The Pathophysiology of Acute Graft-Versus-Host Disease

Novel T cell/organoid culture system allows ex vivo modeling of intestinal graft-versus-host disease

Acute graft-versus-host disease (GvHD) remains the biggest clinical challenge and prognosis-determining complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Donor T cells are acceptedly key mediators of alloreactivity against host tissues and here especially the gut. In support of previous studies, we found that the intestinal intra-epithelial lymphocyte (IEL) compartment was dynamically regulated in the course of MHC class I full mismatch allo-HSCT. However, while intestinal epithelial cell (IEC) damage endangers the integrity of the intestinal barrier and is a core signature of intestinal GvHD, the question whether and to what degree IELs are contributing to IEC dysregulation is poorly understood. To study lymphoepithelial interaction, we employed a novel ex vivo T cell/organoid co-culture model system. Here, allogeneic intra-epithelial T cells were superior in inducing IEC death compared to syngeneic IEL and allogeneic non-IEL T cells. The ability to induce IEC death was predominately confined to TCRβ+ T cells and was executed in a largely IFNγ-dependent manner. Alloreactivity required a diverse T cell receptor (TCR) repertoire since IELs genetically modified to express a TCR restricted to a single, non-endogenous antigen failed to mediate IEC pathology. Interestingly, minor histocompatibility antigen (miHA) mismatch was sufficient to elicit IEL-driven IEC damage. Finally, advanced live cell imaging analyses uncovered that alloreactive IELs patrolled smaller areas within intestinal organoids compared to syngeneic controls, indicating their unique migratory properties within allogeneic IECs. Together, we provide here experimental evidence for the utility of a co-culture system to model the cellular and molecular characteristics of the crosstalk between IELs and IEC in an allogeneic setting ex vivo. In the light of the emerging concept of dysregulated immune-epithelial homeostasis as a core aspect of intestinal GvHD, this approach represents a novel experimental system to e.g. screen therapeutic strategies for their potential to normalize T cell/IEC- interaction. Hence, analyses in pre-clinical in vivo allo-HSCT model systems may be restricted to hereby positively selected, promising approaches.

Polyphenolic Extract (PE) from Olive Oil Exerts a Potent Immunomodulatory Effect and Prevents Graft-versus-Host Disease in a Mouse Model

Polyphenols are a group of chemical substances found in plants, with immunomodulatory, antiproliferative, and anti-inflammatory properties that might be useful in the prophylaxis and treatment of graft-versus-host disease (GVHD). Polyphenolic extract (PE) obtained from extra virgin olive oil (EVOO) decreased the activation and proliferation of activated T cells. In addition, a decreased production of proinflammatory cytokines was observed upon exposure to PE. Western blot assays showed a marked inhibition of Akt phosphorylation and nuclear translocation of NF-κB in activated T cells. In a murine model of acute GVHD, we observed that mice that received a diet supplemented in PE (600 ppm) presented a higher survival rate and lower risk of developing GVHD when compared with the group that received a control diet. Histopathologic examination showed a significantly lower gut involvement in mice receiving PE, with a decrease in proinflammatory cytokines (IL-2, IL-17, and TNF-α) in serum and the reestablishment of butyrate concentration in the gut. In conclusion, PE obtained from EVOO exerted a potent immunomodulatory effect, reducing the activation and proliferation of activated T cells and the production of proinflammatory cytokines. In a murine model of acute GVHD, a PE-supplemented diet reduced the incidence and severity of the disease and increased survival after transplantation.

The impact of cytokine gene polymorphisms on the outcome of HLA matched sibling hematopoietic stem cell transplantation

Graft-versus-host disease (GVHD) is the major complication of allogeneic hematopoietic stem cell transplantation (HSCT); cytokines are recognized as important mediators in its pathogenesis. In this study we investigated the role of cytokine gene polymorphisms on HSCT outcome. A total of 106 patient and 98 donors were genotyped by polymerase chain reaction sequence specific primers (PCR-SSP) based assay for tumor necrosis factor-α-308 (TNFα -308), interleukin (IL)-6-174, IL-10-1082, -819, -592, Interferon-γ+874 (IFN-γ+874), and transforming growth factor-β1 (TGF-β1) codon10 and 25 polymorphisms. Except one in each category, all patients and donors were TNFα -308 high producers and the majority were IL-6-174 high producers (93.3% and 90.8% respectively); a pattern that would alleviate any potential biological impact. Patient's IFN-γ+874 showed significant association with the development of chronic GVHD. Patients with IFN-γ +874 high producer showed an 8 folds likelihood to develop chronic GVHD as compared to those with IFN-γ+874 low producer predicted phenotype (95% CI: 1.59-40.2, p = 0.01). Patient's TGFβ1-codon 10 and 25 high/intermediate producers showed a lower incidence of acute GVHD though it did not achieve statistical significance (p = 0.065) on account of the low frequency of this genotype in our patients and donors (11.4 and 8.2% respectively). Other factors contributing to risk of GVHD included older age for both acute and chronic (p = 0.01 and 0.02 respectively) with age 24 as the best discriminating cutoff; CD34+ cell dose for chronic GVHD (p = 0.045) with a dose of 8 × 10⁶/kg as the best discriminating cutoff; and conditioning regimen with Flu/Bu associated with the lowest incidence of acute GVHD (p = 0.003) and no impact on chronic GVHD. In conclusion the current study further indicates a potential role of some cytokine gene polymorphisms in the development of GVHD. The relative distribution of high and low producer genotypes in different ethnic groups contributes to their biological impact in different populations.

