Cytokine gene expression in peripheral blood mononuclear cells during graft-versus-host disease after allogeneic bone marrow transplantation

Herpesvirus Screening in Childhood Hematopoietic Transplant Reveals High Systemic Inflammation in Episodes of Multiple Viral Detection and an EBV Association with Elevated IL-1β, IL-8 and Graft-Versus-Host Disease

Infections remain a major cause of morbidity and mortality among hematopoietic stem cell transplant (HSCT) recipients. Unlike Epstein–Barr Virus (EBV) and Human Cytomegalovirus (HCMV), Human Herpesvirus (HHV) 6, HHV7 and HHV8 are not routinely monitored in many centers, especially in the pediatric population of low–medium income countries. We screened EBV, HCMV, HHV6, HHV7 and HHV8 in 412 leukocytes-plasma paired samples from 40 pediatric patients assisted in a tertiary hospital in Mexico. Thirty-two underwent allo-HSCT, whereas eight received auto-HSCT. Overall viral detection frequencies in allo- and auto-HSCT were: EBV = 43.7% and 30.0%, HCMV = 5.0% and 6.7%, HHV6 = 7.9% and 20.0% and HHV7 = 9.7% and 23.3%. HHV8 was not detected in any sample. Interestingly, HHV6 and HHV7 were more frequent in auto-HSCT, and HHV6 was observed in all episodes of multiple detection in auto-HSCT patients. We found EBV DNA in plasma samples, whereas HCMV, HHV6 and HHV7 DNA were predominantly observed in leukocytes, indicative of their expansion in cellular compartments. We also found that IL-1β, IL-2, IL-6 and IL-8 were significantly increased in episodes in which multiple viruses were simultaneously detected, and samples positive for EBV DNA and graft-versus-host disease had a further increase of IL-1β and IL-8. In conclusion, the EBV, HCMV, HHV6 and HHV7 burdens were frequently detected in allo- and auto-HSCT, and their presence associated with systemic inflammation.

Biomarkers of graft-vs-host disease: Understanding and applications for the future

Hematopoietic stem cell transplantation (HSCT) is widely performed as a treatment for malignant blood disorders, such as leukemia. To achieve good clinical outcomes in HSCT, it is necessary to minimize the unfavorable effects of acute graft-vs-host disease (GVHD) and induce the more tolerable, chronic form of the disease. For better management of GVHD, sensitive and specific biomarkers that predict the severity and prognosis of the disease have been intensively investigated using proteomics, transcriptomics, genomics, cytomics, and tandem mass spectrometry methods. Here, I will briefly review the current understanding of GVHD biomarkers and future prospects.

Targeting Signal 3 Extracellularly and Intracellularly in Graft-Versus-Host Disease

Allogeneic hematopoietic stem cell transplantation (allo-HCT) holds curative potential for many hematological disorders. However, the pathophysiology of the desired graft-versus-tumor effect is linked to life-threatening complications of acute graft-versus-host disease (GVHD). Allogeneic donor T lymphocytes are essential for causing GVHD, and their activation relies on the coordination of TCR engagement and co-stimulation, also known as Signal 1 and Signal 2. In addition to these signals, a network of secreted cytokines by immune cells provides a third signal, Signal 3, that is critical for the initiation and maintenance of GVHD. Strategies to target Signal 3 in human diseases have shown therapeutic benefit for inflammatory disorders such as Rheumatoid Arthritis and Inflammatory Bowel Disease. However, despite our growing understanding of their role in GVHD, the success of targeting individual cytokines has been modest with some notable exceptions. This review aims to describe current approaches toward targeting Signal 3 in clinical GVHD, and to highlight emerging studies in immune cell biology that may be harnessed for better clinical translation.

Gene Expression and Cardiometabolic Phenotypes of Vitamin D-Deficient Overweight and Obese Black Children

Associations between whole blood transcriptome and clinical phenotypes in vitamin D-deficient overweight and obese children can provide insight into the biological effects of vitamin D and obesity. We determined differentially expressed genes (DEGs) in relation to body mass index (BMI) in vitamin D-deficient black children with a BMI ≥ 85th percentile and ascertained the cardiometabolic phenotypes associated with the DEGs. We examined whole-blood transcriptome gene expression by RNA sequencing and cardiometabolic profiling in 41, 10- to 18-year-old children. We found 296 DEGs in association with BMI after adjusting for age, race, sex, and pubertal status. Cardiometabolic phenotypes associated with the BMI-related DEGs, after adjusting for age, sex, pubertal status, and %total body fat, were (i) flow-mediated dilation (marker of endothelial function), (ii) c-reactive protein (marker of inflammation), and (iii) leptin (adipocytokine). Canonical pathways of relevance for childhood obesity and its phenotypes that were significantly associated with the BMI-related DEGs affected immune cell function/inflammation, vascular health, metabolic function, and cell survival/death; several immune and inflammatory pathways overlapped across the three phenotypes. We have identified transcriptome-based biomarkers associated with BMI in vitamin D-deficient, overweight and obese black children. Modulating effects of vitamin D supplementation on these biomarkers and their related phenotypes need further exploration.

Characterization of monocyte subtypes regarding their phenotype and development in the context of graft-versus-host disease

Graft-versus-host disease (GvHD) is a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). In this study, monocyte subtypes were characterized regarding cytokine expression pattern and development in the context of GvHD. Using inflammatory S100 proteins for monocyte stimulation, it could be demonstrated that intermediate monocytes are the main producers of inflammatory cytokines such as IL-6 and TNFα known to be involved in the development of Th17 cells pointing towards an inflammatory phenotype of this monocyte subtype. Furthermore, novel aspects regarding monocyte subtype development were found. Our data reveal that prednisolone promotes the induction of intermediate monocytes from classical monocytes which correlates with HSP70 expression levels. However, 1α,25-Dihydroxyvitamin D3 treatment results in the abrogation of the prednisolone-mediated induction of this inflammatory monocyte subset and low HSP70 expression levels. Treatment of classical monocytes with pifithrin-μ, a specific HSP70 inhibitor, also leads to an inhibited induction of intermediate monocytes in the presence of prednisolone. These data point towards a predominant role of HSP70 in the development of intermediate monocytes. Thus, HSP70 might be a promising target for GvHD therapy, especially in combination with glucocorticoids, in order to decrease intermediate monocyte subset levels.

Non-HLA genomics: does it have a role in predicting haematopoietic stem cell transplantation outcome?

