A signal-seeking Phase 2 study of olaparib and durvalumab in advanced solid cancers with homologous recombination repair gene alterations.

PURPOSE: To determine the safety and efficacy of PARP plus PD-L1 inhibition (olaparib + durvalumab, O + D) in patients with advanced solid, predominantly rare cancers harbouring homologous recombination repair (HRR) defects. PATIENTS AND METHODS: In total, 48 patients were treated with O + D, 16 with BRCA1/2 alterations (group 1) and 32 with other select HRR alterations (group 2). Overall, 32 (66%) patients had rare or less common cancers. The primary objective of this single-arm Phase II trial was a progression-free survival rate at 6 months (PFS6). Post hoc exploratory analyses were conducted on archival tumour tissue and serial bloods. RESULTS: The PFS6 rate was 35% and 38% with durable objective tumour responses (OTR) in 3(19%) and 3(9%) in groups 1 and 2, respectively. Rare cancers achieving an OTR included cholangiocarcinoma, perivascular epithelioid cell (PEComa), neuroendocrine, gallbladder and endometrial cancer. O + D was safe, with five serious adverse events related to the study drug(s) in 3 (6%) patients. A higher proportion of CD38 high B cells in the blood and higher CD40 expression in tumour was prognostic of survival. CONCLUSIONS: O + D demonstrated no new toxicity concerns and yielded a clinically meaningful PFS6 rate and durable OTRs across several cancers with HRR defects, including rare cancers.

Treg-mediated prolonged survival of skin allografts without immunosuppression.

Injection of Interleukin-2 (IL-2) complexed with a particular anti-IL-2 monoclonal antibody (mab) JES6-1 has been shown to selectively expand CD4+Foxp3+ T regulatory T cells (Tregs) in vivo. Although the potency of this approach with regard to transplantation has already been proven in an islet transplantation model, skin graft survival could not be prolonged. Since the latter is relevant to human allograft survival, we sought to improve the efficiency of IL-2 complex (cplx) treatment for skin allograft survival in a stringent murine skin graft model. Here, we show that combining low doses of IL-2 cplxs with rapamycin and blockade of the inflammatory cytokine IL-6 leads to long-term (>75 d) survival of major histocompatibility complex-different skin allografts without the need for immunosuppression. Allograft survival was critically dependent on CD25+FoxP3+ Tregs and was not accompanied by impaired responsiveness toward donor alloantigens in vitro after IL-2 cplx treatment was stopped. Furthermore, second donor-type skin grafts were rejected and provoked rejection of the primary graft, suggesting that operational tolerance is not systemic but restricted to the graft. These findings plus the lack of donor-specific antibody formation imply that prolonged graft survival was largely a reflection of immunological ignorance. The results may represent a potentially clinically translatable strategy for the development of protocols for tolerance induction.

IL-2 Shapes the Survival and Plasticity of IL-17-Producing γδ T Cells.

IL-17-producing γδ T (γδT-17) cells have proved to be an important early source of IL-17 in many inflammatory settings and are emerging as an important participant in protumor immune responses. Considering that their peripheral activation depends largely on innate signals rather than TCR ligation, it is important to understand what mechanisms exist to curb unwanted activation. Expression of the high-affinity IL-2R on γδT-17 cells prompted us to investigate a role for this cytokine. We found γδT-17 cells to be enriched, not depleted, in IL-2-deficient mice. The absence of IL-2 also resulted in higher IL-17 production and the emergence of IL-17+IFN-γ+ double producers. Furthermore, the addition of IL-2 to in vitro cultures of sorted γδT-17 cells was able to moderate IL-17 and affect differentiation into polyfunctional cytokine-producing cells. Interestingly, the Vγ6+ subset was more susceptible to the effects of IL-2 than Vγ4+ γδT-17 cells. We also found that unlike other γδ T cells, γδT-17 cells do not produce IL-2, but express Blimp-1, a known transcriptional repressor of IL-2. Although IL-2 was able to induce robust proliferation of γδT-17 cells, it did not sustain viability, negatively impacting their survival via downregulation of the IL-7R. Taken together, these data indicate that IL-2 can augment the γδT-17 response in favor of short-lived effectors with limited plasticity, particularly in the presence of IL-1ß and IL-23. In this way, IL-2 may act to curtail the innate-like response of γδT-17 cells upon arrival of IL-2-producing adaptive immune cells at the site of inflammation.

The majority of murine γδ T cells at the maternal-fetal interface in pregnancy produce IL-17.

Compared with lymphoid tissues, the immune cell compartment at mucosal sites is enriched with T cells bearing the γδ T-cell receptor (TCR). The female reproductive tract, along with the placenta and uterine decidua during pregnancy, are populated by γδ T cells predominantly expressing the invariant Vγ6(+)Vδ1(+) receptor. Surprisingly little is understood about the function of these cells. We found that the majority of γδ T cells in the non-pregnant uterus, pregnant uterus, decidua and placenta of mice express the transcription factor RORγt and produce interleukin-17 (IL-17). In contrast, IFNγ-producing γδ T cells were markedly reduced in gestational tissues compared with uterine-draining lymph nodes and spleen. Both uterine-resident invariant Vγ6(+) and Vγ4(+) γδ T cells which are more typically found in lymphoid tissues and circulating blood, were found to express IL-17. Vγ4(+) γδ T cells were particularly enriched in the placenta, suggesting a pregnancy-specific recruitment or expansion of these cells. A small increase in IL-17-producing γδ T cells was observed in allogeneic compared with syngeneic pregnancy, suggesting a contribution to regulating the maternal response to paternally-derived alloantigens. However, their high proportions also in non-pregnant uteri and gestational tissues of syngeneic pregnancy imply a role in the prevention of intrauterine infection or quality control of fetal development. These data suggest the need for a more rigorous evaluation of the role of IL-17 in sustaining normal pregnancy, particularly as emerging data points to a pathogenic role for IL-17 in pre-eclampsia, pre-term birth, miscarriage and maternal immune activation-induced behavioral abnormalities in offspring.

