Pathogenesis and treatment of graft-versus-host disease after bone marrow transplant

Clinical molecular imaging in intestinal graft-versus-host disease: mapping of disease activity, prediction, and monitoring of treatment efficiency by positron emission tomography

Gastrointestinal graft-versus-host disease (GVHD) is a common and potentially life-threatening complication after allogeneic hematopoietic stem-cell transplantation (HSCT). Noninvasive tests for assessment of GVHD activity are desirable but lacking. In the present study, we were able to visualize intestinal GVHD-associated inflammation in an allogeneic murine transplantation model by (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in vivo. A predominant localization of intestinal GVHD to the colon was verified by histology and fluorescence reflectance imaging of enhanced green fluorescent protein (EGFP)-expressing donor cells. Colonic infiltration by EGFP(+) donor lymphocytes matched increased FDG uptake in PET examinations. These preclinical data were prospectively translated into 30 patients with suspected intestinal GVHD beyond 20 days after transplantation. A total of 14 of 17 patients with a diagnostic histology showed significant FDG uptake of the gut, again predominantly in the colon. No increased FDG uptake was detected in 13 patients without histologic evidence of intestinal GVHD. Our findings indicate that FDG-PET is a sensitive and specific noninvasive imaging technique to assess intestinal GVHD, map its localization, and predict and monitor treatment responsiveness. Novel targeted tracers for PET may provide new insights into the pathophysiology of GVHD and bear the potential to further improve GVHD diagnosis.

Photopheresis in pediatric graft-versus-host disease after allogeneic marrow transplantation: clinical practice guidelines based on field experience and review of the literature

BACKGROUND

Extracorporeal photochemotherapy (ECP) gives positive results in the management of graft-versus-host disease (GVHD), but in children, specific difficulties can outweigh this benefit. These difficulties must be taken into consideration when establishing a standardized reproducible procedure for implementation under a quality management plan.

STUDY DESIGN AND METHODS

Twenty-seven children underwent ECP for severe acute GVHD (aGVHD) or chronic GVHD (cGVHD) after allogeneic marrow transplantation. Data were collected prospectively, with particular emphasis placed on technical, biologic, immunologic, clinical, and long-term follow-up issues.

RESULTS

The 27 children underwent a total of 750 sessions. Mononuclear cells were collected on a commercially available apheresis system (COBE Spectra, Gambro BCT). Overall survival was 73 percent, and ECP led to significant improvement in 21 of the 27 patients (11 with complete response and 10 with partial response, i.e., >50% of organ involvement). Tolerance was good overall, the main limiting factors being vascular access and the psychological impact of repeated apheresis procedures. Children weighing less than 25 kg were not more susceptible to side effects.

CONCLUSION

A specifically pediatric-dedicated and -experienced team faces only limited difficulties when treating children with GVHD by ECP. Overall, ECP is efficient and well tolerated. Our experience was therefore pooled together with available pediatric data to establish clinical practice guidelines. These guidelines consider ECP as a first-line therapy in Grade IV aGVHD (in association with conventional pharmacologic approaches) and limited cGVHD and as a second-line therapy in steroid-resistant Grades II to III aGVHD and extensive cGVHD.

T cell allorecognition and MHC restriction--A case of Jekyll and Hyde?

A great paradox in cellular immunology is how T cell allorecognition exists at high frequencies (up to 10%) despite the stringent requirements of discriminating 'self' from 'non-self' imposed by MHC restriction. Thus, in tissue transplantation, a substantial proportion of the recipient's T cells will have the ability to recognize the graft and instigate an immune response against the transplanted tissue, ultimately resulting in graft rejection--a manifestation of T cell alloreactivity. Transplantation of human organs and lymphoid cells as treatment for otherwise life-threatening diseases has become a more routine medical procedure making this problem of great importance. Immunologists have gained important insights into the mechanisms of T cell alloreactivity from cytotoxic T cell assays, affinity-avidity studies, and crystal structures of peptide-MHC (pMHC) molecules and T cell receptors (TCRs) both alone and in complex. Despite the clinical significance of alloreactivity, the crystal structure of an alloreactive human TCR in complex with both cognate pMHC and an allogeneic pMHC complex has yet to be determined. This review highlights some of the important findings from studies characterizing the way in which alloreactive T cell receptors and pMHC molecules interact in an attempt to resolve this great irony of the cellular immune response.

Absence of Cutaneous TNFα-Producing CD4+ T Cells and TNFα may Allow for Fibrosis Rather than Epithelial Cytotoxicity in Murine Sclerodermatous Graft-Versus-Host Disease, a Model for Human Scleroderma

Graft-versus-host disease (GVHD) is a complication of hematopoietic cell transplantation and is a major source of morbidity and mortality. Two main forms of GVHD occur: cytotoxic GVHD (Cyt GVHD), in which TNFalpha is a critical cytokine in epithelial injury, and sclerodermatous GVHD (Scl GVHD), in which TGFbeta plays a major role in fibrosis. To understand the critical early events in GVHD and scleroderma, we are studying a murine model that uses differences in minor histocompatibility antigens to generate Scl GVHD. We asked the question: what is the immune environment in this model that promotes fibrosis rather than the epithelial injury of Cyt GVHD? We found that in Scl GVHD, cutaneous CD4+ T cells produced IFNgamma and IL-2 but not TNFalpha, also absent by gene array analysis. The role of cutaneous CD4+ T cells in Scl GVHD may not be an active process through production of TGFbeta, but may rather be a passive one due to lack of antigen-presenting cell (APC) support for CD4+ T cells and failure to produce TNFalpha, a potent inhibitor of TGFbeta-induced fibrosis as well as inducer of keratinocyte apoptosis. These APC-T cell interactions and the cytokine environment promote fibrosis rather than cytotoxic epithelial injury in skin in Scl GVHD.

