Effects of cyclosporine A on T cell development and clonal deletion

Post-transplant cyclophosphamide in matched donor transplantation: are we there yet?

Graft-versus-host disease (GvHD) is a frequent cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (alloHCT) and optimal approaches for its prevention have been recently updated. Post-transplant cyclophosphamide (PTCy) has demonstrated impressive results in the setting of haploidentical donor transplantation, allowing for a more widespread application of alloHCT. For this reason, over the years, several groups have implemented the use of PTCy in the context of transplantation from HLA-matched related and unrelated donors, as a replacement for standard GvHD prophylaxis based on calcineurin inhibitors and methotrexate. With increasing results from retrospective studies and new insights from prospective clinical trials, this comprehensive reevaluation of the literature aims to clarify the precise role of PTCy in this context. This review will summarize and critically discuss the overall results of the use of PTCy in alloHCT from HLA-matched donors, unmet needs, and future perspectives.

A real-world disproportionality analysis of cyclosporine from the FDA Adverse Event Reporting System (FAERS) database

Cyclosporine is an immunosuppressant used to prevent organ rejection in kidney, liver, and heart allogeneic transplants. This study aimed to assess the safety of cyclosporine through the analysis of adverse events (AEs) related to cyclosporine in the US Food and Drug Administration Adverse Event Reporting System (FAERS). To detect AEs associated with cyclosporine, a pharmacovigilance analysis was conducted using four algorithms on the FAERS database: reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN), and empirical Bayes geometric mean (EBGM). A statistical analysis was performed on data extracted from the FAERS database, covering 19,582 case reports spanning from 2013 to 2022. Among these cases, 3,911 AEs were identified, with 476 linked to cyclosporine as the primary suspected drug. Cyclosporin-induced AEs targeted 27 System Organ Classes (SOCs). Notably, the highest case at the SOC level included eye disorders, injury, poisoning, and procedural complications, as well as immune system disorders, all of which are listed on the cyclosporine label. Furthermore, we discovered novel potential AEs associated with hepatobiliary disorders, among others. Moreover, unexpected adverse drug reactions (ADRs), such as biliary anastomosis complication and spermatozoa progressive motility decrease, were identified. Importantly, these newly identified ADRs were not mentioned on the cyclosporine label, which were involved in injury, poisoning, and procedural complications, and investigations at the SOC level. The study used pharmacovigilance analysis of FAERS database to identify new and unexpected potential ADRs relating to cyclosporine, which can provide safety tips for the safe use of cyclosporine.

Calcineurin inhibition rescues alloantigen-specific central memory T cell subsets that promote chronic GVHD

Calcineurin inhibitors (CNIs) constitute the backbone of modern acute graft-versus-host disease (aGVHD) prophylaxis regimens but have limited efficacy in the prevention and treatment of chronic GVHD (cGVHD). We investigated the effect of CNIs on immune tolerance after stem cell transplantation with discovery-based single-cell gene expression and T cell receptor (TCR) assays of clonal immunity in tandem with traditional protein-based approaches and preclinical modeling. While cyclosporin and tacrolimus suppressed the clonal expansion of CD8+ T cells during GVHD, alloreactive CD4+ T cell clusters were preferentially expanded. Moreover, CNIs mediated reversible dose-dependent suppression of T cell activation and all stages of donor T cell exhaustion. Critically, CNIs promoted the expansion of both polyclonal and TCR-specific alloreactive central memory CD4+ T cells (TCM) with high self-renewal capacity that mediated cGVHD following drug withdrawal. In contrast to posttransplant cyclophosphamide (PT-Cy), CSA was ineffective in eliminating IL-17A-secreting alloreactive T cell clones that play an important role in the pathogenesis of cGVHD. Collectively, we have shown that, although CNIs attenuate aGVHD, they paradoxically rescue alloantigen-specific TCM, especially within the CD4+ compartment in lymphoid and GVHD target tissues, thus predisposing patients to cGVHD. These data provide further evidence to caution against CNI-based immune suppression without concurrent approaches that eliminate alloreactive T cell clones.

The CD4 Versus CD8 T Cell Fate Decision: A Multiomics-Informed Perspective

The choice of developing thymocytes to become CD8+ cytotoxic or CD4+ helper T cells has been intensely studied, but many of the underlying mechanisms remain to be elucidated. Recent multiomics approaches have provided much higher resolution analysis of gene expression in developing thymocytes than was previously achievable, thereby offering a fresh perspective on this question. Focusing on our recent studies using CITE-seq (cellular indexing of transcriptomes and epitopes) analyses of mouse thymocytes, we present a detailed timeline of RNA and protein expression changes during CD8 versus CD4 T cell differentiation. We also revisit our current understanding of the links between T cell receptor signaling and expression of the lineage-defining transcription factors ThPOK and RUNX3. Finally, we propose a sequential selection model to explain the tight linkage between MHC-I versus MHC-II recognition and T cell lineage choice. This model incorporates key aspects of previously proposed kinetic signaling, instructive, and stochastic/selection models.

Immunopathology of and potential therapeutics for secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome: a translational perspective

Secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome (sHLH/MAS) is a life-threatening immune disorder triggered by rheumatic disease, infections, malignancies, or medications. Characterized by the presence of hemophagocytic macrophages and a fulminant cytokine storm, sHLH/MAS leads to hyperferritinemia and multiorgan failure and rapidly progresses to death. The high mortality rate and the lack of specific treatments necessitate the development of a new drug. However, the complex and largely unknown immunopathologic mechanisms of sHLH/MAS, which involve dysfunction of various immune cells, diverse etiologies, and different clinical contexts make this effort challenging. This review introduces the terminology, diagnosis, and clinical features of sHLH/MAS. From a translational perspective, this review focuses on the immunopathological mechanisms linked to various etiologies, emphasizing potential drug targets, including key molecules and signaling pathways. We also discuss immunomodulatory biologics, existing drugs under clinical evaluation, and novel therapies in clinical trials. This systematic review aims to provide insights and highlight opportunities for the development of novel sHLH/MAS therapeutics.

Risk of Paradoxical Eczema in Patients Receiving Biologics for Psoriasis

Importance

Biologics used for plaque psoriasis have been reported to be associated with an atopic dermatitis (AD) phenotype, or paradoxical eczema, in some patients. The risk factors for this are unknown.

Objective

To explore risk of paradoxical eczema by biologic class and identify factors associated with paradoxical eczema.

Design, Setting, and Participants

This prospective cohort study used data from the British Association of Dermatologists Biologics and Immunomodulators Register for adults treated with biologics for plaque psoriasis who were seen at multicenter dermatology clinics in the UK and Ireland. Included participants were registered and had 1 or more follow-up visits between September 2007 and December 2022.

Exposures

Duration of exposure to tumor necrosis factor (TNF) inhibitors, interleukin (IL) 17 inhibitors, IL-12/23 inhibitors, or IL-23 inhibitors until paradoxical eczema onset, treatment discontinuation, last follow-up, or death.

Main Outcomes and Measures

Incidence rates of paradoxical eczema, paradoxical eczema risk by biologic class, and the association of demographic and clinical variables with risk of paradoxical eczema were assessed using propensity score-weighted Cox proportional hazards regression models.

