Antitumor activity without on-target off-tumor toxicity of GD2-chimeric antigen receptor T cells in patients with neuroblastoma.

The reprogramming of a patient's immune system through genetic modification of the T cell compartment with chimeric antigen receptors (CARs) has led to durable remissions in chemotherapy-refractory B cell cancers. Targeting of solid cancers by CAR-T cells is dependent on their infiltration and expansion within the tumor microenvironment, and thus far, fewer clinical responses have been reported. Here, we report a phase 1 study (NCT02761915) in which we treated 12 children with relapsed/refractory neuroblastoma with escalating doses of second-generation GD2-directed CAR-T cells and increasing intensity of preparative lymphodepletion. Overall, no patients had objective clinical response at the evaluation point +28 days after CAR-T cell infusion using standard radiological response criteria. However, of the six patients receiving ≥108/meter2 CAR-T cells after fludarabine/cyclophosphamide conditioning, two experienced grade 2 to 3 cytokine release syndrome, and three demonstrated regression of soft tissue and bone marrow disease. This clinical activity was achieved without on-target off-tumor toxicity. Targeting neuroblastoma with GD2 CAR-T cells appears to be a valid and safe strategy but requires further modification to promote CAR-T cell longevity.

Experiences of shame and intellectual disabilities: Two case studies.

Shame is a trans-diagnostic phenomenon that underlies a variety of mental health difficulties. People with intellectual disabilities (IDs) are reported to be one of the most stigmatized and excluded groups in society and are more likely to experience mental health problems than the general population. Consequently, this group may be at a significant risk of shame-related distress. However, there is a lack of research that investigates the experience of shame in people with ID, and there is currently a lack of interventions targeting shame in people with ID. Two case studies were undertaken to document the experiences of stigma, discrimination, and shame in people with ID and to explore how shame may present in this population. Shame was found to be a significant barrier to social inclusion and to contribute towards poor psychological health in people with ID. The development of interventions that specifically target shame in this population is recommended.

Retention of Ag-specific memory CD4+ T cells in the draining lymph node indicates lymphoid tissue resident memory populations.

Several different memory T-cell populations have now been described based upon surface receptor expression and migratory capabilities. Here we have assessed murine endogenous memory CD4+ T cells generated within a draining lymph node and their subsequent migration to other secondary lymphoid tissues. Having established a model response targeting a specific peripheral lymph node, we temporally labelled all the cells within draining lymph node using photoconversion. Tracking of photoconverted and non-photoconverted Ag-specific CD4+ T cells revealed the rapid establishment of a circulating memory population in all lymph nodes within days of immunisation. Strikingly, a resident memory CD4+ T cell population became established in the draining lymph node and persisted for several months in the absence of detectable migration to other lymphoid tissue. These cells most closely resembled effector memory T cells, usually associated with circulation through non-lymphoid tissue, but here, these cells were retained in the draining lymph node. These data indicate that lymphoid tissue resident memory CD4+ T-cell populations are generated in peripheral lymph nodes following immunisation.

Transient inhibition of ROR-γt therapeutically limits intestinal inflammation by reducing TH17 cells and preserving group 3 innate lymphoid cells.

RAR-related orphan receptor-γt (ROR-γt) directs differentiation of proinflammatory T helper 17 (TH17) cells and is a potential therapeutic target in chronic autoimmune and inflammatory diseases. However, ROR-γt-dependent group 3 innate lymphoid cells ILC3s provide essential immunity and tissue protection in the intestine, suggesting that targeting ROR-γt could also result in impaired host defense after infection or enhanced tissue damage. Here, we demonstrate that transient chemical inhibition of ROR-γt in mice selectively reduces cytokine production from TH17 but not ILCs in the context of intestinal infection with Citrobacter rodentium, resulting in preserved innate immunity. Temporal deletion of Rorc (encoding ROR-γt) in mature ILCs also did not impair cytokine response in the steady state or during infection. Finally, pharmacologic inhibition of ROR-γt provided therapeutic benefit in mouse models of intestinal inflammation and reduced the frequency of TH17 cells but not ILCs isolated from primary intestinal samples of individuals with inflammatory bowel disease (IBD). Collectively, these results reveal differential requirements for ROR-γt in the maintenance of TH17 cell and ILC3 responses and suggest that transient inhibition of ROR-γt is a safe and effective therapeutic approach during intestinal inflammation.

ICOS is required for the generation of both central and effector CD4(+) memory T-cell populations following acute bacterial infection.

Interactions between ICOS and ICOS ligand (ICOSL) are essential for the development of T follicular helper (Tfh) cells and thus the formation and maintenance of GC reactions. Given the conflicting reports on the requirement of other CD4(+) T-cell populations for ICOS signals, we have employed a range of in vivo approaches to dissect requirements for ICOS signals in mice during an endogenous CD4(+) T-cell response and contrasted this with CD28 signals. Genetic absence of ICOSL only modestly reduced the total number of antigen-specific CD4(+) T cells at the peak of the primary response, but resulted in a severely diminished number of both T central memory and T effector memory cells. Treatment with blocking anti-ICOS mAb during the primary response recapitulated these effects and caused a more substantial reduction than blocking CD28 signals with CTLA4Ig. During the memory phase of the response further signals through ICOS or CD28 were not required for survival. However, upon secondary challenge only Tfh cell expansion remained heavily ICOS-dependent, while CD28 signals were required for optimal expansion of all subsets. These data demonstrate the importance of ICOS signals specifically for memory CD4(+) T-cell formation, while highlighting the potential of therapeutically targeting this pathway.

CCR7-dependent trafficking of RORγ⁺ ILCs creates a unique microenvironment within mucosal draining lymph nodes.