Dendritic cell homeostasis and trafficking in transplantation

Hematopoietic cell transplantation and solid organ transplantation are definitive therapies for several otherwise fatal conditions. Post-transplant immune reactions are the major cause of morbidity after transplantation and limit the extended use of these critical therapies. Post-transplant immune complications include graft rejection by the host and injury to the host mediated by the graft. Dendritic cells (DCs), a population of professional antigen-presenting cells, are thought to be crucial in triggering primary immune responses against both the graft and the host. Here, we review studies on DC homeostasis and trafficking after transplantation, and examine the role of the host and graft DC in post-transplant immune responses. We also discuss the therapeutic implications of these studies.

Predominant immature CD8?+dendritic cells prevent graft-vs.-host disease but do not increase the risk of leukemia recurrence

Graft-vs.-host disease (GVHD) remains the major limitation of allogeneic bone marrow transplantation (BMT) and stem cell transplantation, and leukemia recurrence is another important complication in leukemia treatment. Immature CD8alpha+ dendritic cells (DC) have good potential in GVHD treatment and immunological tolerance studies. To find a new way to prevent GVHD, not increasing the risk of leukemia recurrence, in this study, predominant CD8alpha+ immature DC were induced from murine bone marrow (BM) cells by 5 ng/mL granulocyte-macrophage colony stimulating factor (GM-CSF) plus 20-ng/mL interleukin (IL)-4, 100-ng/mL stem cell factor (SCF) and 25-ng/mL Flt3L, and 97.09 of prepared DC were CD8alpha+ on day 3. These DC were identified as morphologically and phenotypically immature CD8alpha+ DC. The suppressive function was observed in vitro, and then in vivo on allo-BMT leukemia model. The prepared predominant immature CD8alpha+ DC were weak syngeneic lymphocyte stimulators and could suppress mixed leukocyte reaction in vitro. In vivo, they prevented the pathological changes of GVHD and prolonged the surviving time of allo-BMT leukemia mice. The effect showed a dose-effect relationship. 86.7% of allo-BMT plus 1 million predominant CD8alpha+ DC leukemia mice reached long-term survival. Although predominant immature CD8alpha+ DC had the function of GVHD suppression, they did not increase leukemia recurrence. The method and findings may have important potency for GVHD treatment in clinical application.

Differential Requirement for a Cellular Type-1 Immune Response in Tumor-Associated Versus Alloantigen-Targeted GvT Effects

BACKGROUND

The major obstacles that impair successful outcome after allogeneic hematopoietic stem cell transplantation (HSCT) for hematologic malignancies remain graft-versus-host disease (GvHD) and tumor relapse. Improved survival after allogeneic HSCT therefore requires more effective control of GvHD while preserving graft-versus-tumor (GvT) effects.

METHODS

Allogeneic parent-into-F1 murine transplant models (BALB/c or C57BL/6 --> F1[BALB/cxC57BL/6]) were used to evaluate the interrelation of GvHD and GvT effects targeting tumor-specific antigens or alloantigens on MethA tumor cells.

RESULTS

Compared with syngeneic F1-into-F1 controls (F1[H-2(b/d)] --> F1: MethA[H-2d]), significant T cell-mediated GvT effects occurred in both allogeneic transplant models, even in the absence of histoincompatibilities between donor cells and host tumor (BALB/c[H-2d] --> F1: MethA[H-2d]). Selective inhibition of type-1 (Th-1/Tc1) immune responses with TAK-603 after HSCT nearly abolished GvHD in both allogeneic transplant models. While GvT effects directed against alloantigens (C57BL/6[H-2b] --> F1: MethA[H-2d]) remained unaffected during type-1-immune suppression, GvT effects targeted against tumor-associated antigens (BALB/c[H-2d] --> F1: MethA[H-2d]) were not evident. CONCLUSIONS.: Our data show that GvHD and GvT effects are in principle separable from each other by selective type-1 inhibition in transplantation models with major histocompatibility complex disparities between tumor, host, and donor. In contrast, in situations that only allow for GvT effects that exclusively target tumor-associated antigens (TAAs), type-1 inhibition results in complete abrogation not only of GvHD but also desired GvT reactions. These differences in GvT effects targeting alloantigens or TAAs and their interrelation to GvHD should be considered in future studies aimed at separating GvT reactions from GvHD.

