UCL3D3 AND UCL4D12 REACTIVITY IN SMALL B-CELL NEOPLASMS WITH SPECIAL EMPHASIS ON MONOCYTOID B-CELL LYMPHOMA

Two recently described monoclonal antibodies, UCL3D3 and UCL4D12, have been reported to have some specificity for mantle zone B lymphocytes and marginal zone/follicular center B lymphocytes, respectively, in th e spleen. Forty-nine B-cell neoplasms, including 20 cases of monocytoi d B-cell lymphoma (MBCL), were studied by frozen section immunohistoch emistry with these antibodies to evaluate their utility. Tonsil, lymph node, and reactive spleen also were studied with the antibodies. Alth ough a wide overlap was observed among the different lymphomas, a majo rity of cases of MBCL and half of cases of hairy cell leukemia (HCL) r eacted with both markers, suggesting both marginal/follicular and mant le cell antigen expression. None of four cases of mantle cell lymphoma reacted with the proposed mantle cell marker UCL3D3, whereas three of these cases immunoreacted with UCL4D12. This marker is known to react with a subpopulation of follicular center cells and possibly with mar ginal zone lymphocytes. A comparison of nodal and extranodal neoplasms failed to show a significant difference in the pattern of immunoreact ivity with these antibodies. Tonsil and lymph node controls showed som e mantle zone staining with both antibodies, and there was a slight ov erlap in mantle and marginal zone staining of the spleen controls. The se findings suggest an immunologic similarity between some cases of HC L and MBCL. However, the findings also would suggest that these antibo dies, particularly UCL4D12, have less specificity than has been previo usly assumed, and UCL4D12 may not have practical utility in the evalua tion of low grade B-cell lymphomas. Copyright (C) 1994 by W.B. Saunder s Company