Prediction of acute graft-versus-host disease and detection of distinct end-organ targets by enumeration of peripheral blood cytokine spot-forming cells

Interleukin-10 spot-forming cells as a novel biomarker of chronic graft-versus-host disease

Although there are National Institutes of Health consensus criteria for the global assessment of chronic graft-versus-host disease, no validated biomarkers have been established for this disease. Furthermore, whereas the role of T cells, B cells, and dendritic cells in chronic graft-versus-host disease has been established, the contribution of monocytes has not been clearly addressed. Using an enzyme-linked immunospot assay, we measured the spot-forming cells for interferon-γ, interleukin-4, interleukin-10, and interleukin-17 in unstimulated peripheral blood of patients following allogeneic hematopoietic stem cell transplantation. Other immunological examinations, including skin biopsy, were also done. Fifty-seven patients were enrolled. Interleukin-10 spot-forming cells were evaluable for therapeutic monitoring in 16 patients with chronic graft-versus-host disease. The number of interleukin-10 spot-forming cells in patients with active chronic graft-versus-host disease was significantly higher than the number in those with no or inactive chronic graft-versus-host disease. Interleukin-10 was predominantly produced by monocytes. CD29 expression on monocytes in patients with active chronic graft-versus-host disease was elevated. The level of plasma fibronectin, a ligand of CD29, correlated with the number of interleukin-10 spot-forming cells. Immunohistochemical analysis of the skin in active chronic graft-versus-host disease showed that infiltrating CD29(+) monocytes might produce interleukin-10. A novel biomarker, interleukin-10 spot-forming cells, shows promise as both a diagnostic and prognostic indicator for chronic graft-versus-host disease, and may allow for early intervention prior to the onset of the disease. Measurement of interleukin-10 spot-forming cells would be helpful in clinical trials and in patients' management.

Increased Level of IFN-γ and IL-4 Spot-Forming Cells on ELISPOT Assay as Biomarkers for Acute Graft-Versus-Host Disease and Concurrent Infections

Acute graft-versus-host disease (aGVHD) remains a significant cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Infections may coexist and in certain circumstances aggravate aGVHD. It was described that type 1 as well as type 2 cytokines are important mediators of aGVHD. We measured spot-forming cells (SFCs) for interferon (IFN)-γ, interleukin (IL)-4, IL-10, and IL-17 in unstimulated peripheral blood from 80 patients with hematological disorders who underwent allogeneic hematopoietic stem cell transplantation by using the enzyme-linked immunospot (ELISPOT) assay that reflects the ongoing in vivo immune status. A serial monitoring showed that both type 1 and type 2 cytokine SFCs were correlated with aGVHD activity. The numbers of IFN-γ and IL-4 SFCs in patients with grade II-IV aGVHD were significantly higher than those in patients with grade 0 and/or I aGVHD. Elevation of IFN-γ and IL-4 SFCs was significantly correlated with the severity of aGVHD, but not with infection itself, e.g., cytomegalovirus infection. Cytokine SFCs are clinically relevant biomarkers for the diagnostic and therapeutic evaluation of aGVHD and concurrent infection.

Cytokine expression in tumors treated with donor lymphocyte infusions after allogeneic hematopoietic stem cell transplantation

AIMS

Risk factors for disease relapse are remaining tumor or leukemic cells or mixed chimerism (MC) following allogeneic hematopoietic stem cell transplantation. Donor lymphocyte infusion (DLI) after stem cell transplantation can contribute to complete donor chimerism and graft-versus-tumor/leukemia effect. We evaluate cytokine secretion at the single-cell level using ELISpot in relation to DLI effect on disease response.

PATIENTS & METHODS

Blood samples were collected from four patients with solid tumors and four with hematological malignancies before DLI, and 1 and 3 weeks after DLI. Tumor response was evaluated according to the international Response Evaluation Criteria In Solid Tumors (RECIST) method. Indications for DLI were stable disease or MC and/or progressive disease in solid tumors, and molecular or early relapse, or MC in hematological malignancies. ELISpot was performed for TNF-α, IFN-γ, IL-12, IL-4, IL-10 and IL-13 cytokines.

RESULTS

Depending on the disease response, patients were divided into two groups: responders and nonresponders. Responders were patients who achieved partial response (one renal cell cancer) or stable disease (one prostate cancer) or clinical remission (two acute myeloid leukemia). Patients who relapsed, progressed or rejected the graft were the nonresponders. DLI rescued the renal cell cancer patient, who has partial response, and two acute myeloid leukemia patients, who are in clinical remission. Patients who responded tended to have a higher expression of TNF-α, IFN-γ, IL-12 and IL-10 than those who did not respond.

CONCLUSIONS

DLI can act when the patients' mononuclear cells have normal or increased capacity to produce TNF-α, IFN-γ, IL-12 and IL-10. Assessment of these cytokines may be useful to predict those patients who will respond to DLI therapy.

Prediction of reactivity to noninherited maternal antigen in MHC-mismatched, minor histocompatibility antigen-matched stem cell transplantation in a mouse model

The immunologic effects of developmental exposure to noninherited maternal Ags (NIMAs) are quite variable. Both tolerizing influence and inducing alloreaction have been observed on clinical transplantation. The role of minor histocompatibility Ags (MiHAs) in NIMA effects is unknown. MiHA is either matched or mismatched in NIMA-mismatched transplantation because a donor of the transplantation is usually limited to a family member. To exclude the participation of MiHA in a NIMA effect for MHC (H-2) is clinically relevant because mismatched MiHA may induce severe alloreaction. The aim of this study is to understand the mechanism of NIMA effects in MHC-mismatched, MiHA-matched hematopoietic stem cell transplantation. Although all offsprings are exposed to the maternal Ags, the NIMA effect for the H-2 Ag was not evident. However, they exhibit two distinct reactivities, low and high responder, to NIMA in utero and during nursing depending on the degree of maternal microchimerism. Low responders survived longer with less graft-versus-host disease. These reactivities were correlated with Foxp3 expression of peripheral blood CD4(+)CD25(+) cells after graft-versus-host disease induction and the number of IFN-γ-producing cells stimulated with NIMA pretransplantation. These observations are clinically relevant and suggest that it is possible to predict the immunological tolerance to NIMA.

