Influence of polymorphism within the heme oxygenase-I promoter on overall survival and transplantation-related mortality after allogeneic stem cell transplantation

AbstractAside from major and minor histocompatibility antigens, genetic polymorphisms of various donor and host genes have been found to be risk factors for graft-versus-host disease and transplantation-related mortality (TRM). The heme oxygenase I (HO-I) protein has been implicated in regulating inflammatory response and has been described as a “protective gene” in solid organ transplantation. In humans, the promoter region displays length polymorphism due to a variable number of GT repeats. Individuals exhibiting 29 or fewer GT repeats express higher levels of HO-I on cellular stress compared with individuals with 30 or more GT repeats. We retrospectively analyzed length polymorphisms of 92 donor–host pairs undergoing allogeneic stem cell transplantation. Our findings demonstrate that mainly donor polymorphism leading to high expression of HO-1 (<30 GT repeats) on stress signals is associated with reduced overall survival, and that TRM is significantly increased in this group. This reduction in survival was most prominent when unrelated donors were used. Polymorphisms of the recipient HO-1 genes did not influence posttransplantation outcomes. We conclude that HO-1 polymorphism represents a new genetic risk factor for TRM and overall survival

Phase 2 Study of Anti-Human Cytomegalovirus Monoclonal Antibodies for Prophylaxis in Hematopoietic Cell Transplantation.

Human cytomegalovirus (HCMV) can cause significant disease in immunocompromised patients, and treatment options are limited by toxicities. CSJ148 is a combination of two anti-HCMV human monoclonal antibodies (LJP538 and LJP539) that bind to and inhibit the functions of viral HCMV glycoprotein B (gB) and the pentameric complex, consisting of glycoproteins gH, gL, UL128, UL130, and UL131. In this phase 2, randomized, placebo-controlled trial, we evaluated the safety and efficacy of CSJ148 for prophylaxis of HCMV in patients undergoing allogeneic hematopoietic stem cell transplantation. As would be expected in the study population, all the patients (100%) reported at least one treatment-emergent adverse event. There were 22 deaths during this study, and over 80% of the patients receiving placebo or CSJ148 developed at least one adverse event of grade 3 or higher severity. No subject who received antibody developed a hypersensitivity- or infusion-related reaction. CSJ148-treated patients showed trends toward decreased viral load, shorter median duration of preemptive therapy, and fewer courses of preemptive therapy. However, the estimated probability that CSJ148 decreases the need for preemptive therapy compared to placebo was 69%, with a risk ratio of 0.89 and a 90% credible interval of 0.61 to 1.31. The primary efficacy endpoint was therefore not met, indicating that CSJ148 did not prevent clinically significant HCMV reactivation in recipients of allogeneic hematopoietic cell transplants. (This study has been registered at ClinicalTrials.gov under identifier NCT02268526 and at EudraCT under number 2017-002047-15.)

Association of uric acid levels before start of conditioning with mortality after allogeneic hematopoietic stem cell transplantation - a prospective, non-interventional study of the EBMT Transplant Complication Working Party

Uric acid is a danger signal contributing to inflammation. Its relevance to allogeneic stem cell transplantation (alloSCT) derives from preclinical models where the depletion of uric acid led to improved survival and reduced graft-versus-host disease (GvHD). In a clinical pilot trial, peri-transplant uric acid depletion reduced acute GvHD incidence. This prospective international multicenter study aimed to investigate the association of uric acid serum levels before start of conditioning with alloSCT outcome. We included patients with acute leukemia, lymphoma or myelodysplastic syndrome receiving a first matched sibling alloSCT from peripheral blood, regardless of conditioning. We compared outcomes between patients with high and low uric acid levels with univariate- and multivariate analysis using a cause-specific Cox model. Twenty centers from 10 countries reported data on 366 alloSCT recipients. There were no significant differences in terms of baseline co-morbidity and disease stage between the high- and low uric acid group. Patients with uric acid levels above median measured before start of conditioning did not significantly differ from the remaining in terms of acute GvHD grades II-IV incidence (Hazard ratio [HR] 1.5, 95% Confidence interval [CI]: 1.0-2.4, P=0.08). However, they had significantly shorter overall survival (HR 2.8, 95% CI: 1.7-4.7, PPeer reviewe

Stromal Interferon-γ Signaling and Cross-Presentation Are Required to Eliminate Antigen-Loss Variants of B Cell Lymphomas in Mice

