THE VALUE OF IMMUNOHISTOCHEMISTRY
IN THE ASSESSMENT OF BONE MARROW DISORDERS
Attilio Orazi, M.D., FRCPath. and Dennis P. O'Malley, M.D.
VON WILLEBRAND FACTOR (Factor VIII-Related Antigen)
vWF is a polyclonal rabbit antibody to an isolate of von Willebrand factor from human plasma. The antibody
reacts to endothelial cells in all tissues of the body and megakaryocytes. The antibody cross-reacts with
von Willebrand factor from other species, as a result, the antibody is not species specific. Although the
manufacturer has suggested proteolytic predigestion, in our laboratory MWO technique provides excellent
results. The stain works well both in formalin fixed and in B5 fixation and is not materially inhibited by
decalcification. We have found that factor VIII antigen is preferable to platelet glycoprotein IIb/IIIa.
Clinical examples of the use of factor VIII-related antigen include the following:
- The identification of early megakaryoblasts in cases of AML-M7 and related disorders (e.g.
myeloproliferative diseases in megakaryoblastic transformation).
- The differentiation of megakaryocytes from other multinucleated cells with may be found in the bone
- Although not widely used or described in the literature, we have found that factor VIII antigen may
highlight the abnormal vascular network which is seen in the marrow in cases of myeloproliferative and
- Gatter KC, Cordell JL. Turley H, et al: The immunohistological detection of platelets, megakaryocytes
and thrombi in routinely processed specimens. Histopathol 1988;13:257.
- Huang MJ, Li CY, Nicholas WL, et al: Acute leukemia with megakaryocytic differentiation: a study of 12
cases identified immunocytochemically. Blood 1984;64:427.
- Innes DJ Jr, Mills SE, Walter GK: Megakaryocytic leukemia. Identification using antifactor VIII
immunoperoxidase. Am J Clin Pathol 1982; 77:107.