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Background: Posttransplant lymphoproliferative disease (PTLD), is a major cause of morbidity and mortality following lung transplantation, responsible for Ϸ4% of mortality after 30 days post-transplant in pediatric recipients. Chemotherapy related mortality in thoracic organ recipients is reported from 30 -70%. Therefore, initial treatment is usually reduced immunosuppression and anti-CD20 monoclonal antibody (rituximab). Rituximab is well tolerated and achieves a 60 -70% response rate. However, rituximab refractory relapse may occur, requiring the use of chemotherapy.The Zevalin therapeutic protocol (ZTP), including radioimmunotherapy with a Yttrium-90 tagged anti-CD20 antibody (ibritumomab tiuxetan; Zevalin), is a minimally toxic, effective therapy for relapsed or refractory low grade, follicular, or transformed B-cell non-Hodgkin's lymphoma (NHL). We found no published reports of radioimmunotherapy for PTLD.We report the successful use of ZTP in a 16-yr-old bilateral cadaveric lung transplant recipient. Abdominal PTLD was diagnosed 8 months post-transplant. Remission was achieved with reduced immunosuppression and rituximab. Relapse occurred 28 months posttransplant. Procedures: Relapsed CD20 positive, monomorphic B-cell PTLD was diagnosed by biopsy of sinus and esophagus. The patient received 1 dose of rituximab and reduced immunosuppression, with some improvement in symptoms. Once available, she received ZTP, including 0.3 mCi/kg Yt-90 ibritumomab tiuxetan. Efficacy was monitored with PET, CT and endoscopic biopsies (GI and lung). The anticipated hypogammaglobulinemia has been treated with IVIG. Results: Treatment with ZTP resulted in a complete remission without evidence of graft dysfunction. At 8 months post-treatment, there was no evidence of recurrent PTLD. There has been no significant infection. Conclusions: In our patient, ZTP was effective treatment of relapsed PTLD. Although further study is needed to confirm this observation, minimal toxicity makes ZTP an attractive alternative to chemotherapy for relapsed or rituximab refractory PTLD.

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A 2-hour infusion of 100 mg recombinant tissue plasminogen activator (rtPA) is approved by the US Food and Drugs Administration (FDA) for eligible patients with acute pulmonary embolism (PE). However, multiple clinical trials showed that a lower dosage of rtPA (0.6 mg/kg, maximum of 50 mg) is equally effective and associated with a potentially lower complication rate than the 100 mg regimen. We conducted a systematic review and meta-analysis to compare the two regimens. METHODS: We conducted a systematic search of the PubMed, EMBASE, and Cochrane databases from inception through January-2020 for studies comparing high dose rtPA (100 mg) and low dose rtPA (0.6 mg/kg, maximum of 50 mg) for the treatment of acute pulmonary embolism. Relevant data were extracted and analyzed using Comprehensive Meta-Analysis software. The random-effects model was used for all variables, and publication bias was assessed using Egger's test.