A kinetic analysis of immune-mediated clearance of erythrocytes.

A mathematical expression has been derived that successfully correlates the kinetic data for the immune-mediated clearance of red blood cells. The expression resulted from the solution of differential equations arising from a clearance mechanism that was, essentially, consistent with that described by Schreiber and Frank. The mathematical expression correlated data for both IgG-and IgM-mediated reactions. Four different rate constants appear in the final kinetic equation; these constants, which measure the rates of the various steps in the clearance process, were evaluated by an iterative curve-matching process. The values of the rate constants were found to be dependent upon type of sensitizing immunoglobulin, number of C1-fixing sites, and several known immune system modifiers. Correlation of the derived rate expression with the experimental data provided a critical test for the Schreiber-Frank mechanism and the values of the rate constants provided additional insights into the immune clearance process.