Reuven Or

ELIMINATION OF GRAFT-VERSUS-HOST DISEASE BY IN-VITRO DEPLETION OF ALLOREACTIVE LYMPHOCYTES WITH A MONOCLONAL RAT ANTI-HUMAN LYMPHOCYTE ANTIBODY (CAMPATH-1)

A new monoclonal rat anti-human lymphocyte antibody (CAMPATH-1) which lyses cells with autologous human complement was used for depletion of T lymphocytes from human bone-marrow allografts in vitro before transplantation in 11 high-risk patients. HLA-matched siblings were used as marrow donors. T-cell depletion was substantial when measured by E-rosette formation (0-0.18% residual T cells) and immunofluorescence with a monoclonal anti-T-cell antibody (0-0.5%). No anti-graft-versus-host disease prophylaxis was given after transplantation. Rapid engraftment was reported in all patients, and the post-transplantation course was uneventful. No signs of graft-versus-host disease developed in any of the patients, who were observed for a maximum period of 12 months. The method might be suitable for larger-scale studies in high-risk patients. The late graft failure seen in 2 patients may reflect residual host resistance uncompromised by GvHD.

Disabling Immune Tolerance by Programmed Death-1 Blockade With Pidilizumab After Autologous Hematopoietic Stem-Cell Transplantation for Diffuse Large B-Cell Lymphoma: Results of an International Phase II Trial

PURPOSE The Programmed Death-1 (PD-1) immune checkpoint pathway may be usurped by tumors, including diffuse large B-cell lymphoma (DLBCL), to evade immune surveillance. The reconstituting immune landscape after autologous hematopoietic stem-cell transplantation (AHSCT) may be particularly favorable for breaking immune tolerance through PD-1 blockade. PATIENTS AND METHODS We conducted an international phase II study of pidilizumab, an anti-PD-1 monoclonal antibody, in patients with DLBCL undergoing AHSCT, with correlative studies of lymphocyte subsets. Patients received three doses of pidilizumab beginning 1 to 3 months after AHSCT. RESULTS Sixty-six eligible patients were treated. Toxicity was mild. At 16 months after the first treatment, progression-free survival (PFS) was 0.72 (90% CI, 0.60 to 0.82), meeting the primary end point. Among the 24 high-risk patients who remained positive on positron emission tomography after salvage chemotherapy, the 16-month PFS was 0.70 (90% CI, 0.51 to 0.82). Among the 35 patients with measurable disease after AHSCT, the overall response rate after pidilizumab treatment was 51%. Treatment was associated with increases in circulating lymphocyte subsets including PD-L1E-bearing lymphocytes, suggesting an on-target in vivo effect of pidilizumab. CONCLUSION This is the first demonstration of clinical activity of PD-1 blockade in DLBCL. Given these results, PD-1 blockade after AHSCT using pidilizumab may represent a promising therapeutic strategy in this disease.

Adoptive transfer of pp65-specific T cells for the treatment of chemorefractory cytomegalovirus disease or reactivation after haploidentical and matched unrelated stem cell transplantation

Cytomegalovirus (CMV) disease and infection refractory to antiviral treatment after allogeneic stem cell transplantation (allo-SCT) is associated with a high mortality. Adoptive transfer of CMV-specific T cells could reconstitute viral immunity after SCT and could protect from CMV-related complications. However, logistics of producing virus-specific T-cell grafts limited the clinical application. We treated 18 patients after allo-SCT from human leukocyte antigen-mismatched/haploidentical or human leukocyte antigen-matched unrelated donors with polyclonal CMV-specific T cells generated by ex vivo stimulation with pp65, followed by isolation of interferon-γ-producing cells. Patients with CMV disease or viremia refractory to antiviral chemotherapy or both were eligible for adoptive T-cell transfer and received a mean of 21 × 10³/kg pp65-specific T cells. In 83% of cases CMV infection was cleared or viral burden was significantly reduced, even in cases of CMV encephalitis (n = 2). Viral control was associated with in vivo expansion of CMV-specific T lymphocytes in 12 of 16 evaluable cases, resulting in reconstitution of antiviral T-cell responses, without graft-versus-host disease induction or acute side effects. Our findings indicate that the infusion of low numbers of CMV-specific T cells is safe, feasible, and effective as a treatment on demand for refractory CMV infection and CMV disease after allo-SCT.