Haematopoietic stem cell transplantation (HSCT) remains the only cure for many haematological neoplasms; however, the mortality rate remains high, at around 30-80%. Complications after HSCT include relapse, graft-versus-host disease, graft rejection and infection. High-resolution HLA matching has improved survival in HSCT over recent years; however, GVHD still remains a serious complication. Single nucleotide polymorphisms (SNPS) within genes that are involved with an individual's capability to mount an immune response to infectious pathogens, residual leukaemia, alloantigens or genes involved in drug metabolism have been studied for their association with HSCT outcome. Indeed, over the last 15 years, several groups, including ourselves, have demonstrated that non-HLA gene polymorphisms can be predictive of HSCT outcome. Can genetic characteristics of the patient and donor be used in the future to tailor HSCT protocols and determine GVHD prophylaxis? This review summarizes some of the recent SNP association studies in HSCT and highlights some of the disparities therein, discussing the integral problems of performing genetic association studies on diseases with complex outcomes using heterogeneous cohorts. The review will comment on recent genomewide association studies (GWAS) and discuss their relevance in this field, and it will also comment on recent meta-analysis combining GWAS studies with other studies such as gene expression micro array data in the field of autoimmune disease and solid organ transplantation. It will mention possible novel candidate gene polymorphisms, for example SNPS in microRNAs. In addition, it will discuss some of the inherent problems associated with gene association studies including the GRIPs (genetic risk prediction studies) recommendations. In summary, this review will assess the usefulness of non-HLA genomic studies in HSCT with regard to predicting outcome and modifying therapy.

Circulating Levels of Adipokines Predict the Occurrence of Acute Graft-versus-host Disease

Currently, detecting biochemical differences before and after allogeneic stem cell transplantation (SCT) for improved prediction of acute graft-versus-host disease (aGVHD) is a major clinical challenge. In this pilot study, we analyzed the kinetics of circulating adipokine levels in patients with or without aGVHD before and after allogeneic SCT. Serum samples were obtained and stored at -80℃ within 3 hours after collection, prior to conditioning and at engraftment after transplantation. A protein array system was used to measure the levels of 7 adipokines of patients with aGVHD (n=20) and without aGVHD (n=20). The resistin level at engraftment was significantly increased (p<0.001) after transplantation, regardless of aGVHD occurrence. In the non-aGVHD group, the concentrations of the hepatocyte growth factor (HGF) (mean values±SD; 206.6±34.3 vs. 432.3±108.9 pg/ml, p=0.040) and angiopoietin-2 (ANG-2) (mean values±SD; 3,197.2±328.3 vs. 4,471.8±568.4 pg/ml, p=0.037) at engraftment were significantly higher than those of the pre-transplant period, whereas in the aGVHD group, the levels of adipokines did not change after transplantation. Our study suggests that changes in serum HGF and ANG-2 levels could be considered helpful markers for the subsequent occurrence of aGVHD.

Helper T-cell differentiation in graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective therapeutic option for many malignant diseases. However, the efficacy of allo-HSCT is limited by the occurrence of destructive graft-versus-host disease (GVHD). Since allogeneic T cells are the driving force in the development of GVHD, their activation, proliferation, and differentiation are key factors to understanding GVHD pathogenesis. This review focuses on one critical aspect: the differentiation and function of helper T (Th) cells in acute GVHD. We first summarize well-established subsets including Th1, Th2, Th17, and T-regulatory cells; their flexibility, plasticity, and epigenetic modification; and newly identified subsets including Th9, Th22, and T follicular helper cells. Next, we extensively discuss preclinical findings of Th-cell lineages in GVHD: the networks of transcription factors involved in differentiation, the cytokine and signaling requirements for development, the reciprocal differentiation features, and the regulation of microRNAs on T-cell differentiation. Finally, we briefly summarize the recent findings on the roles of T-cell subsets in clinical GVHD and ongoing strategies to modify T-cell differentiation for controlling GVHD in patients. We believe further exploration and understanding of the immunobiology of T-cell differentiation in GVHD will expand therapeutic options for the continuing success of allo-HSCT.

Association of IL-1β -511 polymorphism with severe veno-occlusive disease in pediatric-matched allogeneic hematopoietic stem cell transplantation

Single nucleotide polymorphisms (SNPs) of the interleukin 1 (IL-1) family have been implicated in acute graft-versus-host disease and mortality postallogeneic hematopoietic stem cell transplantation (HSCT) in adults. Hepatic veno-occlusive disease (VOD) is a well-known complication of HSCT and can result in an increased risk of mortality. In this study, we sought to investigate the association of both patient and donor genotypes at the IL-1β -511 cytidine/thymidine (C/T) polymorphic site with hepatic VOD and mortality in an exclusive pediatric cohort undergoing matched myeloablative allogeneic HSCT. Donor TT genotype was associated with higher cumulative incidence of grade III-IV hepatic VOD at 3 months after transplantation relative to donor CT and CC genotypes (25±13.1% in TT, 2.9±2.9% in CT, and 3.6±3.6% in CC; P=0.024). Neither recipient nor donor IL-1β -511 single nucleotide polymorphisms genotypes were associated with mortality or relapse. Our findings suggest that donor, rather than host, genotype at the IL-1β -511 polymorphic site may associate with higher risk for severe VOD after matched allogeneic HSCT. Our findings challenge the assumption that host factors are exclusively responsible for VOD and suggest a novel role for the donor inflammasome pathway in inducing injury and microvascular disease after HSCT, which merits further study in a larger cohort analysis.

Decreased activity of soluble thrombomodulin and plasma procoagulant phospholipids in childhood bone marrow transplantation with severe complications

BACKGROUND

Complications of bone marrow transplantation (BMT) are usually considered to be related to the secretion of inflammatory cytokines, which generate membrane microparticles rich in procoagulant phospholipids (PPL) from different cellular origins and release of endothelial proteins such as thrombomodulin (TM). The use of soluble TM quantified by ELISA (TM:Ag) as a marker of endothelial injury is complex in children since it is age-dependent.

MATERIALS AND METHODS

Using a functional assay which quantifies the activity of sTM activity (TMa), we performed a pilot study to analyze the ratio TMa/TM:Ag in a control group of 25 healthy children, 8 children with autologous and 16 children with allogeneic BMT. In this last group, 8 experienced BMT complications. In addition, we used a functional assay which quantifies PPL.

RESULTS

In healthy children the ratio TMa/TM:Ag was independent of age and stable in children with a favorable outcome but significantly (p<0.05) reduced by the use of antithymocyte globulin during the conditioning regimen, and regularly decreased in children with BMT complications. Surprisingly, low plasma PPL levels were associated with a poor outcome.

CONCLUSION

The ratio TMa/TM:Ag could constitute a marker of endothelium injury, and its follow-up could be of interest for an early discrimination of children with high risk of complications during allogeneic BMT. The decrease of PPL could be also another marker of a poor evolution and deserves further investigations.