The initial phase of graft-versus-host disease is associated with a decrease of CD4+CD25+ regulatory T cells in the peripheral blood of patients after allogeneic stem cell transplantation

The mechanisms that induce and control the alloimmune inflammation of graft-versus-host disease (GvHD) after allogeneic stem cell transplantation (allo-SCT) are still incompletely understood. In the murine system, GvHD can be suppressed by CD4(+)CD25(+) regulatory T cells (TREG), which are generally involved in the suppression of inflammatory reactions. A disruption of the homeostasis between TREG and conventional T cells might therefore be associated with the inflammatory reactions of GvHD. We repetitively measured the frequency of TREG in the peripheral blood of 29 patients within the first 71-373 days after allo-SCT and correlated the results with the clinical course. We demonstrate that the initial phase of GvHD is associated with a significant reduction of TREG in the peripheral blood, while at later stages and during intensified immunosuppressive therapy, increased numbers of TREG appear. These results might indicate a pathogenic role for reduced numbers of TREG in the induction of human GvHD.

Effective graft depletion of MiHAg T-cell specificities and consequences for graft-versus-host disease

Minor histocompatibility antigen (MiHAg) differences between donor and recipient in MHC-matched allogeneic hematopoietic stem cell transplantation (allo-HSCT) often result in graft-versus-host disease (GVHD). While MiHAg-specific T-cell responses can in theory be directed against a large number of polymorphic differences between donor and recipient, in practice, T-cell responses against only a small set of MiHAgs appear to dominate the immune response, and it has been suggested that immunodominance may predict an important contribution to the development of GVHD. Here, we addressed the feasibility of graft engineering by ex vivo removal of T cells with 1 or more defined antigen specificities in a well-characterized experimental HSCT model (B6 → BALB.B). We demonstrate that immunodominant H60- and H4-specific CD8+ T-cell responses can be effectively suppressed through MHC class I tetramer–mediated purging of the naive CD8+ T cell repertoire. Importantly, the development of GVHD occurs unimpeded upon suppression of the immunodominant MiHAg-specific T-cell response. These data indicate that antigen-specific graft engineering is feasible, but that parameters other than immunodominance may be required to select T-cell specificities that are targeted for removal.

Prediction of graft-versus-host disease in humans by donor gene-expression profiling

BACKGROUND

Graft-versus-host disease (GVHD) results from recognition of host antigens by donor T cells following allogeneic hematopoietic cell transplantation (AHCT). Notably, histoincompatibility between donor and recipient is necessary but not sufficient to elicit GVHD. Therefore, we tested the hypothesis that some donors may be "stronger alloresponders" than others, and consequently more likely to elicit GVHD.

METHODS AND FINDINGS

To this end, we measured the gene-expression profiles of CD4(+) and CD8(+) T cells from 50 AHCT donors with microarrays. We report that pre-AHCT gene-expression profiling segregates donors whose recipient suffered from GVHD or not. Using quantitative PCR, established statistical tests, and analysis of multiple independent training-test datasets, we found that for chronic GVHD the "dangerous donor" trait (occurrence of GVHD in the recipient) is under polygenic control and is shaped by the activity of genes that regulate transforming growth factor-beta signaling and cell proliferation.

CONCLUSIONS

These findings strongly suggest that the donor gene-expression profile has a dominant influence on the occurrence of GVHD in the recipient. The ability to discriminate strong and weak alloresponders using gene-expression profiling could pave the way to personalized transplantation medicine.

Identification of a radio-resistant and cycling dermal dendritic cell population in mice and men

In this study, we explored dermal dendritic cell (DC) homeostasis in mice and humans both in the steady state and after hematopoietic cell transplantation. We discovered that dermal DCs proliferate in situ in mice and human quiescent dermis. In parabiotic mice with separate organs but shared blood circulation, the majority of dermal DCs failed to be replaced by circulating precursors for >6 mo. In lethally irradiated mice injected with donor congenic bone marrow (BM) cells, a subset of recipient DCs remained in the dermis and proliferated locally throughout life. Consistent with these findings, a large proportion of recipient dermal DCs remained in patients' skin after allogeneic hematopoietic cell transplantation, despite complete donor BM chimerism. Collectively, our results oppose the traditional view that DCs are nondividing terminally differentiated cells maintained by circulating precursors and support the new paradigm that tissue DCs have local proliferative properties that control their homeostasis in the steady state. Given the role of residual host tissue DCs in transplant immune reactions, these results suggest that dermal DC homeostasis may contribute to the development of cutaneous graft-versus-host disease in clinical transplantation.

