Ribonucleic Acid in Canine Mast Cell Granules and the Possible Interrelationship of Mast Cells and Plasma Cells

Abstract

RNase-sensitive pyroninophilia has been demonstrated in neoplastic and non-neoplastic canine mast cell granules and it was concluded that these granules contain RNA. When combined with (1) the observed morphologic similarities between mast cells and plasma cells, (2) the presence of common distinctive ultrastructures, (3) the differentiation of both cells from a common precursor and (4) the participation in a common reaction, the presence of RNA in mast cell granules is offered as additional evidence for a mast cell-plasma cell relationship. A proposed functional relationship between these two cells is discussed and the “plasma mast cell” is proposed as a possible transitional form between mast cells and plasma cells.