Graft-versus-host-reactions: the history that never was, and the way things happened to happen

Endothelial damage is aggravated in acute GvHD and could predict its development

The aim of the present study was to explore whether there is enhanced endothelial dysfunction in patients developing acute GvHD (aGvHD) after allogeneic hematopoietic cell transplantation (allo-HCT) and to identify biomarkers with predictive and/or diagnostic value. In in vitro experiments, endothelial cells (ECs) were exposed to serum from patients with (aGvHD, n=31) and without (NoGvHD, n=13) aGvHD, to evaluate changes in surface adhesion receptors, the reactivity of the extracellular matrix by measuring the presence of Von Willebrand factor (VWF) and platelet adhesion, and the activation of intracellular signaling proteins. Plasma levels of VWF, ADAMTS-13, TNF receptor 1 (TNFR1), soluble vascular cell adhesion molecule 1 and soluble intercellular adhesion molecule 1 were also measured. In vitro results showed a more marked proinflammatory and prothrombotic phenotype in ECs in association with aGvHD. Regarding circulating biomarkers, levels of VWF and TNFR1 above an optimal cutoff score, taken independently or combined, at day 7 after allo-HCT, would be able to positively predict that around 90% of patients will develop aGvHD. Our results demonstrate that endothelial damage is aggravated in those allo-HCT recipients developing aGvHD, and that VWF and TNFR1 are promising predictive aGvHD biomarkers. These findings could contribute to improve the understanding of the pathophysiology of aGvHD.

Peripheral Blood Stem Cell Transplantation and Graft-versus-Host Disease: A Case Study

Peripheral blood stem cell transplantation is an acceptable treatment option for children with hematologic malignancies that are refractory to traditional treatments. Reports in the literature suggest that acute graft-verus-host disease (aGVHD), a common complication of peripheral blood stem cell transplantation, is associated with significant morbidity and mortality. aGVHD, a complex immunologic response, is reported in allogeneic transplants in which there is antigen presentation and activation of the donor T cell. The release of cytokines from the activated lymphocytes results in host cell death. This article reports on a 3-year-old child with a hematologic malignancy who, upon relapse, had received an identically matched allogeneic stem cell transplant from a sibling. Prophylaxis against aGVHD included several immunosuppressive agents. The dosage and serum levels of mycophenolate mofetil and tacrolimus were carefully monitored; however, the aGVHD progressed to include the liver and gut. As the child continued to deteriorate the aggressive treatment against aGVHD continued without success. A review of this case of aGVHD will provide nurses a knowledge base that is necessary to provide optimal care to the patient and family members alike.

Fashioning the immunological self: the biological individuality of F. Macfarlane Burnet

During the 1940s and 1950s, the Australian microbiologist F. Macfarlane Burnet sought a biologically plausible explanation of antibody production. In this essay, we seek to recover the conceptual pathways that Burnet followed in his immunological theorizing. In so doing, we emphasize the influence of speculations on individuality, especially those of philosopher Alfred North Whitehead; the impact of cybernetics and information theory; and the contributions of clinical research into autoimmune disease that took place in Melbourne. We point to the influence of local experimental and intellectual currents on Burnet's work. Accordingly, this essay describes an arc distinct from most other tracings of Burnet's conceptual development, which focus on his early bacteriophage research, his fascination with the work of Julian Huxley and other biologists in the 1920s, and his interest in North Atlantic experimental investigations in the life sciences. No doubt these too were potent influences, but they seem insufficient to explain, for example, Burnet's sudden enthusiasm in the 1940s for immunological definitions of self and not-self. We want to demonstrate here how Burnet's deep involvement in philosophical biology - along with attention to local clinical research - provided him with additional theoretic tools and conceptual equipment, with which to explain immune function.

