Immune profiling of patients with extranodal natural killer/T cell lymphoma treated with daratumumab.

Natural killer/T cell lymphoma (NKTCL) is a highly aggressive, heterogeneous non-Hodgkin lymphoma resulting from malignant proliferation of cytotoxic natural killer (NK) or T cells. Previous studies demonstrated variable expression of CD38 on NKTCL tumors. Daratumumab, a human IgGκ monoclonal antibody targeting CD38 with a direct on-tumor and immunomodulatory mechanism of action, was hypothesized to be a novel therapeutic option for patients with relapsed or refractory (R/R) NKTCL. In the phase 2 NKT2001 study (ClinicalTrials.gov Identifier: NCT02927925) assessing the safety and efficacy of daratumumab, a suboptimal overall response rate was seen in R/R NKTCL patients. One patient, whose tumors did not express CD38, responded to treatment, suggesting that the immunomodulatory activities of daratumumab may be sufficient to confer clinical benefit. To understand the suboptimal response rate and short duration of response, we investigated the immune profile of NKTCL patients from NKT2001 in the context of daratumumab anti-tumor activity. Tumor tissue and whole blood were, respectively, analyzed for CD38 expression and patient immune landscapes, which were assessed via cytometry by time-of-flight (CyTOF), multiparameter flow cytometry (MPFC), clonal sequencing, and plasma Epstein-Barr virus (EBV)-DNA level measurements. Changes observed in the immune profiles of NKTCL patients from NKT2001, including differences in B and T cell populations between responders and nonresponders, suggest that modulation of the immune environment is crucial for daratumumab anti-tumor activities in NKTCL. In conclusion, these findings highlight that the clinical benefit of daratumumab in NKTCL may be enriched by B/T cell-related biomarkers.

SIGIRR Negatively Regulates IL-36-Driven Psoriasiform Inflammation and Neutrophil Infiltration in the Skin.

SIGIRR has been described as a negative regulator of several IL-1R/TLR family members and has been implicated in several inflammatory disease conditions. However, it is unknown whether it can suppress IL-36 family cytokines, which are members of the broader IL-1 superfamily that have emerged as critical orchestrators of psoriatic inflammation in both humans and mice. In this study, we demonstrate that SIGIRR is downregulated in psoriatic lesions in humans and mice, and this correlates with increased expression of IL-36 family cytokines. Using Sigirr -/- mice, we identify, for the first time (to our knowledge), SIGIRR as a negative regulator of IL-36 responses in the skin. Mechanistically, we identify dendritic cells and keratinocytes as the primary cell subsets in which IL-36 proinflammatory responses are regulated by SIGIRR. Both cell types displayed elevated IL-36 responsiveness in absence of SIGIRR activity, characterized by enhanced expression of neutrophil chemoattractants, leading to increased neutrophil infiltration to the inflamed skin. Blockade of IL-36R signaling ameliorated exacerbated psoriasiform inflammation in Sigirr -/- mice and inhibited neutrophil infiltration. These data identify SIGIRR activity as an important regulatory node in suppressing IL-36-dependent psoriatic inflammation in humans and mice.

Sitagliptin and Narrow-Band Ultraviolet-B for Moderate Psoriasis (DINUP): A Randomised Controlled Clinical Trial.

BACKGROUND: Sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor licensed for the treatment of type 2 diabetes mellitus (T2DM), has been reported to improve psoriasis. OBJECTIVE: We compared the effects of sitagliptin treatment, a DPP-4 inhibitor, in combination with narrow-band ultraviolet-B (NB-UVB) phototherapy compared to NB-UVB alone on psoriasis severity, quality of life, cardiovascular disease risk factors and immune parameters in people with moderate psoriasis without T2DM. METHODS: In this 39-week, single-centre, randomised controlled trial, people were allocated randomly to receive sitagliptin for 24 weeks with NB-UVB or NB-UVB alone. The primary endpoint was the change in Psoriasis Area and Severity Index (PASI) from baseline to 24 weeks. We estimated that 120 participants would be needed to have 80% power to find a significant difference between the groups. RESULTS: A total of 118 patients were randomised. The median (IQR) baseline PASI was 8.8 (7.5-11.6). At 24 weeks, the mean difference from baseline in PASI (-1.0 [95% CI -2.0 to 0.0]) was significantly larger in the sitagliptin/NB-UVB arm than in the NB-UVB-alone arm (p = 0.044). There were significant differences in the change in Hospital Anxiety and Depression Scale (-2.5 [95% CI -4.0 to -1.0]; p = 0.002) and EuroQol 5-item questionnaire (0.1 [95% CI 0.0-0.1]; p = 0.036) values from baseline to 24 weeks between the sitagliptin/NB-UVB and the NB-UVB-alone arm. There were no treatment-related serious adverse events. CONCLUSION: Sitagliptin therapy combined with NB-UVB phototherapy significantly improved psoriasis severity, albeit modestly, compared to NB-UVB phototherapy alone in patients with moderate psoriasis without T2DM.