Immunomodulatory mechanisms of mesenchymal stem cells and their therapeutic applications

In the recent years, many studies have shown that MSCs must be stimulated by pro-inflammatory cytokines or other immune mediators before they can modulate immune cells in inflamed and damaged tissues. MSCs appear to be involved in inducing several regulatory immune cells, such as Tregs, Bregs, and regulatory NK cells. This new immune milieu created by MSCs may establish a tolerogenic environment that leads to an optimal condition for the treatment of immune diseases. The mechanisms of MSC action to treat immune disorders need to be further investigated in more detail. Since there have been some contradictory outcomes of clinical trials, it is necessary to perform large-scale and randomized clinical studies, such as a phase 3 placebo-controlled double-blind study of a third party MSCs to optimize MSC administration and to prove safety and efficacy of MSC treatment. MSCs offer great therapeutic promise, especially for the treatment of difficult-to-treat immune diseases.

Genetic Association of Hematopoietic Stem Cell Transplantation Outcome beyond Histocompatibility Genes

The outcome of hematopoietic stem cell transplantation (HSCT) is controlled by genetic factors among which the leukocyte antigen human leukocyte antigen (HLA) matching is most important. In addition, minor histocompatibility antigens and non-HLA gene polymorphisms in genes controlling immune responses are known to contribute to the risks associated with HSCT. Besides single-nucleotide polymorphisms (SNPs) in protein coding genes, SNPs in regulatory elements such as microRNAs (miRNAs) contribute to these genetic risks. However, genetic risks require for their realization the expression of the respective gene or miRNA. Thus, gene and miRNA expression studies may help to identify genes and SNPs that indeed affect the outcome of HSCT. In this review, we summarize gene expression profiling studies that were performed in recent years in both patients and animal models to identify genes regulated during HSCT. We discuss SNP–mRNA–miRNA regulatory networks and their contribution to the risks associated with HSCT in specific examples, including forkheadbox protein 3 and regulatory T cells, the role of the miR-155 and miR-146a regulatory network for graft-versus-host disease, and the function of MICA and its receptor NKG2D for the outcome of HSCT. These examples demonstrate how SNPs affect expression or function of proteins that modulate the alloimmune response and influence the outcome of HSCT. Specific miRNAs targeting these genes and directly affecting expression of mRNAs are identified. It might be valuable in the future to determine SNPs and to analyze miRNA and mRNA expression in parallel in cohorts of HSCT patients to further elucidate genetic risks of HSCT.

[Effects of IL10-592 locus of AA genotype on the incidence of aGVHD and survival after HLA-matched unrelated allogeneic hematopoietic stem cell transplantation]

OBJECTIVE

To explore the impact of IL10-592 (rs1800872) single nucleic acid polymorphism (SNP) on the prognosis of HLA matched unrelated hematopoietic stem cell transplantation (HSCT).

METHODS

The polymorphism of IL10-592 in 104 recipient-donor pairs and 100 healthy volunteers was analyzed with sequence based typing (SBT).

RESULTS

When the genotype of IL10-592 in donors and recipients matched, AA/AA genotype had higher incidence of Ⅲ-Ⅳ aGVHD than AC/AC or CC/CC genotype (47.1%, 3.7%, 0, P=0.002). When the genotype of IL10-592 in donors and recipients mismatched, recipients with AC genotype or donors with AA genotype, there was significant different incidence of Ⅲ-ⅣaGVHD among donors or recipients with different genotype (P=0.046, P=0.041). The recipients with AA genotype had higher incidence of Ⅲ-Ⅳ aGVHD than AC or CC genotype (27.8% vs 10.2%, 11.1%; P=0.072), and higher incidence of intestinal aGVHD (22.2% vs 5.1%,11.1%; P=0.040) , lower incidence of 2-year overall survival (OS: 48.2% vs 75.1%, 85.7%; P=0.002), lower incidence of 2 year disease free survival (DFS: 48.5% vs 66.3%, 76.2%; P=0.045). Patients had higher incidence of Ⅲ-Ⅳ aGVHD with donors of AA genotype than with donors of AC or CC genotype (26.5% vs 8.9%, 0; P= 0.024), and higher incidence of intestinal aGVHD (20.4% vs 4.4%, 0; P=0.026). In multivariate analysis, the genotype of IL10-592AA in recipients and donors had increased risk of Ⅲ-Ⅳ aGVHD (OR=3.3, P= 0.049; OR=3.9, P=0.043). There were no statistical differences on the incidence of cGVHD and relapse.

CONCLUSION

In HLA-10/10 matched unrelated HSCT, the presence of IL10-592 AA genotype in recipients and/or donors is an adverse factor for Ⅲ-ⅣaGVHD, worse OS and 2-year DFS.

Lithothamnion muelleri controls inflammatory responses, target organ injury and lethality associated with graft-versus-host disease in mice

Lithothamnion muelleri (Hapalidiaceae) is a marine red alga, which is a member of a group of algae with anti-inflammatory, antitumor, and immunomodulatory properties. The present study evaluated the effects of treatment with Lithothamnion muelleri extract (LM) in a model of acute graft-versus-host disease (GVHD), using a model of adoptive splenocyte transfer from C57BL/6 donors into B6D2F1 recipient mice. Mice treated with LM showed reduced clinical signs of disease and mortality when compared with untreated mice. LM-treated mice had reduced tissue injury, less bacterial translocation, and decreased levels of proinflammatory cytokines and chemokines (interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), chemokine (C-C motif) ligand 2 (CCL2), chemokine (C-C motif) ligand 3 (CCL3) and chemokine (C-C motif) ligand 5 (CCL5)). The polysaccharide-rich fraction derived from LM could inhibit leukocyte rolling and adhesion in intestinal venules, as assessed by intravital microscopy. LM treatment did not impair the beneficial effects of graft-versus-leukaemia (GVL). Altogether, our studies suggest that treatment with Lithothamnion muelleri has a potential therapeutic application in GVHD treatment.

