Treatment with Apocynin Limits the Development of Acute Graft-versus-Host Disease in Mice.

Graft-versus-host disease (GVHD) is the most serious complication limiting the clinical utility of allogeneic hematopoietic stem cell transplantation (HSCT), in which lymphocytes of donors (graft) are activated in response to the host antigen. This disease is associated with increased inflammatory response through the release of inflammatory mediators such as cytokines, chemokines, and reactive oxygen species (ROS). In this study, we have evaluated the role of ROS in GVHD pathogenesis by treatment of recipient mice with apocynin (apo), an inhibitor of intracellular translocation of cytosolic components of NADPH oxidase complex. The pharmacological blockade of NADPH oxidase resulted in prolonged survival and reduced GVHD clinical score. This reduction in GVHD was associated with reduced levels of ROS and TBARS in target organs of GVHD in apocynin-treated mice at the onset of the mortality phase. These results correlated with reduced intestinal and liver injuries and decreased levels of proinflammatory cytokines and chemokines. Mechanistically, pharmacological blockade of the NADPH oxidase was associated with inhibition of recruitment and accumulation of leukocytes in the target organs. Additionally, the chimerism remained unaffected after treatment with apocynin. Our study demonstrates that ROS plays an important role in mediating GVHD, suggesting that strategies aimed at blocking ROS production may be useful as an adjuvant therapy in patients subjected to bone marrow transplantation.

Inhibition of 5-lipoxygenase alleviates graft-versus-host disease.

Leukotriene B4 (LTB4), a proinflammatory mediator produced by the enzyme 5-lipoxygenase (5-LO), is associated with the development of many inflammatory diseases. In this study, we evaluated the participation of the 5-LO/LTB4 axis in graft-versus-host disease (GVHD) pathogenesis by transplanting 5-LO-deficient leukocytes and investigated the effect of pharmacologic 5-LO inhibition by zileuton and LTB4 inhibition by CP-105,696. Mice that received allogeneic transplant showed an increase in nuclear 5-LO expression in splenocytes, indicating enzyme activation after GVHD. Mice receiving 5-LO-deficient cell transplant or zileuton treatment had prolonged survival, reduced GVHD clinical scores, reduced intestinal and liver injury, and decreased levels of serum and hepatic LTB4 These results were associated with inhibition of leukocyte recruitment and decreased production of cytokines and chemokines. Treatment with CP-105,696 achieved similar effects. The chimerism or the beneficial graft-versus-leukemia response remained unaffected. Our data provide evidence that the 5-LO/LTB4 axis orchestrates GVHD development and suggest it could be a target for the development of novel therapeutic strategies for GVHD treatment.

Reduced BUCY 2 and G-CSF-primed bone marrow associates with low graft-versus-host-disease and transplant-related mortality in allogeneic HSCT.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the ideal treatment for several diseases. However, the morbidity and mortality associated with the procedure might limit its widespread use; therefore, we implemented reduced BUCY2 as conditioning method along with the use of G-CSF-primed bone marrow (G-BM) in order to reduce complications, including graft-versus-host-disease (GVHD), and to improve survival in these patients. An analysis of transplant characteristics, complications, and survival of patients undergoing an allo-HSCT using this conditioning regimen (busulfan 12 mg/kg and cyclophosphamide 80 mg/kg) plus G-BM was performed. Forty patients were included from 1999 to 2015. All of them had a HLA-matched donor, with a median age of 32 years (range 16-59), and 55% were male. The most frequent diagnosis was myelodysplastic syndrome (MDS) in 14 patients (35%), followed by acute lymphoid leukemia (ALL) in 12 (30%). The mean of CD34+ was 2.09 × 106/kg. The mean time to neutrophil and platelet recovery was 20 and 18 days, respectively. The most common toxicity was mucositis (75%) with grade III-IV in 53% of cases. Acute GVHD appeared in 12.5 and 35% of patients developed chronic GVHD. Transplant-related mortality (TRM) was 10%. Five-year relapse-free survival was 69%, and the 5-year overall survival was 69.5%. Our conditioning method along with G-BM preserves an immunosuppressive and myeloablative effect allowing eradication of the malignant clone and achieving adequate bone marrow engraftment with acceptable toxicity, low incidence of GVHD, and low TRM, representing a favorable alternative for allo-HSCT.

LL-37 boosts immunosuppressive function of placenta-derived mesenchymal stromal cells.

