Paraffin-resistant antigens detectable by antibodies L26 and polyclonal CD3 predict the B- or T-cell lineage of 95% of diffuse aggressive non-Hodgkin's lymphomas.

The reactivity of eight preferential B-cell (L26, 4KB5, and KiB3) and T-cell (polyclonal CD3, Leu22, MT-1, UCHL-1, and OPD4) antibodies which detect paraffin-resistant antigens was examined by a three-step immunoperoxidase technique in 111 formalin-fixed, paraffin-embedded diffuse aggressive non-Hodgkin's lymphomas (NHLs) to determine the optimal panel for accurate lineage assignment. L26 (CD20) and polyclonal CD3 (CD3) were the most sensitive (> 95%) and specific (100%) antibodies. They identified the B- or T-cell lineages correctly in 106 (95%) cases. The five L26-negative, polyclonal CD3-negative cases included all three precursor B lymphoblastic NHLs and two (one B and one T) diffuse large-cell NHLs. Immunostaining with the second most sensitive preferential B-cell (4KB5) and T-cell (Leu22) antibodies correctly identified the lineage in two additional NHLs, but one false-positive result occurred. Preferential B-cell antibody KiB3 reacted with two precursor B lymphoblastic NHLs. Use of additional paraffin-reactive antibodies did not increase the number of NHLs assigned to the correct cell lineage. In conclusion, it appears that a two-tiered approach, with a first-line panel consisting of L26 and polyclonal CD3, followed by 4KB5 and Leu22 in nonlymphoblastic NHLs and by KiB3 in lymphoblastic NHLs, represents the most efficient method of correctly identifying the B- or T-cell lineage of diffuse aggressive NHLs by paraffin tissue section immunohistochemistry.