The role of chemokines in mediating graft versus host disease: opportunities for novel therapeutics

Bone marrow transplantation (BMT) is the current therapy of choice for several malignancies and severe autoimmune diseases. Graft versus host disease (GVHD) is the major complication associated with BMT. T lymphocytes and other leukocytes migrate into target organs during GVHD, become activated and mediate tissue damage. Chemokines are well known inducers of leukocyte trafficking and activation and contribute to the pathogenesis of GVHD. Here, we review the major animal models used to study GVHD and the role of chemokines in mediating tissue damage in these models. The role of these molecules in promoting potential beneficial effects of the graft, especially graft versus leukemia, is also discussed. Finally, the various pharmacological strategies to block the chemokine system or downstream signaling events in the context of GVHD are discussed.

PI3Kγ controls leukocyte recruitment, tissue injury, and lethality in a model of graft-versus-host disease in mice

PI(3)Kγ is thought to mediate leukocyte migration to injured tissues and may be important in the pathogenesis of various T-lymphocyte-dependent pathologies, including autoimmune and inflammatory diseases. The present study evaluated the relevance of PI(3)Kγ in donor cells for the pathogenesis of acute GVHD using a model of adoptive transfer of splenocytes from WT or PI(3)Kγ(-/-) C57BL/6J mice to B6D2F1 mice, and mice that received PI(3)Kγ(-/-) cells showed reduced clinical signs of disease, bacterial translocation, tissue injury, and lethality rates. This was associated with reduced production of proinflammatory cytokines and chemokines (TNF-α, IFN-γ, CCL2, CCL3, and CCL5) and reduced infiltration of CD8(+), CD4(+), and CD11c(+) cells in the small intestine. Mechanistically, in addition to decreasing production of proinflammatory mediators, absence or pharmacological blockade of PI(3)Kγ was associated with decreased rolling and adhesion of leukocytes to the mesenteric microcirculation, as assessed by intravital microscopy. Despite decreased GVHD, there was maintained GVL activity when PI(3)Kγ(-/-) leukocytes were transferred into WT mice. In conclusion, PI(3)Kγ plays a critical role in GVHD by mediating leukocyte influx and activation in tissues. PI(3)Kγ inhibitors may be useful in the treatment of GVHD in patients undergoing BMT.

Investigation of the effect of donor platelet endothelial cell adhesion molecule 1 polymorphism on the graft-vs.-host disease occurrence in Tunisian recipients of hematopoietic stem cells

OBJECTIVE

The aim of this study is to examine the effect of donor PECAM-1 alleles and haplotypes for the SNPs L98V, S536N, and R643G on the occurrence of GVHD in Tunisian recipients of HSCs.

DESIGN AND METHODS

This study enrolled 102 patients and their 102 respective HLA-identical sibling donors of HSCs. The PECAM-1 SNPs genotyping assay was performed using sets of sequence specific primers (SSP-PCR).

RESULTS

The single marker association analysis showed that the L98 allele, in a recessive genetic model, may be a potential risk factor only for acute GVHD (p=0.036, OR=2.580, 95% C.I. = 1.053-6.326). However, the haplotype analysis showed a lack of association between donor's PECAM-1 SNPs and GVHD incidence in recipient.

CONCLUSION

The homozygosity state for donor PECAM-1L98 allele may be a significant risk factor for acute GVHD. This is probably due to its action on the function of donor leukocytes especially during the extravasation process.

Outcome of children treated with haematopoietic-stem cell transplantations from donors expressing the rare C77G variant of the PTPRC (CD45) gene

The uncommon C77G polymorphism of the Protein-Tyrosine Phosphatase (PTPRC) gene (PTPRC; previously termed CD45) could confer an increased risk of immunopathology. This study compared the outcome of children following human leucocyte antigen-matched unrelated haematopoïetic-stem cell transplantations (HSCT) from donors carrying (C77G cases: n = 8) or not (controls: n = 36) the PTPRC C77G polymorphism. Transmission of the PTPRC C77G polymorphism through the graft was suggested by unusual CD45RA phenotype in the donors and/or in the recipients after, but not before HSCT. Restriction-Fragment Length Polymorphism and sequencing confirmed the polymorphism. Overall survival rates were similar in C77G cases and controls (63% vs. 61%). Acute leukaemia relapse tended to be less frequent in C77G cases (0% vs. 32%; P = 0·09). Among recipients surviving ≥ 30 d, acute GVHD (aGVHD) ≥ grade 2 tended to be more frequent (100% vs. 58%; P = 0·07) and the rate of steroid-refractory or -dependant aGVHD higher (67% vs. 28%) in C77G cases. Finally, extensive chronic GVHD tended to occur more frequently (40% vs. 9%) in C77G cases. Recovery of lymphocyte subsets and virus-specific CD4 was similar in C77G cases and controls while interleukin 2 (IL2)-responses through CD3 stimulation were higher in C77G cases (P = 0·004). In conclusion, HSCT from PTPRC C77G donors could increase GVHD risk without compromising overall survival. Altered IL2-responses could be involved in this process.

Kinetics of CD4+ and CD8alpha+ T-cell subsets in graft-versus-host reaction (GVHR) in ginbuna crucian carp Carassius auratus langsdorfii

We have previously demonstrated the presence of graft-versus-host reaction (GVHR) in fish employing a model system of clonal triploid ginbuna and tetraploid ginbuna-goldfish hybrids. To elucidate the role of CD8alpha+ T cells in the induction of GVHR, we investigate the kinetics of CD4+ and CD8+ T-cell subsets in GVHR along with the pathological changes associated with GVH disease (GVHD) in ginbuna. GVHR was not induced with a leukocyte fraction lacking CD8alpha+ T cells separated by magnetic cell sorting. Ploidy and immunofluorescence analysis revealed that CD4+ and CD8alpha+ T cells from sensitized donors greatly increased in the host trunk kidney, constituting more than 80% of total cells 1-2 weeks after donor cell injection, while those from non-sensitized donors constituted less than 50% of cells present. The increase of CD4+ T cells was greater and more rapid than that of CD8alpha+ T cells. The number of donor CD4+ and CD8alpha+ T cells was highest in trunk kidney followed by spleen. Increases in donor CD4+ and CD8alpha+ T cells were also found in liver and PBL, although the percentages were not as high. Pathologic changes similar to those in human and murine acute GVHD were observed in the lymphoid organs as well as target organs such as skin, liver and intestine, including the destruction of cells and tissues and massive leukocyte infiltration. The pathologic changes became more severe with the increase of CD8alpha+ T cells. These results suggest that donor-derived CD8alpha+ T cells play essential roles for the induction of acute GVHR/D in teleosts as in mammals.

