Ectopic production of salivary-type amylase by a IgA-lambda-type multiple myeloma.

A patient with IgA-lambda-type multiple myeloma who appeared to be secreting salivary-type amylase ectopically is reported. Both the patient's serum and urine contained high levels of amylase. Amylase activity in the supernatant of cultured myeloma cells, obtained from the patient's pleural effusion while he had malignant pleuritis, increased almost linearly from the time of cell seeding. The presence of IgA and S-type amylase in the myeloma cells was demonstrated cytochemically and by immunoelectron microscopy. These observations showed that amylase was produced by these human myeloma cells.