IMMUNOGOLD LABELING OF LEUKEMIC HAIRY-CELLS WITH THE B-LY7 MONOCLONAL-ANTIBODY - AN SEM AND TEM STUDY

Two cases of hairy cell leukemia have been studied by immuno-TEM and i mmuno-SEM after immunogold labelling of the cell surface antigen recog nized by the B-ly7 monoclonal antibody. Most hairy cells appeared sign ificantly labeled, although the density of the expression of the antig en, as demonstrated by immunogold labelling, seems variable from cell to cell. Moreover, some cells with the morphology of hairy cells and w hich could not be identified as monocytes were not labeled. Labelling for the antigen identified by the B-ly7 mAb does not seem to correlate with the presence of ribosome lamellae complexes which were present o nly in one of the two cases studied. Rare lymphocytes of unidentified lineage were labeled. Monocytes were significantly absent from the sam ples of peripheral blood of the two patients studied. In one normal co ntrol sample, monocytes were observed unlabelled. The results are disc ussed in reference to the pathogenesis of hairy cell leukemia, its sur prisingly low mitotic rate, and its distinct response to chemotherapy. (C) 1994 Wiley-Liss, Inc.