The effects of BCG on the dog bladder.

Immunostimulation with agents such as Bacillus Calmette-Guérin (BCG) may represent an adjunctive treatment modality in patients with cancer of the bladder. To investigate the effects of direct inoculation, BCG was injected into the bladder of sensitized (PPD) and nonsensitized dogs. A marked and predictable inflammatory reaction was seen in all of the sensitized and in some of the nonsensitized dogs. This reaction was characterized by an extensive histiocytic infiltration with varying proportions of polymorphonuclear leukocytes, plasma cells, and lymphocytes. Follow-up examination of one dog 7 weeks after initial biopsy showed that this marked inflammatory reaction had resolved. Our findings suggest that in the future nonspecific immunopotentiators may play a role in the treatment of cancer of the bladder.