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Syngeneic graft vs. host disease (SGVHD) was first described as a graft vs. host disease-like syndrome that developed in rats following syngeneic bone marrow transplantation (BMT) and cyclosporin A (CsA) treatment. SGVHD can be induced by reconstitution of lethally irradiated mice with syngeneic bone marrow cells followed by 21 days of treatment with the immunosuppressive agent CsA. Clinical symptoms of the disease appear 2-3 wk following cessation of CsA therapy, and disease-associated inflammation occurs primarily in the colon and liver. CD4(+) T cells have been shown to play an important role in the inflammatory response observed in the gut of SGVHD mice. Time-course studies revealed a significant increase in migration of CD4(+) T cells into the colon during CsA therapy, as well as significantly elevated mRNA levels of TNF-α, proinflammatory chemokines, and cell adhesion molecules in colonic tissue of CsA-treated animals compared with BMT controls, as early as day 14 post-BMT. Homing studies revealed a greater migration of labeled CD4(+) T cells into the gut of CsA-treated mice at day 21 post-BMT than control animals via CsA-induced upregulation of mucosal addressin cell adhesion molecule. This study demonstrates that, during the 21 days of immunosuppressive therapy, functional mechanisms are in place that result in increased homing of CD4(+) T effector cells to colons of CsA-treated mice.

The murine model of cyclosporine A (CsA)-induced syngeneic graft-versus-host disease (SGVHD) is a bone marrow (BM) transplantation model that develops chronic colon inflammation identical to other murine models of CD4(+) T cell-mediated colitis. Interestingly, SGVHD animals develop chronic liver lesions that are similar to the early peribiliary inflammatory stages of clinical chronic liver disease, which is frequently associated with inflammatory bowel disease (IBD). Therefore, studies were initiated to investigate the chronic liver inflammation that develops in the SGVHD model. To induce SGVHD, mice were lethally irradiated, reconstituted with syngeneic BM, and treated with CsA. All of the SGVHD animals that developed colitis also develop chronic liver inflammation. Liver samples from control and SGVHD animals were monitored for tissue pathology, RNA for inflammatory mediators, and phenotypic analysis and in vitro reactivity of the inflammatory infiltrate. Diseased animals developed lesions of intrahepatic and extrahepatic bile ducts. Elevated levels of mRNA for molecules associated with chronic liver inflammation, including mucosal cellular adhesion molecule -1, the chemokines CCL25, CCL28, CCR9, and T(H)1- and T(H)17-associated cytokines were observed in livers of SGVHD mice. CD4(+) T cells were localized to the peribiliary region of the livers of diseased animals, and an enhanced proliferative response of liver-associated mononuclear cells against colonic bacterial antigens was observed. The murine model of SGVHD colitis may be a valuable tool to study the entero-hepatic linkage between chronic colon inflammation and inflammatory liver disease.

Background: Syngeneic graft-versus-host disease (SGVHD) develops after lethal irradiation, reconstitution with syngeneic bone marrow (BM), and treatment with a 21-day course of the immunosuppressant cyclosporine A (CsA). Clinical symptoms of SGVHD appear 2-3 weeks after CsA treatment, with inflammation in the colon and liver. It has been demonstrated that CD4+ T cells and a T helper cell type 1 cytokine response (Th1) are involved in the development of SGVHD associated intestinal inflammation. The immune response associated with SGVHD is thought to be the result of the reconstitution of the recipient immune system with the syngeneic donor BM. However, definitive studies have not addressed this issue experimentally., Methods: To determine the origin of the effector cells that participate in SGVHD, C3H/HeN recipient mice were lethally irradiated and transplanted with BM from normal immunocompetent mice or from immunodeficient, severe combined immune deficient, or Rag-2-/- animals., Results: CsA-treated animals, but not control animals, developed inflammation characteristic of SGVHD in the colon and liver regardless of the source of the donor marrow. Furthermore, immunologically, all CsA treated animals responded similarly with increased production of inflammatory cytokines and an increase in activated CD4+ T cells in the periphery and colon relative to controls., Conclusion: These results demonstrate that after lethal irradiation and in the absence of donor T cells, T cells of recipient origin can expand and mediate the induction of CsA-induced SGVHD.

Syngeneic graft-versus-host disease (SGVHD) develops following lethal irradiation, reconstitution with syngeneic bone marrow, and treatment with a short course of cyclosporin A (CsA) therapy. The disease is characterized by the development of a T helper cell type 1-like cytokine response [interleukin (IL)-12, interferon-gamma (IFN-gamma), and tumor necrosis factor alpha], and macrophage activation is central to development of the syndrome. It has been shown that nitric oxide (NO) participates significantly in the development of allogeneic GVHD. Studies were initiated to determine if NO participates in the pathology associated with SGVHD. Significant increases in inducible NO synthase (iNOS) mRNA and circulating NO were found in the tissues of SGVHD versus control animals. Treatment of SGVHD animals with the iNOS inhibitor aminoguanidine (AG) reversed the pathology associated with this disease. Furthermore, AG treatment reduced the production of IL-12 and IFN-gamma mRNA in the colons of CsA-treated mice. These studies demonstrate that NO participates in the pathological processes that are associated with the development of murine SGVHD.

