A cytological analysis of FMC-7 positive leukaemias

The subdivision of the B lymphoid leukaemias by conventional techniques is subjective and poorly reproducible, with a range of cytological diagnoses available for cases which are not typical examples of chronic lymphatic leukaemia or acute lymphoblastic leukaemia. The monoclonal antibody FMC-7 recognizes a determinant on a subpopulation of B lymphoid cell and stains follicular B cells. Routiune FACS analysis of chronic lymphoid leukaemias with a panel of monoclonal antibodies identified a subset of lymphoproliferative disorders (20 of 88) which were FMC-7 positive. a careful 'blind' cytological assessment of this subset gave some support for the suggestion that they were examples of lymphoproliferative disease of follicular origin. Eight cases, however, were considered cytologically typical of CLL. The wider application of this antibody, particularly in sequential studies over a longer time scale may improve objectivity in the classification of this group of diseases.