Change of the fraction of immunocompetent cells after intravesical BCG instillation

Ahn, Han Jong; Cho, Seung Phil; Cho, Young Joo; Kim, Choung Soo; Ahn, Tai Young; Kim, Kwang Hoon

Abstract

Intrarvesical instillation of Bacillus-Calmette-Guerin (BCG) is known to be one of the most effective treatment for prevention of recurrent transitional cell carcinoma of the bladder, but its mechanism of action is not well defined yet. We evaluated the fraction of immunocompetent cells in peripheral blood of 17 patients with transitional cell carcinoma of the bladder before and after intravesical instillation of BCG. Among them, 7 patients had TURB and instillation of BCG(BCG group) and others had TURB only (non-BCG group). The fraction of B cells, total T (T3) cells, helper T (T4) cells, suppresser T (T8) cells, and natural killer (NK) cells in peripheral blood was determined using flowcytometric analysis. No significant changes of the fraction of B cells, T3, T4, T8 cells and T4/T8 ratio were noted after BCG instillation. The fraction of NK cells was significantly increased at 1 month after the start of BCG instillation (P=0.03), however, there was no significant increase in the fraction of them at 1 month after completion of 6 week course BCG instillation. In addition, none of parameters measured in this study showed any significant difference between BCG group and non-BCG group either before or after BCG instillation. Since no significant changes of systemic immune parameters in patients with transitional cell carcinoma of the bladder were observed after BCG instillation, local immune response may play a major role in the mechanism of BCG action for prevention of tumor recurrence.