Physiopathological aspects of plasma cell dyscrasias: A forum

BARLOGIE: High RNA content is associated with immunoglobulin production and perhaps one might speculate the high RNA reflects more differentiated plasma cells. On the other hand, CALLA is considered to be a very early B-cell marker. One could speculate on why a primitive marker is preserved in a more differentiated plasma cell and what that means. There is however a wide dispersion in plasma cell RNA content differing in the individual patient by factor as high as 20-fold. We suspected that a considerable RNA bioeterogeneity would also be expressed otherwise, i.e. we are looking for means to relate to each other the RNA and phenotype expression. We speculate that RNA as an indicator merely of potential protein synthesis would be fairly low in myeloma progenitor cells. Thus, CALLA-positive cells, not co-expressing cytoplasmic immunoglobulin, probably have low RNA content. But I’ve no good idea why the CALLA antigen is maintained and is not shut off as cells progress down the differentiation pathway.