Alloreaction increases or restores CD40, CD54, and/or HLA molecule expression in acute myelogenous leukemia blasts, through secretion of inflammatory cytokines: dominant role for TNFβ, in concert with IFNγ

We have previously reported that alloreaction can lead to activation of dendritic cells through secretion of inflammatory cytokines. Here, we addressed whether alloreaction-derived cytokines may also lead to acute myelogenous leukemia (AML) blast differentiation. With this aim, supernatant (sn) harvested from major or minor histocompatibility antigen-mismatched mixed lymphocyte reaction (MLR) were used to culture French American Bristish (FAB) type M4 or M5 AML blasts. Our results showed that the secreted factors induced upregulation of CD40, CD54, and/or HLA molecules in AML blasts. Protein fractionation, blockade experiments and exogenous cytokine reconstitution demonstrated the involvement of TNF in the upregulation of CD54, CD40 and HLA-class II molecules, and of IFNgamma in the increase of HLA-class I and class II molecule expression. But, in line of its much higher levels of secretion, TNFbeta, rather than TNFalpha, was likely to play a preponderant role in AML blast differentiation. Moreover TNFbeta and IFNgamma were also likely to be involved in the AML blast differentiation-mediated by HLA-identical donor T-cell alloresponse against recipient AML blasts. In conclusion, we show herein that upon allogeneic reaction, TNFbeta secretion contributes, in concert with IFNgamma, to increase or restore surface molecules involved in AML blast interaction with T cells.

Poor oral nutrition after allogeneic stem cell transplantation correlates significantly with severe graft-versus-host disease

It has previously been shown that enteral nutrition has several advantages compared to parenteral nutrition (PN) in critically ill patients. The nutritional history was studied in 231 patients after allogeneic stem cell transplantation (SCT). Parenteral nutrition was given for a median of 10 (0-74) days. Patients with graft-versus-host disease (GVHD) grades III-IV received more PN (median 20, range 0-67) than patients with GVHD grades 0-II (10, 0-74, P=0.016). Eighty-five (37%) patients were not able to eat anything for a median of 4 days (1-37). We found a correlation between the number of days with no oral intake (before the diagnosis of acute GVHD) and the incidence of acute GVHD grades III-IV. In patients with 1-4 days of no oral intake, the incidence of grades III-IV acute GVHD was 6%, in those with 5-9 days it was 17%, and in those with >9 days it was 38%. On multivariate analysis, we found that more than 9 days with no oral intake was associated with acute GVHD grades III-IV (odds ratio 7.66, confidence interval 1.44-40.7, P=0.016). Poor oral intake early after SCT may be associated with an increased risk of developing severe acute GVHD.

Nephrotic syndrome in a child after umbilical-cord-blood transplantation

We report a 12-year-old girl who developed nephrotic syndrome 6 months after umbilical-cord-blood transplantation (UCBT) for acute lymphoblastic leukemia (L2). In addition to nephrotic syndrome, she also showed autoimmune hemolytic anemia, thrombocytopenia and gastrointestinal symptoms. Since these symptoms were manifested during the course of tapering immunosuppressive agents, a diagnosis of chronic graft-versus-host disease (GVHD) was made. Findings from a kidney biopsy were compatible with minimal-change disease (MCD), and focal glomerular capillary thrombosis and mild tubular damage were also noted. She was treated with methylprednisolone pulse therapy followed by oral prednisolone. Proteinuria disappeared in 14 days. Gastrointestinal symptoms, anemia and thrombocytopenia were also corrected. This is a case report of nephrotic syndrome as a manifestation of chronic GVHD developed after stem-cell transplantation. A review of the cases reported in the literature is also made.

Prophylaxis and treatment of acute graft-versus-host disease

Acute graft-versus-host disease (GVHD) remains a major obstacle to successful allogeneic hematopoietic stem cell transplantation (HSCT). The ability to prevent GVHD--the application of successful prophylaxis--is crucial as treatment when prophylaxis fails or remains suboptimal. A calcineurin inhibitor in combination with methotrexate is still the mainstream regimen for prophylaxis of GVHD. Despite a steady increase in the repertoire of available drugs, corticosteroids remain the first-line therapy for patients who fail prevention and develop GVHD. Pan T-cell depletion studies suggest that success in prophylaxis and treatment of GVHD will depend on whether GVHD can be prevented without losing anti-malignancy and anti-infectious effects. Better understanding of the allogeneic response that is responsible for GVHD will facilitate the development of such an approach.

Graft-vs-host disease: nutrition therapy in a challenging condition

Graft-vs-host disease (GVHD) is a major complication after allogeneic hematopoietic stem cell transplantation. Both acute and chronic forms of GVHD are challenging to manage medically and nutritionally. Patients with advanced GVHD commonly become depleted nutritionally, with loss of lean body mass (LBM) and functional status. We present 2 case reports of patients who developed GVHD and subsequent nutrition decline. Although both patients were candidates for specialized nutrition support (SNS), only 1 was able to receive enteral and parenteral nutrition due to GVHD complications preventing access for provision of SNS. Fortunately, the patients have remained in remission from their hematologic malignancy, but they continue to cope with chronic GVHD and its consequences. These cases exhibit the complexity of managing a patient with extensive GVHD and nutrition interventions for clinicians to consider to optimize outcomes.

Maturation state of dendritic cells during the extracorporeal photopheresis and its relevance for the treatment of chronic graft-versus-host disease

BACKGROUND

Chronic graft-versus-host disease (cGVHD) represents a major cause of morbidity and mortality after allogeneic bone marrow transplantation (BMT). Extracorporeal photochemotherapy (ECP), a technique used in the treatment of cutaneous T-cell lymphoma, has also shown clinical efficacy in the treatment of refractory cGVHD.

