Immunological markers and functional activity of lymphocytes from lymphatic tissue in suspension in the differential diagnosis of non-Hodgkin's B and T lymphomas versus thymoma

In the present study fresh tissue specimens, in addition to being embedded in paraffin for routine histological studies, were dispersed in medium to make a cell suspension for study of phenotype markers. In 6 patients chosen out of 90 patients studied multiple marker analysis led to the diagnosis of B or T cell lymphoma or thymoma in less than 48 h. The similarities between the surface markers of lymphocytes from thymoma and those from normal thymus, together with antikeratin staining made it possible to differentiate between thymoma and lymphoma. In patient Z.A. (No. 4) lymphocytes obtained from a mediastinal mass had characteristics of cortical thymocytes. Staining with antikeratin was positive. These findings led to the diagnosis of thymoma, lymphocytic predominance. Among the other 5 biopsies studied, 2 had T-helper cell phenotypic markers and no ability to induce GVHR. Both patients' (Nos. 1 2) T lymphocytes, in spite of having the OKT4+ phenotype, showed suppressor activity. Both had cutaneous T lymphoma. Patient AR's (No. 5) biopsy revealed normal findings - 18% had SIg; 69% formed E rosettes at 4°C. of which 46% were OKT4+ and 26% OKT8+. Patient AE was diagnosed as immunoblastic lymphoma with 98% of the cells being high density IgM+ Kappa+ and 76% forming rosettes with mouse erythrocytes. Patient P.L. showed, on microscopic examination of the mediastinal mass, a diffuse distribution of lymphoblasts of uniform size. (99% of these lymphoblasts had the OKT4+ phenotype, 27% of them also showed the OKT6+ and OKT8+ markers. This patient was diagnosed as T lymphoblastic lymphoma, prethymocyte type. In these 6 patients it was demonstrated that multiple marker analysis of lymphatic tissue in suspensions is a valuable clinical tool in the diagnosis. The functional activity of T cells when found to be suppressive seemed to bode a poor prognosis, while the morphological subtype and the immunophenotype profile did not predict the outcome of the patient.