We have previously shown that the novel hexapeptide
WKYMVm can stimulate bactericidal activity in neutrophils obtained from neutropenic patients treated with chemotherapeutic agents for solid
tumors. To extend these observations, we evaluated whether
WKYMVm can enhance leukocyte bactericidal activity in patients with acute
leukemia (AL). Using blood samples withdrawn from 28 AL patients and 31 healthy controls, we found that, in the absence of exogenous
WKYMVm,
WKYMVm receptor and bactericidal activity did not differ between patients and controls. Addition of
WKYMVm markedly increased the bactericidal activities of these cells in a dose-dependent manner. During
induction chemotherapy, there were significant increases in bactericidal activity in the presence and absence of 1nM
WKYMVm, with higher bactericidal activities at the time of complete remission than at the time of diagnosis or on day 15. During
consolidation chemotherapy,
WKYMVm had no effect on bactericidal activities. Patients showed significant increase in the concentrations of
TNF alpha, IL-1b,
IL-6 and
IL-8, but significant decrease in the concentrations of
IL-2,
IL-4 and
IL-12.
TNF alpha, IL-1b and
IL-6 showed significant negative correlations with bactericidal activities of patient neutrophils at time of diagnosis, and
IL-4 showed a significant positive correlation with bactericidal activities. Taken together, these findings indicate that
WKYMVm enhances bactericidal activity in patients with AL.