Effector CD4+ T cells, the cytokines they generate, and GVHD: something old and something new

GVHD is a syndrome that results from minor and major histocompatibility complex incompatibilities between the donor and recipient. More than 50 years after its initial description, the pathophysiology of GVHD remains poorly understood. Nonetheless, donor T cells have been shown to be critical to the pathophysiology of acute and chronic GVHD, yet precisely how they function remains unclear. The effector mechanisms by which donor T cells mediate tissue inflammation is even less well understood. Identification of several new lineages of CD4(+) T cells made in the past decade and their roles in the pathophysiology of T cell-mediated diseases has shed new light on these effector mechanisms. In this review, we summarize the recent descriptions of these T-cell lineages and the current data supporting their role in acute and to a lesser extent chronic GVHD. Investigations into the activity of these new T-cell lineages may provide more rationale approaches to the treatment or prevention of GVHD.

Pathogenesis and management of graft-versus-host disease

Allogeneic hematopoietic cell transplantation (HCT) is an important therapeutic option for various malignant and nonmalignant conditions. As allogeneic HCT continues to increase, greater attention is given to improvements in supportive care, infectious prophylaxis, immunosuppressive medications, and DNA-based tissue typing. However, graft versus host disease (GVHD) remains the most frequent and serious complication following allogeneic HCT and limits the broader application of this important therapy. Recent advances in the understanding of the pathogenesis of GVHD have led to new approaches to its management, including using it to preserve the graft versus leukemia effect following allogeneic transplant. This article reviews the important elements in the complex immunologic interactions involving cytokine networks, chemokine gradients, and the direct mediators of cellular cytotoxicity that cause clinical GVHD, and discusses the risk factors and strategies for management of GVHD.

Graft-versus-leukemia effect of nonmyeloablative stem cell transplantation

Nonmyeloablative stem cell transplantation (NST) is increasingly used with beneficial effects because it can be applied to older patients with hematological malignancies and those with various complications who are not suitable for conventional myeloablative stem cell transplantation (CST). Various conditioning regimens differ in their myeloablative and immunosuppressive intensity. Regardless of the type of conditioning regimen, graft-versus- host disease (GVHD) in NST occurs almost equally in CST, although a slightly delayed development of acute GVHD is observed in NST. Although graft-versus-hematological malignancy effects (i.e., graft-versus-leukemia effect, graft-versus-lymphoma effect, and graft-versus-myeloma effect) also occur in NST, completely eradicating residual malignant cells through allogeneic immune responses is insufficient in cases with rapidly growing disease or uncontrolled progressive disease. Donor lymphocyte infusion (DLI) is sometimes combined to support engraftment and to augment the graft-versus-hematological malignancy effect, such as the graft-versus-leukemia effect. DLI is especially effective for controlling relapse in the chronic phase of chronic myelogenous leukemia, but not so effective against other diseases. Indeed, NST is a beneficial procedure for expanding the opportunity of allogeneic hematopoietic stem cell transplantation to many patients with hematological malignancies. However, a more sophisticated improvement in separating graft-versus-hematological malignancy effects from GVHD is required in the future.

Relation of Soluble Endothelial Protein C Receptor and Cytokines After Allogeneic Hematopoietic Stem Cell Transplantation

Aim: The objective of this study was to elucidate the effects of tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), interleukin 2 (IL-2), interleukin 6 (IL-6), and interleukin 8 (IL-8) on the expression of soluble endothelial protein C receptor (sEPCR) in the pathogenesis of thrombotic complications after hematopoietic stem cell transplantation (HSCT).

Methods: The relationship between plasma concentrations of proinflammatory cytokines (TNF-α, IL-1β, IL-2, IL-6, and IL-8) and sEPCR was evaluated in 32 consecutive allogeneic hematopoietic stem cell—transplanted patients prior to conditioning regimen and randomly once between +5 and +30 days after transplantation and compared these results with 20 healthy controls.

Results: Soluble endothelial protein C receptor levels did not indicate any significant difference between pre- and posttransplantation period, and sEPCR levels showed a significantly negative correlation between IL-6 and IL-8 (sEPCR and IL-6, r = —.43, P < .01; sEPCR and IL-8, r = —.57, P < .01). There was no correlation between sEPCR levels and TNF-α, IL-1β, or IL-2 (sEPCR and TNF-α, r = —.13, P > .05; sEPCR and IL-1β, r = —.1, P ≥ .05; sEPCR and IL-2, r = —.07, P > .05).

Conclusions: Our results suggest that the production of sEPCR was not affected by allogeneic HSCT. Soluble endothelial protein C receptor did not show any positive correlation between these proinflammatory cytokines (TNF-α, IL-1β, IL-2, IL-6, and IL-8), on the contrary a significantly negative correlation was determined between sEPCR and either IL-6 or IL-8. This negative correlation may be a protective mechanism in the pathway of protein C activation.

Pathophysiology of acute graft-versus-host disease: recent advances

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy for many malignant and nonmalignant hematologic diseases. Donor T cells from the allografts are critical for the success of this effective therapy. Unfortunately these T cells not only recognize and attack the disease cells/tissues but also the other normal tissues of the recipient as "foreign" or "nonself" and cause severe, immune-mediated toxicity, graft-versus-host disease (GVHD). Several insights into the complex pathophysiology of GVHD have been gained from recent experimental observations, which show that acute GVHD is a consequence of interactions between both the donor and the host innate and adaptive immune systems. These insights have identified a role for a variety of cytokines, chemokines, novel T-cell subsets (naĩve, memory, regulatory, and NKT cells) and for non-T cells of both the donor and the host (antigen presenting cells, delta T cells, B cells, and NK cells) in modulating the induction, severity, and maintenance of acute GVHD. This review will focus on the immunobiology of experimental acute GVHD with an emphasis on the recent observations.

Cytokine Gene Expression in Peripheral Blood Mononuclear Cells and Alloreactivity in Hematopoietic Cell Transplantation with Nonmyeloablative Conditioning

Cytokines are thought to play an important role in the pathophysiology of graft-versus-host disease (GVHD). To study the relationship between cytokines and GVHD, we obtained peripheral blood mononuclear cells (MNCs) from 21 patients with hematologic malignancies and their HLA-identical sibling donors before and sequentially after hematopoietic cell transplantation (HCT) with nonmyeloablative conditioning. The MNCs were cultured for 72 hours either alone or in mixed lymphocyte cultures with irradiated MNCs of recipient, donor, or HLA-mismatched third-party origin. The gene expression of interleukin (IL)-2, IL-4, IL-10, IL-18, tumor necrosis factor alpha, and transforming growth factor beta in each culture was then measured by real-time quantitative reverse transcriptase-polymerase chain reaction. The composition of the responder MNCs differed between patients and donors and changed after HCT, with a possible influence on the results. Early after transplantation (day +14), the IL-10 messenger RNA (mRNA) level in response to recipient or donor antigens was higher in patients who did not develop clinically significant acute GVHD when compared with the level in patients who subsequently developed acute GVHD grades II to IV (P = .005 and P = .004, respectively). The IL-10 mRNA level on day +14 was highly correlated with the pretransplantation mRNA level of the recipient MNCs but not with the level of the donor MNCs; this suggests that the IL-10 mRNA detected on day +14 originated from responder cells of recipient origin. A higher IL-10 mRNA level was found in MNCs obtained before transplantation from recipients whose disease progressed or relapsed after the transplantation when compared with the level in patients whose disease did not progress or relapse (P = .03). In conclusion, a high IL-10 gene expression in the recipient MNCs may be related to a reduced incidence of acute GVHD grades II to IV and a reduced graft-versus-tumor effect after HCT with nonmyeloablative conditioning.

