A practical approach to immunophenotyping of lymphomas. Comparison of immunohistologic and immunocytologic techniques

Comparison of immunohistologic (IH) and immunocytologic (IC) techniques was conducted on 86 specimens. Forty-seven B-cell, five T-cell, and two null-cell lymphomas were identified by IH as well as 16 cases of lymphoid hyperplasia. The results of IC were generally identical to those of IH except for two T-cell and two B-cell lymphomas. The diagnosis of T-cell lymphoma was a major problem for IC because of the presence of normal T-cell count and/or normal helper/suppressor ratio in these cases. Twenty-one percent of the B-cell lymphomas failed to express surface immunoglobulin but did express B1 and HLA-DR antigens. Such a discrepancy was not demonstrated in cases of lymphoid hyperplasia, thus serving as a useful criterion in the diagnosis of B-cell lymphoma. While combined IH and IC should be used for immunophenotyping in large medical centers, IH is recommended for community hospitals. The identification of kappa, lambda, B1 and T11 (Leu 5) antigens in frozen sections with the immunoperoxidase technique should be sufficient to phenotype most lymphoproliferative diseases. The criteria for immunophenotyping of lymphomas are discussed.