Is decreased imipramine binding by platelet membranes in major depression associated with plasma autoantibodies to imipramine binding sites?

Decreases in super(3)H-imipramine binding sites on platelets (B sub(max)) without a significant change in the ligand affinity (K sub(d)) are found in some patients with major depression. The mechanism underlying the reduction in binding site density is not understood. IgGautoantibodies binding to a variety of specific receptors are known to be important in the pathogenesis of several diseases, including Addison's disease, Graves' disease, myasthenia gravis, and insulin-resistant diabetes mellitus. Accordingly, we studied the effects of IgG from untreated patients with major depression on super(3)H-imipramine binding on platelets from normal volunteers.