The Pathophysiology of Acute Graft-Versus-Host Disease

Despite improvements in allogeneic stem cell transplantation, acute graft-versus-host disease (GVHD) remains a significant problem after transplantation, and it is still a major cause of post-transplant mortality. Disease progression is characterized by the differentiation of alloreactive T cells to effector cells leading to tissue damage, recruitment of additional inflammatory cell populations and further cytokine dysregulation. To make the complex process of acute GVHD more explicit, the pathophysiology of acute GVHD is often divided into three different phases. This review summarizes the mechanisms involved in the three phases of acute GVHD.

The Pathophysiology of Acute Graft-versus-Host Disease

The pathophysiology of acute graft-versus-host disease (GVHD) is a complex process that can be conceptualized in three phases. In the first phase, high-dose chemoradiotherapy causes damage to host tissues, including a self-limited burst of inflammatory cytokines such as tumor necrosis factor (TNF)-alpha and interleukin 1. These cytokines activate host antigen-presenting cells (APCs). In the second phase, donor T-cells recognize alloantigens on host APCs. These activated T-cells then proliferate, differentiate into effector cells, and secrete cytokines, particularly interferon (IFN)-gamma. In the third phase, target cells undergo apoptosis mediated by cellular effectors (eg, donor cytotoxic T-lymphocytes) and inflammatory cytokines such as TNF-alpha. TNF-alpha secretion is amplified by stimuli such as endotoxin that leaks across damaged gastrointestinal mucosa injured by the chemoradiotherapy in the first phase. TNF-alpha and IFN-gamma cause further injury to gastrointestinal epithelium, causing more endotoxin leakage and establishing a positive inflammatory feedback loop. These events are examined in detail in the following review.

Veno-occlusive disease: cytokines, genetics, and haemostasis

Hepatic veno-occlusive disease (VOD) is a major cause of morbidity and mortality following high dose cytotoxic therapy for stem cell transplantation (SCT). Pre-existing liver damage, SCT-related therapy, and genetic polymorphisms all appear to increase the risk of developing VOD. Studies of biological markers during SCT suggest that cytokines, haemostasis, and hepatic drug metabolism via the glutathione pathway are all involved in the pathogenesis of VOD. Until recently, treatment options were limited and experimental therapies directed at the pathogenesis of the disease were mostly unsuccessful. However, Defibrotide, a relatively new agent that has modulatory effects on vascular endothelium, cytokine release, and haemostasis, has been used with some success in the management and prophylaxis of VOD. In the future, a better understanding of genetic polymorphisms and biological markers which may be important in the pathogenesis of VOD, may enable us to predict which patients are most likely to be affected.

Role of tumor necrosis factor-alpha in graft-versus-host disease and graft-versus-leukemia responses

Tumor necrosis factor-alpha (TNF-alpha) antagonist therapy has proven effective in inflammatory conditions such as rheumatoid arthritis and Crohn's disease. There is substantial evidence that TNF-alpha also plays a role in the development of graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation, which along with leukemia relapse remains one of the 2 major impediments to success of the approach. Using a recently developed potent rat/mouse chimeric monoclonal antibody directed against murine TNF-alpha (CNTO2213), the authors investigated the effect of TNF-alpha blockade on GVHD mediated by either CD4(+) or CD8(+) donor T cells. The results indicated that the treatment had only a moderate effect on both a CD8(+) T cell-mediated major histocompatibility complex-matched GVHD model involving multiple minor histocompatibility antigens and a p-->F(1) acute GVHD model directed against a haplo-mismatched major histocompatibility complex barrier involving both CD4(+) and CD8(+) T cells. In contrast, treatment with the anti-TNF-alpha antibody had a highly significant effect (100% survival rate) on the CD4(+) T cell-mediated component of this latter model. Importantly, anti-TNF-alpha antibody did not block the development of a graft-versus-leukemia effect against a murine myeloid leukemia challenge in either a syngeneic or allogeneic p-->F(1) setting. This suggests that the inhibition of TNF-alpha during allogeneic hematopoietic cell transplantation may be able to diminish the inflammatory GVHD reaction without hindering effective graft-versus-leukemia responses.

Immune reconstitution and tolerance after allogeneic hematopoietic stem cell transplantation

We have evaluated recovery of CD56 positive and other cell types following allogeneic stem cell transplantation and have found that the recovery of CD56 positive cells was faster than other lymphoid cells after allogeneic stem cell transplantation, while the recovery of CD4 positive cells was markedly delayed. Chimerism analysis showed that mixed chimerism was often observed in younger (<30 years old) patients. Mixed chimerism in older (> or =30 years old) patients was associated with rejection and relapse, while this was not found in younger patients. Among the chimerism of various cell populations, donor-derived CD56-positive cells are important in early engraftment when determined in allogeneic nonmyeloablative stem cell transplantation (allo-NST), regardless of the proportion of donor-derived CD3-positive cells. Complementarity-determining region three (CDR3) size spectratyping in T-cell receptor (TCR) chain subfamilies (Vbeta) showed that high level of diversity in TCR Vbeta repertoire is important for a late rejection and skewed TCR Vbeta repertoire is correlated with the occurrence of graft-versus-host disease (GVHD) especially chronic GVHD. Expression of inhibitory natural killer (NK) cell receptors such as CD158b and CD94/NKG2A on peripheral CD3-negative and -positive cells were increased in parallel with GVHD. Interestingly, these cells appeared to control GVHD, while preserving graft-versus-leukemia (GVL) effect. Analysis of cytokine gene expression in peripheral blood mononuclear cells showed that type 1 helper T cells (Th1)-derived cytokines increased in severe GVHD, while Th2-derived cytokines such as IL-4, IL-10 and IL-13 increased in mild GVHD. These results indicate that Th2 cells suppress GVHD, although Th1 cells augment GVHD. Taken together, evaluation of immune reconstitution and tolerance in patients receiving allogeneic stem cell transplantation from the various viewpoints is essential and useful to obtain better clinical outcome.

