Circulating immune complexes containing bovine insulin in a patient with systemic allergic manifestations

A woman treated for 15 days with bovine insulin for gestational diabetes presented with severe urticaria of the chest and back, distant from the injection site. She had neither local reaction nor general manifestations. Replacement of bovine NPH insulin by biosynthetic human NPH was followed by regression of urticaria. We isolated the circulating immune complex (CIC), mainly of IgG class, from the patient's serum. It disappeared when bovine insulin administration had been ceased for 48 h. There were no specific IgE-insulin-antibodies. The IgG-CIC were dissociated. Insulin was identified by RIA in the CIC. Insulin characterization was carried out by high-performance liquid chromatography (HPLC), which showed that the insulin in the complexes was injected bovine insulin.