Ocular graft-versus-host disease after allogeneic stem cell transplantation

PURPOSE

To determine the prevalence and manifestations of ocular graft-versus-host disease (GvHD) after allogeneic stem cell transplantation (allo-SCT).

METHODS

Prospective study of 101 consecutive patients who received allo-SCT from 2004 to 2007. All patients received ophthalmologic examination for 3 months after allo-SCT, and those with ocular complaints were evaluated at 12 and 24 months thereafter. We registered ophthalmologic and hematological data, including the indication for allo-SCT, occurrence of systemic and ocular GvHDs, ocular manifestations, and various ocular treatments.

RESULTS

Over time, ocular GvHD developed in 54% of patients and consisted mainly of dry eyes and conjunctivitis, which increased in severity during follow-up; blepharitis and uveitis were less often encountered. Acute systemic GvHD, especially the involvement of mouth and skin, was strongly associated with ocular GvHD at 3 months (P = 0.000). Chronic GvHD was associated with the occurrence of ocular GvHD (P = 0.000), especially with the development of the dry eye. Although eye symptoms affecting activities of daily living were reported in 24 of 54 patients (44%) and 16 of 54 patients (30%) experienced temporary loss of visual acuity of more than 2 Snellen lines, only 1 developed permanent unilateral loss (counting fingers) because of ischemic vasculopathy. Cataract development was not encountered, and only 1 eye developed intraocular infection.

CONCLUSION

Ocular GvHD develops in a substantial part of patients after allo-SCT and decreases the activities of daily living.

The CCL3/macrophage inflammatory protein-1alpha-binding protein evasin-1 protects from graft-versus-host disease but does not modify graft-versus-leukemia in mice

CCL3 is a protein of the CC chemokine family known to be important for T cell recruitment in inflammatory diseases. The aim of the current study was to evaluate the effects and putative mechanism of action of evasin-1, a novel CCL3-binding protein, in the pathogenesis of acute graft-versus-host disease (GVHD). GVHD was induced by the transplantation of splenocytes from C57BL/6J to B6D2F1 mice. Treatment of recipient mice with evasin-1 prevented mortality associated with GVHD. This was correlated with reduced weight loss and clinical disease severity. Analysis of the small intestine showed that evasin-1 treatment reduced the histopathological score and decreased levels of IFN-gamma and CCL5. Mechanistically, evasin-1 treatment reduced the number of CD4(+) and CD8(+) T cells infiltrating the small intestine, as assessed by immunohistochemistry, and the adhesion of leukocytes to intestinal venules of recipient mice, as assessed by intravital microscopy. Evasin-1 was also able to decrease liver damage, as seen by reduction of inflammatory infiltrate and IFN-gamma levels. Treatment with evasin-1 did not interfere with graft-versus-leukemia. Altogether, our studies demonstrate that CCL3 plays a major role in mediating GVHD, but not graft-versus-leukemia in mice and suggest that blockade of CCL3 with evasin-1 has potential therapeutic application in patients undergoing bone marrow transplantation.

Adenosine A2A receptor activation limits graft-versus-host disease after allogenic hematopoietic stem cell transplantation

GVHD is a major barrier to broader use of allogenic HSCT for nonmalignancy clinical applications such as the treatment of primary immunodeficiencies and hemoglobinopathies. We show in a murine model of C57BL/6J (H2-k(b)) --> B6D2F1/J (H2-k(b/d)) acute GVHD that when initiated 2 days before transplant, the activation of the adenosine A(2A)R with the selective agonist ATL146e inhibits the weight loss and mortality associated with disease progression. Furthermore, circulating levels of proinflammatory cytokines and chemokines, including IFN-gamma, IL-6, CCL2, KC, and G-CSF, are reduced significantly by 14-day ATL146e treatment. The up-regulation of CD25, CD69, and CD40L expression by donor CD4(+) and CD8(+) T cells is inhibited by A(2A)R activation; fewer CD3(+) T cells are found in the liver, skin, and colon of ATL146e-treated mice as compared with vehicle-treated controls; and associated tissue injury is lessened. The delayed administration of ATL146e, beginning 9 days after HSCT, reverses GVHD-associated body weight loss successfully, and improvement is sustained for the duration of treatment. We conclude that the selective activation of the A(2A)R has therapeutic potential in the prevention and treatment of acute GVHD.

Safety profile and clinical outcomes in a phase I, placebo-controlled study of siplizumab in acute graft-versus-host disease

BACKGROUND

Acute graft-versus-host disease (GVHD) is a major complication of both bone marrow and hematologic stem cell allografts. T cells and natural killer (NK) cells have been linked to the development of GVHD. Modulation of these cells via the CD2 receptor may be a potentially important approach to the management of this disease.

METHODS

The safety profile and tolerability of siplizumab (MEDI-507), a humanized anti-CD2 IgG-1kappa monoclonal antibody, in the treatment of GVHD were evaluated in a phase I, double-blind, multiple-dose, placebo-controlled study. Thirty-four subjects with at least grade II acute GVHD were randomized to receive four doses of 0.012, 0.04, 0.12, or 0.4 mg/kg siplizumab or placebo intravenously every 3 days. Subjects received concurrent 2 mg/kg per day methylprednisolone for more than or equal to 10 days.

RESULTS

No meaningful difference occurred between siplizumab and placebo groups in the incidence or severity of adverse events or laboratory test results. No increase in incidence of infection secondary to siplizumab treatment was observed. During 100 days postinitial infusion, a modest increase in resolution of GVHD, grade 0 (67% vs. 54%, P=0.0629), was reported for the siplizumab-treated group.