Interleukin-1 blockade does not prevent acute graft-versus-host disease: results of a randomized, double-blind, placebo-controlled trial of interleukin-1 receptor antagonist in allogeneic bone marrow transplantation

Acute graft-versus-host disease (GVHD) is thought to derive from direct T-cell injury of target tissues through perforin/granzyme, Fas/FasL interactions, and the effects of inflammatory cytokines. Animal models and some clinical trials support the notion that inhibition of inflammatory mediators such as interleukin-1 (IL-1), tumor necrosis factor alpha, and interferon gamma may ameliorate or prevent GVHD. We hypothesized that blockade of IL-1 during the period of initial T-cell activation would reduce the risk of severe GVHD. We tested this hypothesis in a double-blind, placebo-controlled randomized trial of recombinant human IL-1 receptor antagonist (IL-1Ra) in 186 patients undergoing allogeneic stem cell transplantation. Randomization was stratified by degree of histocompatibility and stem cell source. All patients were conditioned with cyclophosphamide and total body irradiation. GVHD prevention consisted of cyclosporine and methotrexate in all patients. Recombinant human IL-1Ra or saline placebo was given from day -4 to day +10. Randomization was stratified according to GVHD risk. The 2 groups were well-matched for pretreatment characteristics. Moderate to severe GVHD (grades B-D) developed in 57 (61%) of 94 patients receiving IL-1Ra and in 51 (59%) of 86 patients on placebo (P =.88). There was no difference in hematologic recovery, transplantation-related toxicity, event-free survival, or overall survival. We conclude that blockade of IL-1 using IL-1Ra during conditioning and 10 days immediately after transplantation is not sufficient to reduce GVHD or toxicity or to improve survival.

Immunological reconstitution and immunoregulatory cells in hematopoietic stem cell transplantation

Analysis of cytokine gene expression in peripheral blood mononuclear cells from patients received allogeneic hematopoietic stem cells transplantation (allo-SCT) showed that type 1 helper T cells (Th1)-derived cytokines increased in severe graft-versus-host disease (GVHD) while Th2-derived cytokines such as IL-4, IL-10, and IL-13 increased in mild GVHD. These results indicate that Th2 cells suppress GVHD although Thl cells augment GVHD. Chimerism analysis showed that mixed chimerism was often observed in younger (<30 years old) patients. Mixed chimerism in older (> or = 30 years old) patients were related to rejection and relapse while this situation is not the case in younger patients, thus indicating that mixed chimerism is an important prognostic factor in older patients. Among the chimerism of various cell populations, donor-derived CD56-positive cells are important in early engraftment when determined in allogeneic nonmyeloablative stem cell transplantation (allo-NST), regardless of the proportion of donor-derived CD3-positive cells. This result suggests that donor-derived CD56-positive cells are a more useful indicator for engraftment and rejection in early time period. Complementary-determining region 3 (CDR3) size spectratyping in T-cell receptor (TCR) chain subfamilies (V beta) showed that high level of diversity in TCR V beta repertoire is important for a late rejection and skewed TCR V repertoire is well correlated to occurrence of GVHD. Expression of inhibitory natural killer (NK) cell receptors such as CD158b and CD94/NKG2A on peripheral CD3-negative and positive cells were increased in parallel with GVHD. Interestingly, these molecules appeared to regulate GVHD while preserving graft-versus-leukemia (GVL) effect.

Numerical, morphological and phenotypic changes in Langerhans cells in the course of murine graft-versus-host disease

BACKGROUND

In the course of graft-versus-host disease (GVHD) or diseases that histologically mimic GVHD (e.g. toxic epidermal necrolysis, Stevens-Johnson syndrome), it is known that epidermal Langerhans cells (LCs) are depleted from the epidermis. However, the mechanism and significance of LC depletion is not well known.

OBJECTIVES

To investigate the numerical, morphological and phenotypic changes in LCs and apoptosis of LCs in the course of GVHD using a non-irradiated mouse GVHD model.

METHODS

BALB/c nu/nu mice and C57BL/6 mice were used as recipients and donors, respectively. Recipient mice were injected with T-cell-enriched donor spleen cells. Skin samples were harvested at various times after the inoculation. The numerical and morphological changes were examined by an immunofluorescence study of epidermal sheets. Apoptosis was studied by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling method and flow cytometric analysis using annexin V. Phenotypic change was studied by flow cytometric analysis of epidermal cell suspensions. The mixed epidermal cell lymphocyte reaction (MELR) was performed to examine functional changes in the epidermal cells.

RESULTS

Five days after inoculation, a graft-versus-host reaction occurred. Epidermal LCs began to decrease from the sixth day. On the fifth day, the LCs became larger and had prominent dendrites. Immediately before the LCs began to decrease, many LCs became round in shape, with scanty dendrites. LC apoptosis was not observed in the epidermis either on the fifth or seventh day. Phenotypically, the expression of CD40, CD80, CD86 and major histocompatibility complex class II antigen on the LCs was upregulated on the fifth and seventh day. Epidermal cells from GVHD mice showed an increased allostimulatory capacity in the secondary MELR.

CONCLUSIONS

These results suggest that at early GVHD onset, most LCs may not undergo apoptosis in the epidermis but are phenotypically activated, resulting in further activation of alloreactive T cells and aggravation of the disease.

Avoiding hepatic veno-occlusive disease: what do we know and where are we going?

Hepatic venocclusive disease (VOD) is a common toxicity associated with myeloablative chemotherapy or chemoradiotherapy used to prepare patients for stem cell transplantation. A sizable proportion of patients who develop VOD die. It is clear that injury to endothelial cells and hepatocytes in zone 3 of the liver acinus is the initial event in the pathogenesis of VOD. What are less clear are the mechanisms of injury and whether this knowledge can be exploited. This manuscript will briefly review some recent data and discuss how that information has influenced clinical practice.

Marked reduction in the incidence of hepatic veno-occlusive disease after allogeneic hematopoietic stem cell transplantation with CD34(+) positive selection

Veno-occlusive disease of the liver (VOD) is a common and severe complication of allogeneic hematopoietic stem cell transplantation (HSCT). To determine the incidence of, and the risk factors for the development of VOD, we performed a retrospective analysis of a series of 178 patients, who underwent allogeneic HSCT at our institution between 1990 and 1999. Busulfan and cyclophosphamide constituted the conditioning regimen most frequently administered. Bone marrow was the source of stem cells in 129 patients (73%), and peripheral blood (PBSC) in 49 patients (27%). Thirty-one patients of the PBSC group received CD34(+) positively selected grafts. Most patients were given cyclosporin A and methotrexate (MTX) as graft-versus-host disease (GVHD) prophylaxis. Overall, 30 patients (17%) developed VOD. In univariate analyses, the incidence of VOD was significantly higher in recipients of unmanipulated grafts (20% vs 0%; P = 0.01), in patients with active malignant disease at transplantation (24% vs 9%; P = 0.03), in recipients of marrow from unrelated donors (33% vs 15%; P = 0.03), in patients grafted with bone marrow (21% vs 6%; P = 0.03), and in those receiving MTX as GVHD prophylaxis (21% vs 6%; P = 0.05). Under multivariate analysis, only CD34(+) positive selection (P = 0.0004) and the status of the disease at transplant (P = 0.03) were statistically significant variables for the development of VOD. We conclude that CD34(+) positively selected PBSC transplantation could result in a marked reduction in the incidence of VOD after allogeneic HSCT.

