Two cases of chronic graft-versus-host disease with elevated levels of soluble Fas ligand in serum

Recombinant CD95-Fc (APG101) prevents graft-versus-host disease in mice without disabling antitumor cytotoxicity and T-cell functions

Graft-versus-host disease (GVHD) induced by transplant-derived T cells represents a major complication after allogeneic bone marrow transplantation (BMT). However, these T cells support engraftment, early T-cell immunity, and mediate the graft-versus-tumor (GVT) effect. Cytotoxic effector functions by transplanted T cells are predominantly mediated by the perforin/granzyme and the CD95/CD95L system. APG101, a novel recombinant human fusion protein consisting of the extracellular domain of CD95 and the Fc domain of an IgG1 antibody inhibited CD95L-induced apoptosis without interfering with T-cell function in vitro and was therefore tested for its ability to prevent GVHD in murine BMT models across minor or major histocompatibility barriers. Starting APG101 treatment either 1 day before or 6 days after transplantation effectively reduced clinical GVHD and rescued survival between 60% and 100% if GVHD was CD95L mediated. APG101 did not interfere with the GVT effect, because P815 mastocytoma and most importantly primary Bcr-Abl-transformed B-cell leukemias were completely eradicated by the alloantigen-specific T cells. Phenotype and homing of alloantigen-specific T cells or their perforin/granzyme-mediated cytotoxicity and proliferative capacity were not affected by APG101 treatment suggesting that APG101 therapy might be useful in GVHD prophylaxis without impairing T-cell function and most importantly preserving GVT activity.

Increased soluble Fas ligand levels in patients with Stevens-Johnson syndrome and toxic epidermal necrolysis preceding skin detachment

BACKGROUND

It is difficult to distinguish the early phase of Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) from other ordinary types of drug-induced skin reactions (ODSRs). Levels of several serum soluble factors, including soluble Fas ligand (sFasL), have been reported to be increased in patients with SJS/TEN; however, the marker to predict the onset of SJS/TEN before the development of skin detachment or mucosal lesions has not been identified.

OBJECTIVE

We sought to determine whether sFasL might be a useful marker in the early stages of SJS/TEN.

METHODS

Sera of 19 patients with SJS and 16 patients with TEN at 1 or multiple time points were obtained from Japanese multiple hospitals. The disease onset (day 1) was defined when erosion/ulceration of the mucocutaneous or ocular lesion first developed. For the investigation of soluble factors, including sFasL, TNF-alpha, IFN-gamma, IL-6, and sCD40 ligand, we used ELISAs and Cytometric Bead Arrays.

RESULTS

Before disease onset (day -4 to approximately -2), 7 samples were available, and we detected the highest concentrations of sFasL in 5 (71.4%) of 7 patients. Increased sFasL levels decreased rapidly within 5 days of disease onset. In all 32 patients with ODSRs and 33 healthy control subjects, no increase of sFasL levels was detected. Other soluble factor concentrations did not show significant difference with those seen in patients with SJS/TEN before disease onset and ODSRs.

CONCLUSION

The sFasL levels of sera in patients with SJS/TEN are significantly increased before development of skin detachment, mucosal lesions, or both.

Evaluation of angiopoietins and cell-derived microparticles after stem cell transplantation

Although stem cell transplantation (SCT) is being used for hematopoietic reconstitution following high-dose chemotherapy for malignancy, it involves certain serious transplant-related complications such as graft-versus-host disease (GVHD). Angiopoietins play important roles in angiogenesis. However, the role of angiopoietins after SCT is poorly understood. In this study, 52 patients underwent SCT; 26 patients received allogeneic SCT, while the remaining 26 received autologous SCT. In 48 of 52 patients, levels of angiopoietins, cytokines, and soluble factors were measured by enzyme-linked immunosorbent assay. Soluble Fas ligand (sFasL) and endothelial cell-derived microparticle (EDMP) exhibited significant elevation in the early phase (2-3 weeks) after SCT. In addition, the elevation of interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and sIL-2 receptor (sIL-2R), which are GVHD markers after allogeneic SCT was observed. The level of angiopoietin (Ang)-2 in allogeneic SCT continued to increase for up to 4 weeks, although the level of Ang-1 did not show significant changes. The patients with high Ang-2 exhibited significant increase of sFasL and EDMP compared with those with low Ang-2. In addition, the patients with high-grade GVHD exhibited a significant increase in Ang-2 compared to patients with low-grade GVHD. In the in vitro experiment using endothelial cells, the suppressive effect of Ang-1 on EDMP generation by TNF-alpha was partially inhibited by the addition of Ang-2. Furthermore, multivariate regression analysis showed that EDMP and sFasL were significant factors in Ang-2 elevation. Our results suggest that Ang-2 generation after allogeneic SCT relates to GVHD.

Shared biology of GVHD and GVT effects: Potential methods of separation

The difficult separation of clinical graft-versus-tumor (GVT) effects from graft-versus-host disease (GVHD) reflects their shared biology. Experimental approaches to mediate GVT effects while limiting GVHD include: (1) allograft T cell depletion followed by immune enhancement; (2) modulation of T cell dose or T cell subset composition; (3) donor lymphocyte infusion; (4) reduced-intensity host preparation; (5) modulation of Th1/Th2 and Tc1/Tc2 cell balance; (6) cytokine therapy or neutralization; (7) T regulatory cell therapy; (8) co-stimulatory pathway modulation; (9) chemokine pathway modulation; (10) induction of antigen-specific T cells; (11) alloreactive NK cell therapy; and (12) targeted pharmaceutical inhibition of proteosome, mammalian target of rapamycin, and histone deacetylase pathways. Clearly, a multitude of approaches exist that hold promise for separating GVT effects from GVHD. Future success in this endeavor will require a strong commitment towards translational research and continued advances in cell, vaccine, cytokine, monoclonal antibody, and targeted molecular therapy.