Differential Responsiveness of Innate-like IL-17- and IFN-γ-Producing γδ T Cells to Homeostatic Cytokines.

γδ T cells respond to molecules upregulated following infection or cellular stress using both TCR and non-TCR molecules. The importance of innate signals versus TCR ligation varies greatly. Both innate-like IL-17-producing γδ T (γδT-17) and IFN-γ-producing γδ T (γδT-IFNγ) subsets tune the sensitivity of their TCR following thymic development, allowing robust responses to inflammatory cytokines in the periphery. The remaining conventional γδ T cells retain high TCR responsiveness. We determined homeostatic mechanisms that govern these various subsets in the peripheral lymphoid tissues. We found that, although innate-like γδT-17 and γδT-IFNγ cells share elements of thymic development, they diverge when it comes to homeostasis. Both exhibit acute sensitivity to cytokines compared with conventional γδ T cells, but they do not monopolize the same cytokine. γδT-17 cells rely exclusively on IL-7 for turnover and survival, aligning them with NKT17 cells; IL-7 ligation triggers proliferation, as well as promotes survival, upregulating Bcl-2 and Bcl-xL. γδT-IFNγ cells instead depend heavily on IL-15. They display traits analogous to memory CD8(+) T cells and upregulate Bcl-xL and Mcl-1 upon cytokine stimulation. The conventional γδ T cells display low sensitivity to cytokine-alone stimulation and favor IL-7 for their turnover, characteristics reminiscent of naive αß T cells, suggesting that they may also require tonic TCR signaling for population maintenance. These survival constraints suggest that γδ T cell subsets do not directly compete with each other for cytokines, but instead fall into resource niches with other functionally similar lymphocytes.

HMGB1 contributes to kidney ischemia reperfusion injury.

High-mobility group box 1 (HMGB1), a nuclear factor released extracellularly as an inflammatory cytokine, is an endogenous ligand for Toll-like receptor 4 (TLR4). TLR4 activation mediates kidney ischemia-reperfusion injury (IRI), but whether HMGB1 contributes to IRI is unknown. Here, treating wild-type mice with neutralizing anti-HMGB1 antibody protected them against kidney IRI, evidenced by lower serum creatinine and less tubular damage than untreated mice. Mice treated with anti-HMGB1 had significantly less tubulointerstitial infiltration by neutrophils (day 1) and macrophages (day 5) and markedly reduced apoptosis of tubular epithelial cells. Furthermore, anti-HMGB1 antibody-treated IRI kidneys had significantly lower levels of IL-6, TNFα, and monocyte chemoattractant protein 1 (MCP1). mRNA, which are downstream of HMGB1. Conversely, administration of rHMGB1 after reperfusion exacerbated kidney IRI in wild-type mice. TLR4 deficient (TLR4(-/-)) mice were protected against kidney IRI; administration of neither anti-HMGB1 antibody nor rHMGB1 affected this renoprotection. In conclusion, endogenous HMGB1 promotes kidney damage after IRI, possibly through the TLR4 pathway. Administration of a neutralizing antibody to HMGB1 either before or soon after ischemia-reperfusion affords significant protection, suggesting therapeutic potential for acute kidney injury.

The effect of obesity on intrahepatic cytokine and chemokine expression in chronic hepatitis C infection.

BACKGROUND: Obese subjects with chronic hepatitis C virus (HCV) infection have more rapidly progressive liver disease. Objective In this study, we aimed to compare the hepatic cytokine and chemokine profiles in obese and lean subjects with chronic HCV infection using qRT-PCR and immunohistochemistry. METHODS: Liver biopsies from 55 subjects were studied, including 20 with chronic hepatitis C, 25 with non-alcoholic fatty liver disease and 10 subjects with non-diseased liver. RESULTS: Compared to the control groups, the liver injury in chronic hepatitis C was characterised by increased expression of several T-helper-1 cytokines including interferon-gamma and tumour necrosis factor-alpha, and chemokines such as RANTES, IP-10 and MCP-1. In particular, in comparison with lean (BMI or=30 kg/m(2)) HCV infected subjects had increased hepatic expression of interferon-gamma (p=0.004) and tumour necrosis factor-alpha (p<0.001), as well as increased expression of IP-10 (p=0.009) and MCP-1 (p<0.001). Localisation of these inflammatory chemokines revealed that in comparison to lean-HCV subjects, HCV infected liver from obese subjects exhibited significantly increased expression of IP-10 (p<0.001) and MCP-1 (p=0.02) in the inflammatory infiltrate of the portal tracts. In parallel, there was increased CD3 infiltration in the liver of obese-HCV subjects. CONCLUSIONS: The data provide important mechanistic information on the cause of hepatic injury in obese-HCV subjects including: (1) enhanced T helper-1 cytokine response patterns-to promote hepatocellular injury; (2) increased expression of the chemokines IP-10 and MCP-1 at both the mRNA and protein levels-to enhance inflammatory cell recruitment; (3) differing localisation of these chemokines within the liver of obese-HCV versus lean-HCV subjects-implying different inducing stimuli and; (4) increased CD3 expression in the liver of obese-HCV subjects-concordant with the increased expression of T cell chemoattractants.