Abstract
A series of 20 bone marrow trephines biopsy and necropsy specimens were stained for IgA1 and IgA2 activity, together with total IgA, by means of an indirect immunoperoxidase technique using murine monoclonal antibodies applied to paraffin sections. The specimens showed normal histoogy and had been taken from patients not known to be suffering from haemtological or related systemic disease. The IgA1, IgA2, and total IgA containing cells were counted and expressed as a percentage of all nucleate cells in the marrow cavities. Remarkably constant percentages of and ratios betwene these cell types were found. The same was true for a further 10 trephines taken from patients undergoing staging procedures for epithelial malignancies, where the marrow histology was normal. The pooled mean percentage of IgA1 containng cells from both groups was 1.18% of all cells, that for IgA2 contianing cells 0.18%, and for total IgA positive cells 1.41%. In addition, 12 trephines containing known IgA producing myeloma were examined. Of these, 11 contained IgA1, the remainder contained IgA2 subclass.