Syngeneic GVHD (SGVHD) develops following syngeneic bone marrow transplantation and treatment with cyclosporine A. Previous studies have demonstrated a role for IL-12, IFN-gamma, and TNF-alpha in the development of murine SGVHD. Macrophages can be activated to secrete IL-12 and TNF-alpha via a T-cell-dependent or T-cell-independent pathway (LPS or bacterial products). Studies were designed to determine if LPS participated in the development of SGVHD in C3H/HeN (LPS-responsive) and C3H/HeJ (LPS-hyporesponsive) mice. C3H/HeJ and C3H/HeN mice had similar levels of disease induction and pathology. Following induction of SGVHD, treatment of C3H/HeN, but not C3H/HeJ, mice with a sublethal dose of LPS resulted in mortality. However, neutralization of IL-12 abrogated the development of disease in C3H/HeJ mice, demonstrating that activated macrophages and their products participated in the development of SGVHD in these animals. These data suggested that LPS responsiveness was not a predisposing factor for SGVHD induction.

Cyclosporin A (CsA) has been used clinically to induce graft-versus-host disease following autologous bone marrow transplantation in an attempt to destroy residual leukemia cells and reduce relapse. To analyze the antitumor potential of murine syngeneic graft-versus-host disease (SGVHD), C3H/HeN mice were lethally irradiated, reconstituted with T cell-depleted syngeneic bone marrow (ATBM) and treated with CsA for 21 days. Graft-versus-leukemia activity was assessed by challenging groups of olive oil-treated control ATBM (OO-ATBM) and CsA-treated (CsA-ATBM) mice 1 week after CsA therapy with graded doses of the syngeneic 38C13 B cell lymphoma. Following CsA treatment, up to 70% of CsA-ATBM developed SGVHD and more than 70% of the animals injected with 500 38C13 cells exhibited long-term survival (MST >80 days). In contrast, none of the OO-ATBM control mice developed SGVHD, and more than 75% of these mice died following injection of 500 38C13 tumor cells (MST = 34 days). Long-term survivors were not resistant to tumor challenge suggesting that tumor-specific immunity did not develop. Finally, class II negative 38C13 cells cultured in IL-4 or IL-10 were not inducible for MHC class II molecules, demonstrating that class II-independent antitumor mechanisms exist in SGVHD mice.

Pulmonary complications are a major clinical problem following allogeneic bone marrow transplantation (BMT), contributing to more than 30% of transplant-related mortalities. Idiopathic pneumonia syndrome is responsible for significant mortality among BMT patients. However, the etiology of injury to the lung parenchyma by this disease syndrome is unknown and it has been difficult to evaluate the cellular and molecular mechanisms underlying IPS in the absence of a suitable animal model. To study post-BMT lung disease during graft-versus-host disease (GVHD), we have developed a murine model that utilizes a semi-allogeneic parental --> F1 transplant strategy to induce a mild form of GVHD. Progressive inflammatory lung disease developed in animals with mild GVHD, as indicated by changes in immune cell distribution and cytokine expression in the lungs of transplanted animals. Histologic analysis of lung tissue from GVHD mice at 3 wk post-BMT showed minor immunopathologic changes compared with control mice. In contrast, lungs of GVHD mice at 12 wk displayed histopathologic hallmarks of interstitial pneumonitis, such as prominent perilumenal mononuclear cell infiltration and areas of alveolar congestion. Flow cytometric analysis of lung interstitial cells of GVHD mice revealed an increase in CD8+ T-cells at week 3, which decreased to normal levels by week 12 post-BMT. Simultaneously, the percentage of CD4+ T-cells increased progressively above normal levels and peaked at week 7 post-BMT. Analysis of cytokine mRNA expression in lung tissue indicated that steady state levels of interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, interferon-gamma, and IL-12 were significantly elevated in lungs of GVHD mice at 3 wk post-BMT compared with untreated controls. Mice that were transplanted with allogeneic bone marrow alone (BMT controls) also displayed elevated expression of these cytokines, although only IL-6 was significantly higher than in untreated controls. In contrast, at 12 wk after transplantation only TNF-alpha and IL-12 levels remained elevated in GVHD mice, suggesting prolonged macrophage activation. On the basis of these findings, we conclude that allogeneic bone marrow transplantation in this mouse model causes a progressive interstitial pneumonitis, which is characterized by an acute influx of CD8+ T-cells, followed in the chronic phase by a prominent accumulation of CD4+ T-cells, and is associated with persistent production of cytokines known to activate macrophages.

Graft-vs-host disease (GVHD) after allogeneic bone marrow transplantation is associated with significant morbidity and mortality. T cell depletion of the marrow graft, which is currently used to prevent GVHD, has been shown to result in increased graft failure and leukemia relapse. To explore the feasibility of controlling GVHD, transgenic mice with the herpes simplex virus thymidine kinase suicide gene linked to the IL-2 promoter were used as a source of T cells to induce GVHD, which would be modulated with ganciclovir. Injection of herpes simplex virus thymidine kinase transgenic B10.A(5R) spleen cells into lethally irradiated DBA/2 mice resulted in severe acute GVHD. Treatment of the recipient mice with ganciclovir significantly inhibited GVHD-mediated weight loss and mortality and reduced the severity of inflammation in the target organs of GVHD.

