In human tuberculosis as in experimental tuberculosis, there exist in the serum of tuberculous patients three different kinds of antibodies completely distinct from each other, antipolysaccharide, antiprotein, and antiphosphatide. The two former antibodies are produced whenever tuberculous infection takes place or exists and they persist for a long period, even though tuberculous disease be arrested. On the contrary, the production of the antiphosphatide seems to be mainly conditioned by the outbreak of tuberculous disease following infection, because none of the tuberculin-positive healthy persons tested gave a positive phosphatide hemagglutination test. The antiphosphatide hemagglutination test furnishes useful information about the extent or the activity of tuberculous disease.
No correlation was noticed between the degree of tuberculin skin hypersensitivity and the amount of any of the three antibodies.
The usefulness of the phosphatide hemagglutination test in the diagnosis of tuberculosis is discussed.