[Macroamylasemia. Immunoglobulin a-amylase-complexes as rare cause of hyperamylasemia (author's transl)].

A 56 year old diabetic woman with persistent hyperamylasemia, with an extremely low renal clearance of amylase and without signs of pancreatic disease was found to have an abnormally large serum amylase. This macroamylase had a molecular size of 450,000 Daltons in gel filtration and could be dissociated at low pH values. By the use of chromatographic, electrophoretic and immuno-chemical tests, it was possible to identify the macroamylase as a complex formed by immunoglobin A (IgA kappa) along with normal pancreatic and parotic amylase. The immunoglobulins had a high affinity for human pancreatic and salivary amylase as well as for hog pancreatic amylase. It remains unclear if the amylase binding immunoglobulins are autoantibodies. The finding of macroamylasemia should prevent patients from being subjected to superflous investigation and meaningless treatment.