BACKGROUND: Although promising for graft-versus-host disease (GvHD) treatment, MSC therapy still faces important challenges. For instance, increasing MSC migratory capacity as well as potentializing immune response suppression are of interest. For GvHD management, preventing opportunistic infections is also a valuable strategy, since immunocompromised patients are easy targets for infections. LL-37 is a host defense peptide (HDP) that has been deeply investigated due to its immunomodulatory function. In this scenario, the combination of MSC and LL-37 may result in a robust combination to be clinically used. METHODS: In the present study, the effects of LL-37 upon the proliferation and migratory capacity of human placenta-derived MSCs (pMSCs) were assessed by MTT and wound scratch assays. The influence of LL-37 over the immunosuppressive function of pMSCs was then investigated using CFSE cell division kit. Flow cytometry and real-time PCR were used to investigate the molecular mechanisms involved in the effects observed. RESULTS: LL-37 had no detrimental effects over MSC proliferation and viability, as assessed by MTT assay. Moreover, the peptide promoted increased migratory behavior of pMSCs and enhanced their immunomodulatory function over activated human PBMCs. Strikingly, our data shows that LL-37 treatment leads to increased TLR3 levels, as shown by flow cytometry, and to an increased expression of factors classically related to immunosuppression, namely IDO, IL-10, TGF-ß, IL-6, and IL-1ß. CONCLUSIONS: Taken together, our observations may serve as groundwork for the development of new therapeutic strategies based on the combined use of LL-37 and MSCs, which may provide patients not only with an enhanced immunosuppression regime, but also with an agent to prevent opportunistic infections.

Platelet-activating factor receptor plays a role in the pathogenesis of graft-versus-host disease by regulating leukocyte recruitment, tissue injury, and lethality.

PAF is a potent lipid mediator involved in several manifestations of acute inflammation, including leukocyte influx, leukocyte interaction with endothelium, and production of inflammatory cytokines. The present study evaluated the relevance of PAFR for the pathogenesis of acute GVHD using a model of adoptive transfer of splenocytes from WT or PAFR(-/-) C57BL/6J to B6D2F1 mice. Mice, which received PAFR(-/-) splenocytes or treatment with the PAFR antagonist, showed reduced clinical signs of disease and no mortality. In GVHD mice receiving PAFR(-/-) splenocytes, there was deceased bacterial translocation and tissue injury. Furthermore, production of proinflammatory cytokines and chemokines (TNF-α, IFN-γ, CCL2, CCL3, and CCL5) and accumulation of CD8(+) cells in intestine and liver were reduced in mice transplanted with the PAFR(-/-) splenocyte. Mechanistically, an absence or pharmacological blockade of PAFR 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 PAFR(-/-) leukocytes were transferred into WT mice. In conclusion, PAFR on donor leukocytes plays a critical role in GVHD by mediating leukocyte influx and cytokine production in target tissues. PAFR antagonist may potentially be useful in the treatment of GVHD in bone marrow-transplanted patients.

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.

Doença enxerto contra hospedeiro crônica em mucosa bucal: relação da concentração de células de Langerhans com a expressão da quimiocina CCL20 e de seu receptor CCR6 / Chronic graft versus host disease in the oral mucosa: concentration of Langerhans cells and its relationship with the chemokine CCL20 and its receptor CCR6

A doença enxerto contra hospedeiro (GVHD) é uma complicação comum nos pacientes submetidos ao transplante de células-tronco hematopoiéticas (TCTH), sendo considerada a maior causa de morbidade e mortalidade nesses pacientes. O principal objetivo do presente estudo foi relacionar a concentração de células de Langerhans em mucosa bucal de pacientes com GVHDc bucal com a expressão da quimiocina CCL20 e de seu receptor CCR6 no epitélio bucal, a fim de elucidar os mecanismos biológicos envolvidos no recrutamento das células de Langerhans na GVHDc. Foram selecionados fragmentos obtidos por biópsia de mucosa bucal de 60 pacientes onco-hematológicos e hematológicos submetidos previamente ao transplante de células tronco hematopoiéticas no Hospital Amaral Carvalho, Jaú SP, onde 30 pacientes desenvolveram GVHDc em mucosa bucal (Grupo 1) e 30 não desenvolveram GVHDc (Grupo 2). Amostras obtidas a partir de 30 biópsias de lesões não inflamatórias em mucosa bucal constituíram o Grupo Controle (Grupo 3). Cortes microscópicos foram avaliados em coloração de rotina Hematoxilina e Eosina, e submetidos à técnica imuno-histoquímica, utilizando-se anticorpos monoclonais anti-CD1a e anti-CCR6, e anticorpos policlonais anti-CCL20. As células de Langerhans CD1a+ foram quantificadas no epitélio da mucosa bucal, e os resultados demonstraram um maior número destas células nos pacientes com GVHDc quando comparados àqueles sem GVHDc e ao Grupo Controle (p<0,001). A análise da imunomarcação das moléculas CCR6 e CCL20 foi subjetiva com aplicação de escores. Quanto à molécula CCR6, houve maior expressão no Grupo 1 (p<0,001) em comparação aos outros Grupos; porém, quanto à expressão de CCL20, não houve diferença estatística entre os três Grupos (p=0,108). Estes resultados sugerem que o aumento das células de Langerhans, na doença enxerto contra hospedeiro crônica, em mucosa bucal, pode estar associado a maior expressão do receptor CCR6. Possivelmente, o maior recrutamento de células de...

