Mononuclear Cells of Blood in Relation to Clinical Findings in Human Tuberculosis. ∗

Abstract

In 1925 a new hypothesis in regard to the propagation and resistance of tuberculosis was presented by Cunningham, Sabin, Sugiyama and Kindwall. 1 The data for their conclusions were obtained from a study of rabbits injected with viable bovine tubercle bacilli; differential blood studies were made throughout the course of the infection by the supra-vital technique of Sabin, and freshly autopsied material was examined by the same technique. They found that, during the course of a tubercular infection, the so-called “reticular cells” are stimulated to an increased production of monocytes and these in turn are transformed into typical epitheloid and giant cells. From a study of the appearance and number of the bacilli, which were found in the monocytes and in the epitheloid cells, they concluded that these cells phagocytize organisms but are unable to destroy them, and hence act virtually as culture tubes. The concept was thus advanced that the monocytes are stimulated, in tubercular infections in rabbits, to such an increase in number and in phagocytic capacity, that, inasmuch as they seem unable to destroy the bacilli, they aid in increasing and disseminating the infection. Furthermore, the authors showed that these changes became more marked as the disease progressed, and receded with improvement; and that, coincident with the numerical changes in the monocytes, the lymphocytes were effected in inverse ratio.

The same technique is now being employed in similar studies upon clinical cases of human tuberculosis. A11 of the cases so far studied have been patients in the Vanderbilt University Hospital, selected for study, irrespective of tht! site or grade of infection or age of the patient. Where cases are in the hospital sufficiently long, or where marked clinical changes occur, the progress is followed by repeated examinations; and whenever tubercular fluids are obtained for clinical reasons they are subjected to study by the supra-vital technique, as are also tissues secured by autopsy or biopsy.