抄録
The principal function of the plasma cell is to secrete immunoglobulins whose presence can easily be demonstrated within the cell in situ. This function is reflected in a variety of morphologic forms of these cells; Mott cells, morula cells, grape cells, flaming cells, thesaurocytes, and various inclusions. On very rare occasions, it has been reported that plasma cells demonstrated phagocytosis of red cells, polymorphonuclear leukocytes, platelets and bacillary agregates.
We report here the phenomenon of phagocytosis of red cells and platelets by the marrow myeloma cells of a patient with well established plasma cell leukemia. In view of the recent renewed interest in the origin of the plasma cell, it is felt that the findings warrant presentation in some detail.
The following three explanations are offered as to the occurrence of phagocytic plasma cells.
(1) Under certain circumstances plasma cells may retain or acquire the phagocytic properties of their precursor cells.
(2) It is unlikely that plasma cells or their precursor cells have phagocytic properties. The phagocytosis exhibited by the myeloma cells may represent a function acquired during malignant transformation.
(3) The phagocytic plasma cells may stem from a small subpopulation of B lymphocytes with phagocytic capabilities.
From this study, we should take a serious view of the first two explanations, (1) and (2). The phenomenon of phagocytosis of the plasma cells gives a new clue to understand the nature of myeloma. Further studies to analyze similar cases more precisely are indicated.