Presentation of peptide:MHCII by RORγ-expressing group 3 innate lymphoid cells (ILC3s), which are enriched within gut tissue, is required for control of CD4 T-cell responses to commensal bacteria. It is not known whether ILC populations migrate from their mucosal and peripheral sites to local draining secondary lymphoid tissues. Here we demonstrate that ILC3s reside within the interfollicular areas of mucosal draining lymph nodes, forming a distinct microenvironment not observed in peripheral lymph nodes. By photoconverting intestinal cells in Kaede mice we reveal constitutive trafficking of ILCs from the intestine to the draining mesenteric lymph nodes, which specifically for the LTi-like ILC3s was CCR7-dependent. Thus, ILC populations traffic to draining lymph nodes using different mechanisms.

OX40 controls effector CD4+ T-cell expansion, not follicular T helper cell generation in acute Listeria infection.

To investigate the importance of OX40 signals for physiological CD4(+) T-cell responses, an endogenous antigen-specific population of CD4(+) T cells that recognise the 2W1S peptide was assessed and temporal control of OX40 signals was achieved using blocking or agonistic antibodies (Abs) in vivo. Following infection with Listeria monocytogenes expressing 2W1S peptide, OX40 was briefly expressed by the responding 2W1S-specific CD4(+) T cells, but only on a subset that co-expressed effector cell markers. This population was specifically expanded by Ab-ligation of OX40 during priming, which also caused skewing of the memory response towards effector memory cells. Strikingly, this greatly enhanced effector response was accompanied by the loss of T follicular helper (TFH) cells and germinal centres. Mice deficient in OX40 and CD30 showed normal generation of TFH cells but impaired numbers of 2W1S-specific effector cells. OX40 was not expressed by 2W1S-specific memory cells, although it was rapidly up-regulated upon challenge whereupon Ab-ligation of OX40 specifically affected the effector subset. In summary, these data indicate that for CD4(+) T cells, OX40 signals are important for generation of effector T cells rather than TFH cells in this response to acute bacterial infection.

CLEC-2 is required for development and maintenance of lymph nodes.

The importance of CLEC-2, a natural ligand/receptor for Gp38/Podoplanin, in the formation of the lymphatic vasculature has recently been demonstrated. As the development and maintenance of lymph nodes (LNs) is dependent on the formation of the lymphatic vasculature and the differentiation of Gp38/Podoplanin(+) stromal cells, we investigated the role of CLEC-2 in lymphoneogenesis and LN homeostasis. Using constitutive Clec1b(-/-) mice, we showed that while CLEC-2 was not necessary for initiation of the LN anlage, it was required at late stages of development. Constitutive deletion of CLEC-2 induced a profound defect in lymphatic endothelial cell proliferation, resulting in lack of LNs at birth. In contrast, conditional deletion of CLEC-2 in the megakaryocyte/platelet lineage in Clec1b(fl/fl)PF4-Cre mice led to the development of blood-filled LNs and fibrosis, in absence of a proliferative defect of the lymphatic endothelial compartment. This phenotype was also observed in chimeric mice reconstituted with Clec1b(fl/fl)PF4-Cre bone marrow, indicating that CLEC-2 expression in platelets was required for LN integrity. We demonstrated that LNs of Clec1b(fl/fl)PF4-Cre mice are able to sustain primary immune responses but show a defect in immune cell recirculation after repeated immunizations, thus suggesting CLEC-2 as target in chronic immune response.

Molecular epidemiology of Clostridium difficile infection in a major chinese hospital: an underrecognized problem in Asia?

Clostridium difficile infection is almost unrecognized in mainland China. We have undertaken a study in a large Chinese teaching hospital in Changsha, Hunan, China, to identify cases of C. difficile, record patient characteristics, and define the molecular epidemiology with respect to ribotype distribution and cross-infection. Between April 2009 and February 2010, we examined fecal samples from 70 hospitalized patients with diarrhea who were receiving or had received antibiotics within the previous 6 weeks. Clinical information was collected and the samples were cultured for C. difficile retrospectively. Isolates were ribotyped, and multiple-locus variable-number tandem-repeat assay (MLVA) subtyping was performed on clusters of the same ribotype. The mean age of patients from whom C. difficile was cultured was 58 years, with only 4/21 patients aged >65 years. All patients, with a single exception, had received a third-generation cephalosporin and/or a quinolone antibiotic. Twenty-one isolates of C. difficile were recovered, and seven different ribotypes were identified, the dominant types being 017 (48%), 046 (14%), and 012 (14%). We identified two clusters of cross-infection with indistinguishable isolates of ribotype 017, with evidence of spread both within and between wards. We have identified C. difficile as a possibly significant problem, with cross-infection and a distinct ribotype distribution, in a large Chinese hospital. C. difficile may be underrecognized in China, and further epidemiological studies across the country together with the introduction of routine diagnostic testing are needed to ascertain the size of this potentially significant problem.

Cutting edge: lymphoid tissue inducer cells maintain memory CD4 T cells within secondary lymphoid tissue.

Phylogeny shows that CD4 T cell memory and lymph nodes coevolved in placental mammals. In ontogeny, retinoic acid orphan receptor (ROR)γ-dependent lymphoid tissue inducer (LTi) cells program the development of mammalian lymph nodes. In this study, we show that although primary CD4 T cell expansion is normal in RORγ-deficient mice, the persistence of memory CD4 T cells is RORγ-dependent. Furthermore, using bone marrow chimeric mice we demonstrate that LTi cells are the key RORγ-expressing cell type sufficient for memory CD4 T cell survival in the absence of persistent Ag. This effect was specific for CD4 T cells, as memory CD8 T cells survived equally well in the presence or absence of LTi cells. These data demonstrate a novel role for LTi cells, archetypal members of the innate lymphoid cell family, in supporting memory CD4 T cell survival in vivo.