IFN-gamma activation of mesenchymal stem cells for treatment and prevention of graft versus host disease

Graft versus host disease (GVHD), mediated by donor T cells, is a significant source of morbidity and mortality following allogeneic stem cell transplantation. Mesenchymal stem cells (MSC) can successfully treat ongoing graft versus host disease, presumably due to their ability to suppress donor T cell proliferation. Little is known about the potential of MSC to prevent GVHD. Here we show that bone marrow-isolated MSC can suppress the development of GVHD if given after donor T cell recognition of antigen. IFN-gamma was required to initiate MSC efficacy. Recipients of IFN-gamma(-/-) T cells did not respond to MSC treatment and succumbed to GVHD. MSC, pre-treated with IFN-gamma, became immediately active and could suppress GVHD more efficiently than a fivefold-greater number of MSC that were not activated. When given at the time of bone marrow transplantation, activated MSC could prevent GVHD mortality (100% survival, p=0.006). MSC activation was dependent on the magnitude of IFN-gamma exposure, with increased IFN-gamma exposure leading to increased MSC suppression of GVHD. Activated MSC present a new strategy for preventing GVHD using fewer MSC.

Skin explant model of human graft-versus-host disease: prediction of clinical outcome and correlation with biological risk factors

A human skin explant model has been used to predict the clinical outcome and to study the immunopathology of human graft-versus-host disease (GVHD). Whether the model gives the same predictive effect for GVHD in different hematopoietic stem cell transplantation (HSCT) settings has not been assessed. It is also unknown whether the skin explant result reflects the known biological risk factors for clinical GVHD. In this study, the skin explant model was used to detect graft-versus-host reactions (GVHR) in vitro for 225 eligible patient/donor pairs. The predicted skin GVHR grade was correlated with the outcome of clinical GVHD, as well as HLA matching status, sex mismatches, and patient age. In sibling HSCT under either myeloablative or reduced-intensity conditioning, a significant correlation was observed between the predicted skin GVHR and clinical GVHD (P < .001 and P = .033, respectively). In HSCT using unrelated donors, the involvement of T-cell depletion led to a sharp increase in false-positive GVHR results, and no correlation was observed between the predicted skin GVHR and clinical GVHD. The skin GVHR grade correlated significantly with the HLA matching status (HLA-matched sibling pairs, HLA-matched unrelated pairs, and HLA-unmatched unrelated pairs). Furthermore, HLA-matched sibling pairs with a female-to-male sex mismatch had a significantly higher overall skin GVHR grade and a higher ratio of high- versus low-grade skin GVHR than the sibling pairs with all other sex combinations. Patient age was not reflected in the skin explant result. In conclusion, the predictive value of the skin explant model for aGVHD varies depending on the clinical transplant protocols, such as the type of GVHD prophylaxis used. Nevertheless, the skin explant model remains a unique in vitro system that provides an in situ histopathologic readout for studying alloreactivity and human GVHD. The model has also the potential to aid the development of novel prophylaxis and treatment for GVHD.

Development of a dendritic cell vaccine against measles for patients following hematopoietic cell transplantation

Most patients who have undergone hematopoietic cell transplantation (HCT) lose specific immunity to measles. However, due to its immunosuppressive potential, it has been recommended that a live attenuated measles vaccination be administered two years following HCT. Measles virus (MV) glycoproteins including hemagglutinin (HA) are expressed on MV-infected dendritic cells (DCs), and they impair efficient antigen presentation between the DC and T cell. We produced a DC-based vaccine against MV by loading DCs with MV-infected autologous DCs. MV in the infected DCs was inactivated using ultraviolet-B. The DC-based vaccine neither expressed HA nor inhibited allogeneic T cell proliferation, while it induced the production of interferon-gamma (IFN-gamma) by autologous CD4 and CD8 naive T cells ex vivo. Importantly, the vaccine derived from patients who had undergone HCT also efficiently induced IFN-gamma producing cells. These findings indicate that our DC-based MV vaccine induces MV-specific immunity even in post-HCT patients without causing immunosuppression.

Discrimination of Acute Graft-versus-Host Disease from Infections by Enumeration of Peripheral Blood Interferon-?? Spot-Forming Cells

Infections may coexist and in certain circumstances aggravate acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation. Early detection of aGVHD is often difficult in patients with concurrent infections. Using an enzyme-linked immunospot assay that reflects ongoing immune status in vivo, we enumerated spot-forming cells (SFCs) for interferon (IFN)-gamma, interleukin (IL)-4, and IL-12 in peripheral blood from 56 patients with hematological disorders. Eleven patients had viral, fungal, or bacterial systemic infections during first 10 weeks posttransplant. Of these, six patients with grade 0-I aGVHD showed normal levels of IFN-gamma SFCs. On the other hand, IFN-gamma SFCs were elevated in five patients with grade II-IV aGVHD. These data indicate that increased IFN-gamma SFCs seemed to be correlated with clinically significant aGVHD, but not with infection itself. IL-4 and IL-12 SFCs increased in some patients with infections, irrespective of the presence of aGVHD. Thus, IFN-gamma SFCs may be used to distinguish systemic infections from aGVHD.