SLT-1 receptor (CD77) expression on lymphoma. The expression of SLT-1 receptors on malignant lymphoma was detected using a fluoresceinated binding subunit of SLT-1 (FITC-SLT-B). Cell suspensions recovered from patient samples (peripheral blood, fine-needle aspirates, lymph node, and BM biopsies) were sent to a flow cytometry unit (Ontario Cancer Institute) for immunophenotyping. A lymphocyte population in which 15% of the cells stained positively with FITC-SLT-B (dashed line) was defined as positive for the presence of SLT-1 receptors. This percentage value (15%) was calculated from the average percentage of FITC-SLT-B–positive cells (3% ± 4%) observed in samples of noncancerous patients, plus 3 SD. Abbreviations used: B-LL/ALL, B-cell lymphoblastic lymphoma/acute lymphoblastic leukemia; ML, LG, malignant lymphoma, low grade (nonclassifiable); B-CLL/SL, small lymphocytic lymphoma with or without chronic lymphocytic leukemia; HCL, hairy cell leukemia; LPL, lymphoplasmacytoid lymphoma; FCC I, follicle center cell lymphoma, follicular, grade I; FCC II, follicle center cell lymphoma, follicular, grade II; FCC III, follicle center cell lymphoma, follicular, grade III; MCL, mantle cell lymphoma; MZL, marginal zone lymphoma; D-M, diffuse-mixed small- and large-cell lymphoma; B-LC, diffuse large B-cell lymphoma; T-PLL, T-cell chronic lymphocytic lymphoma, prolymphocytic leukemia; AILD, angioimmunoblastic T-cell lymphoma; ALCL, anaplastic large-cell lymphoma; ATL/L, adult T-cell lymphoma/leukemia; T-LL/ALL, T-cell lymphoblastic lymphoma/acute lymphoblastic leukemia; T-LC, T-cell intermediate-grade large-cell lymphoma. Patients with diffuse large B-cell lymphoma who had a documented history of follicle center cell lymphoma were included in the FCC-III category.