Demonstration of immunoglobulin production by tumor cells in non-Hodgkin's and Hodgkin's malignant lymphomas and its significance for their classification.

Combined application of morphologic, immunochemical, and immunologic methods has led to a reinterpretation of non-Hodgkin's lymphomas and to the establishment of the Kiel classification. In the present paper, the main Ig-producing entities are considered. These are: 1. Chronic lymphocytic leukemia of the B-type (B-CLL)--a proliferation of lymphocytes and a few so-called prolymphocytes and lymphoblasts. The mean tissue IgM value is slightly increased; the serum IgM level is normal or reduced. The tumor cells bear SIg, and a majority of them have a receptor for C3d but always lack CIg and are usually devoid of receptors for C3b. 2. Lymphoplasmacytoid immunocytoma--a mixed proliferation of lymphocytes and centrocytes, blast cells, plasma cells, or plasmacytoid cells. The tissue Ig content is most often (91%) and most highly increased in this group, whereas the serum Ig level is increased in only 20% of the cases. The tissue IgM of 17 cases was shown to be monoclonal by IEF. Most tumor cells have SIg and a variable numbear CIg. The tumor cells bear both complement receptor subtypes, only a receptor for C3b, or no complement receptors at all. 3. Centroblastic/centrocytic lymphoma--usually a follicular proliferation of abundant small germinal center cells (centrocytes) and some large germinal center cells (centroblasts). The tumor cells bear SIg and both complement receptor subtypes. The C3b- and C3d-positive cells are located in the follicles, as in nonneoplastic lymphatic tissue. 4. Centrocytic lymphoma--a purebred, diffuse proliferation of the small germinal center cells (centrocytes). These cells bear SIg and receptors for C3b and C3d but usually lack CIg. 5. Centroblastic lymphoma--a proliferation of the large germinal center cells (centroblasts). 6. Lymphoblastic lymphoma of Burkitt's type. 7. Immunoblastic lymphoma--a diffuse proliferation of large basophillic cells resembling immunoblasts. The tissue IgM content is increased in 60% of the cases. It proved to be monoclonal with IEF in all five cases studied. The cells of five cases with increased tissue Ig content bore SIg. Nearly half of the cases studied showed CIg. Besides non-Hodgkin's lymphomas, paraffin sections of 87 biopsies from Hodgkin's disease were investigated for CIg in Hodgkin's and Sternberg-Reed cells. These cells stained positively in 68 cases, most often for IgG, followed by IgD. In five cases of the lymphocyte-depleted type, the staining of the Hodgkin's and Sternberg-Reed cells was restricted to one light chain type.