B-cell malignancy and monoclonal gammopathy, and idiotype of cell surface and serum immunoglobulin.

We studied cell surface membrane immunoglobulins (SmIg), intracytoplasmic Ig (CIg) and monoclonal Ig (M protein) in patients with the B-cell series malignancies; malignant lymphoma, chronic lymphocytic leukemia (CLL), Waldenström's macroglobulinemia (WM), multiple myeloma (MM), and monoclonal gammopathy (MG) associated with Sjögren's syndrome (SS). The patients were examined for idyotype (Id) determinants on the cell surface and in the cytoplasm of malignant cells as well as serum M proteins. Twenty-two patients had malignant lymphoma with monoclonal SmIg. The malignant cells of 11 patients contained CIg; four of these 11 patients had a small amount of serum M protein. SmIg of the IgM class was most frequent (12/22) and the lambda type light chain was predominant (kappa/lambda ratio = 4/8). By means of rabbit anti-Id antisera prepared against M proteins, Id determinants were demonstrated on the cell surface and in the cytoplasm of malignant cells as well as in the serum M proteins, indicating that the malignant cells proliferated monoclonally producing monoclonal IgM on the cell surface and in the cytoplasm and secreting it to the serum. Six CLL patients were included in our series; one manifested monoclonal IgM in the serum. The Id determinants of M protein was detected on the cell surface and in the cytoplasm of pathologic cells in the peripheral blood. Eight of ten WM patients were examined for SmIg; all had monoclonal SmIg on the surface of cells from peripheral blood or bone marrow. Id determinants were detected on the cell surface and in the cytoplasm of malignant cells in four WM patients. There were 42 patients with MM; 10 of them were examined for SmIg and three of these had monoclonal SmIg on plasma cells derived from the bone marrow. By immunofluorescent and mixed rosette methods, Id-bearing B (0-20%) and T cells (0-2%) were identified in the peripheral blood of MM patients who had no plasma cells in the peripheral blood. Our findings suggest that a monoclonal change may occur at the B-cell level and that Id-bearing T cells may exist as regulatory T cells. Ten SS patients had M proteins. Non-IgM class M proteins (2 IgG and 4 IgA) were more frequent than the IgM class (3 IgM). Four M proteins with rheumatoid factor (RF) activity were found among these 10 M proteins.(ABSTRACT TRUNCATED AT 400 WORDS)