Late-onset neutropenia in patients treated with rituximab for non-Hodgkin's lymphoma.

Late-onset grade 4 neutropenia occurred in 3 (5.6%) of 54 non-Hodgkin's lymphoma patients treated with rituximab between September 2001 and March 2004. Neutropenia appeared 5 to 25 weeks after administration of cytotoxic agents in combination with rituximab and recurred 4 and 17 weeks after the first onset in 2 patients. Five episodes occurred in a total of 332 cycles of rituximab therapy. Bone marrow findings at the time of late-onset neutropenia showed neutrophil maturation arrest with or without reversible myeloid dysplasia in 3 episodes and selective depletion of the myeloid series in 1 episode. Neither circulating immune complexes nor antineutrophil antibodies were detected during the 3 episodes that we evaluated. Bone marrow cells stained CD8- and CD57-. Late-onset neutropenia resolved 5 to 7 days after granulocyte colony-stimulating factor therapy was started. Further studies are needed to determine how rituximab functions and to identify appropriate countermeasures.

CD20-negative pyothorax-associated B cell lymphoma.

We describe an 86-year-old male who developed CD20-negative pyothorax-associated B cell lymphoma 64 years after he had suffered from tuberculous pleuritis. Therapy with 8 courses of THP-COP at 2-week intervals was followed by involved-field radiotherapy of 30 Gy. Uncertain complete remission was achieved. Thereafter, local recurrence of pyothorax-associated lymphoma (PAL) at the primary site was seen. The patient received salvage radiotherapy of 50 Gy. The patient died of pneumonia during a second uncertain complete remission. The progression-free survival and overall survival of this patient were 10 and 15 months, respectively. When compared with the median survival of 9 months reported in the literature, the adverse effect of CD20 negativity on prognosis may not apply to PAL patients with an occasional aberrant phenotype.