THE VALUE OF IMMUNOHISTOCHEMISTRY
IN THE ASSESSMENT OF BONE MARROW DISORDERS

Attilio Orazi, M.D., FRCPath. and Dennis P. O'Malley, M.D.

ANTI-IMMUNOGLOBIN HEAVY CHAIN (IgG, IgA, IgM) These are polyclonal antibodies made from rabbits against the mu chains of IgM and a pool of normal human serum, in the case of the other antibodies. Although these antibodies react in formalin, B5 and Zenker-fixed tissues, we have found that they are of less use than the light chains. They are technically more difficult to perform, with a high degree of background non-specific staining and do not demonstrate clonality as does the demonstration of light chain restriction. These reagents are only rarely useful. References Ben-Ezra JM et al. Staining for Bcl-2 protein helps to distinguish benign from malignant lymphoid aggregates in bone marrow biopsies. Mod Pathol. 1994 ;7:560-4. Chetty et al: Immunohistochemistry in apparently normal bone marrow trephine specimens from patients with nodal follicular lymphoma. J Clin Pathol. 1995; 48:1035-8. Fakan et al: Expression of bcl-2 protein in distinguishing benign from malignant lymphoid aggregates in bone marrow biopsies. Gen Diagn Pathol. 1996;141:359-63.