Allogeneic T Cells That Express an Anti-CD19 Chimeric Antigen Receptor Induce Remissions of B-Cell Malignancies That Progress After Allogeneic Hematopoietic Stem-Cell Transplantation Without Causing Graft-Versus-Host Disease.

PURPOSE: Progressive malignancy is the leading cause of death after allogeneic hematopoietic stem-cell transplantation (alloHSCT). After alloHSCT, B-cell malignancies often are treated with unmanipulated donor lymphocyte infusions (DLIs) from the transplant donor. DLIs frequently are not effective at eradicating malignancy and often cause graft-versus-host disease, a potentially lethal immune response against normal recipient tissues. METHODS: We conducted a clinical trial of allogeneic T cells genetically engineered to express a chimeric antigen receptor (CAR) targeting the B-cell antigen CD19. Patients with B-cell malignancies that had progressed after alloHSCT received a single infusion of CAR T cells. No chemotherapy or other therapies were administered. The T cells were obtained from each recipient's alloHSCT donor. RESULTS: Eight of 20 treated patients obtained remission, which included six complete remissions (CRs) and two partial remissions. The response rate was highest for acute lymphoblastic leukemia, with four of five patients obtaining minimal residual disease-negative CR. Responses also occurred in chronic lymphocytic leukemia and lymphoma. The longest ongoing CR was more than 30 months in a patient with chronic lymphocytic leukemia. New-onset acute graft-versus-host disease after CAR T-cell infusion developed in none of the patients. Toxicities included fever, tachycardia, and hypotension. Peak blood CAR T-cell levels were higher in patients who obtained remissions than in those who did not. Programmed cell death protein-1 expression was significantly elevated on CAR T cells after infusion. Presence of blood B cells before CAR T-cell infusion was associated with higher postinfusion CAR T-cell levels. CONCLUSION: Allogeneic anti-CD19 CAR T cells can effectively treat B-cell malignancies that progress after alloHSCT. The findings point toward a future when antigen-specific T-cell therapies will play a central role in alloHSCT.

[Kaposiform haemangioendothelioma associated with B-cell acute lymphoblastic leukemia]. / Hémangioendothéliome kaposiforme associé à une leucémie aiguë lymphoblastique B.

BACKGROUND: Herein, we report the first case of kaposiform haemangioendothelioma (KHE) associated with acute B-lymphoblastic leukemia (B-ALL). PATIENTS AND METHODS: A five-month-old infant presented a plaque of angiomatous appearance on the forearm that had increased in volume since birth, as well as pallor and cutaneous haematomas. Kasabach-Merritt syndrome (KMS) was evoked despite hepatomegaly and considerable splenomegaly. Laboratory tests revealed severe anaemia and thrombocytopenia as well as major hyperleukocytosis with 90% blasts. Skin biopsy revealed vast vascular lobules containing cohesive fusiform endothelial cells not expressing Glut1, bound up in a dense infiltrate of B-lymphoblast cells. It was in fact KHE associated with B-ALL confirmed by the myelogram. The child was treated with the INTERFANT 2006 protocol followed by allograft of haematopoietic stem cells, which resulted in complete haematological remission. At the same time, almost total regression of KHE was noted. DISCUSSION: In this infant, KHE had an inflammatory appearance and was associated with thrombocytopenia, evocative of KMS. Analysis of blood and marrow samples resulted in a diagnosis of B-ALL. Histopathological examination of the angioma revealed a typical appearance of KHE associated with dense lymphoblastic proliferation. This appearance could have resulted either from passive contamination by circulating blast cells or from active recruitment of tumor cells at the KHE site. CONCLUSION: HK mimicking KMS may reveal B-ALL.

Massive immune haemolysis after allogeneic peripheral blood stem cell transplantation with minor ABO incompatibility.

Immune haemolysis as a result of minor ABO incompatibility is an underappreciated complication of haematopoietic transplantation. The increased lymphoid content of peripheral blood stem cell (PBSC) transplants may increase the incidence and severity of this event. We observed massive immune haemolysis in 3 out of 10 consecutive patients undergoing HLA-identical, related-donor PBSC transplants with minor ABO incompatibility. Non-ablative conditioning had been given in 9 of these 10 cases, including two with haemolysis. Cyclosporin alone was used as prophylaxis against graft-vs.-host disease (GVHD). Catastrophic haemolysis of 78% of the circulating red cell mass led to anoxic death in the first case seen, but severe consequences were avoided by early, vigorous donor-compatible red cell transfusions in the subsequent two cases. Haemolysis began 7-11 d after PBSC infusion and all patients with haemolysis had a positive direct antiglobulin test (DAT), with eluate reactivity against the relevant recipient antigen. However, neither the intensity of the DAT, the donor isohaemagglutinin titre, nor other factors could reliably be used to predict the occurrence of haemolysis. Our data indicate that haemolysis may be frequent and severe after transplantation of minor ABO-incompatible PBSCs when utilizing cyclosporin alone to prevent GVHD. Meticulous clinical monitoring and early, vigorous donor-compatible red cell transfusions should be practiced in all instances.