Results

Of 56 553 drug exposures considered, 24 997 from 13 699 participants were included. The 24 997 included exposures (median age, 46 years [IQR, 36-55 years]; 57% male) accrued a total exposure time of 81 441 patient-years. A total of 273 exposures (1%) were associated with paradoxical eczema. The adjusted incidence rates were 1.22 per 100 000 person-years for IL-17 inhibitors, 0.94 per 100 000 person-years for TNF inhibitors, 0.80 per 100 000 person-years for IL-12/23 inhibitors, and 0.56 per 100 000 person-years for IL-23 inhibitors. Compared with TNF inhibitors, IL-23 inhibitors were associated with a lower risk of paradoxical eczema (hazard ratio [HR], 0.39; 95% CI, 0.19-0.81), and there was no association of IL-17 inhibitors (HR, 1.03; 95% CI, 0.74-1.42) or IL-12/23 inhibitors (HR, 0.87; 95% CI, 0.66-1.16) with risk of paradoxical eczema. Increasing age (HR, 1.02 per year; 95% CI, 1.01-1.03) and history of AD (HR, 12.40; 95% CI, 6.97-22.06) or hay fever (HR, 3.78; 95% CI, 1.49-9.53) were associated with higher risk of paradoxical eczema. There was a lower risk in males (HR, 0.60; 95% CI, 0.45-0.78).

Conclusions and Relevance

In this study, in biologic-treated patients with psoriasis, paradoxical eczema risk was lowest in patients receiving IL-23 inhibitors. Increasing age, female sex, and history of AD or hay fever were associated with higher risk of paradoxical eczema. The overall incidence of paradoxical eczema was low. Further study is needed to replicate these findings.

Mass cytometric analysis unveils a disease-specific immune cell network in the bone marrow in acquired aplastic anemia

Idiopathic acquired aplastic anemia (AA) is considered an immune-mediated syndrome of bone marrow failure since approximately 70% of patients respond to immunosuppressive therapy (IST) consisting of a course of anti-thymocyte globulin (ATG) followed by long-term use of ciclosporin. However, the immune response that underlies the pathogenesis of AA remains poorly understood. In this study, we applied high-dimensional mass cytometry on bone marrow aspirates of AA patients pre-ATG, AA patients post-ATG and healthy donors to decipher which immune cells may be implicated in the pathogenesis of AA. We show that the bone marrow of AA patients features an immune cell composition distinct from healthy donors, with significant differences in the myeloid, B-cell, CD4+ and CD8+ T-cells lineages. Specifically, we discovered that AA pre-ATG is characterized by a disease-specific immune cell network with high frequencies of CD16+ myeloid cells, CCR6++ B-cells, Th17-like CCR6+ memory CD4+ T-cells, CD45RA+CCR7+CD38+ CD8+ T-cells and KLRG1+ terminally differentiated effector memory (EMRA) CD8+ T-cells, compatible with a state of chronic inflammation. Successful treatment with IST strongly reduced the levels of CD16+ myeloid cells and showed a trend toward normalization of the frequencies of CCR6++ B-cells, CCR6+ memory CD4+ T-cells and KLRG1+EMRA CD8+ T-cells. Altogether, our study provides a unique overview of the immune landscape in bone marrow in AA at a single-cell level and proposes CCR6 as a potential new therapeutic target in AA.

NFAT Factors Are Dispensable for the Development but Are Critical for the Maintenance of Foxp3+ Regulatory T Cells

The transcription factors of the nuclear factor of activated T cell (NFAT) family play a crucial role in multiple aspects of T cell function. It has recently been reported that NFATs play an important role in the suppressive function of CD4⁺CD25⁺Foxp3⁺ regulatory T (T_reg) cells. In this study, we have investigated the role of NFATs in the thymic development of T_reg cells in mice. We show that NFAT factors are dispensable for the development of Foxp3⁺ T_reg cells in the thymus but are critical for the maintenance of both the phenotype and survival of T_reg cells in the thymus as well as in peripheral lymphoid organs. Specifically, the homeostasis of CD4⁺CD25⁺Foxp3⁺ but not the CD4⁺CD25⁻Foxp3⁺ fraction is severely perturbed when NFAT signaling is blocked, leading to a strongly reduced T_reg population. We underscored this intriguing effect of NFAT on CD4⁺CD25⁺Foxp3⁺ T_reg cells to the disruption of survival signals provided by interleukin 2 (IL-2). Accordingly, blocking T_reg cell death by abolishing the activity of pro-apoptotic Bcl-2 family member Bim, compensated for the survival defects induced due to a lack of NFAT-IL-2-IL-2R signaling. Inhibition of NFAT activity led to a strong reduction in the number of Foxp3⁺ T_reg cells; however, it did not influence the level of Foxp3 expression on an individual cell basis. In addition, we show a differential effect of IL-2 and IL-7 signaling on Foxp3⁺ T_reg versus CD4⁺CD25⁻ T cell development, again underlining the dispensability of NFAT signaling in the development, but not in the maintenance of Foxp3⁺ T_reg cells.

Updates in chronic graft-versus-host disease

Chronic graft-versus-host disease (GVHD) is the leading cause of late morbidity and mortality after allogeneic hematopoietic cell transplantation. Symptoms and manifestations of chronic GVHD are heterogeneous and pleomorphic, and there are no standard treatments beyond corticosteroids. Therapy is typically prolonged, and chronic GVHD and its treatment are associated with adverse effects that have a significant impact on long-term quality of life and functional status. Several advances have been made over the last 2 decades to define the diagnosis of chronic GVHD as well as its severity and response criteria for clinical trials. Further understanding into the biologic mechanisms of the development of chronic GVHD has led to the investigation of several novel immunomodulatory and targeted therapies. Multi-institutional collaboration and pharmaceutical support in the development of therapies based on sound biologic mechanisms and clinical trials with defined end points and responses have led to several promising agents on the horizon of approval for treatment of chronic GVHD. This article reviews advances in our knowledge of chronic GVHD and its biologic framework to improve approaches to prevention and treatment.

Cyclosporin A: A Repurposable Drug in the Treatment of COVID-19?

Coronavirus disease 2019 (COVID-19) is now at the forefront of major health challenge faced globally, creating an urgent need for safe and efficient therapeutic strategies. Given the high attrition rates, high costs, and quite slow development of drug discovery, repurposing of known FDA-approved molecules is increasingly becoming an attractive issue in order to quickly find molecules capable of preventing and/or curing COVID-19 patients. Cyclosporin A (CsA), a common anti-rejection drug widely used in transplantation, has recently been shown to exhibit substantial anti-SARS-CoV-2 antiviral activity and anti-COVID-19 effect. Here, we review the molecular mechanisms of action of CsA in order to highlight why this molecule seems to be an interesting candidate for the therapeutic management of COVID-19 patients. We conclude that CsA could have at least three major targets in COVID-19 patients: (i) an anti-inflammatory effect reducing the production of proinflammatory cytokines, (ii) an antiviral effect preventing the formation of the viral RNA synthesis complex, and (iii) an effect on tissue damage and thrombosis by acting against the deleterious action of angiotensin II. Several preliminary CsA clinical trials performed on COVID-19 patients report lower incidence of death and suggest that this strategy should be investigated further in order to assess in which context the benefit/risk ratio of repurposing CsA as first-line therapy in COVID-19 is the most favorable.