CONCLUSION

Siplizumab administered with corticosteroid therapy for grade II or higher acute GVHD treatment exhibited an acceptable safety profile that would support further clinical development.

A murine model of graft-vs-host disease after in utero hematopoietic cell transplantation

PURPOSE

Graft-vs-host disease (GvHD) is a known complication of in utero bone marrow transplantation. However, GvHD has been difficult to study owing to frequent fetal demise. We describe the first consistent murine model of GvHD with postnatal survival after in utero hematopoietic cell transplantation.

METHODS

A 50/50 mixture of bone marrow and splenocytes (10(6)) from 6-week-old C57/BL6 (H2-b) mice was injected intraperitoneally into Balb/c (H2-d) fetuses at e14 to 16. Live born pups were followed for clinical GvHD. Peripheral blood and hematopoietic organ chimerism was confirmed by flow cytometry and polymerase chain reaction. Organ samples were isolated for histology.

RESULTS

Twenty-seven (75%) of 36 surviving pups displayed clinical GvHD by 2 weeks compared with 9 developmentally normal pups. Mean difference in weight between the 2 groups was 2.9 g at 7 days and 5.2 g at 14 days of life (P < .0001). All 27 pups with clinical GvHD and 1 normal-appearing pup had blood chimerism ranging from 1.5% to 65%. Eight of the 9 normal-appearing pups had 0% chimerism. Histologic analysis revealed findings of GvHD in liver, spleen, small intestine, and skin specimens of only chimeric pups.

CONCLUSIONS

A consistent murine model of GvHD can be achieved after in utero transplantation of major histocompatibility complex-mismatched bone marrow and splenocytes. Future studies will use this model to examine approaches to prevent GvHD after in utero stem cell transplantation.

Association of IL6 and CCL2 gene polymorphisms with the outcome of allogeneic haematopoietic stem cell transplantation

Various polymorphisms of non-HLA genes have recently been investigated as candidate risk factors in allogeneic haematopoietic SCT (aHSCT). Our study aimed at exploring possible associations of IL6 and CCL2 single nucleotide polymorphisms (SNP) with aHSCT outcome. A total of 166 HLA-identical aHSCT pairs recruited in were genotyped for IL6 -174 G/C, IL6 -597 G/A, CCL2 -2518 A/G and CCL2 -2076 A/T SNPs by PCR with sequence-specific primers (PCR-SSP). The association between IL6 -174 GG genotype and increased risk of acute GVHD was found in whole study group (P=0.03) and in the subgroup of related aHSCT (P=0.01), association between IL6 -597 GG genotype and the occurrence of acute GVHD was detected only in the related aHSCT pairs (P=0.02). Furthermore, reduction in OS was revealed among recipients possessing IL6 -174(*)G allele in the group of related aHSCT pairs (P=0.04). Presence of CCL2 -2076 TT genotype was associated with decrease of OS (P=0.04) and increase of TRM (P=0.02) in patients transplanted by related donor. These results, in the context of previous findings, suggest that IL6 gene polymorphisms may be associated with aHSCT outcome, particularly in patients transplanted from a related donor.

Clinical scale expanded adult pluripotent stem cells prevent graft-versus-host disease

Adherent bone marrow adult stem cells have been used in the treatment of GVHD. In this study, we investigate the capacity of a newly characterized population of stem cells, the Multipotent Adult Progenitor Cells (MAPC), to modulate acute GVHD. These cells were derived from bone marrow cells and grown extensively without evidence for replicative senescence or loss of differentiating capacity. MAPC significantly decreased mortality of acute GVHD. Moreover, they were non immunogenic and they were not sensitive to NK-lysis. When these cells were added to a mixed lymphocyte reaction (MLR), a dose-dependent suppression of T cell proliferation was observed that was non-MHC restricted, was reversible upon removal of MAPC from culture and was mediated by soluble factors. These data show that in vitro expanded adult stem cells can efficiently control an allo-reactive response associated with acute GVHD, that they are immuno-privileged and present strong immunosuppressive properties.

Mesenchymal stem cells enhance the induction of mixed chimerism and tolerance to rat hind-limb allografts after bone marrow transplantation

BACKGROUND

Mixed hematopoietic chimerism via bone marrow transplantation has been shown to induce donor specific tolerance to solid organ allografts, but graft versus host disease (GVHD) remains to be a risk. Composite tissue allografts may need a higher percentage of donor chimerism compared with less immunogenic solid organ allografts. In this study, we investigated the potential of mesenchymal stem cells (MSCs) in the induction of stable and high level chimerism and subsequent donor-specific tolerance to composite tissue allograft without the incidence of graft versus host disease (GVHD).

METHODS

Fully mismatched, 4- to 8-wk-old Brown Norway (RT1(n)) and Lewis (RT1(1)) rats were used as cell or hind-limb donors and recipients, respectively. Recipients received a conditioning regimen consisting of antilymphocyte serum, standard immunosuppressive therapy (rapamycin: 0.2 mg/kg/d; days 0 approximately 130) and 3 Gy total body irradiation, followed by an intraportal co-infusion of allogeneic MSCs and bone marrow cells (day 0); then performing hind-limb allotransplants (30 d after BMT); 100 d after hind-limb transplantations, immunosuppressive therapy was stopped and to observe the survival time of the hind-limb allografts.

RESULTS

When co-infusion of allogeneic MSCs was administered, 14/15 recipients developed stable and high level chimerism. Subsequently, in the donor specific group, the survival time of hind-limb allografts without RAPA were remarkably prolonged compared with other groups. The results of the histopathological evaluation of skin biopsy and mixed lymphocyte cultures confirmed this operational donor specific tolerance. Without MSCs, only 2/7 of the recipients developed stable chimerism, but GVHD occurred in both of them, and the level of the chimerism was much lower. On the other hand, GVHD was not observed in any of the recipients infused with MSCs (0/15).

