Acute Splenic Tumor Produced by Non-Bacterial Antigens

Abstract

It is well known that during the course of bacterial infections the spleen undergoes a change designated by the term “acute splenic tumor”. The significance of this change has never been clearly understood. The essential microscopic characteristic of the condition is an increase in mononuclear cells which have not the appearance of ordinary lymphocytes. These cells appear first in the margins of the Malpighian bodies and spread throughout the pulp in advanced cases. Some are definitely plasma cells, but the majority have large vesicular nuclei and abundant basophilic cytoplasm, and there has never been any general agreement as to their nature or function. Some have described them as macrophages, some as lymphoblastic cells, but most writers have regarded them as young myeloid cells and have interpreted their presence as representing an activity of the spleen in the manufacture of granulocytes under the stimulus of the infection.

Although young myeloid cells may be found in the spleen (as in the blood) in bacterial infections, and although myeloid cell formation may undoubtedly occur in the spleen during the course of some infections, no acceptable evidence has ever been brought forth that the great body of newly formed mononuclear cells characteristic of acute splenic tumor are myeloid cells. They are non-granular cells, and the writer has never been able to observe any indication of their transformation into granulocytes. In view of the large amount of evidence that the spleen plays an important rôle in antibody production, and since acute splenic tumor and antibody production are factors that are common to bacterial infections of widely different nature, it has been suggested from time to time that acute splenic tumor may be an expression of the formation of protective substances active against the infecting bacteria and their products.