Maternal, foetal and child consequences of immunosuppressive drugs during pregnancy in women with organ transplant: a review

Although pregnancy remains exceptional in women after heart, liver or lung transplant, obstetricians and nephrologists are regularly confronted with pregnancy in renal transplant recipients. National and international registries have described the epidemiology of maternal, foetal and neonatal complications, and transplantation societies have published recommendations on the monitoring of these high-risk pregnancies. In this review, we summarize the existing data on maternal and foetal complications of pregnancies in women after renal transplant, especially the management of immunosuppression. We also describe the few available data on the middle- and long-term outcomes of their children who were exposed in utero to immunosuppressive drugs.

IL-Y Aggravates Murine Chronic Graft-Versus-Host Disease by Enhancing T and B Cell Responses

IL-Y, a synthetic member of IL-12 cytokine family, was found to exert potent immunosuppressive effects by inhibiting the differentiation and activation of Th1 and Th17 cells. However, the role of IL-Y in the development of chronic graft-versus-host disease (cGVHD) remains unknown. Here, using murine models of scleroderma-like and lupus-like cGVHD, we examined the function of IL-Y in the pathogenesis of cGVHD by hydrodynamically injecting minicircle-IL-Y expressing plasmids (MC IL-Y). In contrast with the reported immune suppressive function of IL-Y, administration of MC IL-Y enhanced cGVHD severity reflected by deteriorated multi-organ pathologic damages. In lupus-like cGVHD model, urine protein and the serum anti-dsDNA antibody (IgG) were significantly upregulated by IL-Y treatment. Further study demonstrated that IL-Y impacts both donor T and B cell response. In T cells, IL-Y inhibited the generation of CD4⁺Foxp3⁺ regulator T (Treg) cells during the development of cGVHD. IL-Y may also increase the infiltration of pathogenic TNF-α producing CD4⁺ and CD8⁺ T cells through IL-27Rα in recipient spleens, as this effect was diminished in IL-27Rα deficient T cells. Moreover, IL-Y enhanced the differentiation of ICOS⁺ T follicular helper (Tfh) cells. In B cells, the percentage of germinal center (GC) B cells in recipient spleens was significantly upregulated by MC IL-Y plasmid administration. The levels of co-stimulatory molecules, MHC-II and CD86, on B cells were also enhanced by IL-Y expression. Taken together, our data indicated that IL-Y promoted the process of cGVHD by activating pathogenic T and B cells.

Trametinib Attenuates Delayed Rejection and Preserves Thymic Function in Rat Lung Transplantation

Delayed immunological rejection after human lung transplantation causes chronic lung allograft dysfunction, which is associated with high mortality. Delayed rejection may be attributable to indirect alloantigen presentation by host antigen-presenting cells; however, its pathophysiology is not fully understood. The mitogen-activated protein kinase pathway is activated in T cells upon stimulation, and we previously showed that the MEK inhibitor, trametinib, suppresses graft-versus-host disease after murine bone marrow transplantation. We investigated whether trametinib suppresses graft rejection after two types of rat lung transplantation and analyzed its immunological mode of action. Major histocompatibility complex-mismatched transplantation from brown Norway rats into Lewis rats and minor histocompatibility antigen-mismatched transplantation from Fischer 344 rats into Lewis rats were performed. Cyclosporine (CsA) and/or trametinib were administered alone or consecutively. Acute and delayed rejection, lymphocyte infiltration, and pulmonary function were evaluated. Administration of trametinib after CsA suppressed delayed rejection, reduced inflammatory cell infiltration and fibrosis within the graft, and preserved pulmonary functions at Day 28. Trametinib suppressed functional differentiation of T and B cells in the periphery but preserved thymic T cell differentiation. Donor B cells within the graft disappeared by Day 14, indicating that delayed graft rejection at Day 28 was mainly due to indirect presentation by host antigen-presenting cells. Finally, trametinib administration without CsA preconditioning suppressed rejection after minor histocompatibility antigen-mismatched transplantation. Trametinib attenuates delayed rejection upon major histocompatibility complex-mismatched transplantation by suppressing indirect presentation and is a promising candidate to treat chronic lung allograft dysfunction in humans.

Clinical value of renal phospholipase A2 receptor deposit in the prognosis evaluation and treatment options of idiopathic membranous nephropathy: A retrospective cohort study

Aim

Phospholipase A2 receptor (PLA2R) is a target antigen for idiopathic membranous nephropathy (IMN). However, the association between renal PLA2R antigen and disease prognosis had not been fully investigated. In addition, there was a paucity of studies investigating the difference of therapeutic effects between cyclophosphamide and cyclosporine A in PLA2R‐associated IMN.

Methods

This retrospective cohort study recruited 300 eligible patients diagnosed with biopsy‐proven IMN between September 2015 and July 2018 in Guangdong Provincial People's Hospital. The remission of proteinuria was compared between PLA2R‐associated and non‐PLA2R‐associated IMN. The difference of therapeutic effects between cyclophosphamide and cyclosporine A were also investigated in PLA2R‐associated IMN.

Results

The positive rate of renal PLA2R antigen in recruited IMN patients was 82.3%. Non‐PLA2R‐associated IMN patients had a higher probability to achieve remission than PLA2R‐associated IMN patients (Log–rank test, P = .013). Multivariate COX analysis showed that renal PLA2R antigen was an independent risk factor for not achieving remission in IMN patients (Hazard Ratio: 1.619; 95% confidence interval: 1.133 to 2.313; P = .008). In PLA2R‐associated IMN, patients receiving cyclophosphamide had a higher probability to achieve remission compared with those receiving cyclosporine A (Log–rank test, P = .018) while there was no difference in renal survival. Multivariate COX regression analysis showed that compared with cyclosporine A, patients receiving cyclophosphamide had a higher probability to achieve remission.

Conclusion

Phospholipase A2 receptor ‐associated IMN patients had a lower probability to achieve remission compared with non‐PLA2R‐associated IMN. Compared with cyclosporine A, cyclophosphamide exerted better therapeutic effects in remission of proteinuria and may be the preferred immunosuppressant for PLA2R‐associated IMN.

