BCG and autoimmunity

The nonspecific effects of BCG are not fully understood nevertheless, “trained immunity” and “heterologous lymphocyte responses” have been suggested. For instance, intravesical BCG therapy used for the treatment of bladder cancer, commonly causes minor side effects following treatment. On the other hand, severe complications, varying from isolated organ involvement to multisystem BCG disease, may occur less frequently but require specific treatment, and in some cases necessitate discontinuation of BCG therapy.