Objectives: The antitumour effect of bacillus Calmette-Gue ́rin (BCG) still
remains relatively undefined. Most investigations on its mechanism of
action have focused on mononuclear cells; little consideration has been
given to granulocytes. Weanalysed urine of patients with bladder cancer
during 8 wk of intravesical BCG prophylaxis. The number of polymorphonuclear
neutrophils (PMNs) and urothelial cells (UCs) was evaluated.
We examined the in vitro response of the T24 UC line to human PMNs
after BCG treatment.
Methods: Seventeen patients were enrolled in the study. Cytologic analyses
were performed on urine samples collected before each BCG
instillation and after 2 h from the first voided urine after BCG instillation.
Elastase activity was determined on these samples to evaluate PMN
activation. PMN-induced damage was measured on the T24 cell line
treated with BCG.
Results: After BCG treatment, a large number of PMNs transmigrated
through the urothelium and PMNs adherent to detached UCs were
found. One patient, who did not respond with significant PMN transmigration,
experienced recurrent disease. The number of eosinophils
that transmigrated was low, with the exception of three patients with
recurrent disease. In vitro, PMNs adhered to BCG-primed T24 cells and
damaged the monolayer.
Conclusions: The results agree with recent evidence that PMNs may play
an important role in the antitumour action of BCG during the BCG induction
period. This role is probably nonspecific because both normal UCs in
vivo and tumour cells in vitro appeared to be injured. As suggested by
results obtained from a limited number of patients, a high number of
eosinophils in the urine may indicate therapy failure.
