per glomerulus than the control contralateral kidney. The ability of heparin to enhance removal of glomerular immune complex deposits is therefore not mediated by anticoagulation.