[Simultaneous presence of macroamylase and macrolipase in a patient]

Here we report a case demonstrating simultaneous macroamylasemia and macrolipasemia. The patient showed persistently elevated serum amylase and lipase activities. On thin-layer gelfiltration, normal serum amylase migrated as a round spot behind albumin. However, serum amylase from this patient migrated slightly ahead of albumin. This finding indicated that serum amylase from this patient had a molecular weight greater than that of normal amylase. Lipase of normal serum was eluted from a Sephacryl S-300 column after the 4S protein. Lipase in the serum from this patient was eluted from the column slightly behind the 19S protein. This finding indicated that serum lipase from this patient also had a molecular weight greater than that of normal lipase. The conversion of macroamylase and macrolipase was observed when the normal serum was mixed with the patient's serum. To determine the isotypes of immunoglobulin (Ig) that was bound to amylase and lipase in the patient's serum, we investigated the effect of adding various anti-human Ig sera to the patient's serum. Amylase activity was precipitated only with anti-IgA lambda and lipase activity was precipitated both with anti-IgA lambda and anti-IgA kappa (anti-IgA kappa > anti-IgA lambda). Taken together, these data indicate that the material that enhanced amylase and lipase activities in the patient's serum was monoclonal IgA; IgA lambda for amylase and both IgA lambda and IgA kappa for lipase.