CONCLUSION

This study indicates a potential use of MSCs for induction of stable and high level mixed hematopoietic chimerism and subsequent donor specific tolerance in clinical composite tissue allotransplantation.

Gene-expression profiles of peripheral blood mononuclear cell subpopulations in acute graft-vs-host disease following cord blood transplantation

OBJECTIVE

Compared with allogeneic hematopoietic stem cell transplantation using other sources, cord blood (CB) transplantation (CBT) has clinical advantages in terms of incidence and severity of acute graft-vs-host disease (GVHD), despite using allogeneic stem cells with more human leukocyte antigen mismatches. However, detailed pathophysiology of acute GVHD developed after CBT has not yet been elucidated. In this study, we aimed to clarify the molecular mechanism of acute GVHD after CBT.

MATERIALS AND METHODS

We performed microarray expression profiling of immunoregulatory genes on each of four subpopulations (CD4+, CD8+, CD14+, and CD56+) of peripheral blood mononuclear cells (PBMCs), which were taken from eight patients with hematologic malignancies who suffered from acute GVHD after unrelated CBT.

RESULTS

We identified 55 genes, which were differentially expressed during acute GVHD compared to recovery phase. Among them, 22 showed differential expression concurrently in multiple PBMC subpopulations. In particular, five genes (TNFSF10/TRAIL, IL1RN, IFI27, GZMB, and CCR5) were upregulated and three genes (CLK1, TNFAIP3 and BTG1) were downregulated in at least three out of four subpopulations during acute GVHD. In addition, downregulation of antiinflammatory factors, such as TNFAIP3, KLF2, ZFP36, and BTG1, seems to be involved in acceleration of immune response, thus exacerbation of acute GVHD. Meanwhile, differential expression of several genes, such as CCL5, TNFAIP3, KLRB1/CD161, BY55/CD160, and PTGS2/COX2, was assumedly affected by the developmental immaturity of CB-derived cells.

CONCLUSIONS

These results will contribute to the understanding of molecular mechanism underlying the behavior of inflammatory cells during acute GVHD following CBT.

Characterization of YM-58483/BTP2, a novel store-operated Ca2+ entry blocker, on T cell-mediated immune responses in vivo

YM-58483/BTP2 is a blocker of store-operated Ca2+ entry (SOCE), which regulates the activation of non-excitable cells such as lymphocytes. YM-58483 has been reported to inhibit cytokine production and proliferation in T cells, and to be useful as a probable medicinal candidate for treatment of bronchial asthma. The present study investigated the pharmacological profile and therapeutic potential of YM-58483 in relation to cell-mediated immune responses. In the mouse graft-versus-host disease (GVHD) model, YM-58483 (1-30 mg/kg, p.o.) and cyclosporine A (1-30 mg/kg, p.o.) inhibited donor anti-host cytotoxic T lymphocyte (CTL) activity and IFN-gamma production, and also reduced the number of donor T cells, especially donor CD8+ T cells, in the spleen. YM-58483 and cyclosporine A inhibited T cell proliferation in a one-way mixed lymphocyte reaction (MLR) with IC50 values of 330 and 12.7 nM, respectively. Additionally, YM-58483 (1-10 mg/kg, p.o.) and cyclosporine A (2, 10 mg/kg, p.o.) inhibited the sheep red blood cell (SRBC)-induced delayed type hypersensitivity (DTH) response. These results suggest that the inhibition of SOCE leads to the prevention of antigen-induced T cell responses, which participate in autoimmune diseases such as autoimmune hepatitis and rheumatoid arthritis.

IL2 and TNFA gene polymorphisms and the risk of graft-versus-host disease after allogeneic haematopoietic stem cell transplantation

This study aimed to analyse the association of gene polymorphisms with the outcome of allogeneic haematopoietic stem cell transplantation. We studied 122 donor/recipient pairs who received HLA-identical transplants from siblings at the Universidade Estadual de Campinas, Brazil, between June 1996 and June 2006. Donor/recipient alleles for TNFA-238 and IL2-330/+166 single-nucleotide polymorphisms (SNP) were analysed by PCR-SSP. No association was observed between the risk of acute graft-versus-host disease (GVHD) and these SNP. However, our findings suggest that the polymorphism of promoter gene TNFA-238GA is associated with the occurrence and severity of chronic GVHD. The probability of chronic GVHD in patients with GA genotype at position -238 of TNFA gene is 91.7% in contrast to 59.4% in patients with GG genotype (P = 0.038). In patients with donor GA genotype the probability of chronic GVHD is 90.8%, and 57.9% in patients with donor GG genotype (P = 0.038). The probability of extensive chronic GVHD in patients with TNFA-238GA is 91.7% compared with 46.3% in patients with TNFA-238GG (P = 0.0046). In patients with donor GA genotype at position -238 of the TNFA gene, it is 81.7%, compared with 44.5% in patients with donor GG genotype (P = 0.016). However, further studies with more patients are required to identify cytokine gene polymorphisms and their association with transplant-related complication in Brazil, particularly due to ethnic background, the relatively low power of detection of genetic markers of this study, and the complexity of the MHC region.

Hematopoietic stem cell transplantation: implications for critical care nurses

Hematopoietic stem cell transplantation (HSCT) is being used increasingly in the treatment of malignant and nonmalignant diseases. The treatment modality has been proven effective but is not without risks. Studies consistently have identified the need for advanced supportive care (e.g., multiple organ dysfunction, vasopressor use, mechanical ventilation) as a negative prognostic indicator in patients who have received HSCT. Among patients who have received HSCT, 15%-40% require critical care monitoring or advanced support. Nurses on intensive care units can positively impact outcomes for transplant recipients when they possess the specialized skills to recognize and promptly intervene when transplant-related complications arise. This article will provide a basic overview of the HSCT process and outline the complications that may necessitate transfer to a higher level of care for specialized skills and equipment in the intensive care setting.

