Immunocytochemical labelling of haematological samples using monoclonal antibodies.

Monoclonal antibodies have become increasingly important in the diagnosis and classification of neoplastic blood disorders. Immunofluorescent labelling of cell surface antigens has been the conventional method used for this purpose. However, this method of antigen detection presents a number of drawbacks when used in a routine hospital haematology laboratory: namely that blood or bone marrow samples must be processed within a short time of collection; antigen labelling is not permanent; and cell morphology cannot be visualised. The present paper describes the method for labelling routine haematological samples by an immunoalkaline phosphatase technique which is used routinely in this laboratory for leukaemia phenotyping. This approach has several practical advantages over conventional immunofluorescent labelling, i.e. staining can be performed on routinely prepared bone marrow and blood smears, samples can be stored for long periods before labelling, cell morphology can be visualised simultaneously with the antigen label and the staining reaction is permanent. As detailed below a wide range of cellular antigens can be detected in marrow and blood smears using this technique.