Immunophenotypic analysis in the diagnosis of malignant lymphoma

Immunophenotypic analysis is capable of distinguishing benign and malignant or determining the lineage of neoplastic cells in most of lymphoproliferative disorders. The methodological approaches can be divided into two major categories; immunohistochemistry and flow cytometry. Both of these techniques can be important adjuncts to histological diagnosis although flow cytometry is not yet common in Japan. The basic features to be checked by immunophenotyping are as follows. IPT-I: Light chain restriction of immunoglobulin. IPT-II: Loss or stronger expression of one or more antigens normally expressed in reactive lymphocytes. IPT-III: Significant increase of a particular cell population that is quite rare or absent from normal tissue at the biopsy site. While IPT-I could be taken as direct evidence of a clonal proliferation of B-lineage cell, IPT-II and -III are the only strong suggestions of a malignant lymphoid proliferation.