Historical overview of transplantation

Except for legends and claims of miracles, most histories of transplantation cover only the last 60 years because there were no earlier successes. However, the story of even this era has been documented in such rich detail that a full account would fill several volumes. Thus, this brief summary must be limited to highly selected "landmarks." Some landmarks had an immediate impact, but the importance of others went unrecognized for decades. Some findings that deserved landmark status were overlooked or forgotten, whereas others of no biological significance had major impact. Placing these events in perspective is challenging. Several of transplantation's pioneers are still alive, and most of the others are within living memory. Virtually all of them have produced their own accounts. For the most part, they agree on what the "landmarks" are, but their differences in emphasis and perspective make an interesting story.

Identification of new major histocompatibility complex class II restriction fragment length polymorphisms in a closed experimental line of Beltsville Small White turkeys

Beltsville Small White (BSW) turkeys have been utilized as an experimental model in the study of bacterial, parasitic, and fungal diseases. Given the critical role of MHC antigens in the initial steps of the immune response to specific pathogens, the MHC Class II of BSW turkeys was characterized. Southern blot analysis of PvuII-digested turkey DNA that was hybridized with a chicken Class II beta gene genomic clone revealed two restriction fragment length polymorphism profiles not previously identified in experimental or commercial breeder lines of turkeys. These fingerprint profiles differed in a single 6.0-kb band that was present in approximately 38% of the birds examined. The DNA fragments of 5.0, 4.1, 3.3, and 3.1 were present in both profiles. Furthermore, no mixed lymphocyte reaction was observed between individuals within the BSW turkey line. The present results indicate that BSW turkeys represent a unique source of genetic diversity for MHC Class II haplotypes.

The lymphocyte in immunology: from James B. Murphy to James L. Gowans

Between 1912 and 1921, James Murphy established conclusively the role of the lymphocyte in tissue and tumor graft rejection and in protection against infection. Contemporary mainstream immunology paid little attention to these findings, until the lymphocyte was "rediscovered" with the advent of modern cellular immunology after the mid-1950s.

Pathophysiology and treatment of graft-versus-host disease

Acute graft-versus-host disease denotes a distinctive syndrome characterized by a triad of dermatitis (rash), hepatitis (jaundice), and gastroenteritis (abdominal pain, diarrhea) developing in the first 100 days after allogeneic hematopoietic cell transplantation. Chronic graft-versus-host disease designates a more diverse syndrome, usually presenting with multiorgan involvement and commonly developing 100 days after hematopoietic cell transplantation. This article discusses the pathophysiology, incidence and predictive factors, clinical manifestations, diagnosis and grading, prevention, and treatment for both types of the disease.

Chicken CD4, CD8alphabeta, and CD8alphaalpha T cell co-receptor molecules

New knowledge has recently been obtained about the evolutionary conservation of CD4, CD8alphaalpha, and CD8alphabeta T cell receptor (TCR) co-receptor molecules between chicken and mammals. This conservation extends from biochemical structure and tissue distribution to function. Panels of monoclonal antibodies and polyclonal antisera against different epitopes of chicken CD8 and CD4 molecules have proven their value in several recent studies. Chicken CD8 allotypes and homozygous strains carrying these allotypes have been established and these strains provide excellent models for further studies. The extensive polymorphism of CD8alpha in chickens has not been observed in any other species, suggesting that CD8alpha and CD8beta have evolved under different selective pressure in the chicken. A large peripheral blood CD4+CD8+ T cell population in chicken resembles that observed in some human individuals but the inheritance of peripheral blood CD4CD8alphaalpha T cells in the chicken is a unique observation, which suggests the presence of a single gene responsible for CD8alpha, but not CD8beta, specific expression. Despite these unique findings in chicken, the data on CD4, CD8alphaalpha, and CD8alphabeta molecules show that they have evolved before the divergence of mammalian and avian branches from their reptilian ancestors.

Gamma delta T cells are secondary participants in acute graft-versus-host reactions initiated by CD4+ alpha beta T cells

To examine the role of T cell subpopulations in an acute graft-versus-host (GVH) reaction, gamma delta T cells and alpha beta T cells expressing one of the two prototypic V beta families were negatively isolated from adult blood samples and injected into allogeneic chick embryos. CD4+ alpha beta T cells expressing either V beta 1 or V beta 2 receptors were equally capable of inducing acute GVH reactions, consistent with the idea that alpha beta T cell alloreactivity is determined by CDR3 variability. By themselves, the gamma delta T cells were incapable of inducing GVH reactions. However, host gamma delta T cells were recruited into the donor alpha beta T cell-initiated lesions, where they were activated and induced to proliferate. The data suggest that gamma delta T cells may play a secondary role in GVH reactions.