The graft versus host disease (GVHD) is a common complication in patients undergoing hematopoietic stem cell transplantation (HSCT), and considered a major cause of morbidity and mortality in these patients. The main objective of this study was to compare the concentration of Langerhans cells in oral mucosa of patients with oral chronic GVHD (GVHDc) with the expression of the chemokine CCL20 and its receptor CCR6 in oral epithelium, in order to clarify the biological mechanisms involved in the recruitment of Langerhans cells in GVHDc. We selected 60 biopsies of oral mucosa from onco-hematological and hematological patients submitted to prior hematopoietic stem cell transplantation at Hospital Amaral Carvalho, Jaú - SP from which 30 patients developed GVHDc in the oral mucosa (Group 1) and 30 did not develop GVHDc (Group 2). The Control Group (Group 3) was obtained from 30 biopsies of non-inflammatory lesions of oral mucosa. Microscopic sections were evaluated in routine Hematoxylin and Eosin staining, and submitted to immunohistochemistry using anti-CD1a and anti-CCR6 monoclonal antibodies, and anti-CCL20 polyclonal antibody. The Langerhans cells (CD1a+) were quantified in the epithelium of the oral mucosa, and the results showed a greater number of these cells in patients with GVHDc compared to those without GVHDc and the Control Group (p<0.001). Analysis of immunostaining of molecules CCL20 and CCR6 were subjective with application of scores. The expression of CCR6 molecule was more significant in Group 1 (p<0.001) compared to other groups, but in relation to CCL20 expression, there was no statistical difference between the three groups (p=0.108). These results suggest that the increase of Langerhans cells in GVHDc affecting oral mucosa may be associated with increased expression of the receptor CCR6. We suggest that the increased recruitment of Langerhans cells to the oral mucosa in patients with transplanted bone marrow contributes...

Perforin and granzyme B involvement in oral lesions of lichen planus and chronic GVHD.

BACKGROUND: Oral lesions of lichen planus and chronic graft-vs.-host disease (cGVHD) have similar clinical and histological features, but distinct etiology. Apoptosis induced by cytotoxic T lymphocyte has been proposed as a mechanism of keratinocytes death. Cytotoxicity can be mediated by granules containing granzyme B and perforin. Since common features can reflect similarities in immunological mechanisms, we studied the role of those molecules in both diseases. METHODS: We analyzed 29 cases of oral lichen planus and 27 of oral cGVHD. The sections were studied on H&E, perforin and granzyme B staining. RESULTS: The total means (epithelium plus connective tissue number) of the granzyme B- and perforin-positive cells were significantly higher in cGVHD than in oral lichen planus lesions (P<0.05). Also, it was found that the higher the number of perforin+ cells, the higher the number of granzyme-B+ cells in the epithelium and in the connective tissue for both groups (P < 0.05). In oral lichen planus, the number of single apoptotic bodies had a positive correlation with connective tissue granzyme immunostaining and a negative correlation with perforin (P<0.01). On the contrary, in oral cGVHD, the number of apoptotic body clusters presented a positive correlation with connective tissue perforin (P<0.01). CONCLUSIONS: Our findings indicate that apoptosis in oral lichen planus seems to be correlated with granzyme B release, while in oral cGVHD, perforin seems to be more important. Although these diseases present clinical and histological similarities, subtle differences seem to exist in their pathogenetic mechanisms.

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.

