AN ENHANCED IMMUNOCYTOCHEMICAL METHOD FOR STAINING BONE-MARROW TREPHINE SECTIONS

Aims - The detection of cellular antigens in fixed decalcified bone ma rrow trephine (BMT) sections depends on the method of processing, the nature of the antigen and antibody, antigen retrieval techniques, and the sensitivity of the immunocytochemical method. This study evaluated a tyramide enhanced avidin-biotin immunostaining method on formalin f ixed decalcified BMT sections to determine whether the method could de tect previously undetectable antigens. Methods - Nineteen BMT biopsies from a range of haematological disorders were evaluated with 43 antib odies to haemopoietic antigens using horseradish peroxidase and alkali ne phosphatase detection methods, using the tyramide enhanced avidin-b iotin immunostaining method. Results - Compared with standard avidin-b iotin immunostaining methods the tyramide enhanced immunostaining meth od showed enhanced signal intensity, gave positive labelling for antig ens that require pretreatment by other methods, and previously unreact ive antigens were detected. Primary antibodies could be used at up to 200 times higher dilutions. Conclusion - The tyramide enhanced immunos taining method, while retaining specificity, is highly sensitive and e nables an increased number and range of antigens to be detected than p reviously possible. The method could be applied to BMT sections for th e routine diagnosis and classification of haematological disorders.