Abstract
A case of diabetes with severe insulin resistance and Sjögren's syndrome was reported by M. Kihata and co-workers in 1973. In 1975, Flier, Kahn and co-workers reported a method for detection of anti-insulin receptor antibodies, and demonstrated the presence of anti-insulin receptor antibodies in the serum of this patient, using circulating human monocytes and cultured human lymphocytes. We attempted to prove the presence of anti-insulin receptor antibodies in the serum of the same patient, using pellets of insulin receptors obtained from human placental tissues (human placental membrane), and obtained the following results.
1) Although this patient had been injected with several thousand units insulin without hypoglycemia, the serum was negative for anti-insulin antibodies and the serum immunoreactiveinsulin (IRI) was 960μu/ml.
2) The binding of 125I-insulin to human placental membrane preincubated by the patient serum was inhibited.
3) Also the binding of 125I-insulin to human placental membrane was markedly inhibited by the protein fraction of the serum eluted with the Sephadex G-50 column.
4) The immunoglobulin class of this protein fraction which inhibited binding was IgG.
It is suggested that the use of human placental membrane for the detection of anti-insulin receptor antibodies in the serum would be possible.