Sparing effect by montelukast treatment for chronic graft versus host disease: a pilot study

BACKGROUND

Chronic graft versus host disease (GvHD) is a major complication after allogeneic stem cell transplantation (SCT), which is usually progression from acute GvHD. Chronic GvHD is the main cause of severe morbidity and mortality in long-term survivors after SCT. The cysteinyl leukotrienes (cysLTs) and eosinophils play an important role in the pathogenesis of GvHD, which is the rationale for the combined use of montelukast (Mk) in the treatment of this illness.

METHODS

Mk was administrated to 19 eligible patients with refractory chronic GvHD, in addition to their standard immunosuppressive regimens. Mk was given orally (10 mg once daily) for a mean period of 10 months (range, 2-21 months). Organ-specific response was determined by the new scoring criteria established by the National Institutes of Health consensus project.

RESULTS

Based on organ involvements endpoints, overall response to the combined therapy with Mk was observed in 15 of 19 (79%) patients. Significant improvement of skin liver and gastrointestinal was observed in 53%, 62%, and 46%, respectively. Generally, Mk was notably beneficial in milder stages of GvHD, which lead to earlier withdrawal of other immunosuppressive agents. Side effects of Mk administration were not documented, nor were cases of relapse of the basic disease.

CONCLUSIONS

Our preliminary prospective investigation supports the potential efficacy of Mk as a safe and toxicity-sparing supplement to standard therapy for patients with chronic GvHD. Future clinical studies are necessary to establish the optimal dose of Mk and its role in the symptomatic and prophylactic treatment of acute and chronic GvHD.

Deletion of Donor-Reactive Cells as a New Conditioning Regimen for Allogeneic Bone Marrow Transplantation

Progress in the development of less toxic conditioning for bone marrow transplantation (BMT) came with the understanding that acceptance of mismatched BM does not require myeloablation of recipients. Lymphocyte deletion by a cocktail of immunosuppressive drugs is generally sufficient to ensure engraftment of compatible BM cells. However, reduced intensity conditioning (RIC) protocols available today do not provide robust tolerance to mismatched allogeneic BM. Herein we discuss 2 new experimental approaches to RIC protocols with the aim of facilitating allogeneic BM engraftment. Both conditioning regimens are based on selective deletion/inactivation of donor-reactive cells before BMT. Our data show that the first conditioning protocol, comprising priming of recipients by a donor-specific lymphocyte transfusion (DST) on day -2 and a single injection of cyclophosphamide, a drug that is predominantly toxic for proliferating cells, on day -1, consistently improves engraftment of allogeneic BM (day 0) in all experimental models tested. The second engraftment enhancing approach is based on the blockade by antagonistic reagents of the signaling pathways that govern the antigen-induced immune response. Combining the signaling blockade with the deletion of activated donor-reactive cells by cytoreductive agents provides additional benefits for transplantation across major histocompatibility barriers.

Mesenchymal stem cells facilitate the induction of mixed hematopoietic chimerism and islet allograft tolerance without GVHD in the rat

Induction of hematopoietic chimerism and subsequent donor-specific immune tolerance via bone marrow transplantation is an ideal approach for islet transplantation to treat type-1 diabetes. We examined the potential of mesenchymal stem cells (MSCs) in the induction of chimerism and islet allograft tolerance without the incidence of graft-versus-host disease (GVHD). Streptozotocin-diabetic rats received a conditioning regimen consisting of antilymphocyte serum and 5 Gy total body irradiation, followed by an intraportal co-infusion of allogeneic MSCs, bone marrow cells (BMCs) and islets. Although all the recipients rejected the islets initially, half of them developed stable mixed chimerism and donor-specific immune tolerance, shown by the engraftment of donor skin and second-set islet transplants and acute rejection of a third-party skin. The engraftment of the primary islet allografts with stable chimerism was achieved by the addition of a 2-week peritransplant administration of 15-deoxyspergualin (DSG). Without MSCs, none of the recipients treated with DSG developed chimerism or reversal of diabetes. GVHD was not observed in any of the recipients infused with MSCs (0/15), whereas it occurred in 4/11 recipients without MSCs. These results indicate a potential use of MSCs for induction of hematopoietic chimerism and subsequent immune tolerance in clinical islet transplantation.

Bone health in children and adolescents after allogeneic stem cell transplantation

BACKGROUND

This cross-sectional study evaluated the overall bone health and the prevalence of vertebral complications after stem cell transplantation (SCT) in prepubertal children and adolescents.

METHODS

A total of 44 children and adolescents (median age, 10 years) were evaluated at a median of 3.8 years after SCT for areal bone mineral density (aBMD) with dual-energy X-ray absoptiometry and for vertebral fractures with instant vertebral assessment. Pretransplant and posttransplant medications and nutritional parameters were recorded, and plasma levels of vitamin D, calcium, phosphate, and parathormone were measured.

RESULTS

Of the 44 patients, 16 (36%) had a BMD Z-score of <-1.0. The patients with low BMD did not differ from the others with regard to their clinical or biochemical characteristics. Prepubertal patients had better BMD Z-scores at all sites compared with pubertal or postpubertal subjects. This was evident especially at the hip, in which the median aBMD Z-score in prepubertal patients (-0.2; range, -0.5 to +1.7) was found to be significantly higher than in pubertal (-1.1; range, -1.5 to +0.4) and postpubertal (-1.1; range, -2.6 to +0.5) patients (P = .03). Five patients (11%) had a history of peripheral fractures. Nine patients (20%) had vertebral compression fractures, which were asymptomatic in 7 patients.

CONCLUSIONS

Approximately one-third of patients who had undergone allogeneic SCT in childhood were found to have a reduced BMD before reaching adulthood. This was due in part to inadequate BMD gain during the pubertal years. The high prevalence of asymptomatic vertebral compression fractures calls for the systematic assessment of spinal health during the posttransplantation follow-up.

