THE VALUE OF IMMUNOHISTOCHEMISTRY
IN THE ASSESSMENT OF BONE MARROW DISORDERS

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

CD43 The various epitopes available usually can be demonstrated well without antigen retrieval. CD43 is a useful second line T-cell marker and can also be used to detect acute leukemia in bone marrow sections. Almost all cases of acute myeloid leukemia, M0 included (but with the exception of M6) express CD43. The antigen is also expressed in blasts in precursor B-cell acute lymphoblastic leukemia (ALL)/lymphoblastic lymphoma and in T-cell ALL/lymphoblastic lymphoma The antigen is also expressed in a proportion of cases of B cell lymphomas and in chronic B cell lymphocytic leukemia (B-CLL). In the latter condition the concomitant expression of CD43 and CD20 supports the diagnosis of B-CLL. Hodgkin's disease is negative with CD43. References Arber et al: Paraffin section immunophenotyping of acute leukemias in bone marrow specimens. Am J Clin Pathol. 1996;106:462-8. Cabecadas et al: Phenotyping of T-cell lymphomas in paraffin sections--which antibodies? Histopathology. 1991;19:419-24. Macon et al: Leu-22 (L60). A more sensitive marker than UCHL1 for peripheral T-cell lymphomas, particularly large-cell types. Am J Clin Pathol. 1991; 95:696-701. Stross et al: Molecule detected in formalin fixed tissue by antibodies MT1, DF-T1, and L60 (Leu-22) corresponds to CD43 antigen. J Clin Pathol. 1989;42:953-61.