Correlation of immunophenotype to morphology in unfavourable non-Hodgkin lymphoma.

The relationship between immunological markers and histology according to the Kiel classification was studied in 40 adult non-Hodgkin lymphoma patients of Rappaport unfavourable histology. The membrane-associated and cytoplasmic Ig as well as receptors for sheep erythrocytes, Fc gamma and C3d receptors were analyzed on cryostate sections and in suspension. In some cases, a more precise immunophenotype was achieved by the use of monoclonal antibodies detecting different T and B cell antigens. Eighty-eight per cent of the lymphomas had B-cell, five per cent T cell and 7 per cent non-B/non-T cell phenotypes. All CBCC and CC lymphomas expressed monotypic Ig, but only 66 per cent of the CB lymphomas. Thus, morphology alone did not consistently predict immunophenotype in large-cell lymphomas. A simultaneous expression of multiple heavy chains and cytoplasmic Ig was found in some lymphomas, suggesting an intratumoral differentiation. The nodular or irregular tissue distribution patterns for Ig and C3d receptors found in histologically diffuse follicle derived lymphomas also suggest intratumoral variations in the marker expression, probably related to differentiation. The results suggest that lymphoma immunophenotype is important in obtaining a definite diagnosis in large-cell lymphomas and that it may lead to a better understanding of the differentiation of lymphomas of low-grade malignancy.