Background
CD22 is a B‐lineage differentiation antigen that has emerged as a leading therapeutic target in acute lymphoblastic leukemia (ALL).
Procedure
Properties of CD22 expression relevant to ...therapeutic targeting were characterized in primary samples obtained from children and young adults with relapsed and chemotherapy refractory B‐precursor (pre‐B) ALL.
Results
CD22 expression was demonstrated in all subjects (n = 163) with detection on at least 90% of blasts in 155 cases. Median antigen site density of surface CD22 was 3,470 sites/cell (range 349–19,653, n = 160). Blasts from patients with known 11q23 (MLL) rearrangement had lower site density (median 1,590 sites/cell, range 349–3,624, n = 20 versus 3,853 sites/cell, range 451–19,653, n = 140; P = <0.0001) and 6 of 21 cases had sub‐populations of blasts lacking CD22 expression (22%–82% CD22 +). CD22 expression was maintained in serial studies of 73 subjects, including those treated with anti‐CD22 targeted therapy. The levels of soluble CD22 in blood and marrow by ELISA were low and not expected to influence the pharmacokinetics of anti‐CD22 directed agents.
Conclusions
These characteristics make CD22 an excellent potential therapeutic target in patients with relapsed and chemotherapy‐refractory ALL, although cases with MLL rearrangement require close study to exclude the presence of a CD22‐negative blast population. Pediatr Blood Cancer Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
The cross-talk between tumor cells, myeloid cells, and T cells can play a critical role in tumor pathogenesis and response to immunotherapies. Although the etiology of mesothelioma is well ...understood, the impact of mesothelioma tumor cells on the surrounding immune microenvironment is less well studied. In this study, the effect of the mesothelioma tumor microenvironment on circulating and infiltrating granulocytes and T cells is investigated.
Tumor tissues and peripheral blood from mesothelioma patients were evaluated for presence of granulocytes, which were then tested for their T-cell suppression potential. Different cocultures of granulocytes and/or mesothelioma tumor cells and/or T cells were set up to identify the mechanism of T-cell inhibition.
Analysis of human tumors showed that the mesothelioma microenvironment is enriched in infiltrating granulocytes, which inhibit T-cell proliferation and activation. Characterization of the whole blood at diagnosis identified similar, circulating, immunosuppressive CD11b
CD15
HLADR
granulocytes at increased frequency compared with healthy controls. Culture of healthy-donor granulocytes with human mesothelioma cells showed that GM-CSF upregulates NOX2 expression and the release of reactive oxygen species (ROS) from granulocytes, resulting in T-cell suppression. Immunohistochemistry and transcriptomic analysis revealed that a majority of mesothelioma tumors express GM-CSF and that higher GM-CSF expression correlated with clinical progression. Blockade of GM-CSF with neutralizing antibody, or ROS inhibition, restored T-cell proliferation, suggesting that targeting of GM-CSF could be of therapeutic benefit in these patients.
Our study presents the mechanism behind the cross-talk between mesothelioma tumors and the immune microenvironment and indicates that targeting GM-CSF could be a novel treatment strategy to augment immunotherapy in patients with mesothelioma.
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Summary Background Chimeric antigen receptor (CAR) modified T cells targeting CD19 have shown activity in case series of patients with acute and chronic lymphocytic leukaemia and B-cell lymphomas, ...but feasibility, toxicity, and response rates of consecutively enrolled patients treated with a consistent regimen and assessed on an intention-to-treat basis have not been reported. We aimed to define feasibility, toxicity, maximum tolerated dose, response rate, and biological correlates of response in children and young adults with refractory B-cell malignancies treated with CD19-CAR T cells. Methods This phase 1, dose-escalation trial consecutively enrolled children and young adults (aged 1–30 years) with relapsed or refractory acute lymphoblastic leukaemia or non-Hodgkin lymphoma. Autologous T cells were engineered via an 11-day manufacturing process to express a CD19-CAR incorporating an anti-CD19 single-chain variable fragment plus TCR zeta and CD28 signalling domains. All patients received fludarabine and cyclophosphamide before a single infusion of CD19-CAR T cells. Using a standard 3 + 3 design to establish the maximum tolerated dose, patients received either 1 × 106 CAR-transduced T cells per kg (dose 1), 3 × 106 CAR-transduced T cells per kg (dose 2), or the entire CAR T-cell product if sufficient numbers of cells to meet the assigned dose were not generated. After the dose-escalation phase, an expansion cohort was treated at the maximum tolerated dose. The trial is registered with ClinicalTrials.gov , number NCT01593696. Findings Between July 2, 2012, and June 20, 2014, 21 patients (including eight who had previously undergone allogeneic haematopoietic stem-cell transplantation) were enrolled and infused with CD19-CAR T cells. 19 received the prescribed dose of CD19-CAR T cells, whereas the assigned dose concentration could not be generated for two patients (90% feasible). All patients enrolled were assessed for response. The maximum tolerated dose was defined as 1 × 106 CD19-CAR T cells per kg. All toxicities were fully reversible, with the most severe being grade 4 cytokine release syndrome that occurred in three (14%) of 21 patients (95% CI 3·0–36·3). The most common non-haematological grade 3 adverse events were fever (nine 43% of 21 patients), hypokalaemia (nine 43% of 21 patients), fever and neutropenia (eight 38% of 21 patients), and cytokine release syndrome (three 14%) of 21 patients). Interpretation CD19-CAR T cell therapy is feasible, safe, and mediates potent anti-leukaemic activity in children and young adults with chemotherapy-resistant B-precursor acute lymphoblastic leukaemia. All toxicities were reversible and prolonged B-cell aplasia did not occur. Funding National Institutes of Health Intramural funds and St Baldrick's Foundation.
