Role of cytokines in allograft rejection

Paeoniflorin Enhances Endometrial Receptivity through Leukemia Inhibitory Factor

Despite advances in assisted reproductive technology, treatment for deficient endometrial receptivity is a major clinical unmet need. In our previous study, the water extract of Paeonia lactiflora Pall. enhanced endometrial receptivity in vitro and in vivo via induction of leukemia inhibitory factor (LIF), an interleukin (IL)-6 family cytokine. In the present study, we found that paeoniflorin, a monoterpene glycoside, is the major active compound of P. lactiflora. Paeoniflorin significantly improved the embryo implantation rate in a murine model of mifepristone (RU486)-induced implantation failure. In addition, paeoniflorin increased the adhesion of human trophectoderm-derived JAr cells to endometrial Ishikawa cells through the expression of LIF in vitro. Moreover, using the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database of the human endometrium, we confirmed that LIF signaling is a key regulator for improving human endometrial receptivity. Therefore, these results suggest that paeoniflorin might be a potent drug candidate for the treatment of endometrial implantation failure by enhancing endometrial receptivity.

Association between interferon gamma +874 T>A polymorphism and acute renal allograft rejection: evidence from published studies

Interferon gamma is involved in the acute rejection (AR) episodes of transplant recipients. However, results from published studies on the association of interferon gamma (IFNG) +874 T>A (rs2430561) polymorphism with AR of renal allograft are conflicting. To investigate the association between IFNG +874 T>A polymorphism with AR after renal transplantation, relevant studies were selected from PUBMED, EMBASE, Wanfang database and China National Knowledge Infrastructure until March 1st 2013. According the predesigned selection criteria, a total of 525 AR cases and 1,126 non-AR cases from 13 case-control studies were included to identify the strength of association with odds ratio (OR) and 95 % confidence intervals (95 % CI). Overall, a significant correlation between IFNG +874 T>A polymorphism and susceptibility to AR was detected (T allele vs. A allele: OR = 1.19, 95 % CI 1.02-1.38; TT/AT vs. AA: OR = 1.36, 95 % CI 1.07-1.73; TT vs. AA: OR = 1.42, 95 % CI 1.05-1.93; AT vs. AA: OR = 1.30, 95 % CI 1.01-1.68). In addition, ethnicity subgroup analysis revealed that high produce genotype (TT/AT) was associated with an increased risk of AR for Caucasians (TT/AT vs. AA: OR = 1.56, 95 % CI 1.14-2.12; TT vs. AA: OR = 1.64, 95 % CI 1.18-2.26). Furthermore, donor source subgroup analysis observed an increased risk for patients undergoing cadaveric kidney transplantation (TT/AT vs. AA: OR = 1.90, 95 % CI 1.12-3.24; TA vs. AA: OR = 2.16, 95 % CI 1.24-3.74). In conclusion, this meta-analysis suggested that IFNG +874 T>A polymorphism was associated with AR of renal transplant recipients, especially among Caucasians and those receiving cadaveric renal allograft. Additional well-designed studies with large sample size are warranted to validate our conclusion.

Gene therapy with adenovirus-delivered indoleamine 2,3-dioxygenase improves renal function and morphology following allogeneic kidney transplantation in rat

BACKGROUND

Indoleamine 2,3-dioxygenase (IDO), the rate-limiting enzyme in the tryptophan catabolism, has recently emerged as an important immunosuppressive enzyme involved in the regulation of both physiologic (maternal tolerance), as well as pathologic (neoplasia, autoimmune diseases, asthma) processes. Accumulating evidence points to a role for IDO in suppressing T-cell responses, thereby promoting tolerance. In the present study, we investigate the effects of adenovirus-mediated gene therapy with IDO on the acute rejection of the transplanted kidneys.

METHODS

The experiments were performed in a rat Fisher to Lewis acute renal rejection model. RGD modified adenovirus carrying IDO gene (RGD-AdTIDO, n = 9) or RGD modified adenovirus carrying green fluorescent protein gene (RGD-AdTL, n = 8) were injected into the renal artery of the donor kidney before transplantation. A group receiving saline (n = 8) served as control. Rats were sacrificed after 7 days.

RESULTS

Successful gene delivery was confirmed with real-time polymerase chain reaction and immunohistochemistry. RGD-AdTIDO significantly decreased elevated plasma creatinine (93.7 ± 18.9 µmol/l) compared to the RGD-AdTL (248.2 ± 43.6 µmol/l) and saline (228.3 ± 46.4 µmol/l) treated rats. Moreover, RGD-AdTIDO therapy diminished the infiltration of CD8+ T cells and macrophages into the graft and reduced renal interstitial pre-fibrosis. Also, it limited the up-regulation of kidney injury molecule-1, interleukin (IL)-2, IL-17 and transforming growth factor-β mRNA expression, and increased foxp3 mRNA expression compared to controls.

CONCLUSIONS

RGD-AdTIDO therapy improves renal function and morphology in a clinically relevant model of acute rejection.

