INTRACYTOPLASMIC AND SURFACE-BOUND IMMUNOGLOBULINS IN NONSECRETORY AND BENCE-JONES MYELOMA

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  • 1 January 1976
    • journal article
    • research article
    • Vol. 25  (3) , 428-436
Abstract
Immunoglobulins [Ig] were studied at the cellular level by direct immunofluorescence in 25 patients with nonsecretory myeloma and 36 patients with Bence-Jones (BJ) myeloma. The results were compared with those obtained in a control group of 36 patients with common secretory myeloma. A monoclonal Ig (IgG in 18, IgA in 3 and .kappa. chains only in 3 cases) was found in the cytoplasm of the plasma cells from all patients with nonsecretory myeloma, with a striking dysbalance in the staining brightness for heavy and the light chains. A similar dysbalance in staining was also observed for plasma cell surface Ig chains but in the opposite way. In 20 patients with BJ myeloma studied for cytoplasmic Ig only, determinants of a heavy chain were found in 4 cases. When surface Ig were also studied the production of .gamma. chains in addition to the light chain could be ascertained in 6 of 16 cases. IgM with the same light chain type as the BJ protein was detected at the cell surface on plasma cells and lymphocytes in 2 of these 16 patients. Monoclonal populations of B [bone marrow-derived] lymphocytes bearing the same Ig chains as those produced by the myeloma cells were detectable in 5 of 11 nonsecretory myeloma and in 5 of 16 BJ myeloma patients. Normal blood B lymphocytes were in decreased number, particularly when a monoclonal lymphocytic population was detected. Data are discussed which suggest that plasma cells from most patients with nonsecretory myeloma might synthesize and secrete Ig molecules with structurally abnormal chains that are quickly degraded.