[Incidence of monoclonal gammopathies in blood donors].

A routine screening of monoclonal gammopathies (M.G.) was performed in the serum from 36, 015 blood donors by cellulose acetate electrophoresis. The incidence of M.G. was estimated to 0.14 per cent. About 86 per cent of cases can be classified as asymptomatic M.G. and 14 per cent as malignant M.G. (myeloma or Waldenström macroglobulinemia). In asymptomatic forms, heavy chain classes are only IgG or IgM with a large predominance of IgG (86,4%). It is suggested that donors in whom M.G. have been detected should not be allowed to give blood. A yearly clinical, hematological and an immunoglobulin check-up is recommended to these patients in order to defect the first sign of a malignant process.