Altered functional status of the hypothalamic dopaminergic tone in patients with chronic graft-versus-host disease after allogeneic hematopoietic stem cell transplantation: a pilot study.

We compared the functional status of the hypothalamic dopaminergic tone in patients given an allogeneic hematopoietic stem cell transplantation (allo-HSCT) with chronic graft-versus-host disease (GVHD) with that observed in patients with allo-HSCT without chronic GVHD and in healthy controls. The effect of acute dopaminergic blockade with intravenous metoclopramide on serum prolactin (PRL) concentrations was evaluated. Twenty volunteers, 20 to 52 years of age, seronegative for both hepatitis C virus and the human immunodeficiency virus, were studied: (1) 10 clinically healthy men (group 1), and (2) 9 patients with leukemia, and 1 patient with refractory aplastic anemia who underwent allo-HSCT, 5 of whom (3 men and 2 women) developed chronic GVHD (group 2), and 5 (3 men and 2 women) who did not develop chronic GVHD (group 3). Serum PRL concentrations were measured both fasting and after intravenous administration of metoclopramide (10-mg bolus). The area under the PRL curve was calculated. Patients in group 2 were older than those in groups 1 and 3 (P<.018), but their body mass index was similar. Fasting serum PRL concentrations were similar among the 3 groups; however, group 2 had higher PRL concentrations throughout the test (P<.001) and a greater area under the PRL curve than groups 1 and 3 (P<.001), without differences between the last 2 groups. The differences remained significant after adjustment for age (P<.01). Our results in a small group of patients with chronic GVHD after allo-HSCT suggest the existence of an increased functional level of their hypothalamic dopamine tone, which would favor a tendency toward a diminished endogenous production, release of pituitary PRL, or both. This could represent an adaptive mechanism aiming to maintain circulating PRL concentrations within a physiological range.

Avaliaçäo da barreira hemato-encefálica no transplante de medula óssea / Blood-brain barrier evaluation in bone marrow transplantation

A barreira hemato-encefálica (BHE) contribui para o isolamento imunológico do sistema nervoso central (SNC). Sua avaliaçäo nunca foi realizada em pacientes submetidos a transplante de medula óssea (TMO). Neste estudo a integridade da BHE foi avaliada através das proteínas do LCR, de forma quantitativa, a fim de observar a incidência e entender a fisiopatologia da doença do enxerto contra o hospedeiro crônica (DECH-C) no SNC. Foram estudadas amostras pareadas de LCR e soro de 33 pacientes com leucemia mielóide crônica submetidos a TMO alogênico, de doador aparentado, HLA idêntico. As amostras foram coletadas nos períodos pré TMO, pós TMO e concomitante à DECH-C. Nao foi evidenciada quebra de BHE durante a DECH-C em enhum dos casos estudados.

[Blood-brain barrier evaluation in bone marrow transplantation]. / Avaliação da barreira hemato-encepfálica no transplante de medula óssea.

The blood-brain barrier (BBB) contributes to the central nervous system (CNS) immunological isolation. BBB has never been studied in patients who developed chronic graft-versus-host disease (GVHD) after allogeneic bone marrow transplants (BMT), from HLA identical related donors. BBB disruption was investigated through the cerebrospinal fluid (CSF) proteins, quantitative and graphically, in order to detect the incidence and possible pathophysiology of the CNS involvement in chronic GVHD. Thirty three CSF and matched serum samples from chronic myeloid leukemia patients were collected pre BMT pos BMT and during chronic GVHD. There was no evidence of BBB disruption in any patient studied.

Positive identification of enterocytes by keratin antibody staining of sloughed intestinal tissue in severe GVHD.

Nine marrow allograft recipients who developed GVHD of the gastrointestinal tract accompanied by the passage of ropey necrotic material per rectum were studied. The material, resembling necrotic intestinal mucosa, was evaluated for the presence of epithelial cells using monoclonal antibodies for keratin and macrophages. Two keratins (AE1/AE3 and 34 beta E12) were detected within cells in all cases while macrophages were found in all but one case. In three cases, some cells were positive for both antibodies suggesting the presence of phagocytosed keratin in macrophage cytoplasm. Search for organisms with Gram and methenamine silver stains showed bacteria in six cases and fungus in one. Some cases of severe GVHD will be associated with the passage of ropey tan material grossly resembling sloughed mucosal tissue, but microscopically consisting largely of fibrin clots. The presence of free intestinal epithelial cells in this material is confirmed by the present study.