Phenotyping of T-cell lymphomas in paraffin sections-which antibodies?

Five antibodies, MT1 (CD43), UCHL1 (CD45RO), OPD4, poly‐CD3 and βF1, were assessed for their reactivity with 50 archival cases of T‐cell lymphoma in formalin‐fixed paraffin‐embedded tissue. All cases had been previously characterized as T‐cell lymphomas, and the histological types included 14 cases of small cerebriform lymphoma, six cases of angioimmunoblastic lymphadenopathy‐like T‐cell lymphoma, four cases of T‐zone lymphoma, five cases of pleemorphic small cell lymphoma, 12 cases of pleomorphic medium and large cell lymphoma, four cases of anaplastic large cell lymphoma, two cases of T‐lymphoblastic lymphoma and three cases of enteropathy‐associated T‐cell lymphoma. UCHL1 and MT1 showed reactivity with the highest percentage of cases (94 and 86% respectively) but lack absolute specificity for T‐cells, especially in high‐grade lymphomas. Poly‐CD3 is highly specific for T‐cells, and stained neoplastic cells in almost 80% of the cases. βF1 stained the lowest percentage of cases (40%). UCHL1 and poly‐CD3 together identified 98% of cases, and this combination is recommended for the diagnosis of T‐cell lymphomas in paraffin sections.