Ex Vivo Soluble Fas Ligand Treatment of Donor Cells to Selectively Reduce Murine Acute Graft Versus Host Disease

BACKGROUND

Allogeneic bone marrow transplantation (BMT) and donor lymphocyte infusion (DLI) provide valuable treatments for a range of diseases. However, the therapeutic utility of BMT and DLI is reduced by the high incidence of graft-versus-host disease (GvHD) mediated by activated donor T lymphocytes directed against recipient alloantigens.

METHODS

Using mouse models, we developed and evaluated a strategy to selectively enhance activation-induced cell death (AICD) of anti-recipient T cells within transplant donor cell populations, with the goal of reducing GvHD. Responder T lymphocytes were incubated ex vivo with irradiated allogenic stimulator cells in a mixed lymphocyte reaction (MLR) in the presence of soluble Fas ligand (sFasL) to induce AICD in alloreactive cells.

RESULTS

This ex vivo sFasL treatment reduced proliferation to the allogeneic stimulator cells in vitro and abrogated acute GvHD capacity in vivo. In contrast, the secondary immune responsiveness of the ex vivo sFasL-treated responder T cells to an unrelated model antigen was preserved. Furthermore, upon adoptive transfer in a DLI model, ex vivo sFasL-treated T cells were able to reject a model tumor. Finally, ex vivo sFasL treatment of bone marrow cells did not reduce their hematopoietic engraftment capacity.

CONCLUSIONS

Thus, ex vivo treatment with sFasL appears to have potential for translation to clinical cell processing of BMT allografts and DLI infusions.

Acute Graft-versus-Host Disease in Pancreas Transplantation: A Comparison of Two Case Presentations and a Review of the Literature

As a complication of solid organ transplantation, acute graft-versus-host disease (GVHD) is most associated with small bowel and liver transplants. We present two cases of acute GVHD following pancreas transplantation. Case 1 was a 27-year-old female who underwent cadaveric pancreas transplant 9 months after a successful live donor kidney transplant. Case 2 was a 38-year-old male who received a simultaneous cadaveric pancreas and live donor kidney transplant. Both patients presented within 30 days of transplant with nonspecific symptoms. Rejection and infection were ruled out. Both subjects had progressive decline in mentation associated with pancytopenia and hyperbilirubinemia. Rash was not present until late in their hospital course. Skin biopsies demonstrated mixed chimerism with pancreas donor DNA diagnostic of GVHD. Acute GVHD is a rare, often fatal, complication of pancreas transplantation, and its presentation appears to differ from acute GVHD associated with stem cell transplantation.

Evidence for involvement of clonally expanded CD8+ T cells in anticancer immune responses in CLL patients following nonmyeloablative conditioning and hematopoietic cell transplantation

We have analyzed the clonotype composition of CD8+ T cells following nonmyeloablative (NMA) conditioning and hematopoietic cell transplantation (HCT), of patients with chronic lymphocytic leukemia (CLL). Consecutive analyses of blood samples taken up to 2 years following HCT, demonstrated that CD8+ T-cell clonality was highly dynamic in the early phases after HCT, but became more stable after 4-5 months. Moreover, donor lymphocyte infusion (DLI) given for disease progression in one of the patients led to establishment of recurrent as well as new T-cell clonotypes. This coincided with disease remission, strongly suggesting that these T cells were engaged with anti-CLL cytotoxicity. To examine the functional capacity of stable clonally expanded T cells after HCT, CD8+ T cells isolated post-transplant from the recipients were stimulated ex vivo with CLL cells and subsequently analyzed by FACS for surface expression of the marker for cytotoxic activity, CD107a. Stimulation with CLL cells indeed led to surface expression of CD107a, and clonotype analyses of sorted cells demonstrated that CD107a positive T cells were stably expanded following HCT. Our data suggest that clonally expanded CD8+ T-cell clones participate in the ongoing T-cell response against CLL cells following HCT with NMA conditioning.

The role of calcium and guanosine 3':5'-monophosphate in the action of acetylcholine on thyroid metabolism

The role of calcium and guanosine 3':5'-monophosphate (cyclic GMP) in the regulation of thyroid metabolism has been investigated in dog thyroid slices. Carbamoylcholine enhanced glucose carbon-1 oxidation, protein iodination, cyclic GMP accumulation and decreased thyrotropin-induced adenosine 3':5'-monophosphate (cyclic AMP) accumulation and iodine secretion; it did not affect protein synthesis. The effects of carbamoylcholine were reproduced under various experimental conditions by supplementary calcium in the medium, ouabain, and in media in which Na+ had been replaced by choline chloride. They were inhibited by lanthanum. These results further support the hypothesis that free intracellular Ca2+ is the intracellular signal for carbamoylcholine effects and suggest that a Na+ -gradient-driven Ca2+ extrusion mechanism operates in the thyroid cell. Mn2+ reproduced the effect of Ca2+ on glucose oxidation, protein iodination and cyclic GMP accumulation in Ca2+ -depleted slices and medium, and thus mimicked some intracellular effects of Ca2+. On the other hand Mn2+ inhibited the carbamoylcholine effect on thyrotropin-induced thyroid secretion and cyclic AMP accumulation, and Ca2+ inhibited the Mn2+-induced cyclic GMP accumulation. This suggests that the two ions compete for the same channel. Similarly Mn2+ inhibited calcium effects in the presence of ionophore A23187. Procaine inhibited protein iodination under all conditions suggesting a primary effect; it also inhibited all carbamoylcholine and ouabain actions. However the drug did not inhibit the effects of choline chloride and its action was reversed by raising carbamoylcholine but not Ca2+ concentration; it is therefore doubtful that procaine acts by blocking Ca2+ channels. In media without added Ca2+, Mn2+ increased cyclic GMP accumulation but did not decrease thyrotropin-induced cyclic AMP accumulation or iodine secretion, which suggests that cyclic GMP cannot be the sole mediator of the latter two effects of carbamoylcholine.