A clinico-pathological and immunological study of unfavourable non-Hodgkin lymphomas. Comparison of the Rappaport and Kiel classifications.

To evaluate the prognostic information of the Kiel classification a homogeneous material of 63 non-Hodgkin lymphomas of unfavourable Rappaport histology were re-evaluated according to the definitions of the Kiel classification. The patients were selected from a prospective lymphoma study including 775 patients. Only ambiguous histological diagnoses analysed independently by two hematopathologists were accepted. Immunological markers of the tumours studied both in suspensions and on cryostate sections were in addition analysed in 40 of the patients. Forty-one per cent (26/63) were of high grade malignancy according to the Kiel classification, 59% (36/63) were of low-grade malignancy. The DLPD group was most heterogeneous while a better concordance was found between DM and CB/CC and between DH and CB cases. However, prognostic subgroups of the two classifications were only partly equivalent. A good correlation was found between the Kiel high-grade malignant group and patients of Rappaport poorest prognosis (DU, DH). Eighty-eight per cent of the lymphomas were of B cell, 5% of T cell and 7% of non-B-non-T phenotypes. Both the Kiel and Rappaport morphologic classifications predicted survival in this selected material. Patients with B phenotypes survived longer than patients with lymphomas of non-B type. Among patients with diffuse lymphomas, those with a nodular and irregular distribution of immunoglobulin and C3d receptors tended to respond better and survived longer. No prognostic information was obtained from immunoglobulin isotypes, C3d or Fc-gamma receptors. It is concluded that the Kiel classification is equally reliable for clinical judgement as the Rappaport system and that immunological marker studies may add prognostic information.