STUDY DESIGN AND METHODS

In this study, the dynamics of dendritic cell (DC) activation were investigated during the process of photopheresis in patients treated for refractory cGVHD.

RESULTS

It is reported that myeloid DCs can be isolated from the photopheretic products before retransfusion to the patient. It is shown that DCs in ECP product are in the immature state with respect to the phenotypic and functional characteristics. In contrast to the in vitro-generated monocyte-derived DCs and DCs not treated by 8-methoxypsoralen and UVA, they produce significant amounts of interleukin-10 (IL-10). They efficiently capture apoptotic lymphocytes and do not induce proliferation of T lymphocytes. They preserve the capacity to be activated by polyriboinosinic polyribocytidylic acid and lipopolysaccharide, however. ECP also induces rapid and massive apoptosis of alloreactive lymphocytes. A model of the potential implication of IL-10-producing DCs in the down regulation of harmful alloreactive immune reaction is presented.

CONCLUSION

It is believed that this study provides a novel insight into the mechanisms of action of ECP in the control of cGVHD.

Extracorporeal photopheresis in children with graft-versus-host disease

Acute and chronic graft-versus-host disease (GVHD) are major complications after allogeneic hematopoietic stem cell transplantation. Systemic corticosteroid is the first line of therapy but only half of the patients will respond. The management of steroid-refractory or steroid-dependent GVHD is challenging. Intensification of immunosuppression has been the main strategy but the response rate is not satisfactory. Furthermore, the incidence of treatment-related toxicity and opportunistic infection is unacceptably high. Extracorporel photopheresis (ECP) has been used in the management of refractory GVHD. Retrospective analysis of the experience in adult patients showed activity in both acute and chronic GVHD. The procedure was well tolerated with minimal changes in the hematologic and biochemical parameters. However the machine currently approved is designed for patients over 40 kg of body weight. Significant fluid shift and venous access are major concerns when ECP is performed in children. Various modifications of the ECP procedure have been tried to manage patients with low body weight. Experience with ECP in children is limited but preliminary data also showed favorable response in children with resistant GVHD. Further investigations are needed to refine the optimal schedule, duration, and treatment technique for pediatric patients.

CD4+CD25+ Regulatory T Cells in Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (SCT) is a well-established treatment modality for malignant and nonmalignant hematologic diseases. High-dose radio- and/or chemotherapy eradicate the hematopoietic system of the patient and induce sufficient immunosuppression to enable donor stem cell engraftment. The replacement of the recipient's immune system with that of the donor significantly contributes to the success of this treatment, since donor immune cells facilitate stem cell engraftment, provide protection from infections, and eliminate residual malignant or nonmalignant host hematopoiesis, thereby protecting from disease relapse in patients transplanted for leukemia or lymphoma (graft-versus-leukemia effect, GVL). Mediators of these beneficial effects are mature T cells within the stem cell graft. However, donor T cells can also attack host tissues and induce a life-threatening syndrome called graft-versus-host disease (GVHD). The challenge of allogeneic SCT is to find a balance between beneficial and harmful T cell effects, which at present is only insufficiently achieved by the use of immunosuppressive drugs. In the future, it might be possible to replace or support such medications by using the intrinsic regulatory capacity of the transplanted immune system, as represented by T cell subpopulations with suppressive activity, such as CD4+ CD25+ regulatory T (Treg) cells. In various mouse model systems, these cells have been shown to suppress GVHD while preserving the GVL effect. As the characterization of their human counterparts is rapidly progressing, their application in allogeneic SCT might soon be explored in clinical trials.

Hematologic aspects of myeloablative therapy and bone marrow transplantation

The transplantation of bone marrow cells or isolated hematopoietic stem cells from the bone marrow or peripheral blood is a widely utilized form of therapy for patients with incurable diseases of the hematopoietic and immune systems. Successful engraftment of the transplanted stem cells in an adequately prepared recipient normally leads to bone marrow reconstitution over a period of several weeks, accompanied by more gradual reconstitution of the immune system. Since the recipient is profoundly ill during the initial treatment period, laboratory data is critical for monitoring engraftment, detecting residual/recurrent disease, and identifying problems that may delay bone marrow reconstitution or lead to other medical complications. Accurate blood cell counts are imperative, and most bone marrow transplantation patients undergo periodic monitoring with bone marrow aspirates and biopsies with cytogenetic, molecular, and multiparametric flow cytometric studies. The potential complications of bone marrow transplantation include engraftment failure and delayed engraftment, infection, residual bone marrow disease, acute and chronic graft versus host disease, myelofibrosis, therapy-related acute leukemia, post-transplant lympho-proliferative disorders, and toxic myelopathy.