Metalloimmunology: The metal ion-controlled immunity

Metals are essential components in all forms of life required for the function of nearly half of all enzymes and are critically involved in virtually all fundamental biological processes. Especially, the transition metals iron (Fe), zinc (Zn), manganese (Mn), nickel (Ni), copper (Cu) and cobalt (Co) are crucial micronutrients known to play vital roles in metabolism as well due to their unique redox properties. Metals carry out three major functions within metalloproteins: to provide structural support, to serve as enzymatic cofactors, and to mediate electron transportation. Metal ions are also involved in the immune system from metal allergies to nutritional immunity. Within the past decade, much attention has been drawn to the roles of metal ions in the immune system, since increasing evidence has mounted to suggest that metals are critically implicated in regulating both the innate immune sensing of and the host defense against invading pathogens. The importance of ions in immunity is also evidenced by the identification of various immunodeficiencies in patients with mutations in ion channels and transporters. In addition, cancer immunotherapy has recently been conclusively demonstrated to be effective and important for future tumor treatment, although only a small percentage of cancer patients respond to immunotherapy because of inadequate immune activation. Importantly, metal ion-activated immunotherapy is becoming an effective and potential way in tumor therapy for better clinical application. Nevertheless, we are still in a primary stage of discovering the diverse immunological functions of ions and mechanistically understanding the roles of these ions in immune regulation. This review summarizes recent advances in the understanding of metal-controlled immunity. Particular emphasis is put on the mechanisms of innate immune stimulation and T cell activation by the essential metal ions like calcium (Ca²⁺), zinc (Zn²⁺), manganese (Mn²⁺), iron (Fe²⁺/Fe³⁺), and potassium (K⁺), followed by a few unessential metals, in order to draw a general diagram of metalloimmunology.

Thymocyte selection: From signaling to epigenetic regulation

During thymocyte development at the double positive stage, thymocytes are subjected to a TCR quality check process termed "thymocyte selection." TCRs with proper binding capabilities to MHC molecules (with self-peptide) are able to transduce cell survival signals and allow the continuing of development to single positive T cells. It has been known that TCRs in DP cells can transduce signals with higher efficiency than peripheral mature T cells, even though they share most of the signaling components. Recent studies have revealed some thymocyte-specific signaling modulators including Themis and Tespa1. The activation of TCR signaling during positive selection results in the activation of several key transcription factors and extensive gene expression change, which has been revealed by newly developed systemic transcriptome analysis tools, and could be used for the evaluation of positive selection process. The fate determination postpositive selection is also governed on the epigenetic level including both DNA methylation and histone modifications.

LPS enhances CTB-INSULIN induction of IDO1 and IL-10 synthesis in human dendritic cells

Autoantigen-specific immunotherapy promises effective treatment for devastating tissue specific autoimmune diseases like multiple sclerosis (MS) and type 1 diabetes (T1D). Because activated dendritic cells (DCs) stimulate the differentiation of autoreactive T cells involved in the initiation of autoimmunity, blocking the activation of DCs may be an effective strategy for inhibiting tissue specific autoimmunity. Following this approach, immature DCs were shown to remain inactive after treatment with chimeric fusion proteins composed of the cholera toxin B subunit adjuvant linked to autoantigens like proinsulin (CTB-INS). Mass spectrometer analysis of human DCs treated with CTB-INS suggest that upregulation of the tryptophan catabolic enzyme indoleamine 2, 3-dioxygenase (IDO1) is responsible for inhibiting DC activation thereby resulting in a state of immunological tolerance within the DC. Here we show that the fusion protein CTB-INS inhibits human monocyte derived DC (moDC) activation through stimulation of IDO1 biosynthesis and that the resultant state of DC tolerance can be further enhanced by the presence of residual E. coli lipopolysaccharide (LPS) present in partially purified CTB-INS preparations. Additional experiments showed that LPS enhancement of DC tolerance was dependent upon stimulation of IDO1 biosynthesis. LPS stimulation of increased levels of IDO1 in the DC resulted in increased secretion of kynurenines, tryptophan degradation products known to suppress DC mediated pro-inflammatory T cell differentiation and to stimulate the proliferation of regulatory T cells (Tregs). Further, the presence of LPS in CTB-INS treated DCs stimulated the biosynthesis of costimulatory factors CD80 and CD86 but failed to upregulate maturation factor CD83, suggesting CTB-INS treated DCs may be maintained in a state of semi-activation. While treatment of moDCs with increasing amounts of LPS free CTB-INS was shown to increase DC secretion of the anti-inflammatory cytokine IL-10, the presence of residual LPS in partially purified CTB-INS preparations dramatically increased IL-10 secretion, suggesting that CTB-INS may enhance DC mediated immunological tolerance by stimulating the proliferation of anti-inflammatory T cells. While the extraction of LPS from bacterial generated CTB-INS may remove additional unknown factors that may contribute to the regulation of IDO1 levels, together, our experimental data suggest that LPS stimulates the ability of CTB-INS to induce IDO1 and IL-10 important factors required for establishment of a state of functional immunological tolerance in human DCs. Regulation of the ratio of LPS to CTB-INS may prove to be an effective method for optimization of readily available "off the shelf" CTB-INS mediated immune-therapy for tissue specific autoimmune diseases including type 1 diabetes.

Long-Lasting Graft-Derived Donor T Cells Contribute to the Pathogenesis of Chronic Graft-versus-Host Disease in Mice

Chronic graft-versus-host disease (cGVHD) is a major complication in long-term survivors of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Graft-derived T cells (T_G) have been implicated in the induction of cGVHD; however, the extent of their contribution to the pathogenesis of cGVHD remains unclear. Using a mouse model of cGVHD, we demonstrate that T_G predominate over hematopoietic stem cell-derived T cells generated de novo (T_HSC) in cGVHD-affected organs such as the liver and lung even at day 63 after allo-HSCT. Persisting T_G, in particular CD8⁺ T_G, not only displayed an exhausted or senescent phenotype but also contained a substantial proportion of cells that had the potential to proliferate and produce inflammatory cytokines. Host antigens indirectly presented by donor HSC-derived hematopoietic cells were involved in the maintenance of T_G in the reconstituted host. Selective depletion of T_G in the chronic phase of disease resulted in the expansion of T_HSC and thus neither the survival nor histopathology of cGVHD was ameliorated. On the other hand, T_HSC depletion caused activation of T_G and resulted in a lethal T_G-mediated exacerbation of GVHD. The findings presented here clarify the pathological role of long-lasting T_G in cGVHD.

The Biology of Chronic Graft-versus-Host Disease: A Task Force Report from the National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease

Chronic graft-versus-host disease (GVHD) is the leading cause of late, nonrelapse mortality and disability in allogeneic hematopoietic cell transplantation recipients and a major obstacle to improving outcomes. The biology of chronic GVHD remains enigmatic, but understanding the underpinnings of the immunologic mechanisms responsible for the initiation and progression of disease is fundamental to developing effective prevention and treatment strategies. The goals of this task force review are as follows: This document is intended as a review of our understanding of chronic GVHD biology and therapies resulting from preclinical studies, and as a platform for developing innovative clinical strategies to prevent and treat chronic GVHD.

Engraftment Syndrome after Autologous Stem Cell Transplantation: An Update Unifying the Definition and Management Approach

Engraftment syndrome (ES) encompasses a continuum of periengraftment complications after autologous hematopoietic stem cell transplantation. ES may include noninfectious fever, skin rash, diarrhea, hepatic dysfunction, renal dysfunction, transient encephalopathy, and capillary leak features, such as noncardiogenic pulmonary infiltrates, hypoxia, and weight gain with no alternative etiologic basis other than engraftment. Given its pleiotropic clinical presentation, the transplant field has struggled to clearly define ES and related syndromes. Here, we present a comprehensive review of ES in all documented disease settings. Furthermore, we discuss the proposed risk factors, etiology, and clinical relevance of ES. Finally, our current approach to ES is included along with a proposed treatment algorithm for the management of this complication.