Allogeneic peripheral blood stem cell transplantation using a fludarabine-based low intensity conditioning regimen for malignant lymphoma

relapse is a serious complication following high-dose therapy and autologous bone marrow transplantation (abmt) for malignant lymphoma (ml). allogeneic transplantation (allosct) is a therapeutic option. however, it is associated with a high incidence of transplant-related organ toxicity and mortality. we recently reported fast engraftment and minimal transplant-related toxicity, using fludarabine-based conditioning with reduced amounts of chemotoxic drugs prior to allosct. we now present our experience with 23 heavily treated high risk ml patients who underwent matched allosct following the same low intensity conditioning. the patients (20 male, three female) were aged 13–63 years. nineteen had nhl and four hd (resistant disease 12, partial remission 11). five were post abmt. twenty-two patients had fully matched sibling donors, and one a fully matched unrelated donor. engraftment was fast. there was no rejection or non-engraftment. organ toxicity was moderate with no liver or renal toxicity >grade ii. four patients developed >grade II graft-versus-host disease (GVHD). Seven patients died – four of grade III–IV GVHD and severe infections, two of bacterial sepsis, one of pulmonary failure. Ten patients are alive after 22.5 (15–37) months. Survival and disease-free survival at 37 months are both 40%. Probability of relapse is 26%. These encouraging results suggest that alloSCT following fludarabine-based low intensity conditioning in high-risk patients merits further evaluation. Bone Marrow Transplantation (2000) 25, 1021–1028.

T-cell-depleted allogeneic bone marrow transplantation for acute leukaemia using Campath-1 antibodies and post-transplant administration of donor's peripheral blood lymphocytes for prevention of relapse

One hundred and forty‐six patients with acute leukaemia (81 with ANLL and 65 with ALL) received allogeneic bone marrow transplantation from their fully matched siblings. 121 patients underwent T‐cell depletion (TCD) using Campath 1 monoclonal rat anti‐human lymphocyte (CDw52) antibodies; 67 with Campath 1M and 54 with Campath 1G isotypes. Patients were conditioned for transplant using either total body irradiation combined with chemotherapy (125 patients) or busulfan and cyclophosphamide (21 patients). 112 recipients of T‐cell depleted allografts received in addition total lymphoid irradiation (TLI) for prevention of rejection. Engraftment of neutrophils (>0.5 × 109/l) and platelets (>25 × 109/l) occurred on days 15 and 18, and on days 18 and 20 in recipients of Campath 1M and Campath 1G treated marrows respectively. Rejection was documented in 6.8% of T‐cell depleted transplants. Leukaemia relapse‐free survival at 2 years was 83% for patients transplanted in first CR, 76% in second CR (P2= 0.34) and 42% in advanced leukaemia (P2= 0.009). 81 marrow recipients, 38 with Campath 1M and 43 with Campath 1G treated marrow, received post‐transplant graded increments of donors peripheral blood lymphocytes (PBL) to induce graft‐versus‐leukaemia (GVL) effects. Administration of donors PBL was associated with clinically significant GVHD and with decreased relapse rate especially in patients with ALL. Our data suggest that in patients receiving marrow allografts depleted of T cells by Campath 1 monoclonal antibodies, rejection can be reduced by adequate pregrafting immunosuppression. In patients with advanced disease, post‐transplant cell‐mediated immunotherapy (CMI) using donors PBL may be beneficial; however, further studies are needed to define the optimal schedule of CMI for safe and effective prevention of relapse following TCD bone marrow transplantation in malignant haematological diseases.

