[Experimental studies of plasmacytoma. The idiotype as "marker"].

The idiotype is a product of malignant plasmacells and can be identified in a highly specific manner by antiidiotypic antisera. The idiotype is usefull as a tumor-specific marker in myelomas and has been worked with in different problems. The main methods used were: immunofluorescence, internal labeling of immunoglobulins with radioactive-labeled aminoacids, radio-immunobinding-inhibition assay. The results are as follows: 1. Idiotype bearing precursor-cells are detectable in the periphery of myeloma patients. But in our experimental approach we were not able to demonstrate, that these cells are in fact synthesizing the idiotype although the methode has been proved to be sensitive enough. 2. The idiotypic proportion of the total immunoglobulin-fraction (= M-component in the electrophorisis) in myelomasera ranges between 40 and 90%. This percentage remains in the order of 40% even in complete remission. 3. The idiotype as tumorspecific marker is only usefull as an early detector of relapse in patients with complete remission.