Optimization of conditioning therapy for leukemia prior to BMT. I. Optimal synergism between cyclophosphamide and total body irradiation for eradication of murine B cell leukemia (BCL1).

The doses of chemotherapy and radiotherapy and the sequence-dependent influence of CY administration and total body irradiation (TBI) on the eradication of murine B cell leukemia (BCL1) were investigated. Tumor-bearing BALB/c mice were treated with either CY followed by TBI (CY/TBI) or in the reverse (TBI/CY) at different time intervals after injection of 10(6) BCL1 cells. The presence of residual tumor cells after cytoreduction was assessed in secondary BALB/c recipients by monitoring leukemia-free survival. The anti-leukemic effect of CY followed by TBI was significantly better than TBI followed by CY. The survival of secondary adoptive recipients inoculated with 10(5) spleen cells obtained from mice treated with CY/TBI was 54% (57 of 105) compared with 25% (25 of 98) of recipients inoculated with 10(5) spleen cells obtained from mice treated with TBI/CY (p = 0.0001).

Characterization of effector cells of graft vs leukemia following allogeneic bone marrow transplantation in mice inoculated with murine B-cell leukemia.

It is now widely accepted that immunocompetent lymphocytes in allogeneic bone marrow grafts exert an antileukemic effect that contributes to the cure of leukemia. Graft vs leukemia (GVL) effects independent of graft vs host disease were investigated in allogeneic bone marrow chimeras tolerant of host and donor alloantigens. The role of Thy1.2, L3T4 and Lyt2 T lymphocytes as effector cells of GVL were investigated in (BALB/c x C57BL/6)F1 mice inoculated with murine B-cell leukemia and subsequently conditioned with total lymphoid irradiation and cyclophosphamide (200 mg/kg). Mice were reconstituted with C57BL/6 bone marrow cells depleted of well-defined T-cell subsets or enriched for stem cells by the soybean agglutination method. Detection of residual tumor cells, an indicator for efficacy of GVL, was carried out by adoptive transfer of peripheral blood or spleen cells obtained from treated chimeras into secondary naive BALB/c recipients at different time intervals following bone marrow transplantation. Treatment of the primary marrow inoculum with monoclonal anti-Thy1.2 or anti-Lyt2 abolished the GVL effects and all secondary BALB/c recipients developed leukemia within 60 days. On the other hand, the treatment with monoclonal anti-L3T4 did not influence the effect of GVL and all treated recipients remained without leukemia. The data suggest that T cells may mediate GVL effects in the absence of graft vs host disease and in circumstances where tolerance to conventional alloantigens is elicited. Effector cells of GVL across the major histocompatibility complex (MHC) in the murine B-cell leukemia tumor model system appear to be Thy1.2+ Lyt2+ L3T4-. Induction of GVL effects by allogeneic cells tolerant of host MHC suggests that these effects may be independent of graft vs host disease.

Differential killing of murine B-cell leukemia (BCL1) by photosensitization with merocyanine 540: implications for autologous bone marrow transplantation.

The efficacy of photosensitization by merocyanine 540 (MC540), a lipophilic fluorescent dye, was investigated in the murine B cell leukemia (BCL1). Normal BALB/c mice were injected with BCL1 cells exposed to MC540, followed by photosensitization with white light for 15 min to 2 h. Mice injected with BCL1 cells exposed for 1 or 2 h showed no sign of leukemia. Lethally irradiated mice were successfully reconstituted with mixtures of syngeneic bone marrow (BM) and BCL1 cells treated with MC540 following exposure to white light. Exposure of BM/BCL1 mixtures for 2 h proved to be effective in purging all BCL1 cells without affecting BM viability, as documented by normal hemopoietic reconstitution of all recipients surviving without evidence of leukemia. All recipients of untreated BM/BCL1 cell mixtures developed leukemia within 42 days. Adoptive transfer of 10(6) spleen cells obtained from treated mice into secondary naive syngeneic recipients was carried out in order to test for dormant BCL1 cells in treated recipients. No leukemia developed in any of the secondary recipients. Previous studies indicate that as few as 10, or possibly less, BCL1 cells are sufficient to cause lethal disease in BALB/c recipients. Our results suggest that MC540 may be an extremely potent tool for in vitro elimination of residual tumor cells while leaving uncommitted progenitor hemopoietic cells intact for hemopoietic reconstitution following lethal marrow ablation.