Possible existence of anti-renal tubular plasma membrane autoantibody which blocked parathyroid hormone-induced phosphaturia in a patient with pseudohypoparathyroidism type II and Sjögren's syndrome.
We examined the effects of serum from a patient with pseudohypoparathyroidism type II and Sjögren's syndrome on renal function in rats. Infusion of 50-100 mg of the patient's immunoglobulin G (IgG) fraction inhibited the PTH-induced increase in urinary phosphate excretion, but had no effect on the PTH-induced increase in urinary cAMP excretion. Infusion of the IgG fraction obtained from the sera of control subjects did not affect PTH-induced increases in urinary excretion of either cAMP or phosphate. Binding of the patient's serum IgG fraction to the membrane of isolated rat renal cortical tubules was observed by immunofluorescent techniques. We conclude that the IgG fraction from the serum of this patient with pseudohypoparathyroidism type II and Sjögren's syndrome contains an autoantibody(ies) reacting with a component(s) of renal tubular plasma membranes and blocking PTH-induced phosphaturia.
D000328:Adult; D001323:Autoantibodies / Q000302:isolation & purification*; D002462:Cell Membrane / Q000276:immunology; D000242:Cyclic AMP / Q000652:urine; D005260:Female; D006801:Humans; D007672:Kidney Cortex / Q000276:immunology; D007684:Kidney Tubules / Q000276:immunology*; D010281:Parathyroid Hormone / Q000037:antagonists & inhibitors*; D010710:Phosphates / Q000652:urine*; D011547:Pseudohypoparathyroidism / Q000276:immunology* / Q000378:metabolism; D012859:Sjogren's Syndrome / Q000276:immunology* / Q000378:metabolism
D001323:Autoantibodies; D010281:Parathyroid Hormone; D010710:Phosphates; D000242:Cyclic AMP