Detection of B- and T-cells in paraffin-embedded tissue sections. Diagnostic utility of commercially obtained 4KB5 and UCHL-1.

Although many recent studies have begun exploring the diagnostic utility of anti-B- and anti-T-cell antibodies that work on paraffin-embedded tissue sections, the most optimal panel to use remains uncertain. In addition, many of the published reports have used antibodies obtained before their commercial formulation and distribution. For these reasons, B5-fixed paraffin-embedded tissue samples from 174 reactive or neoplastic lymphoid and hematopoietic proliferations were immunostained with the commercially obtained antibodies 4KB5, UCHL-1, and, in selected cases, L26. In reactive nodes, 4KB5 stained B-cell areas and UCHL-1 T-cell areas. Seventy-nine percent of the B-cell neoplasms were 4KB5 positive, and only 2% were UCHL-1 positive. Two cases of myeloma were 4KB5 and UCHL-1 negative. The 4KB5-negative B-cell lymphomas (ML-B) were all L-26 positive. UCHL-1 stained 78% of the T-cell lymphomas (ML-T), and 4KB5 stained 14%. In the five 4KB5-positive putative T-cell lymphomas, immunoglobulin and T-cell receptor gene rearrangement studies were performed. In Hodgkin's disease (HD), Reed-Sternberg (RS) cells were UCHL-1 negative in 75% of cases and occasionally positive in 25%. Definite 4KB5 positivity of RS cells was identified in both cases of lymphocyte predominant HD and in one case of nodular sclerosing HD with monomorphic large cell areas. With the exception of 1 of 15 acute nonlymphocytic leukemias that was UCHL-1 positive, all acute leukemias were 4KB5 and UCHL-1 negative. In summary, commercially obtained 4KB5 and UCHL-1 form a useful but not absolutely specific or sensitive paraffin section immunoperoxidase panel for the categorization of B- and T-cell lymphoid neoplasms. Addition of L26 appears to add to the sensitivity and specificity of the panel. Definite immunophenotypic distinction of HD from non-Hodgkin's lymphomas, particularly of T-cell type, often was not possible.