The incidence and severity of GVHD following bone marrow transplantation increases with recipient age. The role of recipient age on the development of GVHD was analyzed in a semi-allogeneic (C57BL/6-->(C57BL/6 x DBA/2)F1) murine GVHD system. Young adult (2 months) and old (12-14 months) recipient mice were lethally irradiated and reconstituted with young adult T cell-depleted bone marrow (ATBM) or ATBM and young spleen cells. A significantly higher percentage of old vs young recipients developed lethal GVHD. Furthermore, while pre-transplant conditioning with irradiation was not required to observe increased mortality in old recipients, irradiation predisposed the older animals for a more severe course of GVHD, suggesting that GVHD occurred in old compared to young animals in the absence of pre-transplant conditioning but was exacerbated by irradiation. Histologically, the immunological responses in the GVHD target organs were more severe in the old GVHD animals. In support of this observation, increased spontaneous proliferation was observed using lymphoid cells isolated from old vs young GVHD mice. These findings demonstrate that old recipients develop a more severe course of GVHD following BMT, and may present a unique opportunity to study age-related factors in the generation of GVHD.

The purpose of presenting this case is to illustrate the importance of high-resolution DNA Class 2 typing when assignment of MHC antigens is of extreme importance (i.e. bone marrow transplantation); suggest this test as a substitute for the mixed lymphocyte culture (MLC), and provide evidence that DRB1 subtype mismatches may be clinically significant. Initial serological and monoclonal HLA Class 1 and low-resolution DNA-SSP Class 2 typing of a potential bone marrow transplant patient and two sisters revealed all to be HLA identical with apparent homozygosity for DRB1 x 04. High-resolution DNA-SSP Class 2 typing was then performed and revealed electrophoretic banding patterns which were not specific for any DRB1 x 04 subtype. One sister and the patient had identical patterns, while the other sister had a different pattern. Complete HLA Class 1 and high-resolution DNA-SSP Class 2 typing of the parents was performed. The mother was found to be heterozygous for Class 1 and Class 2 antigens and possess the DRB1 x 0404, 0405 subtypes. In contrast, the father was found to be homozygous for Class 1 antigens, heterozygous for Class 2 antigens and possess the DRB1 x 0404, 0407 subtypes. This led to the initial false assumption of HLA identity for the patient and her two sisters. However, assignment of haplotypes revealed one sister to be HLA identical with the patient and the other sister to be a one-haplotype five-antigen match with the patient, mismatching for one DRB1 allele. Bone-marrow transplantation was performed utilizing the latter sister, which resulted in intractable acute graft vs. host disease that resulted in the patient's demise.

A syngeneic graft-versus-host disease (GVHD)-like syndrome has been shown to be inducible in some strains of mice after lethal irradiation, reconstitution with syngeneic bone marrow (BM), and treatment with a short course of CsA therapy. Since Thy1+ BM cells have been shown to regulate the development of other experimental autoimmune diseases, it was important to determine their role in the inducibility of syngeneic GVHD (SGVHD) in different strains of mice. Lethally irradiated mice were reconstituted with either syngeneic BM or T cell-depleted syngeneic BM, then treated with CsA or diluent. Removal of Thy1+ cells from BM before reconstitution of an inducible strain, C3H/HeN, exacerbated SGVHD when compared with animals given whole BM cells before CsA treatment. Furthermore, a noninducible strain, C57BL/6 mice, developed SGVHD when reconstituted with T cell-depleted syngeneic BM but not BM before CsA therapy. These results suggest that Thy1+ BM cells may regulate the development of SGVHD, and be of importance in controlling autoreactivity after bone marrow transplantation.

Clinical acute graft-versus-host disease (aGVHD) was correlated with alterations in PBL phenotype and skin immunohistology in 52 patients transplanted with HLA-identical bone marrow. Concurrent with the emergence of aGVHD, there was a profound decrease in absolute number of CD3- T cells and an increase in CD3-CD16+, CD56+ (a subset of which coexpress CD8+ "dim") NK cells in the PBL. CD4+ T and CD20+ B lymphocytes failed to recover within 90 days in the patients with grades II-IV aGVHD. Ex vivo partial T cell depletion, in itself, did not significantly impair T cell recovery as compared to that in non-T-depleted recipients unless aGVHD occurred. Although leukocytic cellular infiltration in the skin was generally sparse, CD16+ NK lymphocytes were significantly increased in grades II-IV aGVHD. By contrast, there was no significant increase in CD3+, CD4+, or CD8+ lymphocytes in these lesions as compared to skin biopsies obtained from BMT patients without aGVHD or from normal skin. Taken together, these findings suggest that NK cells may be important in the pathogenesis of human aGVHD.