Role of CD8-positive cells in radioimmunotherapy utilizing (177)Lu-mAbs in an immunocompetent rat colon carcinoma model

Background

CD8-positive cells might play a crucial role in the therapeutic response to radiation, which has however not been investigated in radioimmunotherapy (RIT). The aim of this study was to evaluate whether cytotoxic T cells affect the response of established tumors and, above all, if they delay or prevent the development of distant metastases after RIT, using an immunocompetent syngeneic rat colon carcinoma model.

Methods

The cytotoxic T cells were depleted in 15 rats by anti-CD8 before the injection of the radioimmunoconjugate (400 MBq/kg body weight ¹⁷⁷Lu-BR96, which binds to the tumor-associated antigen Lewis Y). Fifteen other rats were treated with RIT only. Both groups were followed for 99 days. Blood samples were collected at least once weekly, and tumors were monitored twice weekly.

Results

Twenty-nine of the 30 animals exhibited local complete response. The non-responder was treated with anti-CD8 and RIT but succumbed later due to metastases. Five animals in the group given anti-CD8 + RIT were sacrificed due to metastatic disease, and 4 additional animals were found to have metastases at autopsy. In the group given RIT, 4 animals developed metastatic disease, but no metastases were found in the remaining 11 animals at autopsy. Thus, at the end of the study, 6 animals in the anti-CD8 + RIT group were free from metastases, while 11 were free from metastases in the group receiving RIT.

CD3⁺CD4⁻CD8⁺ lymphocytes were consistently depleted by the anti-CD8 treatment. The myelosuppression was otherwise similar in the two groups. The initial depletion of CD8-positive cells in our syngeneic rat colon carcinoma model resulted in a higher frequency of animals developing metastases.

Conclusions

Depletion of CD8-positive cells during RIT in an immunocompetent rat tumor model might influence the number of animals developing metastases, indicating that the immune system may be important in the long-term outcome of RIT.

Placing ion channels into a signaling network of T cells: from maturing thymocytes to healthy T lymphocytes or leukemic T lymphoblasts

T leukemogenesis is a multistep process, where the genetic errors during T cell maturation cause the healthy progenitor to convert into the leukemic precursor that lost its ability to differentiate but possesses high potential for proliferation, self-renewal, and migration. A new misdirecting "leukemogenic" signaling network appears, composed by three types of participants which are encoded by (1) genes implicated in determined stages of T cell development but deregulated by translocations or mutations, (2) genes which normally do not participate in T cell development but are upregulated, and (3) nondifferentially expressed genes which become highly interconnected with genes expressed differentially. It appears that each of three groups may contain genes coding ion channels. In T cells, ion channels are implicated in regulation of cell cycle progression, differentiation, activation, migration, and cell death. In the present review we are going to reveal a relationship between different genetic defects, which drive the T cell neoplasias, with calcium signaling and ion channels. We suggest that changes in regulation of various ion channels in different types of the T leukemias may provide the intracellular ion microenvironment favorable to maintain self-renewal capacity, arrest differentiation, induce proliferation, and enhance motility.

Autologous graft-versus-host disease in a child with stage IV neuroblastoma

Graft-versus-host disease (GVHD) is an underappreciated complication of autologous hematopoietic stem cell transplantation (AHSCT) that can affect the skin, gastrointestinal tract, and liver. The development of this rare condition is probably due to an impairment of immunologic tolerance that can occur spontaneously through T-cell dysregulation, possibly from intensive conditioning chemotherapy regimens, or intentionally through administration of cyclosporine in the hopes of promoting an antitumor response. We present the case of a 2-year-old boy with metastatic neuroblastoma who spontaneously developed autologous GVHD after AHSCT. Severe pruritus and an inability to taper his oral steroids without a disease flare marked his disease. Eventually partial relief was achieved with initiation of cyclosporine and a strict soak and smear protocol using topical triamcinolone 0.1% ointment.

Phase II Trial of Graft-versus-Host Disease Prophylaxis with Post-Transplantation Cyclophosphamide after Reduced-Intensity Busulfan/Fludarabine Conditioning for Hematological Malignancies

Graft-versus-host disease (GVHD) prophylaxis with post-transplantation cyclophosphamide (CY) after ablative HLA-matched bone marrow (BM) transplantation has been reported to have comparable rates of acute GVHD with an apparent reduction in chronic GVHD and infections when compared to historical prophylaxis with a calcineurin-inhibitor (CNI) and methotrexate (MTX). We conducted a phase II trial of post-transplantation CY (post-CY) after reduced-intensity conditioning (RIC) using intravenous busulfan (area under the curve of 4000 micromolar minute), fludarabine (40 mg/m(2)) for 4 days, and CY 50 mg/kg on days +3 and +4 after BM or peripheral blood (PB) transplantations from matched related (MRD) or unrelated donors (MUD). MUD recipients received antithymocyte globulin (ATG); however, a later amendment removed ATG. Forty-nine patients were treated (acute myeloid leukemia/myelodysplastic syndrome, 82%). Median age was 62 years (range, 39 to 72). Fifteen patients received an MRD (9 PB/6 BM); 34 had a MUD (2 PB/32 BM). The cumulative incidence of grade II to IV acute GVHD, III to IV acute GVHD, and chronic GVHD was 58%, 22%, and 18%, respectively. A matched cohort analysis compared outcomes to tacrolimus/methotrexate GVHD prophylaxis and indicated higher rates of acute GVHD grade II to IV (46% versus 19%; hazard ratio [HR], 2.8; P = .02) and treatment-related mortality (HR, 3.3; P = .035) and worse overall survival (HR, 1.9; P = .04) with post-CY. The incidence of chronic GVHD and CMV reactivation did not differ. This study suggests that post-CY should not be used as sole GVHD prophylaxis after a RIC transplantation from HLA-matched donors.

Aldehyde dehydrogenase expression drives human regulatory T cell resistance to posttransplantation cyclophosphamide

High-dose, posttransplantation cyclophosphamide (PTCy) is an effective strategy for preventing graft-versus-host disease (GVHD) after allogeneic blood or marrow transplantation (alloBMT). However, the mechanisms by which PTCy modulates alloimmune responses are not well understood. We studied early T cell reconstitution in patients undergoing alloBMT with PTCy and the effects of mafosfamide, a cyclophosphamide (Cy) analog, on CD4(+) T cells in allogeneic mixed lymphocyte reactions (MLRs) in vitro. Patients exhibited reductions in naïve, potentially alloreactive conventional CD4(+) T cells with relative preservation of memory CD4(+)Foxp3(+) T cells. In particular, CD4(+)CD45RA(-)Foxp3(+hi) effector regulatory T cells (Tregs) recovered rapidly after alloBMT and, unexpectedly, were present at higher levels in patients with GVHD. CD4(+)Foxp3(+) T cells from patients and from allogeneic MLRs expressed relatively high levels of aldehyde dehydrogenase (ALDH), the major in vivo mechanism of Cy resistance. Treatment of MLR cultures with the ALDH inhibitor diethylaminobenzaldehyde reduced the activation and proliferation of CD4(+) T cells and sensitized Tregs to mafosfamide. Finally, removing Tregs from peripheral blood lymphocyte grafts obviated PTCy's GVHD-protective effect in a xenogeneic transplant model. Together, these findings suggest that Treg resistance to Cy through expression of ALDH may contribute to the clinical activity of PTCy in preventing GVHD.