Medium dose long-wavelength ultraviolet A (UVA1) phototherapy for the treatment of acute and chronic graft-versus-host disease of the skin

Long-wavelength ultraviolet A (340-400 nm UVA1) phototherapy has been reported to be effective in atopic dermatitis, localized scleroderma and other T-cell-derived skin diseases. UVA1 as an adjunct to systemic immunosuppressive treatment was found to be safe, and effective in 10 patients with chronic cutaneous (seven lichenoid and three sclerodermoid) graft-versus-host disease (GVHD) after stem cell transplantation. Complete and partial responses were achieved in six (60%), and in three (30%) patients, respectively. One patient had improvement of sclerotic skin lesions. At a median follow-up of 14 months, two patients with lichenoid lesions relapsed. Both responded to another treatment cycle. Furthermore, we treated seven patients with UVA1 as primary therapy for acute cutaneous GVHD grades II and III in a pilot experience. Five patients had a complete response with no relapse at a median follow-up of 9 months after UVA1. Two patients showed no response and systemic steroids had to be started. UVA1 therapy is feasible, well tolerated and can be effective in treating chronic as well as acute GVHD confined to the skin thereby avoiding systemic steroids. Our results should be confirmed in larger studies and the effectiveness of UVA1 compared to other established treatment modalities.

Treatment of Gastrointestinal Acute Graft-Versus-Host Disease

Therapy of acute graft-versus-host disease (GVHD) aims to selectively alter the graft- host interactions to foster antitumor effect and minimize antihost effects. The immunosuppression produced by the various therapies ranges from broad, nonselective effects to relatively narrow targeted impact. Despite advances in understanding the pathophysiology of GVHD, newer agents with more selective effects have not yet produced therapeutic advances. The newer targeted agents continue to produce a degree of immunosuppression in which infection and relapse of malignancy are all too common. High-dose systemic steroids remain, as they have for two decades, the initial treatment of choice. Patients failing to respond to steroids continue to represent a challenge, as no second-line therapy is clearly superior to the others. However, some of the new agents appear to be particularly effective in certain organs involved with acute GVHD. For those patients with steroid-refractory GVHD involving primarily the gut, we favor infliximab with concomitant antifungal therapy. For those with primarily skin or liver disease, we favor extracorporeal photochemotherapy.

Lymphocytic pneumonitis as the manifestation of acute graft-versus-host disease of the lung

Acute graft-versus-host disease is a common complication after allogeneic stem cell transplantation. It normally affects the skin, liver, and gut. We report a 54-year-old male who developed shortness of breath, cough, and bilateral pulmonary infiltrates in which the work-up failed to demonstrate an infectious etiology 165 days post-HLA-matched allogeneic peripheral blood stem cell transplant. Eighteen days before, his tacrolimus had been tapered and it was subtherapeutic on admission. A transbronchial biopsy showed a perivascular and interstitial lymphocytic infiltrate without evident pathogens on histology or extensive work-up. The clinical picture was suggestive of pulmonary acute graft-versus-host disease. No disease was present elsewhere. Accordingly, the patient was treated with steroids and tacrolimus. After 12 hr on methylprednisolone, his symptoms disappeared with eventual resolution radiologically. Acute graft-versus-host disease of the lung is a very uncommon complication after stem cell transplant, but it should be considered in patients who are at high risk for graft-versus-host disease or developing symptoms soon after discontinuing immunosuppression. Its diagnosis requires work-up to rule out an infectious etiology and a biopsy to confirm histology.

Cost-efficacy of imatinib versus allogeneic bone marrow transplantation with a matched unrelated donor in the treatment of chronic myelogenous leukemia: a decision-analytic approach

STUDY OBJECTIVE

To develop and populate a decision-analytic model for comparing the 2-year cost and efficacy of imatinib versus allogeneic bone marrow transplantation (BMT) with a matched unrelated donor in the treatment of a 35-year-old man with newly diagnosed, Philadelphia chromosome-positive (Ph[+]) chronic myelogenous leukemia (CML) in the chronic phase.

DESIGN

Markov cohort analysis and first-order Monte Carlo microsimulation.

MEASUREMENTS AND MAIN RESULTS

Direct medical costs were measured from the perspective of a third-party payer. Efficacy data and probabilities were obtained from survivability findings, most of which were derived from randomized controlled trials. We employed a 2-year time horizon with 3-month treatment cycles. The comparator was BMT with a matched unrelated donor, and the base case was defined as a 35-year-old, Ph(+) man with newly diagnosed CML. The Monte Carlo microsimulation indicated that the incremental cost:efficacy ratio was -$5000 for imatinib (95% confidence interval -$70,000-84,000). Analysis of the cost-efficacy plane revealed that imatinib was dominant over BMT in 84.69% of cases, whereas BMT dominated imatinib in 0.76% of cases. Trade-offs were warranted in the remaining cases. Sensitivity analyses of costs and discount rates found these results to be generally robust.

CONCLUSION

In most cases, imatinib was both less costly and more efficacious than BMT in the 2-year treatment of CML. Results of this investigation should be viewed in the context of emerging long-term clinical data. These data are necessary to assess cost-efficacy beyond the short-term time horizon of this study.

Hydroxychloroquine causes severe vacuolar myopathy in a patient with chronic graft-versus-host disease

A 51-year-old man developed progressive debilitating limb and respiratory muscle weakness while undergoing treatment for chronic graft-versus-host disease secondary to allogeneic bone marrow transplant for mantle cell lymphoma. He had a normal serum creatine kinase level and acetylcholine receptor antibodies were negative. Electromyography showed a severe, nonirritable myopathy and a sensory motor axonal polyneuropathy. A muscle biopsy showed a necrotizing, vacuolar myopathy with many fibers containing autophagic and red-rimmed vacuoles, suggestive of an amphiphilic drug myopathy. The patient's strength and function improved significantly after discontinuation of hydroxychloroquine.

