Immunohistochemical demonstration of follicular dendritic cells in bone marrow involvement of B-cell chronic lymphocytic leukemia.

Using a sensitive immunohistochemical technique and a specific monoclonal antibody (RFD-3), follicular dendritic cells (FDC) have been demonstrated in a significant proportion (6/12) of bone marrow samples from patients with nodular marrow involvement of B-cell chronic lymphocytic leukemia (B-CLL). In all cases with "packed marrow" involvement and advanced stages of disease the FDC were absent. As these accessory cells are normally present only in the lymph nodes, their presence in the bone marrow is in accord with the view that B-CLL might be the malignancy of an immature subpopulation of lymph node lymphocytes that invade the bone marrow.