Voices in the Wilderness

Analysis of tissue sections from transurethrally resected bladder tumours using anti-CD3 antibody showed the presence of T lymphocytes in intra-epithelial layers in eight of 12 cases investigated. In a larger group of patients, Tumour Infiltrating Lymphocyte (TIL) growth was established from six of 19 cases using Interleukin-2 (IL-2) and conditioned medium (CM) and resulted in the expansion of TILs up to 100-fold. TILs from these individuals were phenotyped with W6/32 (anti-HLA-A,B,C), HB55 (anti-DR) and anti-CD3 antibodies using FAC sorter. The mean±s.d. frequency of positive staining with these antibodies were 96.7±4.0%, 87.5±10.0% and 82.5±7.8% respectively, indicating the activated nature of these T cells. The cytotoxic activity of these TILs against Daudi (ie, LAK activity) cell line at 25/1 E/T ratios varied from 26.3±3.2 to 62.8±5.2%. In one case where TILs and autologous tumour cell line were established, cytotoxicity studies showed low level of cytotoxicity against the autologous tumour cells (15.8±1.6%) compared with 62.8 ± 5.2% against Daudi. Staining of tumour sections from these 19 individuals with W6/32 and BBM.I revealed positive staining in six of six that developed TILs but only six of 13 (46%) cases, whose tumour failed to grow TILs (P < 0.02, Fisher exact test). These results are indicative of the presence of IL-2 passageable T cells in bladder cancer biopsy and demonstrate that the successful expansion of these cells correlates with the normal expression of class I antigens on the tumour cells. Recently there has been speculation from results in vitro studies that interleukin-2 induced T lymphocyte mediated tumour rejection response may be the mechanism by which intravesical BCG produces durable long term disease free survival in more than 50% of patients with recurrent superficial bladder cancer (Anon, 1991; Ratliff et al., 1991). As a consequence, there has been increased interest in study of T lymphocyte activity in bladder tumours since it has long been known that the extent of lymphocyte infiltration in tumours is of prognostic significance (Dayan et al. Studies of melanoma patients have demonstrated that IL-2 can be used to expand TILs from tumour biopsy (Topalian et al., 1987) and in nearly half the cases these TILs showed HLA class I antigen restricted T cell cytotoxicity against the autologous tumour (Itoh et al., 1988). These cells labelled with a neomycin resistance gene have been demonstrated in the circulation for up to 200 days, and at sites where the tumour underwent rejection, up to 70 …