Expression of Leu-8 surface antigen in B-cell lymphomas. Correlation with other B-cell markers

Using in situ immunohistological analysis, expression of Leu-8 and its correlation with other B-cell markers were investigated in 21 selected lymphomas of different categories, each one expressing its own typical immunophenotype. These categories included eight follicular centroblastic/centrocytic (CB/CC) lymphomas, eight intermediately differentiated lymphocytic lymphomas (ILL)/mantle zone lymphomas (MZL), and five lymphocytic lymphomas (LL) associated with chronic lymphocytic leukaemia (CLL). Four reactive lymph nodes and three tonsils were also studied using double immunolabelling procedures. Cell suspensions were also performed in three CB/CC and four ILL/MZL cases. Leu-8 was consistently expressed in ILL/MZL and LL but it was absent in most (7/8) CB/CC lymphomas. In reactive tissues, the Leu-8-positive B cells were strictly confined to the mantle zones. A close association emerged between Leu-1 (CD5) and Leu-8, both being present in ILL/MZL and LL but absent in CB/CC. A consistent lack of association was found between Leu-8 or CD5 antigens and common acute lymphoblastic leukaemia antigen (CD10) and BA-2 (CD9) antigen, whereas Leu-8 and CD5 were strictly associated with surface IgD. Reactivity with Leu-8 provides a means of distinguishing between CB/CC and ILL/MZL. Furthermore, shared immunoreactivity for Leu-8 in ILL/MZL and LL may represent a potential clue to the still uncertain cellular derivation of LL/B-CLL.