Immunohistochemical staining of non-Hodgkin's lymphoma with monoclonal antibodies specific for the leucocyte common antigen.

Forty cases of non-Hodgkin's lymphoma (NHL) have been stained with monoclonal antibodies (F8-11-13, F-10-89-4 and Dako LC) to the Leucocyte Common Antigen (LC) in both cryostat and paraffin sections with an immunoperoxidase technique. In cryostat sections all B-cell lymphomas (25/25) reacted with F10-89-4 and Dako LC, whilst the majority (23/25) stained with F8-11-13; of the T-cell lymphomas studied, all reacted with F10-89-4 (6/60 and Dako LC (4/4), however 2/6 did not react with F8-11-13. Similar variability in reaction was observed in malignant histiocytosis where 1/3 did not react with F8-11-13 whilst all three reacted with F10-89-4 and Dako LC. In paraffin sections (using the two MCabs F8-11-13 and Dako LC) three of the 25 B-cell lymphomas failed to stain with either F8-11-13 or Dako LC (one lymphocytic lymphoma and two lymphomas showing plasmacytic differentiation). The remainder of the B-cell lymphomas reacted with both antibodies. Six out of 12 T-cell lymphomas did not stain with either F8-11-13 or Dako LC, using our standard immunoperoxidase procedure. Staining with Dako LC was however detected in all cases of T-cell lymphoma when incubation with primary antibody was extended from thirty minutes (standard) to overnight. This study confirmed that LC can be detected in all NHL in cryostat sections, and that in the majority of B-cell NHL the higher molecular weight component of LC was demonstrable using F8-11-13. Difficulty in detecting LC determinants after tissue processing for paraffin sections in a number of cases of NHL, especially those of T-cell type or showing plasmacytic differentiation, suggests that lack of reaction with these antibodies does not always preclude the diagnosis of lymphoma.