Chicken thymic nurse cells: an overview

Thymic nurse cells are multicellular complexes located in the subcortical area of the thymus of all avian, mammalian and amphibian species investigated so far. Since their first description in 1980 many studies have been carried out to characterize their morphological and functional properties. The purpose of this review is to summarize recent morphological as well a functional analyses of chicken thymic nurse cells which suggest a role of these cell complexes in T cell selection.

Is the immune system necessary for placental reproduction? A hypothesis on the mechanisms of alloimmunotherapy in recurrent spontaneous abortion

Recurrent spontaneous abortion is being treated with alloimmunotherapy which consists of the inoculation of allogeneic mononuclear cells. However the mechanisms explaining the benefits of this therapy are not clear yet. Taking the immunotrophic hypothesis as the paradigm of the field of reproductive immunology, hereby we present a hypothesis to propose a role for the immune system in reproduction and at the same time to explain how alloimmunotherapy may work. We base our view on several facts: first, immunodeficient mice reproduce--albeit their progeny may not be as robust and numerous as that from normal individuals. Second, maternal lymphocytes cross the placenta and may induce graft versus host disease. Third, graft versus host disease in newborn F1 mice inoculated with paternal lymphocytes can be prevented by inoculation of the mother with the same paternal lymphocytes before and during pregnancy. We propose that: 1) the immune system by itself is not necessary for placental reproduction; 2) the immune system plays its major role in reproduction by counteracting the allogeneic response generated against the fetus; 3) recurrent spontaneous abortion represents a type of graft versus host disease induced by maternal cells infiltrating the fetus; and 4) alloimmunotherapy induces an antiidiotypic response necessary to counteract the graft versus host reaction in the fetus.

In situ analyses of in ovo graft-vs.-host reaction induced by thymic nurse cell lymphocytes

In both mammalian and avian systems, thymic nurse cells (TNC) have been shown to harbor a heterogeneous population of T lymphocytes (TNC-L) some of which exhibit a postselectional phenotype. By transplanting micromanipulated single chicken TNC onto the chorionallantoic membrane (CAM) of major histocompatibility complex (MHC)-disparate embryos, an experimental system which allows for the detection of lymphocytes with graft-vs.-host (GVH) reactivity, we demonstrate here that TNC enclose lymphocytes that can develop into both CD4+ single-positive (sp) and CD8+ sp, T cell receptor (TcR) alpha beta+, or TcR gamma delta+ cells. This finding was additionally confirmed by serial transfer of primary expanded alloreactive T cells onto the CAM of secondary hosts. All donor TNC-L expressed MHC class II molecules and the interleukin-2 receptor alpha chain in primary and secondary GVH reactions. Furthermore, we observed selective accumulation of CD8+ and TcR gamma delta+ host lymphocytes in the CAM upon the induction of a local GVH reaction, most probably as a consequence of the pathological alteration of the epithelium.

The turkey major histocompatibility complex: characterization by mixed lymphocyte, graft-versus-host splenomegaly, and skin graft reactions

A turkey subline at the Ohio Agricultural Research and Development Center was developed by DNA typing of the MHC using a chicken MHC Class II probe, and it segregated for specific MHC genotypes. Histocompatibility was examined between turkeys of known MHC genotype using skin graft procedures, mixed lymphocyte reactions (MLR), and graft-versus-host reactions (GVHR). Skin grafts were exchanged among 3-wk-old turkeys and it was found that when birds shared DNA patterns (genotypes), the skin grafts were usually accepted. In contrast, skin grafts were always rejected when birds did not share the identical DNA pattern. Similarly, MLR only occurred when the lymphocytes were derived from birds that did not share the same DNA pattern. Lastly, GVHR were examined in embryos injected with either sire or dam blood. The GVHR in embryos was dependent on the parental MHC genotype. Four MHC haplotypes were identified in the turkey subline. The turkey MHC has been designated MhcMega-B, and each of the haplotypes, Mega-B(1) through Mega-B(4).