Cyclosporine A for the treatment of refractory nephrotic syndrome with renal dysfunction

Cyclosporine A (CsA) is an immunosuppressant agent and is utilized as a second-line drug therapy for refractory nephrotic syndrome (RNS). In general, the use of CsA is strictly controlled in patients with an estimated glomerular filtration rate (eGFR) <30–40 ml/min/1.73 m², and little is known about the safety and efficacy of CsA treatment in patients with RNS complicated by renal dysfunction. In the present study, the clinical data of 10 patients with RNS and renal dysfunction, who received CsA treatment between 2000 and 2009 in the Kidney Institute of PLA, were reviewed retrospectively. Pathologically, these patients included six cases with minimal change, two cases of diffuse mesangial proliferation and two cases of focal segmental glomerulosclerosis. Six months subsequent to the initiation of the CsA treatment, six patients achieved complete remission, two patients achieved remarkable remission and two patients achieved partial remission. Renal function was improved in all patients as represented by the improvement in the eGFR (28.6±3.8 ml/min/1.73 m² prior to treatment versus 99.3±21.9 ml/min/1.73 m² 6 months subsequent to treatment). Few adverse CsA-related events were observed. These results suggest that renal dysfunction is not an absolute contraindication for CsA treatment in patients with RNS. The use of CsA is safe and efficacious and may, in certain cases, improve renal function in patients with RNS and renal impairment.

Single infusion of donor mononuclear early apoptotic cells as prophylaxis for graft-versus-host disease in myeloablative HLA-matched allogeneic bone marrow transplantation: a phase I/IIa clinical trial

Because of its potent immunomodulatory effect, an infusion of donor mononuclear early apoptotic cells (ApoCell) was tested in addition to cyclosporine and methotrexate as prophylaxis for acute graft-versus-host disease (GVHD) after HLA-matched myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) from a related donor. In a phase I/IIa clinical trial, we treated 13 patients (median age, 37 years; range, 20 to 59 years) with hematologic malignancies: 7 patients with acute lymphoblastic leukemia, 5 patients with acute myeloid leukemia, and 1 patient with chronic myeloid leukemia, who received conventional myeloablative conditioning, with 35, 70, 140, or 210 × 10(6) cell/kg of donor ApoCell, on day -1 of transplantation. Engraftment was successful in all patients with median time to neutrophil recovery of 13 days (range, 11 to 19), and platelet recovery of 15 days (range, 11 to 59). Serious adverse effects were reported on 10 occasions in the trial, all of which were considered unrelated (n = 7) or unlikely to be related (n = 3) to ApoCell infusion. The nonrelapse mortality at day 100 and 180 after transplantation was 7.7% and the overall survival at 100 and 180 days after transplantation was 92% and 85%, respectively. All ApoCell preparations showed an in vitro significant tolerogenic effect upon interaction with dendritic cells. The overall incidence of acute grades II to IV GVHD was 23%, whereas among those receiving the 2 higher doses (n = 6), the rate was 0%. These results suggest that a single infusion of donor ApoCell in HLA-matched allogeneic HSCT is a safe and potentially effective prophylaxis for acute GVHD occurring after myeloablative conditioning. No dose limiting toxicity was observed. (Clinicaltrials.gov no. NCT00524784).

Metallophilic macrophages of the rodent thymus

For a very long time, we studied the metallophilic macrophages of the rodent thymus and in this review our results on morphological, histochemical, enzymehistochemical, immunohistochemical, ultrastructural and functional features of these cells, as well as the molecular regulation of their development, will be presented. Furthermore, the differences between species will also be discussed and the comparisons with similar/related cell types (metallophilic macrophages in the marginal sinus of the spleen, subcapsular sinus of the lymph nodes and germinal centers of secondary lymphoid follicles) will be made. Metallophilic macrophages are strategically positioned in the thymic cortico-medullary zone and are very likely to be involved in: (i) the metabolism, synthesis and production of bioactive lipids, most likely arachidonic acid metabolites, based on their histochemical and enzymehistochemical features, and (ii) the process of negative selection that occurs in the thymus, based on their ultrastructural features and their reactivity after the application of toxic or immunosuppressive/immunomodulatory agents. Taken together, their phenotypic and functional features strongly suggest that metallophilic macrophages play a significant role in the thymic physiology.

Cross-study homogeneity of psoriasis gene expression in skin across a large expression range

BACKGROUND

In psoriasis, only limited overlap between sets of genes identified as differentially expressed (psoriatic lesional vs. psoriatic non-lesional) was found using statistical and fold-change cut-offs. To provide a framework for utilizing prior psoriasis data sets we sought to understand the consistency of those sets.

METHODOLOGY/PRINCIPAL FINDINGS

Microarray expression profiling and qRT-PCR were used to characterize gene expression in PP and PN skin from psoriasis patients. cDNA (three new data sets) and cRNA hybridization (four existing data sets) data were compared using a common analysis pipeline. Agreement between data sets was assessed using varying qualitative and quantitative cut-offs to generate a DEG list in a source data set and then using other data sets to validate the list. Concordance increased from 67% across all probe sets to over 99% across more than 10,000 probe sets when statistical filters were employed. The fold-change behavior of individual genes tended to be consistent across the multiple data sets. We found that genes with <2-fold change values were quantitatively reproducible between pairs of data-sets. In a subset of transcripts with a role in inflammation changes detected by microarray were confirmed by qRT-PCR with high concordance. For transcripts with both PN and PP levels within the microarray dynamic range, microarray and qRT-PCR were quantitatively reproducible, including minimal fold-changes in IL13, TNFSF11, and TNFRSF11B and genes with >10-fold changes in either direction such as CHRM3, IL12B and IFNG.

CONCLUSIONS/SIGNIFICANCE

Gene expression changes in psoriatic lesions were consistent across different studies, despite differences in patient selection, sample handling, and microarray platforms but between-study comparisons showed stronger agreement within than between platforms. We could use cut-offs as low as log10(ratio) = 0.1 (fold-change = 1.26), generating larger gene lists that validate on independent data sets. The reproducibility of PP signatures across data sets suggests that different sample sets can be productively compared.

