A novel soluble form of Tim-3 associated with severe graft-versus-host disease.

The T cell Ig and mucin domain 3 (Tim-3) receptor has been implicated as a negative regulator of adaptive immune responses. We have utilized a proteomic strategy to identify novel proteins associated with graft versus host disease (GVHD) after allogeneic hematopoietic cell transplantation (HCT). Mass spectrometry analysis of plasma from subjects with mid-gut and upper-gut GVHD compared with those without GVHD identified increased levels of a protein identified with high confidence as Tim-3. A follow-up validation study using an immunoassay to measure Tim-3 levels in individual plasma samples from 127 patients demonstrated significantly higher plasma Tim-3 concentrations in patients with the more severe mid-gut GVHD, compared with those with upper-gut GVHD (P = .005), patients without GVHD (P = .002), and normal controls (P < .0001). Surface expression of Tim-3 was increased on CD8(+) T cells from patients with grade 2 to 4 acute GVHD (P = .01). Mass spectrometry-based profiling of plasma from multiple subjects diagnosed with common diseases provided evidence for restricted release of soluble Tim-3 in the context of GVHD. These findings have mechanistic implications for the development of novel strategies for targeting the Tim-3 immune regulatory pathway as an approach to improving control of GVHD.

Activation and expansion of CD8(+) T effector cells in patients with chronic graft-versus-host disease.

We tested the hypothesis that changes in the phenotype of CD8(+) T cells from patients with chronic graft-versus-host disease (cGVHD) correlate with disease activity, and resolve or normalize in clinically tolerant patients successfully withdrawn from immunosuppression therapy (IST). No significant difference was found in the absolute CD8(+) T cell counts among cGVHD patients, tolerant patients, and healthy controls. However, compared with healthy normal controls, CD8(+) T cells from cGVHD patients had decreased expression of the IL-7 receptor and an increase in effector T cells, Ki-67, and perforin expression and apoptosis, suggesting that activation, differentiation, and proliferation of host-reactive CD8(+) effector T cells is a mechanism by which cGVHD is sustained and persists. The increase in effector T cells was most prominent in older patients and patients who were cytomegalovirus seropositive before transplantation. Use of IST was associated with a decreased number of CD45RA(-) CD8(+) effector T cells, a decreased expression of Ki-67, and an increased expression of CD95 (Fas). Together, these results demonstrate that CD8(+) T cells in patients with cGVHD are characterized by an increased level of activation and proliferation, and an expansion of effector cells that appear to be selectively sensitive to IST compared with other CD8(+) T cells. In GVHD-free tolerant patients, CD8(+) T cells showed an increased expression of granzyme and HLA-DR molecules compared with CD8(+) T cells from healthy controls, indicating that clinical tolerance in these patients can occur without full normalization of the CD8(+) T cell phenotype.

IL10 and IL10 receptor gene variation and outcomes after unrelated and related hematopoietic cell transplantation.

BACKGROUND: Results of a previous study with human leukocyte antigen (HLA)-identical siblings showed individual and synergistic associations of single nucleotide polymorphisms in the promoter region of the recipient's IL10 gene and the donor's IL10 receptor beta (IL-10RB) gene with development of grades III-IV acute graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation. METHODS: In this study of 936 patients who had unrelated donors, genotypes of single nucleotide polymorphisms in the IL10 gene and the IL-10RB gene were evaluated as correlates with outcomes after transplantation. RESULTS: We found no statistically significant associations of polymorphisms at positions -3575, -2763, -1082, and -592 of the IL10 gene or codon 238 of the IL10RB gene with severe acute GVHD, extensive chronic GVHD or nonrelapse mortality after hematopoietic cell transplantation. Among HLA-matched unrelated pairs, the patient's IL10/-592 genotype and donor's IL10RB/c238 genotype showed trends suggesting individual and combined associations with grades III-IV acute GVHD similar to those observed among patients with HLA-identical sibling donors. CONCLUSIONS: Although genetic variation in IL10 pathway affects risk of acute GVHD and non-relapse mortality in HLA-identical sibling transplants, the current results indicate that genetic variation in the IL10 pathway does not significant affect these outcomes in unrelated donor transplants suggesting that the strength of the alloimmune response in the latter exceeds the anti-inflammatory activity of IL10.