Purpose: The aim of the present study was to elucidate whether only local, or also systemic immunomodulatory effects may be induced by intravesical BCG therapy of superficial urinary bladder cancer.
Materials and methods: A total of 37 patients with stages Ta to T1b superficial transitional cell bladder carcinomas received 6 weekly BCG instillations after transurethral resection of the tumor. In a first group of 19 patients blood was taken before each BCG instillation and 6 weeks after the last one. In a second group of 18 patients blood and urine was taken before and 2, 6, and 24 hours after each BCG instillation. In the mitogen-stimulated whole blood cell cultures and in the urine samples the levels of the cytokines IL-1beta, IL-2, IL-10, TNF-alpha and IFN-gamma were determined by enzymoimmunological tests. Additionally, in all plasma and urine samples the levels of TNF-p75-receptor (TNF-p75-R) were measured.
Results: Comparison of ex vivo leukocyte cytokine production in the blood cell cultures of the patients of group I revealed no significant change in the levels of the cytokines. In contrast, TNF-p75-R plasma levels increased significantly during the experimental time of 12 weeks (p < or =0.01). In the blood cell cultures of the group II patients a different daytime variation of cytokine production was seen, compared to the 19 healthy controls. After BCG instillation the normal peak cytokine production in the evening was suppressed. A significant rise in plasma TNF-p-75-R levels was measured 24 hours after BCG instillation (p < or =0.05). In the urine of these patients significantly higher levels of all measured cytokines and TNF-p75-R were observed 6 to 24 hours after the instillation.
Conclusions: The results suggest that besides the well known local immune activation, BCG instillation also leads to a modulation of peripheral immune mechanisms.