Comparative studies of a monoclonal IgG lambda and two IgE kappa components from an individual patient: evidence for shared idiotypic determinants between the two IgE proteins but not with the IgG lambda protein.

An IgG lambda and two IgE kappa proteins were isolated from the serum of a patient (DB) with anaemia associated with myelofibrosis. Idiotype-specific antisera produced against the three proteins were studied by precipitation in double immunodiffusion and by enzyme-linked immunosorbent assay (ELISA) and indicated that the two IgE kappa components shared idiotypic determinants while the IgG lambda protein did not show any cross-idiotypic reaction. The idiotypic determinants of the three proteins were not present in pooled normal serum, normal IgG, normal IgE or IgE from a patient with multiple myeloma.