Low-intensity conditioning is sufficient to ensure engraftment in matched unrelated bone marrow transplantation

OBJECTIVE Matched unrelated bone marrow transplantation (BMT) for patients with hematological malignancies is associated with a high incidence of transplant-related complications due to high doses of chemoradiotherapy administered pre-BMT to ensure engraftment. The aim of this study was to investigate the feasibility of low-intensity conditioning for BMT from matched unrelated donors. MATERIALS AND METHODS Sixteen patients with hematologic malignancies underwent non-T-cell-depleted BMT following a low-intensity conditioning regimen consisting of fludarabine monophosphate 30 mg/m(2)/day for 6 days, busulfan 4 mg/kg/day for 2 days, anti-T lymphocyte globulin 10 mg/kg/day for 4 days. Seven of the patients suffered from chronic myelogenous leukemia, four from acute lymphoblastic leukemia, four from acute myelogenous leukemia, and one from Ki-1 non-Hodgkins lymphoma. Three of the patients had secondary leukemia and two were post-autologous BMT (ABMT). All patients were transplanted from fully matched unrelated donors. RESULTS Fifteen of the 16 patients had 100% donor chimerism; no graft rejection was observed. None of the patients developed >Grade II veno-occlusive disease, sepsis, multiorgan failure, or renal or pulmonary toxicity. Four patients died posttransplant; one of thrombocytopenia and severe hemorrhagic cystitis, one of central nervous system toxicity, one of Grade IV graft-vs-host disease, and one following relapse (9 months post-BMT). Survival and disease-free survival at 36 months are 75% (95% confidence interval 46-90%) and 60% (95% confidence interval 30-80%), respectively. CONCLUSION These results indicate that low-intensity conditioning is sufficient to ensure stable engraftment of bone marrow grafts in a matched unrelated setting.

Graft vs autoimmunity following allogeneic non-myeloablative blood stem cell transplantation in a patient with chronic myelogenous leukemia and severe systemic psoriasis and psoriatic polyarthritis.

OBJECTIVE No specific therapy exists for autoimmune diseases caused by self-reactive lymphocytes. As shown in experimental animals, which led to pilot clinical studies, elimination of self-reactive lymphocytes can be accomplished with high-dose chemoradiotherapy, followed by autologous stem cell transplantation, by re-establishment of unresponsiveness to self antigens of newly generated lymphocytes, due to a mechanism of central clonal deletion. We hypothesized that self-reactive lymphocytes causing autoimmune disease may be successfully eliminated by highly immunosuppressive yet not necessarily myeloablative conditioning in conjunction with allogeneic blood stem cell transplantation, since immunocompetent alloreactive lymphocytes of donor origin can effectively eliminate residual host-type hematopoietic cells, self-reactive lymphocytes included, by a mechanism that resembles graft-vs-leukemia (GVL) effects. The present report is an attempt to confirm the existence of graft-vs-autoimmunity (GVA) effects in parallel with amplification of the alloreactive potential of donor lymphocytes following allogeneic non-myeloablative stem cell transplantation (NST). METHODS We identified a patient with severe psoriatic arthritis who also had Philadelphia (bcr/abl) positive chronic myelogenous leukemia and therefore was fully eligible for NST. Both diseases responded initially to non-myeloablative conditioning involving fludarabine 30 mg/m2 x 6, anti-T-lymphocyte globulin 10 mg/kg X 4, and busulfan 4 mg/kg x 2. RESULTS The initial NST procedure was uneventful and resulted in elimination of all signs of autoimmunity (psoriasis and arthritis). Recurrence of polyarthritis and exacerbation of psoriasis were observed in parallel with a significant increase in the proportion of male (host) DNA, and 5% of the mitoses were bcr/abl positive, indicating an increase in the clone of CML. Both bcr/abl-positive cells identified by RT-PCR and psoriatic arthritis were successfully eliminated following discontinuation of anti-GVHD prophylaxis with cyclosporine A (CSA), which resulted in activation of the alloreactive potential of donor T cells, accompanied by graft-vs-host disease (GVHD), suggesting the existence of GVA effects. RT-PCR for bcr/abl remains consistently negative for nearly 3 years, and all DNA remains donor type. CONCLUSIONS The response of autoimmune disease manifestations to GVA effects in parallel with elimination of all host-derived hematopoietic cells supports our working hypothesis that autoimmune diseases caused by self-reactive lymphocytes may be effectively treated by elimination of alloreactive self-reactive lymphocytes following induction of host-vs-graft tolerance, in analogy with replacement of malignant or genetically abnormal host cells following DLI. It is therefore suggested that intentional GVA effects may be inducible by DLI following a conventional or preferably safer non-myeloablative regimen in recipients with life-threatening autoimmune diseases resistant to conventional modalities. Adoptive immunotherapy of autoimmunity may thus involve a two-step procedure: first, inducing host-vs-graft and graft-vs-host transplantation tolerance through a transient stage of mixed chimerism; second, inducing controlled GVA effects, initially by discontinuation of CSA and then, if indicated, by late outpatient DLI to eradicate residual hematopoietic cells of host origin.

