Rituximab, an anti-CD20 human-mouse chimeric monoclonal antibody has been shown to improve response rates when it is combined with standard salvage chemotherapy in patients with relapsed or refractory intermediate-grade B-cell non-Hodgkin's lymphoma. A vast majority of these patients subsequently undergo high-dose therapy followed by stem cell transplantation. However, the impact of rituximab on stem cell mobilization kinetics is not well characterized. The purpose of this study was to study the effect of high-dose rituximab given with chemotherapy on stem cell mobilization in patients with intermediate-grade B-cell non-Hodgkin's lymphoma. Thirty-six patients received ifosfamide, etoposide, and rituximab followed by filgrastim for stem cell mobilization. The chemotherapy regimen was well tolerated. Thirty-four of 36 patients (94%) were able to mobilize at least 2 x 10(6) CD34+ cells/kg body weight after a median of 2 apheresis procedures. The median CD34+ cell dose collected per kilogram of recipient body weight was 6.5 x 10(6) (range, 4.65-31.15). All patients who subsequently underwent high-dose chemotherapy and stem cell transplantation experienced sustained engraftment. In conclusion, high-dose rituximab given during stem cell mobilization does not negatively affect stem cell mobilization kinetics.