Renal cell carcinomas produce IL-6, IL-10, IL-11, and TGF-beta 1 in primary cultures and modulate T lymphocyte blast transformation

We investigated the immunomodulatory capacity of primary cultures of renal cell carcinomas (RCC) by assessing production of cytokines and modulation of mitogen-induced T lymphocyte blast transformation. The results clearly show that immunomodulatory capacity is a common feature of RCC and that in vitro these tumors can produce interleukin-10 (IL-10) up to 20 ng/ml, IL-6 up to 35 micrograms/ml (> 250 kU/ml in the B9 system), IL-11 up to 15 micrograms/ml, and transforming growth factor-beta 1 (TGF-beta 1) up to 22 ng/ml. Furthermore, these tumors have the capacity to modulate T cell blast transformation over two orders of magnitude in each direction. The correlations of the immunologic properties of tumor cell cultures with the conventional classification of tumors (histology, cytology, staging, grading, presence of metastases, and secondary tumors) are analyzed. The significance of these findings for modulation of local immunity by RCC as well as for patient outcome is discussed.

Transforming growth factor beta 1 is significantly elevated in plasma of patients suffering from renal cell carcinoma

The levels of active and latent transforming growth factor beta 1 (aTGF-beta 1, ITGF-beta 1, respectively) in plasma samples were measured by enzyme-linked immunoabsorbent assay (ELISA). Samples were collected from patients suffering from renal cell carcinoma (RCC) before they underwent tumour resection. In all cases tested, the levels of latent TGF-beta 1 were much higher (n = 23, 41.0 +/- 13.9, range 19.3-78.1 ng/ml) than in healthy controls (n = 21, 3.8 +/- 2.9, range 0.6-9.9, P < < 0.0001), while active TGF-beta 1 did not differ that impressively (n = 38, 1.2 +/- 1.3, range 0.0-4.5 for RCC, n = 21, 0.1 +/- 0.2, range 0.0-1.1 in controls, P < 0.001). As for TGF-beta 1 production by proximal tubulus cells has been shown, it was speculated that these high TGF-beta 1 levels might be due to secretion by the tumour, which usually originates from proximal tubuli. Indeed, production of TGF-beta 1 was found in culture supernatants, and it was possible to show TGF-beta 1 mRNA expression in tumour samples. This TGF-beta 1 was predominantly secreted in the latent form. This is in contrast to data from other authors, who found TGF-beta 1 to be secreted mainly in the active form, but need not mean that it is inactive locally as the low pH encountered within tumours is in the range necessary for its activation. It is concluded that elevated latent TGF-beta 1 is common in RCC, is at least partially produced by the tumour and might be a cause for local immunosuppressive effects within the tumour.