In Vitro Depletion of Tissue-Derived Dendritic Cells by CMRF-44 Antibody and Alemtuzumab: Implications for the Control of Graft-Versus-Host Disease

Graft-versus-host disease (GvHD), a life-threatening complication of bone marrow transplantation, is initiated by donor T cells reacting to recipient dendritic cells (DC). GvHD can be controlled by attenuating donor T cells, but few strategies exist to target DC, particularly resident tissue DC, despite recent evidence of their importance. In this report, CMRF-44, a mouse monoclonal IgM reactive to human DC, is tested against human Langerhans cells (LC) in vitro. CMRF-44 antigen is expressed at low level on fresh LC but is up-regulated 40-60-fold during migration. CMRF-44 and complement kill more than 97% of migratory LC in vitro and inhibit allostimulation by LC up to 95%. In comparison, alemtuzumab, which binds CD52, reacts weakly with primary LC and fails to induce significant lysis with complement (less than 5%). These results highlight the potential of new therapeutic antibodies active against tissue DC to control graft-versus-host reactions.

Monocyte-mediated T-cell suppression and augmented monocyte tryptophan catabolism after human hematopoietic stem-cell transplantation

T-cell dysfunction after human hematopoietic stem-cell transplantation (HSCT) is generally attributed to intrinsic T-cell defects. Here we show that the characteristic impaired proliferative responses to polyclonal stimulation of post-HSCT peripheral blood mononuclear cells (PB-MCs) were markedly (4-fold) improved by T-cell enrichment. Conversely, addback of post-HSCT monocytes to these enriched T cells dampened their proliferative responses, suggesting that post-HSCT monocytes effectively mediate T-cell suppression. As a mechanism possibly contributing to monocyte-mediated T-cell suppression, we investigated monocyte tryptophan catabolism by indoleamine 2,3-dioxygenase into kynurenine, which has been implicated in regulating T-cell responses. Compared with controls, all post-HSCT monocyte-containing cell cultures (total PBMCs, monocytes, and monocyte/T-cell cocultures), but not monocyte-depleted populations, secreted elevated amounts of kynurenine. Blockade of tryptophan catabolism improved the proliferative responses. The slightly increased kynurenine release and substantial release of neopterin by unstimulated post-HSCT monocytes suggests that they were in a state of continuous activation. Superimposed on this state, stimulation of these cells caused a striking, additional increase (10-fold) in kynurenine release, and they triggered marked apoptosis of autologous post-HSCT T cells. We conclude that the amplified kynurenine release by post-HSCT monocytes, particularly induced upon stimulation, may underlie their suppressor activity, which in turn may contribute to the depressed T-cell immune responses after HSCT.

Gene expression analysis of peripheral T cells in a subgroup of common variable immunodeficiency shows predominance of CCR7(-) effector-memory T cells

Common variable immunodeficiency (CVID) represents a heterogeneous group of antibody deficiency syndromes, characterized by defective antibody production in which T cell deficiency may play a pathogenic role. A subgroup of CVID patients has impaired in vitro T cell proliferation. Using microarray analyses of T cells from these patients, we found a gene expression pattern different from healthy controls and patients with X-linked agammaglobulinaemia. The profile of the differentially expressed genes suggests enhanced cytotoxic effector functions, antigen experienced or chronically activated T cells and a predominance of CCR7(-) T cells. Further experiments using flow cytometry revealed a striking predominance of CCR7(-) T cells in a subgroup of CVID patients, and an association with impaired T cell proliferation. Our observations indicate that a predominance of CCR7(-) T cells with effector-memory cell features and with reduced proliferative capacity may characterize a subgroup of CVID.

Acute graft-versus-host disease: Pathophysiology, clinical manifestations, and management

Hematopoietic stem cell transplantation has evolved as a central treatment modality in the management of different hematologic malignancies. Despite adequate posttransplantation immunosuppressive therapy, acute graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality in the hematopoietic stem cell transplantation setting, even in patients who receive human leukemic antigen (HLA) identical sibling grafts. Up to 30% of the recipients of stem cells or bone marrow transplantation from HLA-identical related donors and most patients who receive cells from other sources (matched-unrelated, non-HLA-identical siblings, cord blood) will develop > Grade 2 acute GVHD despite immunosuppressive prophylaxis. Thus, GVHD continues to be a major limitation to successful hematopoietic stem cell transplantation. In this review, the authors summarize the most current knowledge on the pathophysiology, clinical manifestations, and management of this potentially life-threatening transplantation complication.