Summary
A biopsy of lymphoid tissue is currently required to diagnose Kaposi sarcoma‐associated herpesvirus (KSHV)‐associated multicentric Castleman disease (KSHV–MCD). Patients showing clinical ...manifestations of KSHV–MCD but no pathological changes of KSHV–MCD are diagnosed as KSHV inflammatory cytokine syndrome. However, a lymph node biopsy is not always feasible to make the distinction. A pathognomonic feature of lymph nodes in KSHV–MCD is the expansion of KSHV‐infected, lambda‐restricted but polyclonal plasmablasts. To investigate whether these cells also reside in extra‐nodal sites, effusion from 11 patients with KSHV–MCD and 19 with KSHV inflammatory cytokine syndrome was analysed by multiparametric flow cytometry. A distinct, lambda‐restricted plasmablastic population (LRP) with highly consistent immunophenotype was detected in effusions in 8/11 patients with KSHV–MCD. The same population was also observed in 7/19 patients with KSHV inflammatory cytokine syndrome. The detection of LRP stratified KSHV inflammatory cytokine syndrome into two clinically distinct subgroups; those with detectable LRP closely resembled KSHV–MCD, showing similar KSHV viral load, comparable severity of thrombocytopenia and hypoalbuminaemia, and similar incidences of hepatosplenomegaly. Collectively, the detection of LRP by flow cytometry can serve as a valuable tool in diagnosing KSHV–MCD. KSHV inflammatory cytokine syndrome with LRP in effusions may represent a liquid‐form of KSHV–MCD.
Summary Background Patients with chronic lymphocytic leukaemia (CLL) with TP53 aberrations respond poorly to first-line chemoimmunotherapy, resulting in early relapse and short survival. We ...investigated the safety and activity of ibrutinib in previously untreated and relapsed or refractory CLL with TP53 aberrations. Methods In this investigator-initiated, single-arm phase 2 study, we enrolled eligible adult patients with active CLL with TP53 aberrations at the National Institutes of Health Clinical Center (Bethesda, MD, USA). Patients received 28-day cycles of ibrutinib 420 mg orally once daily until disease progression or the occurrence of limiting toxicities. The primary endpoint was overall response to treatment at 24 weeks in all evaluable patients. This study is registered with ClinicalTrials.gov , number NCT01500733 , and is fully enrolled. Findings Between Dec 22, 2011, and Jan 2, 2014, we enrolled 51 patients; 47 had CLL with deletion 17p13.1 and four carried a TP53 mutation in the absence of deletion 17p13.1. All patients had active disease requiring therapy. 35 enrolled patients had previously untreated CLL and 16 had relapsed or refractory disease. Median follow-up was 24 months (IQR 12·9–27·0). 33 previously untreated patients and 15 patients with relapsed or refractory CLL were evaluable for response at 24 weeks. 32 (97%; 95% CI 86–100) of 33 previously untreated patients achieved an objective response, including partial response in 18 patients (55%) and partial response with lymphocytosis in 14 (42%). One patient had progressive disease at 0·4 months. 12 (80%; 95% CI 52–96) of the 15 patients with relapsed or refractory CLL had an objective response: six (40%) achieved a partial response and six (40%) a partial response with lymphocytosis; the remaining three (20%) patients had stable disease. Grade 3 or worse treatment-related adverse events were neutropenia in 12 (24%) patients (grade 4 in one 2% patient), anaemia in seven (14%) patients, and thrombocytopenia in five (10%) patients (grade 4 in one 2% patient). Grade 3 pneumonia occurred in three (6%) patients, and grade 3 rash in one (2%) patient. Interpretation The activity and safety profile of single-agent ibrutinib in CLL with TP53 aberrations is encouraging and supports its consideration as a novel treatment option for patients with this high-risk disease in both first-line and second-line settings. Funding Intramural Research Program of the National Heart, Lung, and Blood Institute and the National Cancer Institute, Danish Cancer Society, Novo Nordisk Foundation, National Institutes of Health Medical Research Scholars Program, and Pharmacyclics Inc.
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