Kinetic analysis of cytokine gene expression in patients with GVHD after donor lymphocyte infusion

Patients who receive a donor lymphocyte infusion (DLI) for the treatment of relapsed leukemia after allogeneic BMT (alloBMT) often developed GVHD. To determine whether cytokines might have a role in GVHD, an intensive kinetic analysis of in vivo cytokine gene expression was performed on PBMC from three such patients. Expression of IL-1beta, IL-2, IFN-gamma, IL-4, IL-5, IL-8, IL-10, IL-12, TNF-alpha, and IL-2Ralpha was examined using a sensitive semi-quantitative reverse transcription (RT)-PCR assay system. Six normal controls were also analyzed for comparison. Expression of type 1 T helper (Th1) cytokines, IL-2 and IFN-gamma was greatly increased in all three patients. In particular, the changes in IL-2 gene expression correlated well with disease progression, suggesting that IL-2 has a critical role in the development of GVHD. Although the pattern of type 2 T helper (Th2) cytokine gene expression differed in each patient, the expression of IL-4 was inversely related to expression of Th1 cytokines. These results suggest that Th1 dominates in the development of human clinical GVHD.

Serum levels of soluble interleukin-2 receptor after bone marrow transplantation: a true marker of acute graft-versus-host disease

To examine whether serum levels of soluble interleukin-2 receptor (sIL-2R) may be a good marker of acute graft-versus-host disease (aGVHD), they were determined weekly in 56 patients receiving bone marrow transplantation (BMT). Because of wide variation in the pre-transplant sIL-2R levels (from 135 to 1918 IU/ml), we used a sIL-2R index in this study by comparing the peak levels with the pre-transplant levels. In agreement with previous reports, there was a significant correlation between the grade of aGVHD and the maximal sIL-2R index. The maximal sIL-2R index was 4.66 in patients with grade I to IV aGVHD, whereas it was 2.68 in patients without GVHD. This marker may be useful for monitoring the status of aGVHD. However, it was interesting that sIL-2R levels were elevated from the time of transplantation until the third week even in patients without GVHD or those who received autologous transplantation. Until the third week, no significant differences were observed in sIL-2R index between these patients and those who developed aGVHD during their clinical courses. After the fourth week, a higher sIL-2R index was observed in patients with aGVHD than in the other patients. Some factors other than GVHD contribute to the elevation of serum sIL-2R levels, and we should recognize the limitations of the measurement of this cytokine.

Expression of HLA-C-specific natural killer cell receptors (CD158a and CD158b) on peripheral blood mononuclear cells after allogeneic bone marrow transplantation

We investigated the expression of natural killer cell receptors (NKRs) for HLA-C on peripheral blood mononuclear cells (PBMCs) in 23 allogeneic bone marrow transplantation (allo-BMT) patients to analyse the role of NKRs in alloresponse concerning graft-versus-host disease (GVHD). CD158a expression was low and there was little change in the expression after allo-BMT. Also, there was no difference in the proportion of CD158a+/CD3- after allo-BMT. In contrast, the proportion of CD158b+/CD3- cells, mainly NK cells, increased in the early stage (< 2 months) after allo-BMT and then gradually decreased (3.3 +/- 2.6% before BMT vs. 15.4 +/- 8. 6% in the early stage after BMT, 8.5 +/- 4.9% during the period 3-6 months after BMT and 7.0 +/- 3.0% > 6 months after BMT; P < 0.05). However, CD158b expression on CD3+ T cells increased 3 months after allo-BMT (1.1 +/- 1.1% before BMT vs. 5.1 +/- 7.7% during the period 3-6 months after BMT and 3.0 +/- 2.4% > 6 months after BMT, P < 0. 05). The highest percentages of CD158 expression in patients without chronic GVHD (cGVHD) and those with cGVHD were compared. The percentage of CD158b+/CD3+ cells and also that of CD158b+/CD8+ cells were significantly increased in patients with cGVHD compared with those in patients without cGVHD (2.6 +/- 2.0% vs. 8.0 +/- 11.2% and 2.3 +/- 1.5% vs. 8.3 +/- 11.7% respectively; P < 0.05). The exact clinical relevance of these CD158b-expressing cells is not clear. However, there is an interesting possibility that CD158b-expressing cells play some role in the regulation of GVHD after allo-BMT.

Evidence of alloreactive T lymphocytes in fetal liver: implications for fetal hematopoietic stem cell transplantation

The use of hematopoietic stem cells for in utero transplantation to create permanent hematochimerism represents a new concept in fetal therapy, although this approach has provided heterogeneous results. In this paper we have undertaken molecular, phenotypic and functional studies aimed at identifying the presence of fully competent T lymphocytes in samples of fetal livers and cord blood. We found mature VDJ TCR beta chain transcripts in fetal liver cells taken from 7 to 16 weeks of gestation and a similar pattern was detected in cord blood cells sampled from 13.5 to 20.5 weeks of gestation. A Vbeta8 gene sequence comparable to that detected in adult PBMC was found in fetal liver samples at 9 or 17 weeks gestation. PreTalpha message was detected in all samples and its expression decreased in fetal blood samples with increasing gestational age while Calpha message appeared at 9.4 weeks and its expression increased during gestational age. T cell clones obtained from fetal liver cells showed a mature TCR alphabeta+, CD8+ phenotype and displayed strong alloreactivity against allo-MHC class I molecules. The presence of alloreactive T lymphocytes may explain the failure to engraft in fetuses older than 13 to 16 weeks and may provide insights into fetal liver transplantation. Bone Marrow Transplantation (2000) 25, 135-141.

Interferon-gamma gene expression during acute graft-versus-host disease: relationship to MHC induction and tissue injury

The pathogenetic role of interferon-gamma (IFN-gamma) in acute graft-versus-host disease (GVHD) was examined in a murine model. IFN-gamma gene expression was evaluated by northern blotting and mRNA in situ hybridization. The temporal and tissue specific patterns of IFN-gamma gene expression were related to the patterns of major histocompatibility complex (MHC) antigen induction and of tissue injury. Markedly increased levels of IFN-gamma transcripts were seen in the spleen during the early lymphoproliferative phase and coincided with widespread MHC induction in non-lymphoid tissues. Increased IFN-gamma transcripts were also found in the non-lymphoid target tissues during the phase of subsequent tissue injury. These findings support a role for IFN-gamma in leading to widespread MHC induction during acute GVHD and suggest that IFN-gamma may also contribute to target tissue injury during acute GVHD.