Cyclolinopeptide derivatives modify methotrexate-induced suppression of the humoral immune response in mice

High doses of chemotherapeutics in clinical treatment, leading to cell toxicity, can be lowered by co-administration of other immunoregulatory drugs. The aim of this study was to evaluate effects of several derivatives of cyclolinopeptide A (CLA), derived from linen seeds, on the suppressive action of metothrexate (MTX) in a mouse model of humoral immune response in vitro. New CLA analogues 1 and 2, and their linear precursors 3 and 4, containing conformationally restricted dipeptide fragment Phe-Phe or D-Phe-D-Phe with ethylene bridge (-CH(2)-CH(2)-) between phenylalanine nitrogens were synthesized. NMR studies and theoretical calculations showed that introduction of locally constraining fragment into CLA molecule increased its overall conformational flexibility. The bioactivity of new CLA analogues was examined in the mouse model of the in vitro secondary humoral immune response, suppressed by methotrexate (MTX). The results revealed differential actions of the peptides such as 1/augmentation of the suppressive activity of MTX or 2/antagonistic effects of the peptides on MTX-induced suppression. Potential advantages for the application of CLA-derived peptides in therapy and structure-activity relationships were discussed.

Role of CCL19/21 and its possible signaling through CXCR3 in development of metallophilic macrophages in the mouse thymus

We have already shown that metallophilic macrophages, which represent an important component in the thymus physiology, are lacking in lymphotoxin-β receptor-deficient mice. However, further molecular requirements for the development and correct tissue positioning of these cells are unknown. To this end, we studied a panel of mice deficient in different chemokine ligand or receptor genes. In contrast to normal mice, which have these cells localized in the thymic cortico-medullary zone (CMZ) as a distinct row positioned between the cortex and medulla, in plt/plt (paucity of lymph node T cells) mice lacking the functional CCL19/CCL21 chemokines, metallophilic macrophages are not present in the thymic tissue. Interestingly, in contrast to the CCL19/21-deficient thymus, metallophilic macrophages are present in the CCR7-deficient thymus. However, these cells are not appropriately located in the CMZ, but are mostly crowded in central parts of thymic medulla. The double staining revealed that these metallophilic macrophages are CCR7-negative and CXCR3-positive. In the CXCL13-deficient thymus the number, morphology and localization of metallophilic macrophages are normal. Thus, our study shows that CCL19/21 and its possible signaling through CXCR3 are required for the development of thymic metallophilic macrophages, whereas the CXCL13-CXCR5 signaling is not necessary.

Manipulating the bioenergetics of alloreactive T cells causes their selective apoptosis and arrests graft-versus-host disease

Cells generate adenosine triphosphate (ATP) by glycolysis and by oxidative phosphorylation (OXPHOS). Despite the importance of having sufficient ATP available for the energy-dependent processes involved in immune activation, little is known about the metabolic adaptations that occur in vivo to meet the increased demand for ATP in activated and proliferating lymphocytes. We found that bone marrow (BM) cells proliferating after BM transplantation (BMT) increased aerobic glycolysis but not OXPHOS, whereas T cells proliferating in response to alloantigens during graft-versus-host disease (GVHD) increased both aerobic glycolysis and OXPHOS. Metabolomic analysis of alloreactive T cells showed an accumulation of acylcarnitines consistent with changes in fatty acid oxidation. Alloreactive T cells also exhibited a hyperpolarized mitochondrial membrane potential (ΔΨm), increased superoxide production, and decreased amounts of antioxidants, whereas proliferating BM cells did not. Bz-423, a small-molecule inhibitor of the mitochondrial F(1)F(0) adenosine triphosphate synthase (F(1)F(0)-ATPase), selectively increased superoxide and induced the apoptosis of alloreactive T cells, which arrested established GVHD in several BMT models without affecting hematopoietic engraftment or lymphocyte reconstitution. These findings challenge the current paradigm that activated T cells meet their increased demands for ATP through aerobic glycolysis, and identify the possibility that bioenergetic and redox characteristics can be selectively exploited as a therapeutic strategy for immune disorders.

High-dose cyclophosphamide for graft-versus-host disease prevention

PURPOSE OF REVIEW

Administration of high-dose cyclophosphamide after transplantation inhibits both graft rejection and graft-versus-host disease (GvHD) in mouse models of allogeneic blood or marrow transplantation (alloBMT). This strategy has recently been adapted to human transplantation.

RECENT FINDINGS

The safety and efficacy of high-dose posttransplantation cyclophosphamide, when given in combination with tacrolimus and mycophenolate mofetil, was first demonstrated after nonmyeloablative conditioning and allografting using human leukocyte antigen (HLA)-mismatched related donors. Further analysis shows that increasing HLA disparity does not worsen overall outcome. High-dose posttransplantation cyclophosphamide was also found to be effective as sole prophylaxis of acute and chronic GvHD after HLA-matched alloBMT.

SUMMARY

Taking advantage of the differential susceptibility of proliferating, alloreactive T cells over nonproliferating, nonalloreactive T cells to high-dose cyclophosphamide, and owing to the drug's stem cell sparing effects, this novel strategy provides a unique opportunity to optimize GvHD prophylaxis after HLA-matched alloBMT and increase the use of HLA-mismatched related donors. Well tolerated and effective mismatched related alloBMT provides access to essentially everyone, such as patients with sickle cell anemia, in need of the procedure.

Reconstitution of self-tolerance after hematopoietic stem cell transplantation

Graft-versus-host disease (GVHD) is a major complication of allogeneic bone marrow or hematopoietic stem cell transplantation. GVHD is thought to be primarily due to the response of mature T cells transferred along with the bone marrow graft to foreign histocompatibility antigens expressed on host tissues. Recent studies, however, have challenged this paradigm set forth in the 1960s and have suggested that self-MHC class II antigens can be recognized in GVHD. Many questions still remain unanswered particularly in regard to the role of immune reconstitution, the ability to recognize and discriminate self and the re-establishment of self-tolerance. In fact, the failure to re-establish tolerance to self can lead to systemic autoimmunity that may exacerbate or even mimic GVHD. The present review summarizes our studies in autologous GVHD characterizing the underlying immune mechanisms and their potential impact in allogeneic hematopoietic stem cell transplantation.

Tenuous paths in unexplored territory: From T cell receptor signaling to effector gene expression during thymocyte selection

During the last step of alphabeta T cell development, thymocytes that have rearranged genes encoding TCR chains and express CD4 and CD8 coreceptors are selected on the basis of their TCR reactivity to escape programmed cell death and become mature CD4 or CD8 T cells. This process is triggered by intrathymic TCR signaling, that activates 'sensor' transcription factors 'constitutively' expressed in DP thymocytes. Eventually, TCR-signaled thymocytes evolve effector transcriptional circuits that control basal metabolism, migration, survival and initiation of lineage-specific gene expression. This review examines how components of the 'sensing' transcription apparatus responds to positive selection signals, and highlights important differences with mature T cell responses. In a second part, we evaluate current observations and hypotheses on the connections between sensing transcription factors and effector circuitries.

High-dose, post-transplantation cyclophosphamide to promote graft-host tolerance after allogeneic hematopoietic stem cell transplantation

Graft-versus-host disease, or GVHD, is a major complication of allogeneic hematopoietic stem cell transplantation (alloHSCT) for the treatment of hematologic malignancies. Here, we describe a novel method for preventing GVHD after alloHSCT using high-dose, post-transplantation cyclophosphamide (Cy). Post-transplantation Cy promotes tolerance in alloreactive host and donor T cells, leading to suppression of both graft rejection and GVHD after alloHSCT. High-dose, post-transplantation Cy facilitates partially HLA-mismatched HSCT without severe GVHD and is effective as sole prophylaxis of GVHD after HLA-matched alloHSCT. By reducing the morbidity and mortality of alloHSCT, post-transplantation Cy may expand the applications of this therapy to the treatment of autoimmune diseases and non-malignant hematologic disorders such as sickle cell disease.

