Early relapse after rituximab chemoimmunotherapy

In relapsed/refractory childhood acute lymphoblastic leukemia (ALL) of the B-cell lineage rituximab, a monoclonal anti-CD20 antibody was used successfully in some cases. We report on a 15-year-old female with relapsed CD20-positive B-cell progenitor ALL treated with rituximab because of positive minimal residual disease signals after chemotherapy, as checked by flow cytometry and real time quantitative-PCR. Rituximab eliminated the CD20-positive subpopulation, but not the more immature leukemic cells. The patient died with fulminant aspergillosis before hematopoietic stem cell transplantation could be performed.