Secretion of immunoglobulin by neoplastic B lymphocytes from lymph nodes of patients with lymphoma.

An investigation has been made into the ability of neoplastic B lymphocytes obtained from lymphoid tissue of patients with non-Hodgkin's lymphoma (NHL) to secrete immunoglobulin (Ig) in vitro. The majority of the cell populations secreted IgM (17/24 patients), identified as pentameric in three cases examined, and free monotypic light chains (23/24 patients) of the same type as the surface Ig. Secretion of IgD (6/21 patients) and IgG (3/21 patients) was found less frequently. The amounts of Ig secreted were variable and there was no significant difference in the patterns of secretion of cells from NHL patients when compared to previous studies of chronic lymphocytic leukaemia (CLL), nor was there any clear correlation with the histological type. For four of the patients, anti-idiotypic antibody was produced and was used to demonstrate the idiotypic nature of the secreted Ig, and also to show its presence in the serum. The level of idiotypic IgM was measured in one patient during chemotherapy and appeared to correlate well with disease. Such idiotypic Ig must be taken into account when planning treatment of B cell neoplasms with antiidiotypic antibody since it could act as a block to antibody attack. Assessment of the ability of tumour cells to secrete Ig in vitro provides a useful preliminary screen when choosing such patients since a high secretion rate together with extensive disease could lead to unacceptable levels of serum idiotypic Ig.