Thymic nurse cell lymphocytes react against self major histocompatibility complex

It has been postulated that thymic nurse cells (TNC), lymphoid-epithelial complexes composed of thymocytes enclosed within major histocompatibility complex (MHC) class I+ and class II+ cortical epithelial cells, may provide an optimal microenvironment for the process of T cell selection. By transplanting single TNC in the avian chorionallantoic membrane assay we demonstrate that a significant portion of intra-TNC lymphocytes (TNC-L) possess reactivity against self-MHC molecules. The frequency of these autoreactive cells among TNC-L exceeds by far that of thymocytes or peripheral blood lymphocytes of the same donor. These results indicate that TNC-L constitute a T cell population enriched for self-MHC reactivity, i.e. cells that have undergone positive selection, but not yet deletion and/or deactivation.

Strong donor mononuclear cell reactivity for herpes simplex virus (HSV) antigen in HSV immune donors combined with recipient seropositivity for HSV is associated with acute graft-versus-host disease

Prior to bone marrow transplantation (BMT) titres of IgG antibodies for cytomegalovirus (CMV), herpes simplex virus (HSV) and varicella zoster virus (VZV) were analysed in 51 donors and recipients of allogeneic bone marrow. Donor mononuclear cells from peripheral blood and bone marrow cells were stimulated with antigen prepared from CMV, HSV and VZV. High IgG titres for HSV in the recipient were associated with grade II-III acute graft-versus-host disease (GVHD) (P = 0.05). Furthermore, the combination of positive IgG titre for HSV antibodies in the recipient, and strong donor blood mononuclear cell reactivity to HSV antigen in HSV immune donors, significantly increased the incidence of grade II-III acute GVHD (P = 0.04). The data suggest that HSV immune donor mononuclear cells may initiate a GVH reaction.

Graft-versus-host disease: the need for a new terminology

For some decades, graft-versus-host (GVH) reactions seemed readily comprehensible. It was generally accepted that after introduction of immunocompetent, histoincompatible lymphocytes into an immunodeficient host the grafted lymphocytes would start a 'rejection' response against their host. As a result, GVH disease developed. Acute disease might result in death and survivors became chimaeras with varying pathology--chronic GVH disease. In recent years, however, some intriguing exceptions to the general rules for the development of GVH disease have been reported. These exceptions, particularly the activation of GVH disease by stimuli other than histocompatibility barriers prompted Gerard Bos and colleagues to propose this change in terminology.

Syngeneic or autologous graft-versus-host disease

Graft-versus-host disease (GVHD) until recently was supposed to occur only when immunocompetent T lymphocytes are infused into immunoincompetent allogeneic hosts that possess histocompatibility antigens not possessed by the donor that could act as targets for cell-mediated cytotoxicity. A syndrome clinically and histologically identical to mild allogeneic GVHD occurs infrequently, following syngeneic or autologous bone marrow transplantation (BMT). This syndrome called syngeneic or autologous GVHD can be regularly produced with Cyclosporine (CsA) in animals undergoing syngeneic or autologous BMT. Animals with this syndrome develop T cells that are autocytotoxic to Ia antigen-bearing cells. The presence of an irradiated thymus and CsA administration is necessary to produce this disease. Operationally, this disease results from a disturbance of balance between a normally present autoregulatory cell and an autocytotoxic T cell. The study of mechanisms involved in the generation of this disease will add to our fundamental understanding of the cellular regulation of autocytotoxic T cell-medicated reactions and diseases. Most recently, we have been able to induce this disease in man with the aim of investigating its therapeutic effect in autologous BMT in patients with Ia-bearing tumors.

