Immunologic markers in the differential diagnosis of non-Hodgkin's lymphomas

Summary

To improve the classification of the phenotypes of the various types of non-Hodgkin's lymphoma (NHL), 250 cases of NHL were analyzed with immunologic and enzyme cytochemical techniques. The results confirmed previous findings. Chronic lymphocytic leukemia of B-cell type (B-CLL) is characterized by a small amount of surface immunoglobulin (SIg), a predominance of C3d receptors, a large number of mouse erythrocyte receptors, and a low T-cell content. Chronic lymphocytic leukemia of T-cell type (T-CLL) has at least two subtypes: one shows a dot-like reaction product in cells stained with acid nonspecific esterase and the other does not. In prolymphocytic leukemia, there is a constantly high percentage of SIg-positive cells and a large amount of SIg on each positive cell; C3b receptors usually preponderate over C3d receptors; and there is a large number of IgG-Fc receptors. The surface marker phenotype of hairy-cell leukemia is similar to that of prolymphocytic leukemia except that hairy cells are devoid of C3 receptors and usually show a high density of IgM-Fc receptors. T-zone lymphoma usually contains both T cells and B cells. The T cells are capable of binding sheep erythrocytes only at 4 °C and can be identified cytologically as the tumor cells. In contrast, the B cells stem from residual follicles, which are often present in T-zone lymphoma at the time of the first biopsy. Three types of lymphoplasmacytic/-cytoid lymphoma (LP immunocytoma) are distinguished on the basis of morphologic features. The marker constellation of the lymphoplasmacytic subtype resembles that of centroblastic-centrocytic lymphoma. The lymphoplasmacytoid subtype and borderline cases between this subtype and B-CLL show the same markers as does B-CLL. The third subtype of LP immunocytoma, the polymorphic subtype, differs in its marker profile from all other types of NHL. The three types of lymphoma derived from germinal center cells resemble each other in the expression of nearly equal numbers of C3b and C3d receptors and a low percentage of IgG-Fc receptors. Centrocytic lymphoma is distunguished from centroblastic-centrocytic lymphoma by a large proportion of cells bearing SIg and C3 receptors and by the absence, or small proportion, of T cells and cells rosetting with mouse erythrocytes. Centroblastic lymphoma shows a marker profile that is similar to that of centroblastic-centrocytic lymphoma. The Burkitt type of lymphoblastic lymphoma shows a unique marker profile, with a high percentage of SIg-positive cells and no other markers. Analysis of lymphoblastic lymphoma of the convoluted-cell type (including cases of acute lymphoblastic leukemia with a focal acid phosphatase reaction) revealed four phenotypes. Cases with the first phenotype show C3 receptors (usually both subtypes) and a lack of sheep erythrocyte receptors. In cases with the second phenotype, the cells express both C3 receptors and sheep erythrocyte receptors. Cases with the third phenotype lack C3 receptors but contain cells rich in receptors for sheep erythrocytes that bind at 37°C. Nearly all of the cases with these three phenotypes are devoid of acid nonspecific esterase. Cases with the fourth phenotype lack C3 receptors, exhibit sheep erythrocyte receptors that bind only at 4°C, and show a focal acid nonspecific esterase reaction. Eight of nine cases of immunoblastic lymphoma showed SIg and were thus identified as B-cell derived. The ninth case was of T-cell type, as indicated by the capacity of the tumor cells to form rosettes with sleep erythrocytes.