Two Cases of Pneumocystis jiroveci Pneumonia with Non-Hodgkin's Lymphoma after CHOP-Based Chemotherapy Containing Rituximab

We report two cases of Pneumocystis jiroveci pneumonia (PCP) with CD20(+) B-cell lymphoma. They were treated by several courses of CHOP-based chemotherapy containing rituximab. We confirmed by flow cytometric analysis that both of them completely lost CD19(+) and CD20(+) B-cells from their peripheral blood after the first course of chemotherapy. They were successfully treated with Trimethoprim-sulfamethoxazole (TMP-SMX) after the diagnosis of PCP by polymerase chain reaction (PCR). We overviewed CD20(+) B-cell lymphoma patients treated with CHOP-based regimens from 1997 until 2005 in our hospital. We treated 114 patients with and 121 patients without rituximab. Five patients in the group with rituximab developed interstitial pneumonia (IP). Two of them were confirmed to have PCP and the other three were suspected cases; however, no patients with IP were seen in the group without rituximab. We strongly suggest the necessity of PCP prophylaxis with oral TMP-SMX when treating B-cell lymphoma patients with chemotherapy containing rituximab.