Abstract

Immunological studies have shown an increased lymphocyte reactivity in patients with early stage bladder cancer and individuals with pre-stage T1 exposed to bladder carcinogens (2-naphthylamine and industrial 1-naphthylamine containing 4-8% 2-naphthylamine) before 1952-that is, those at high risk of developing bladder cancer. Because of the close chemical similarity of Tobias acid (2-naphthylamine-1 sulphonic acid) to 2-naphthylamine, the lymphocytotoxicity of workers exposed to this chemical was investigated. The results show that the workers using Tobias acid unlike those exposed to 2-naphthylamine have lymphocytes with a normal range of reactivity towards bladder cancer cells, which is in keeping with the suggestion that Tobias acid is non-carcinogenic. The probable reason for its non-carcinogenicity is that the relatively very large size and hydropholic properties of the sulphonic acid group prevents enzymic action on the amino group by steric hindrance. The present lymphocytotoxicity results strengthens our earlier conclusion that the observed increased lymphocyte reactivity in workers exposed to bladder carcinogens is specific.