Idiopathic pneumonia after bone marrow transplantation: cytokine activation and lipopolysaccharide amplification in the bronchoalveolar compartment

OBJECTIVE

To determine whether idiopathic pneumonia syndrome (IPS), a form of noninfectious lung injury that follows bone marrow transplantation, is associated with cytokine activation and increased susceptibility to lipopolysaccharide (LPS).

DESIGN

Case series.

SETTING

Tertiary referral center for marrow transplantation.

PATIENTS

Recipients with biopsy-confirmed IPS; normal volunteers and marrow transplant recipients without IPS were analyzed as controls.

MEASUREMENTS AND MAIN RESULTS

Levels of lymphocyte and macrophage-derived cytokines as well as components of the LPS, LPS-binding protein (LBP), and CD14 system in bronchoalveolar lavage (BAL) fluid were determined. We found evidence of increased vascular permeability (BAL protein) and inflammatory cytokine activation (interleukin-1, interleukin-2, interleukin-6, and tumor necrosis factor-alpha) in patients with IPS. Patients without IPS had BAL fluid cytokine and protein levels that were similar to levels in BAL fluid from normal volunteers. Moreover, components of the LPS amplification system (LBP and soluble CD14) were increased in patients with IPS but not in patients without IPS.

CONCLUSIONS

These results provide direct evidence for proinflammatory cytokine activation in IPS and suggest that these patients might be at increased risk for LPS-mediated injury through the LBP amplification pathway.

Enterobacterial infection modulates major histocompatibility complex class I expression on mononuclear cells

Major histocompatibility complex (MHC) class I expression is reduced in several viral infections, but it is not known whether the same happens during infections caused by intracellular enterobacteria. In this study, the expression of MHC class I antigens on peripheral blood mononuclear cells (PBMC) from 16 patients with Salmonella, Yersinia, or Klebsiella infection was investigated. During or after the acute infection, the expression of MHC class I antigens was markedly decreased in eight patients, all with genotype HLA-B27, and six out of eight with reactive arthritis (ReA). A significant decrease of monomorphic MHC class I was found in three patients, of HLA-B27 in eight (P<0.05) and of HLA-A2 in two. However, patients negative for the HLA-B27 genotype, or healthy HLA-B27-positive individuals, did not have a significant decrease of MHC class I antigens. During the decreased expression on the cell surface, intracellular retention of MHC class I antigens was observed, whereas HLA-B27 mRNA levels did not vary significantly. This is the first evidence that enterobacterial infection may down-regulate expression of MHC class I molecules in vivo and that down-regulation is predominant in patients with the HLA-B27 genotype.

Possible role of granulocyte colony-stimulating factor in increased serum soluble interleukin-2 receptor-alpha levels after allogeneic bone marrow transplantation

Serum soluble interleukin-2 receptor - alpha (sIL-2R) levels markedly increased at the engraftment period in patients who underwent allogeneic bone marrow transplantation (BMT). Since serum G-CSF levels increased during G-CSF administration and decreased after the cessation, increased sIL-2R levels appeared to be induced by G-CSF administration. There was no increase in sIL-2R levels in a patient given macrophage colony-stimulating factor (M-CSF). The sIL-2R levels at the engraftment period and the onset of acute graft-versus-host disease (GVHD) were higher in patients who developed acute GVHD during G-CSF administration than in those who developed acute GVHD after G-CSF cessation. This finding suggests that G-CSF administration may possibly augment acute GVHD. However, it appears to be unlikely, because in the entire population, 18 of 35 patients had acute GVHD while only 6 of 17 patients had acute GVHD during G-CSF administration. Further analysis is still needed in order to draw definite conclusions. Preconditioning regimens did not appear to affect the sIL-2R levels, when the variable frequencies of methotrexate (MTX) administration were compared.

Serum cytokine levels after HLA-identical bone marrow transplantation

BACKGROUND

Altered profiles of cytokine production are observed after bone marrow transplantation (BMT). The presence of certain cytokines in serum can be indicative for BMT-related complications, such as graft-versus-host disease (GVHD) and infections. The putative correlation between abnormal serum cytokine levels and BMT-related complications was further analyzed in this retrospective study.

METHODS

Serum levels of a panel of cytokines and cytokine-associated molecules (i.e., interleukin [IL]-1alpha, IL-1beta, IL-4, IL-6, IL-10, IL-12, IL-1 receptor antagonist, and the soluble a chain of the IL-2 receptor [sIL-2R alpha]) were assessed in 329 sera of 46 patients who had undergone HLA-identical or autologous BMT. Serum cytokine levels of the BMT donor and of the patients before BMT and at different time points during the post-BMT period were measured. The results were correlated with relapse, acute GVHD, chronic GVHD, and infections.

RESULTS

Serum levels of IL-1alpha, IL-1beta, IL-4, and IL-12 were undetectable. The transplantation regimen itself causes a significant rise in IL-10 and sIL-2R alpha levels in patients receiving allogeneic bone marrow. In the post-BMT period, increased IL-6 serum levels were significantly correlated with infections. Increased IL-10 levels were significantly correlated with acute graft-versus-host disease, chronic GVHD, and infections. Increased sIL-2R alpha levels were correlated with chronic GVHD, as were IL-1 receptor antagonist levels.

CONCLUSIONS

During the post-HLA-identical BMT period, the serum cytokine levels of IL-6 were enhanced during infections, whereas the sIL-2R alpha levels were increased during chronic GVHD. The serum levels of IL-10 and of the cytokine-related molecule IL-1ra were enhanced during both infections and chronic GVHD. These results further substantiate the complex cytokine cascade that is initiated by the conditioning regimen and that evolves further in reaction to BMT-related complications and their treatments.

Cytokine mRNA expression and proliferative responses induced by pertussis toxin, filamentous hemagglutinin, and pertactin of Bordetella pertussis in the peripheral blood mononuclear cells of infected and immunized schoolchildren and adults

Pertussis infection is increasingly recognized in older children and adults, indicating the need of booster immunizations in these age groups. We investigated the induction of pertussis-specific immunity in schoolchildren and adults after booster immunization and natural infection. The expression of mRNA of gamma interferon (IFN-gamma), interleukin-2 (IL-2), IL-4, and IL-5 in the peripheral blood mononuclear cells (PBMCs) was assayed by reverse transcription-PCR. The PBMCs of 17 children immunized with one dose of an acellular vaccine containing pertussis toxin (PT), filamentous hemagglutinin (FHA), and pertactin (PRN) significantly proliferated in vitro after stimulation with the vaccine antigens. The PBMCs of seven infected individuals markedly proliferated in the presence of PT and FHA, but the cells of only two of these subjects responded to PRN. At least one of the antigens induced mRNA for IL-4 and/or IL-5 in the cells of 93% of tested vaccinees and patients, and FHA induced IFN-gamma mRNA in the cells of two-thirds of them. Expression of mRNA for IFN-gamma correlated with the production of the cytokine protein. Anti-FHA immunoglobulin G antibodies significantly correlated with FHA-induced proliferative responses both before and after immunization. These results show that booster immunization with acellular pertussis vaccine induces both antibody- and cell-mediated immune responses in schoolchildren. Further, booster immunization and natural infection seem to induce the expression of mRNA of T-helper 1 (Th1) and Th2 type cytokines in similar manners. This observation supports the use of acellular pertussis vaccines for booster immunizations of older children, adolescents, and adults.

