SummaryObinutuzumab is a novel glycoengineered Type-II CD20 monoclonal antibody. CD20 is expressed in approximately 100% of children and adolescents with Burkitt lymphoma (BL) and 40% with precursor B-cell acute lymphoblastic leukaemia (pre-B-ALL). We evaluated the anti-tumour activity of obinutuzumab versus rituximab against rituximab-resistant (Raji 4RH) and -sensitive (Raji) BL and pre-B-ALL (U698-M) cells in vitro and in human BL or Pre-B-ALL xenografted mice. We demonstrated that obinutuzumab compared to rituximab significantly enhanced cell death against Raji 35Á6 AE 3Á1% vs. 25Á1 AE 2Á0%, (P = 0Á001), Raji4RH 19Á7 AE 2Á2% vs. 7Á9 AE 1Á5% (P = 0Á001) and U-698-M 47Á3 AE 4Á9% vs. 23Á2 AE 0Á5% (P = 0Á001), respectively. Obinutuzumab versus rituximab also induced a significant increase in antibody-dependent cellular cytotoxicity (ADCC) with K562-IL15-41BBL expanded NK cells against Raji 73Á8 AE 8Á1% vs. 56Á81 AE 4Á6% (P = 0Á001), Raji-4RH 40Á0 AE 1Á6% vs. 0Á5 AE 1Á1% (P = 0Á001) and U-698-M 70Á0 AE 1Á6% vs. 45Á5 AE 0Á1% (P = 0Á001), respectively. Overall survival in tumour xenografted mice receiving 30 mg/kg of obinutuzumab was significantly increased when compared to those receiving 30 mg/kg of rituximab in BL; Raji (P = 0Á05), Raji4RH (P = 0Á02) and U698-M (P = 0Á03), respectively. These preclinical data suggest obinutuzumab is significantly superior to rituximab in inducing cell death, ADCC and against rituximab-sensitive/-resistant BL and pre-B-ALL xenografted mice. Taken together, these preclinical results provide evidence to suggest that future investigation of obinutuzumab is warranted in patients with relapsed/refractory CD20 + BL and/or pre-B-ALL.

Primary effusion lymphoma (PEL) is a rare mature B‐cell non‐Hodgkin’s lymphoma arising in body cavities and presenting with effusions. It has been described predominantly in patients with impaired immunity from the acquired immunodeficiency syndrome and is associated with the Human Herpesvirus‐8 (HHV‐8). Seldom has PEL been diagnosed in persons negative for the human immunodeficiency virus (HIV), and in such cases it has occurred primarily in the setting of posttransplant immunosuppression. We report an instructive case of a Caribbean‐American HIV‐negative orthotopic heart transplant recipient with a history of HHV‐8‐associated Kaposi's sarcoma who developed HHV‐8 viremia and PEL of the pleural space early in the posttransplant course. This case highlights the importance of considering PEL in the differential diagnosis of a new pleural effusion in a transplant recipient at risk for HHV‐8‐associated disease.

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Extramedullary hematopoiesis (EMH) is a rare cause of spinal cord compression (SCC). EMH represents the growth of blood cells outside of the bone marrow and occurs in a variety of hematologic illnesses, including various types of anemia and myeloproliferative disorders. Although EMH usually occurs in the liver, spleen, and lymph nodes, it may also occur within the spinal canal. When this occurs, the mass effect can compress the spinal cord, potentially leading to the development of neurological deficits. We present a case of SCC secondary to EMH. This report illustrates the importance of considering EMH in the differential diagnosis of SCC, even in the absence of signs of its most common etiologies.