An immunocytochemical study of T-cell lymphomas using monoclonal and polyclonal antibodies effective in routinely fixed wax embedded tissues.

Formalin fixed and paraffin wax embedded tissue from 24 cases of T-cell lymphoma diagnosed using immunocytochemistry on cryostat sections was examined using a panel of eight monoclonal and three polyclonal antisera. The monoclonal antibodies UCHL1 and MT1 proved to be comparable and reliable markers of neoplastic cells in T-cell lymphomas. The B-cell specific marker, MB1, strongly stained all cells in two cases of pleomorphic large cell T-cell lymphoma, large cells in two cases of pleomorphic mixed medium and large cell lymphoma, and isolated clusters of blast cells in four cases of T-zone and angioimmunoblastic lymphadenopathy-like T-cell lymphoma. The cells stained by MB1 expressed T suppressor/cytotoxic surface markers on frozen section. Epithelial membrane antigen, as detected by a polyclonal anti-EMA and the monoclonal antibody HMFG2, was expressed in 36% of tumours especially those of monomorphic large cell and pleomorphic large cell phenotype. Single granules or finely dispersed cytoplasmic granularity was seen in four tumours using the anti-granulocyte reagent Leu M1. Tumour cells in one case stained in a pattern identical to Reed-Sternberg cells in Hodgkin's disease. Granular alpha-1-antitrypsin staining was found in 10 cases of pleomorphic large cell and monomorphic large cell lymphoma. No staining was observed using anti-lysozyme or the monoclonal macrophage specific marker Mac411. Monomorphic and pleomorphic large cell lymphomas tended to show a common immunophenotype with the majority of cells co-expressing alpha-1-antitrypsin HLA-DR and epithelial membrane antigen. Scattered large transformed blast cells in cases of angioimmunoblastic lymphadenopathy-like T-cell lymphomas and T-zone lymphomas shared a similar immunophenotype with the large cell lymphomas. Using a panel of monoclonal antibodies effective in paraffin embedded tissue, diagnostically useful staining profiles which correlate with the morphological phenotype can be established in T-cell lymphomas.