Early Posttransplant Inflammation Promotes the Development of Alloimmunity and Chronic Human Lung Allograft Rejection

BACKGROUND

Chronic human lung allograft rejection, represented by bronchiolitis obliterans syndrome (BOS), is the single most important factor that limits the long-term survival following lung transplantation (LT). However, the pathogenesis of BOS remains unclear. We hypothesized that the early posttransplant inflammation would promote the development of donor anti-human leukocyte antigen (HLA) alloimmunity and predispose to BOS.

METHODS

Serum levels of interleukin (IL)-1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13, IL-15, IL-17, Eotaxin, IP-10, MIG, MCP-1, MIP-1alpha, MIP-1beta, RANTES, tumor necrosis factor (TNF)-alpha, interferon (IFN)-alpha, IFN-gamma, granulocyte-macrophage colony-stimulating factor, IL-1Ralpha, and IL-2R were serially analyzed in 31 BOS+ and matched 31 BOS- patients using quantitative multiplex bead immunoassays. Donor-specific HLA class II cellular immunity was analyzed using enzyme-linked immunospot (ELISPOT) by testing recipient peripheral blood mononuclear cells against mismatched donor HLA-DR peptides. Anti-HLA class II antibodies were monitored using flow panel reactive antibodies.

RESULTS

There was early posttransplant elevation in basal serum levels of proinflammatory chemokines IP-10 and MCP-1 and Th1-cytokines IL-1beta, IL-2, IL-12, and IL-15 in BOS+ patients, compared to BOS- and normal subjects. In addition, a threefold decline in IL-10 levels was found during BOS development. BOS+ patients revealed increased development of HLA class II alloantibodies and Th1-predominant donor-specific cellular immunity with high frequency of IFN-gamma and low IL-5 producing T-cells.

CONCLUSION

Early posttransplant elevation of proinflammatory mediators is associated with alloimmunity and chronic human lung allograft rejection.

Immunological analogy between allograft rejection, recurrent abortion and pre-eclampsia - the same basic mechanism?

There are still controversies concerning the role of immunological mechanisms engaged both in recurrent abortions (RA) and pre-eclampsia (PE). According to some opinions, recurrent miscarriage is comparable to organ-specific autoimmune disease. Analysis of immune reactions shows that graft rejection shares many similar mechanisms with RA and PE. This fact allows us to conclude that rejection of transplanted alloantigenic organs and pregnancy loss have probably the same evolutionary origin. Subsets and functions of immunocompetent cells (T CD4, suppressor gammadeltaT, cytotoxic T CD8, Treg, Tr1, uterine NK cells), over-activation of innate immunity (activation of NK cytotoxic cells, macrophages, neutrophils and complement), changes of Th1/Th2 cytokine balance (IL-2, IL-12, IL-15, IL-18, IFNgamma, TNFalpha vs. IL-4, IL-10, TGFbeta), importance of HLA-G molecule, CD200/CD200R interaction, over-expression of adhesion molecules, fgl2 prothrombinase activation and stimulation of IDO and HO expression, all suggest that RA and PE are syndromes of fetal allograft rejection, and not organ-specific autoimmune diseases. According to that supposition, an analogy might exist between acute graft rejection and recurrent abortion, and between chronic graft rejection and pre-eclampsia.

Soluble fibrinogen-like protein 2/fibroleukin exhibits immunosuppressive properties: suppressing T cell proliferation and inhibiting maturation of bone marrow-derived dendritic cells

Fibrinogen-like protein 2 (fgl2)/fibroleukin is a member of the fibrinogen-related protein superfamily. In addition to its established role in triggering thrombosis, it is known to be secreted by T cells. The soluble fgl2 ((s)fgl2) protein generated in a baculovirus expression system bound to both T cells and bone marrow-derived dendritic cells (DC) in a specific manner. (s)fgl2 exhibited immunomodulatory properties capable of inhibiting T cell proliferation stimulated by alloantigens, anti-CD3/anti-CD28 mAbs, and Con A in a dose-dependent manner; however, it had no inhibitory effects on CTL activity. The time- and dose-dependent inhibitory effect of (s)fgl2 on alloreactive T cell proliferation could be neutralized by a mAb against mouse fgl2. Polarization toward a Th2 cytokine profile with decreased production of IL-2 and IFN-gamma and increased production of IL-4 and IL-10 was observed in (s)fgl2-treated allogeneic cultures. Exposure of immature DC to (s)fgl2 abrogated the expression of CD80(high) and MHC class II(high) molecules and markedly inhibited NF-kappaB nuclear translocation, thus inhibiting their maturation. (s)Fgl2-treated DC had an impaired ability to stimulate allogeneic T cell proliferation. Maximal inhibition of proliferation was observed when allogeneic T cells were cultured with (s)fgl2-treated DC and (s)fgl2 protein was added in the culture. These data provide the first evidence to demonstrate that (s)fgl2 exerts immunosuppressive effects on T cell proliferation and DC maturation.