Kinetic of regulatory CD25high and activated CD134+ (OX40) T lymphocytes during acute and chronic graft-versus -host disease after allogeneic bone marrow transplantation

Graft-versus-host disease (GVHD) is still a major complication after allogeneic stem cell transplantation. In murine models, freshly isolated or ex vivo expanded CD4(+)CD25(high) regulatory T cells (Treg) are able to ameliorate GVHD while maintaining graft-versus-leukaemia reactions. However, in the human setting, prospective studies of this population and its interaction with activated non-regulatory CD134(+) (OX40) lymphocytes during post-transplant follow-up are lacking. In this study, we prospectively quantified CD4(+)CD25(high) and activated CD134(+) lymphocytes in 119 peripheral blood samples from 35 consecutive patients who underwent allogeneic bone marrow transplantation (BMT). Fifty-five samples obtained less than 100 d after allogeneic BMT, were not statistically different regarding CD4(+)CD25(high) Treg or CD134(+) lymphocytes compared with those obtained from patients with (n = 35) or without (n = 20) acute GVHD. Chronic GVHD was associated with a small, but not statistically significant, increase in the number of Treg (9.9 vs. 6.7 x 10(6)/L). However, the CD134/CD25(high) ratio was significantly higher during chronic GVHD (cGHVD) when compared with either patients without cGVHD (67.7 +/- 40.3 vs. 4.0 +/- 0.9, P < 0.01) or cGVHD after treatment (67.7 +/- 40.3 vs. 3.7 +/- 0.8, P < 0.01). Our findings suggest that the suppressive activity of CD4(+)CD25(high) Treg could be abrogated in vivo during cGVHD by CD134 expression in a much higher number of activated donor T lymphocytes. In addition to CD4(+)CD25(high)ex vivo expansion protocols, OX40 blocking might be crucial to optimize the use of Treg to prevent GVHD.

Prevention of murine acute graft-versus-host disease by recipient-derived TGFβ1-treated dendritic cells

Acute graft-versus-host disease (GVHD) remains the major barrier to allogeneic bone marrow transplantation (allo-BMT). Evidence has accumulated that transforming growth factor beta1-treated dendritic cells (TGFbeta-DC), deficient in surface costimulatory molecules, inhibit alloantigen-specific T-cell responses and induce graft hyporeactivity. To analyze the effect of TGFbeta-DC on GVHD after allo-BMT, 5.0 x 10(6) recipient-derived TGFbeta-DC were injected into C57BL/6 (H-2b) with bone marrow-splenocyte grafts from major histocompatibility complex (MHC) disparate BALB/c mice (H-2d). Survival analysis showed TGFbeta-DC cotransplantation resulted in significant prolongation of allograft survival, namely a mean survival time (MST) of 44.3 +/- 4.5 days, versus the untreated MST of 9.5 +/- 0.6 days (P < .01). However, mature DC aggravated the GVHD with an MST of 6.6 +/- 0.6 days (P < .01). In addition, the third-party C3H-derived TGFbeta-DC did not enhance the survival rate (MST = 9.7 +/- 0.5 days). Furthermore, serum IFN-gamma, IL-12, and IL-18 levels in TGFbeta-DC cotransplanted mice were reduced compared with untreated BMT hosts, while serum IL-10 levels were not changed. These results suggest that TGFbeta-DC cotransplantation may attenuate the severity of GVHD after BMT.

Acute graft versus host disease following liver transplantation: the enemy within

This article reviews acute graft vs. host disease (GVHD) as a complication of orthotopic liver transplantation (OLT). The incidence, presentation, clinical course and outcome of GVHD after OLT are summarized and the pathogenesis is discussed, drawing parallels with GVHD after allogeneic haematopoietic stem cell transplantation. Risk factors for GVHD after OLT are examined and the potential role of donor lymphocyte macrochimerism in the recipient peripheral blood as a diagnostic aid for GVHD is discussed. Finally, treatment of GVHD after OLT is reviewed with particular emphasis on the potential role of some of the newer biological agents.

Topical corticosteroid therapy for cicatricial conjunctivitis associated with chronic graft-versus-host disease

A retrospective chart review was performed on seven patients treated with topical ocular corticosteroid therapy for progressive cicatricial conjunctivitis associated with chronic graft-versus-host disease (GVHD) following hematopoietic stem cell transplantation. A clinical grading criteria for conjunctival GVHD based on the degree of cicatrization was developed and patients graded prior to therapy. During the treatment course, the dose and frequency of topical corticosteroids and clinical outcomes were recorded. A complete response was defined as a complete resolution of the conjunctival hyperemia with either total resolution of the conjunctival fibrovascularization or presence of inactive conjunctival scarring. Prednisolone acetate 1% eye drops were used in a total of eight courses of therapy in seven patients. A complete response was documented in all seven patients with a total treatment duration of 7 weeks (median, range: 3-16 weeks). Additional studies are required to determine the long-term safety and efficacy of topical corticosteroids for cicatricial conjunctivitis associated with ocular GVHD in the context of a randomized, prospective clinical trial.

The current status of hematopoietic cell transplantation

Hematopoietic cell transplantation is the preferred therapy for a substantial proportion of patients with life-threatening diseases of the lymphohematopoietic system. Recent advances in donor identification, disease eradication, and supportive care measures have broadened the application of transplantation and improved outcomes. This article provides a brief review of the major clinical principles of transplantation and results achieved to date.