Demonstration of normoblasts in tissue sections by means of an immunohistochemical technique for haemoglobin.

Abstract

The morphological differentiation between normoblasts and lymphocytes in conventionally stained sections of bone marrow trephines may be difficult.' This is unfortunate, especially since the distinction between the two cell types may be quintessential in cases of suspected chronic lymphocytic leukaemia, lymphocytic lymphoma, or other low grade nonHodgkin lymphomas. Guidelines to this problem include the careful observation of nuclear detailfor example, normoblasts have homogenous densely basophilic round nuclei with cytoplasm which shows halo artefact. Conversely, the nuclei of lymphocytes are of a finely granular chromatin pattern and the cells appear to possess no cytoplasm.' None the less, the differences between the cell types are subjective and appearances may be altered by fixation technique. To enable the recognition of normoblasts in paraffin embedded sections of bone marrow trephines we have made use of the peroxidaseantiperoxidase (PAP) method using a primary antiserum against human haemoglobin.t