Effect of adrenocorticotropin and dietary ascorbic acid on the graft-versus-host reaction capacity of chickens

Two trials using the splenomegaly assay were conducted to assess the effects of adrenocorticotropin (ACTH) and dietary ascorbic acid (AA) on the ability of chickens to mount a graft-vs.-host reaction (GVHR). Broiler chicks served as blood donors. Birds received AA at levels of 0, 150, or 300 mg/kg of feed (ppm). At 6 wk of age, donor birds from each AA group received either three intramuscular injections of ACTH in gelatin at 12-h intervals, comparable injections of the gelatin, or no injections. Thirteen-day-old Single Comb White Leghorn embryos served as recipients. Two recipient embryos per donor were injected in a chorioallantoic vein with either whole blood (Trial 1) or saline-washed and reconstituted blood cells (Trial 1). Eggs were further incubated for 6 days, at which time the embryos were killed and each spleen excised. Relative spleen weights were expressed as milligrams of spleen/100 g embryonic body weight. Significant differences in relative spleen weight or donor plasma corticosterone (CS) levels did not occur in Trial 1. In Trial 2, regardless of AA treatment, relative spleen weights of embryos that received blood cells from donors treated with ACTH were significantly lower than controls. Donor CS was significantly lower in birds that received ACTH. These results indicate that, when washed and reconstituted blood cells are injected into recipients and donor plasma CS is decreased, GVHR capacity is suppressed in ACTH-treated donors.

The induction of organ-specific antibodies during the graft-vs.-host reaction

During the parent (P) into F1 hybrid graft-vs.-host reaction (GVHR), nuclear, leukocyte and erythrocyte autoantibodies are commonly seen. The specificity of these autoantibodies is reminiscent of those found in systemic lupus erythematosus (SLE) patients and SLE-prone mice. Organ-specific antibodies, however, including thyro-globulin (Tg) antibodies do not arise spontaneously. There have been conflicting reports about the ability of exogenous Tg to induce an anti-Tg response during the GVHR. We have re-examined this question in greater detail. Using the murine P----F1 GVHR system, the results of this work demonstrate that mouse thyroglobulin (MTg)-specific antibodies can be induced during a GVHR. However, mice must both be undergoing a GVHR, and have received exogenous MTg. The highest autoantibody response occurs if mice are injected with mouse thyroid extract or purified MTg at the time of P----F1 cell transfer. The anti-MTg response is MTg dose dependent. The ability to induce anti-MTg antibody was not major histocompatibility complex restricted, for both the DBA/2----B6D2F1 (low responder H-2 haplotypes to MTg), and AKR or DBA/2----AKD2F1 (high/low responder----high responder haplotype) GVHR gave similar responses. The anti-MTg titers peaked between days 7-10 and declined thereafter. In contrast, antibodies to dsDNA were not present at this early time, but developed after several weeks. We conclude that organ-specific autoantibodies can be induced during a GVHR if the appropriate antigen(s) are presented near the time of GVHR induction.

Risk factors for acute graft-versus-host disease

Acute graft-versus-host disease (GvHD) is an important complication of bone marrow transplantation in humans. Risk factors are imprecisely defined and controversial. We analysed data from 2036 recipients of HLA-identical sibling transplants for leukaemia or aplastic anaemia to identify risk factors for GvHD. Analyses indicate that grading of GvHD can be reproducibly divided into absent or mild versus moderate to severe; 2-year actuarial probability was 54% (95% confidence interval 52-56%) for absent or mild and 46% (44-48%) for moderate to severe. Factors predictive of development of moderate to severe GvHD include donor/recipient sex-match (female----male greater than others, relative risk 2.0, P less than 0.001). This risk was markedly increased if female donors for male recipients were previously pregnant or transfused (relative risk 2.9, P less than 0.0001). Older patients were at increased risk of GvHD (relative risk 1.6, P less than 0.001), but the age gradient was modest, even the youngest patients had a substantial risk of GvHD and, if parous or transfused female----male transplants were excluded, age was not a significant risk factor. Cyclosporine or methotrexate were equally effective at preventing GvHD and were superior to no prophylaxis (relative risk 2.3, P less than 0.01). These data should be useful in estimating the risk of acute GvHD in an individual patient and in designing clinical trials to investigate methods to modify or prevent GvHD.