Combined assay of surface immunoglobulin intensity and mouse rosettes. A practical parameter in the differential diagnosis of small lymphocytic and follicular center cell lymphomas.

Cell suspensions from the lymph nodes of small lymphocytic lymphoma (n = 94) and nodular and diffuse follicular center cell lymphomas (n = 330) were analyzed to evaluate the diagnostic significance of the surface immunoglobulin (SIg) intensity and mouse rosette assay (MR). In small lymphocytic lymphoma, SIg was monoclonal in 65 cases (69.15%), with weak fluorescence in 59 (90.77%). It was not detected in 29 cases (30.85%). The MR findings were positive in 68 cases (72.34%) and negative in 26 (27.66%). The combined results of these two assays showed the following: weak SIg/MR+, 35 (37.23%); weak SIg/MR-, 24 (25.53%); strong SIg/MR+, 6 (6.38%); strong SIg/MR-, 0; undetected SIg/MR+, 27 (28.72%); and undetected SIg/MR-, 2 (2.13%). By performing the assays for these two markers and accepting weak SIg/MR+, weak SIg/MR-, strong SIg/MR+, or undetected SIg/MR+ as sufficient for diagnosis, 92 cases (97.87%) were diagnosed. In diffuse follicular center cell lymphomas, SIg was monoclonal in 287 cases (86.97%), with strong fluorescence in 258 (89.9%) and weak fluorescence in 29 (10.1%). It was not detected in 43 cases (13.03%). The MR results were positive in 34 cases (10.3%) and negative in 296 (89.7%). The combined findings of these two assays showed that strong SIg/MR- was present in 244 cases (73.94%). The diagnostic value of the combined assay in the differential diagnosis between small lymphocytic lymphoma and diffuse follicular center cell lymphomas was proved using five statistical parameters.