Nosocomial colonization, septicemia, and Hickman/Broviac catheter-related infections in bone marrow transplant recipients. A 5-year prospective study.

&NA; Abbreviations used in this article: BMT, bone marrow transplantation; CVC, central venous catheter; GVHD, graft‐versus‐host disease; PMNs, polymorphonuclear neutrophils; VOD, veno‐occlu‐sive disease.

Right atrial thrombi are related to indwelling central venous catheter position: Insights into time course and possible mechanism of formation

We studied the effect of central line catheters on thrombus formation in the right atrium (RA), including the incidence and echocardiographic characteristics of the catheter-associated thrombus as well as possible clinical implications in patients. We prospectively studied 55 patients by transesophageal echocardiography within 1 week after Hickman catheter implantation and on a follow-up study at 6 to 8 weeks. We succeeded in imaging the catheter tip in 48 of the 55 patients (87%). In the baseline study 13 had the tip placed in the RA, eight at the superior vena cava-atrium junction, and 27 in the superior vena cava. An abnormal mass, consistent with a thrombus, was found in 12.5% of the patients, all of which were seen within the 13-patient (46%) group with the Hickman catheter tip placed in the RA. Hickman catheter insertion is associated with high incidence (12.5%) of early formation of RA thrombus. The formation of these thrombi is asymptomatic and highly associated (p < 0.001) with the catheter tip position in the RA, in contrast to their positioning in the superior vena cava or in its junction with the right atrium. On the basis of these findings, we recommend that special attention and effort be given to placing of the catheter tip in the superior vena cava and avoiding the RA during the implantation procedure.

Low molecular weight heparin for the prevention of veno-occlusive disease of the liver in bone marrow transplantation patients

Hepatic veno-occlusive disease (VOD), a common complication of bone marrow transplantation (BMT), is a result of intensive conditioning by chemo-radiotherapy. Endometrial injury causes fibrin deposition in the affected hepatic venules, leading to abnormal laboratory parameters followed by lethal full-blown disease. Previous studies have shown that unfractionated heparin can prevent VOD in BMT patients. Since low molecular weight heparin (LMWH) preserves the antithrombotic, but not the anticoagulant, activity of unfractionated heparin, we initiated a pilot study to determine the safety of LMWH for the prevention of VOD. Sixty-one patients undergoing BMT (allogeneic, n=24; autologous, n=37) were randomized to receive subcutaneous injection of enoxaparin (40 mg/day x 1) or a placebo prior to BMT conditioning and until day 40 after transplantation or discharge from the hospital. LMWH administration did not influence marrow engraftment, nor was it associated with bleeding tendency. Hemorrhagic events occurred significantly less frequently (P=0.025) were shorter duration (P=0.006) in the LMWH group than in the placebo group. Time to platelet recovery was significantly shorter (16.5 vs 29.6 days, (P=0.0075), and platelet transfusion requirements were lower (p=0.05) in the LMWH patients. VOD parameters occurred less frequently in the experimental group, including duration of elevated bilirubin levels (P=0.01) and incidence of hepatomegaly (P=0.04). LMWH, which seems to enhance platelet recovery, may be safely administrated to BMT patients in an attempt to prevent VOD of the liver.