Elevation of serum interleukin-6 levels before peak of serum granulocyte colony-stimulating factor level in chemotherapy-induced myelosuppressive patients.

The aim of this study was to ascertain whether any cytokines that function in earlier stages of hematopoiesis also fluctuate in conjunction with granulocyte colony-stimulating factor (G-CSF) in chemotherapy-induced myelosuppression. A total of seven patients were studied. All patients received 3 days of intravenous injection of combination chemotherapy. Patients' absolute neutrophil count (ANC), platelet count, serum G-CSF, interleukin-6 (IL-6), IL-3, and IL-1 alpha were monitored before chemotherapy, and then daily or every other day thereafter during the entire treatment course until the ANC returned to normal. The results showed very obvious elevation of serum IL-6 level before or concurrent with the elevation of serum G-CSF levels at the neutrophil nadir in all seven patients. The rise of IL-6 also correlated with nadir platelet levels in six of seven patients. The finding of serum IL-6 elevation was statistically significant both in neutropenic and thrombocytopenic stages. Serum IL-3 level was below minimum detectable concentrations in all seven patients. Serum IL-1 alpha was below minimum detectable concentration in six patients and demonstrated no obvious fluctuation in the remaining patient. Therefore, the present study demonstrated the chronological time sequence of cytokine fluctuation, IL-6 peak before G-CSF, in chemotherapy-induced myelosuppression. According to this finding, when cytokines are used for prevention of myelosuppression or for acceleration of its recovery, it may be logical to use a combination of cytokines in sequence, such as IL-6 initially followed by G-CSF.