Clinical relevance of serum soluble interleukin-2 receptor levels in acute and chronic graft-versus-host disease

Soluble interleukin-2 receptor (sIL-2R) levels were analyzed in the sera from 27 patients who underwent allogeneic bone marrow transplantation (BMT) in order to to examine whether there was any correlation between sIL-2R levels and graft-versus-host disease (GVHD). The sIL-2R levels markedly increased at the engraftment period, mainly due to cytokine administration shortly after BMT. Although the sIL-2R levels increased at the onset of acute GVHD, the subsequent development of GVHD could not be predicted by the sIL-2R levels documented before acute GVHD. As acute GVHD improved, the sIL-2R levels decreased, thus showing that the sIL-2R levels correlated with the disease status. In patients without acute GVHD, the sIL-2R levels gradually decreased with time and returned to the pretransplant levels after about 12 weeks post BMT. The sIL-2R levels were higher in unrelated allogeneic BMT patients with acute GVHD when compared with related allogeneic BMT patients. There was a significant increase in the sIL-2R levels at the engraftment period and at the onset of acute GVHD. At the onset of chronic GVHD, the sIL-2R levels once again increased and then decreased as chronic GVHD improved. Prolonged increase in sIL-2R levels was followed by subsequent development of chronic GVHD. Patients with a poor prognosis had higher sIL-2R levels than those with a good prognosis. Therefore, it seems that sIL-2R is a useful marker for monitoring the disease status of acute and chronic GVHD.

Graft-versus-leukemia effect and its clinical implications

Graft-versus-leukemia (GVL) effect is an immunologically important phenomenon which decreases the relapse rate of leukemia after allogeneic bone marrow transplantation. GVL effect is sometimes associated with the occurrence of graft-versus-host disease (GVHD). Analyses of GVL effect and GVHD showed that these two phenomena were separable in some conditions. Although we cannot yet completely control the development of the GVL effect without inducing GVHD in humans, basic analyses using animal models show potential benefits of the GVL effect for clinical applications. Autologous GVHD is another important phenomenon which can help to eradicate minimal residual disease. Interleukin 2 and/or cyclosporin A are extensively used in animal models and in humans to induce autologous GVHD, showing beneficial effects. In the future, cytokine usage and allogeneic stem cell transplantation or leukocyte infusion appear to be promising in the control of minimal residual disease. Further studies on the mechanisms of GVL effects and GVHD may well open a new era for cell transplantation.

Inhibition of the human allogeneic mixed lymphocyte response by cyclosporin A: relationship with the IL-12 pathway

Interleukin-12 (IL-12) is an important cytokine in the control of cell-mediated immunity. We have previously shown that endogenous IL-12 plays a role in the development of human allogeneic response. In the present study, we investigated the relationship between Cyclosporin A (CsA)-inhibitory effect and IL-12 pathway during human alloreaction in vitro. CsA addition at the sensitizing phase of primary mixed lymphocyte reaction (MLR) resulted in the inhibition of both p40 and p70 IL-12 production in a dose-dependent manner. In contrast, CsA had no effect on IL-12-receptor beta 1 chain (IL-12 R beta 1) expression in T cells induced upon allogeneic activation. Addition of exogenous IL-12 significantly restored CsA-inhibited alloreactive cytotoxic T lymphocyte (CTL) generation and had a marginal effect on T cell proliferative response. The IL-12-induced restoration of CTL generation was IFN gamma-mediated, as it was significantly altered when anti-IFN gamma was added. The restoration of CTL activity by exogenous IL-12 correlated with the capacity of this cytokine to partially restore granzyme B mRNA expression in alloreactive CTL. This study indicates that inhibition of IL-12 production is a novel additional mechanism for the inhibitory effect of CsA on the development of human allogeneic cytotoxic response.

A clinical phase I/II study of recombinant human interleukin-1 receptor in glucocorticoid-resistant graft-versus-host disease

Graft-versus-host disease (GVHD) is the major complication of allogeneic bone marrow transplantation. GVHD is accompanied by the release of inflammatory cytokines, including interleukin (IL)-1, and previous work has demonstrated that IL-1 participates in the pathogenesis of GVHD. The recombinant human IL-1 receptor (rhuIL-1R) is the soluble form of the type I IL-1 receptor that can bind to IL-1 and prevent cellular activation. We report a phase I/II trial utilizing the rhuIL-1R in the treatment of allogeneic bone narrow transplant patients not improving with glucocorticoid therapy. RhuIL-R was given at four dose levels for 21 days to 14 patients with progressive or persistent acute GVHD. The study drug had no clinical or persistent hematopoiesis and the treatment was tolerated by patients without toxicity at all dose levels. Eight of 14 patients (57%) had an improvement of GVHD after rhuIL-1R therapy. Improvement in GVHD was noted at each dose level, although a dose-response effect for rhuIL-1R treatment was not observed. This work supports the concept that IL-1 plays a role in the inflammation associated with acute GVHD. A controlled study of the rhuIL-1R for treatment of prophylaxis of GVHD is warranted.

Antitumor effect in cyclosporine A- or FK506-treated mice after syngeneic bone marrow transplantation

We investigated the possibility for induction of graft-versus-tumor (GVT) effects in cyclosporine A (CsA)- or FK506 (FK)-treated DBA/2 mice after syngeneic bone marrow transplantation (BMT). For in vitro assays of spleen cells, the CsA-treated mice had more enhanced cytotoxic activity against YAC1 and P388, while the FK-treated animals had more against P815, YAC1, and P388. IL-4 mRNA expression was detected in spleen cells of the FK-treated mice and IL-6 mRNA expression was clearly detected in both the treated groups. Concerning GVT effects, FK had more pronounced immunostimulatory potential than CsA in this experimental setting using DBA/2 mice. In tumor-loading in vivo experiments, we could not show any antitumor effect on survival. However, this immunostimulation could be expected to eradicate the minimal residual disease after autologous BMT and autologous peripheral blood stem cell transplantation.