FREQUENT EXPRESSION OF SHARED IDIOTYPES IN MANTLE CELL LYMPHOMA AND EXTRANODAL SMALL LYMPHOCYTIC NON-MANTLE CELL DIFFUSE SMALL CLEAVED LYMPHOMA/

A panel of 14 anti-shared idiotype (Sld) monoclonal antibodies selecte d according to their high cross-reactivity to various lymphomas was im munohistologically tested for reactivity with seven reactive lymphoid tissue specimens and 227 B cell lymphoma specimens obtained from Japan ese patients. In the reactive lymphoid tissues, the anti-Sld antibodie s each reacted with a subpopulation of cells in the mantle zone and in terfollicular areas; they rarely reacted with cells in the germinal ce nter. In the B cell lymphomas, 13 anti-Sld antibodies reacted with a t otal of 78 of 186 (42%) specimens bearing immunoglobulin; none of the antibodies reacted with 41 specimens not bearing immunoglobulin. In ma ntle cell lymphomas (15/19, 79%) and extranodal small lymphocytic/non- mantle cell diffuse small cleaved lymphomas (11/15, 73%), the reactivi ty of the antibodies was high compared with that in the other lymphoma s (52/152, 34%; P = 0.0002 and 0.004, respectively), including follicu lar lymphomas (11/42, 27%; P = 0.002 and 0.002, respectively). Since i diotypes are associated with the hypervariable regions and antigen-bin ding sites of immuno-globulin, these findings may reflect the differen ces in the regions/sites in each of these diseases.