High-dose cyclophosphamide as single-agent, short-course prophylaxis of graft-versus-host disease

Because of its potent immunosuppressive yet stem cell-sparing activity, high-dose cyclophosphamide was tested as sole prophylaxis of graft-versus-host disease (GVHD) after myeloablative allogeneic bone marrow transplantation (alloBMT). We treated 117 patients (median age, 50 years; range, 21-66 years) with advanced hematologic malignancies; 78 had human leukocyte antigen (HLA)-matched related donors and 39 had HLA-matched unrelated donors. All patients received conventional myeloablation with busulfan/cyclophosphamide (BuCy) and T cell-replete bone marrow followed by 50 mg/kg/d of cyclophosphamide on days 3 and 4 after transplantation. The incidences of acute grades II through IV and grades III through IV GVHD for all patients were 43% and 10%, respectively. The nonrelapse mortality at day 100 and 2 years after transplantation were 9% and 17%, respectively. The actuarial overall survival and event-free survivals at 2 years after transplantation were 55% and 39%, respectively, for all patients and 63% and 54%, respectively, for patients who underwent transplantation while in remission. With a median follow-up of 26.3 months among surviving patients, the cumulative incidence of chronic GVHD is 10%. These results suggest that high-dose posttransplantation cyclophosphamide is an effective single-agent prophylaxis of acute and chronic GVHD after BuCy conditioning and HLA-matched BMT (clinicaltrials.gov no. NCT00134017).

Metallophilic macrophages are fully developed in the thymus of autoimmune regulator (Aire)-deficient mice

Thymic metallophilic macrophages represent a significant component in the thymus physiology. Recently, we showed their presence to be dependent on functional lymphotoxin-beta receptor (LT beta R) signaling pathway. However, it is unknown whether the development of metallophilic macrophages also requires the Autoimmune regulator (Aire) transcription factor, as suggested by some studies for medullary thymic epithelial cells, or perhaps the presence of Aire-expressing thymic epithelial cells themselves. Therefore, we investigated the presence of metallophilic macrophages in Aire-deficient thymus. Our study shows that the metallophilic macrophages are fully developed in the Aire-deficient thymus; their development is not regulated via Aire transcription factor and does not require the presence of Aire-expressing epithelial cells. On the contrary, in alymphoplasia (ALY) mice (deficient in nuclear factor-kappaB-inducing kinase, NIK), which we used as negative control, thymic metallophilic macrophages are completely lacking, similarly as in LT beta R-deficient animals. Together, these results show that the development/maintenance of thymic metallophilic macrophages is executed via LT beta R circumventing the Aire transcription factor. Thus, we shed a new light on the molecular requirements for development of these cells and also show that LT beta R pathway is a common developmental regulator of metallophilic macrophages in different lymphatic organs (i.e., thymus and spleen).

Eruption of lymphocyte recovery or autologous graft-versus-host disease?

Maculopapular exanthemas have a particular high incidence among patients treated with autologous hematopoietic stem cell transplantation (HSCT). In most cases, a viral or drug induced origin is easily identified. However, the transplantation itself may also induce similar skin changes. These exanthemas are known under various names, such as autologous graft-versus-host disease (GVHD), engraftment syndrome (ES) or eruption of lymphocyte recovery (ELR). Given the clinical and histopathological similarities of these disorders, it can prove difficult to establish a diagnosis. Here, we describe a patient who developed a maculopapular exanthema after autologous stem cell transplantation for multiple myeloma, diagnosed as autologous GVHD. We also briefly review the current knowledge of the pathogenesis of autologous GVHD, ES, and ELR. Based on these data we would like to suggest that the latter two do not reflect own disease entities but rather different presentations of autologous GVHD.

Calcium signaling in immune cells

Calcium acts as a second messenger in many cell types, including lymphocytes. Resting lymphocytes maintain a low concentration of Ca2+. However, engagement of antigen receptors induces calcium influx from the extracellular space by several routes. A chief mechanism of Ca2+ entry in lymphocytes is through store-operated calcium (SOC) channels. The identification of two important molecular components of SOC channels, CRACM1 (the pore-forming subunit) and STIM1 (the sensor of stored calcium), has allowed genetic and molecular manipulation of the SOC entry pathway. In this review, we highlight advances in the understanding of Ca2+ signaling in lymphocytes with special emphasis on SOC entry. We also discuss outstanding questions and probable future directions of the field.

Prevention of chronic GVHD

Chronic graft-versus-host disease (GVHD) is the most frequent late complication after hematopoietic-cell transplantation, and it has a major impact on quality of life and survival. As the pathophysiology is still incompletely understood, it has been difficult to design effective prophylactic regimens. However, prevention of acute GVHD appears to result in a lower incidence of chronic GVHD. The use of younger, non-allo-sensitized donors, preferentially of the same sex as the patient, and the use of stem cells other than peripheral-blood cells mobilized by granulocyte colony-stimulating factor (G-CSF), also are associated with a lower frequency of chronic GVHD. Furthermore, there are data to suggest that incorporation of thymoglobulin into the conditioning regimen is beneficial in reducing chronic GVHD and delayed complications.

Pregnancy after kidney transplantation

Reproductive success is a common, expected outcome for male and female recipients of solid-organ transplants. Men can father children, and women can become pregnant and carry the fetus to delivery. There are, however, important maternal and fetal complications that need to be considered to provide optimal care to the mother and her infant. Although pregnancy is common after the transplantation of all solid organs, guidelines for optimal counseling and clinical management are limited. This review discusses information to help the physician counsel the kidney transplant recipient about risks of pregnancy for the mother and the fetus and provides information to help guide treatment of the pregnant transplant recipient.

Gene transfer of antisense B7.1 attenuates acute rejection against splenic allografts in rats

Blockade of CD80-CD28 costimulatory pathway induces unresponsiveness of T cells to alloantigens and protects allografts against immune rejection in numerous animal models. The aim of this study was to investigate whether blocking expression of B7.1 (CD80) on donor splenocytes by an antisense technique protected splenic allografts against immune rejection. Splenic grafts from Wistar-Furth rats were intra-arterially transfused with an antisense B7.1 expression vector, before they were transplanted into Sprague-Dawley rats. The rats were sacrificed at scheduled times, and the splenic allografts histologically examined. Antisense gene transfer resulted in marked down-regulation of B7.1 in donor spleens, hyporesponsiveness of recipient T cells, and attenuated acute immune rejection against splenic allografts. No obvious damage to skin, liver, or gut due to graft-versus-host disease was detected in the recipients. In conclusion, blocking expression of B7.1 in donor spleens by antisense gene therapy represented a potential alloantigen-specific immunosuppressive strategy to inhibit acute rejection against splenic allografts.