CNA.42, A NEW MONOCLONAL-ANTIBODY DIRECTED AGAINST A FIXATIVE-RESISTANT ANTIGEN OF FOLLICULAR DENDRITIC RETICULUM CELLS

A new monoclonal antibody (MAb), CNA.42,was generated using the CEM T- cell Line. It recognizes a 120-kd formalin-resistant glycosylated anti gen that is mainly expressed by follicular dendritic reticulum cells ( FDRCs), This antigen is also expressed by a few mononuclear cells in t he paracortical area of reactive lymph nodes and by some cortical thym ocytes. Two hundred and eighty-nine cases of hematopoietic tumors of v arious types were tested with this antibody, They showed either intact FDRC networks or FDRC networks dispersed among malignant cells, In fo llicular lymphomas, the follicular pattern was highlighted by CNA.42 M Ab. Expanded FDRC networks were found in angioimmunoblastic T-cell lym phomas, Neoplastic cells were positive in 43.6% (24/55) of T-cell and 4.6% (6/129) of B-cell lymphomas. The highest percentage of cases with positive neoplastic cells was found in anaplastic large-cell lymphoma s (62.5%; 15/24), In Hodgkin's disease, FDRC networks, sometimes encas ing Hodgkin and Reed-Sternberg (HRS) cells, were found, HRS cells were also stained by this antibody in 23 (21.9%) of the 105 cases examined , A variety of normal nonlymphoid tissues and nonhematopoietic tumors, such as some neurogenic tumors, carcinoma, and occasional sarcomas, m ere found to be positive, Analysis of the reactivity of CNA.42 antibod y with FDRCs of lymphoid tissue from different animal species showed s imilar reactivity to that observed in humans, suggesting widespread ev olutionary conservation of the antigen recognized by this antibody, In daily diagnostic practice, CNA.42 MAb seems to be a suitable FDRC mar ker and possibly has an auxiliary role in recognizing T-cell lymphomas .