To study mechanisms of T cell-mediated rejection of B cell lymphomas, we developed a murine lymphoma model wherein three potential rejection antigens, human c-MYC, chicken ovalbumin (OVA), and GFP are expressed. After transfer into wild-type mice 60–70% of systemically growing lymphomas expressing all three antigens were rejected; lymphomas expressing only human c-MYC protein were not rejected. OVA expressing lymphomas were infiltrated by T cells, showed MHC class I and II upregulation, and lost antigen expression, indicating immune escape. In contrast to wild-type recipients, 80–100% of STAT1-, IFN-γ-, or IFN-γ receptor-deficient recipients died of lymphoma, indicating that host IFN-γ signaling is critical for rejection. Lymphomas arising in IFN-γ- and IFN-γ-receptor-deficient mice had invariably lost antigen expression, suggesting that poor overall survival of these recipients was due to inefficient elimination of antigen-negative lymphoma variants. Antigen-dependent eradication of lymphoma cells in wild-type animals was dependent on cross-presentation of antigen by cells of the tumor stroma. These findings provide first evidence for an important role of the tumor stroma in T cell-mediated control of hematologic neoplasias and highlight the importance of incorporating stroma-targeting strategies into future immunotherapeutic approaches

Isolation and transplantation of allogeneic pulmonary endothelium derived from GFP transgenic mice

The isolation of primary endothelial cells from murine tissues has long been a challenge and remains a difficult task. Using GFP transgenic C57/BL6 mice as donors, we describe a reliable method to isolate pulmonary endothelial cells by flow cytometry after staining with DiI-Ac-low density lipoprotein (LDL). After mechanical dissociation of murine lung tissue and enzymatic digestion, adherent cells can be quickly stained and sorted by flow cytometry. The isolated cells express endothelial cell markers such as CD31, MECA32 and CD106 and stained positive for Isolectin B4. After 50-fold expansion using standard endothelial growth media, cells could be transplanted into lethally irradiated allogeneic hosts and were detectable using fluorescence microscopy up to 24-h post-transplantation in pulmonary tissue

Cobalt protoporphyrine IX-mediated heme oxygenase-I induction alters the inflammatory cytokine response, but not antigen presentation after experimental allogeneic bone marrow transplantation

Acute graft-versus-host disease (aGvHD) remains the major cause of mortality after allogeneic stem cell transplantation. Acute GvHD can be partially prevented when heme oxygenase-1 (HO-1) is induced in the recipient prior to transplantation but the mechanisms are not fully understood. Using a murine haploidentical bone marrow transplantation (BMT) model (C57Bl/6 right curved arrow B6D2F1) we tested whether HO-1 induction altered the alloreactive T cell response or rather modulated the inflammatory cytokine profile early after BMT. In vivo administration of cobalt protoporphyrin IX (CoPP) did not affect the expression of MHC class I and II or the costimulatory molecules CD80 and CD86 on murine peritoneal and on splenic dendritic cells (DCs). Allospecific T cell proliferation and interferon gamma secretion did not differ in mixed lymphocyte reactions using either CoPP-pretreated allogeneic recipients or control-treated DCs as stimulators. Furthermore, splenic DCs, isolated one to four days after BMT from CoPP-pretreated recipients did not show any differences in the expression of costimulatory molecules compared to untreated controls, and T cell expansion and the cytolytic capacity 14 days after BMT were equal in the control and CoPP-treated allogeneic groups. Serum tumor necrosis factor alpha levels were significantly reduced in CoPP-treated allogeneic recipients when compared to allogeneic controls and did not differ from the syngeneic recipients. Our results indicate that the protective effects of CoPP-mediated HO-1 induction on survival and aGvHD after allogeneic BMT involve a reduction in the proinflammatory cytokine milieu rather than alteration in allospecific T cell stimulation

Probiotic effects on experimental graft-versus-host disease: let them eat yogurt

Acute graft-versus-host disease (aGVHD) often limits feasibility and outcome of allogeneic bone marrow transplantation. Current pathophysiologic concepts of aGVHD involve conditioning regimens, donor-derived T cells, proinflammatory cytokines, and bacterial lipopolysaccharide (LPS) as a major trigger for aGVHD. LPS derives mostly from gram-negative bacteria and can enter circulation through the impaired mucosal barrier after the conditioning regimen. Probiotic microorganisms have been shown to alter the composition of the intestinal microflora and thereby mediate anti-inflammatory effects. We hypothesized that modifying the enteric flora using the probiotic microorganism Lactobacillus rhamnosus GG, would ameliorate aGVHD. Here we show that oral administration of Lactobacillus rhamnosus GG before and after transplantation results in improved survival and reduced aGVHD. Furthermore, subculturing of mesenteric lymph node tissue revealed a reduced translocation of enteric bacteria. Our findings suggest that alteration of the intestinal microflora plays an important role in the initiation of experimental aGVHD