IMMUNOLOGICAL STUDIES ON PATIENTS WITH PNEUMOCOCCIC PNEUMONIA TREATED WITH SULFAPYRIDINE

Abstract

The results of the bactericidal tests with Types I, III, and V pneumococci indicated that the blood of patients undergoing treatment with sulfapyridine has marked bacteriostatic and considerable bactericidal action on the homologous type of pneumococcus. This effect was independent of the immune mechanism residing in the blood. This action of sulfapyridine was the same as that noted when comparable concs. of the drug were added to artificial media or to human blood in vitro. The greatest and most rapid bactericidal activity occurred in the presence of heat-stable antibodies (agglutinins, protection, opsonins). The results of tests for bactericidal action at the end of 3 hours indicate that the pneumococcidal action resulting from the immune mechanism is exerted rapidly and is practically carried to completion before any bacteriostatic effect of sulfapyridine becomes evident. The antibody response of patients with pneumococcic pneumonia treated with sulfapyridine, as far as could be detd., was comparable in every respect to that resulting from spontaneous recovery. Protective antibodies rarely developed before the 6th day and agglutinins rarely appeared before the 7th day of the disease. Entirely apart from observed clinical results and only from the point of the mechanism of action of serum and sulfapyridine as observed in patients undergoing treatment, the combination of these 2 agents is the treatment of choice.