Establishment of idiotype bearing B-lymphocyte clones from a patient with monoclonal gammopathy.

B-lymphocyte clones bearing an idiotypic Ig structure, which could also be found on the serum M-component, have been isolated from peripheral blood of a patient with monoclonal gammopathy (MG) using an immune-rosetting technique and limiting dilution. The majority of the cells had the surface phenotype id+/CD19+/CD20+/CD21+ or id+/CD19+/CD20+/CD21-. Some of the clones originated from spontaneous outgrowth of lymphocytes and some were derived from in vitro Epstein-Barr virus-infected lymphocytes. Three of the B-lymphocyte clones and the patient's bone marrow plasma cells appeared to have clonal identity as shown by the same Ig heavy chain gene rearrangements in Southern blot analysis using a JH probe. The study further supports the notion that the peripheral blood of patients with MG contains B lymphocytes that belong to the tumor clone.