Interleukin-1 and IL-23 induce innate IL-17 production from gammadelta T cells, amplifying Th17 responses and autoimmunity.

Th17 cells, CD4(+) T cells that secrete interleukin-17 (IL-17), are pathogenic in autoimmune diseases and their development and expansion is driven by the cytokines IL-6, TGF-beta, IL-21, IL-1, and IL-23. However, there are also innate sources of IL-17. Here, we show that gammadelta T cells express IL-23R and the transcription factor RORgammat and produce IL-17, IL-21, and IL-22 in response to IL-1beta and IL-23, without T cell receptor engagement. IL-17-producing gammadelta T cells were found at high frequency in the brain of mice with experimental autoimmune encephalomyelitis (EAE). gammadelta T cells activated by IL-1beta and IL-23 promoted IL-17 production by CD4(+) T cells and increased susceptibility to EAE, suggesting that gammadelta T cells act in an amplification loop for IL-17 production by Th17 cells. Our findings demonstrate that gammadelta T cells activated by IL-1beta and IL-23 are an important source of innate IL-17 and IL-21 and provide an alternative mechanism whereby IL-1 and IL-23 may mediate autoimmune inflammation.

Notch-1 mediates endothelial cell activation and invasion in psoriasis.

Notch receptor-ligand interactions are critical for cell proliferation, differentiation and survival; however, the role of Notch signalling in psoriasis remains to be elucidated. Serum amyloid A (A-SAA) is an acute-phase protein with cytokine-like properties, regulates cell survival pathways and is implicated in many inflammatory conditions. To examine the role of Notch-1 signalling in the pathogenesis of psoriasis, Notch-1, DLL-4, Jagged-1, Hrt-1/Hrt-2, A-SAA, Factor VIII and vascular endothelial growth factor (VEGF) mRNA and/or protein expression in psoriasis skin biopsies, serum and dHMVEC were assessed by immunohistology, dual-immunofluorescence, real-time PCR, ELISA and Western blotting. A-SAA-induced angiogenesis and invasion in the presence of Notch-1 siRNA was assessed by matrigel tube formation assays and Transwell invasion assay. Increased Notch-1, its ligand DLL-4 and Hrt-1 expression were demonstrated in lesional skin compared with non-lesional skin, with greatest expression observed in the dermal vasculature (P < 0.05). Dual-immunofluorescent staining demonstrated co-localization of Notch-1 to endothelial cell marker Factor VIII. A significant increase in A-SAA levels was demonstrated in psoriasis serum compared with healthy control serum (P < 0.05), and A-SAA expression was higher in lesional skin compared with non-lesional. In dHMVEC, A-SAA significantly induced Jagged-1, Hrt-1 and VEGF mRNA expression (P < 0.05) and activated Notch-1 IC indicative of transcriptional regulation. In contrast, A-SAA significantly inhibited DLL-4 mRNA expression (P < 0.05). Finally A-SAA-induced angiogenesis and invasion were inhibited by Notch-1 siRNA (P < 0.05). Notch receptor-ligand interactions mediate vascular dysfunction in psoriasis and may represent a potential therapeutic target.

Rare missense variants in the SH3 domain of PSTPIP1 are associated with hidradenitis suppurativa.

Hidradenitis suppurativa (HS) is a chronic, debilitating skin disease for which few treatment options are available. While most HS is sporadic, some rare kindred show a high-penetrance, autosomal-dominant inheritance. We wanted to identify rare variants that could contribute to HS risk in sporadic cases using candidate gene sequencing. We ultimately identified 21 genes for our capture panel. We included genes of the γ-secretase complex (n = 6) because rare variants in these genes sometimes cause familial HS. We added Notch receptor and ligand genes (n = 13) because γ-secretase is critical for processing Notch receptor signaling. Clinically, some people with PAPA (pyogenic arthritis, pyoderma gangrenosum, and acne) syndrome, a rare inflammatory disease, have concurrent HS. Rare variants in PSTPIP1 are known to cause PAPA syndrome, so we included PSTPIP1 and PSTPIP2 in the capture panel. We screened 117 individuals with HS for rare variations and calculated the expected burden using Genome Aggregation Database (gnomAD) allele frequencies. We discovered two pathogenic loss-of-function variants in NCSTN. This class of NCSTN variant can cause familial HS. There was no increased burden of rare variations in any γ-secretase complex gene. We did find that individuals with HS had a significantly increased number of rare missense variants in the SH3 domain of PSTPIP1. This finding, therefore, implicates PSTPIP1 variation in sporadic HS and further supports dysregulated immunity in HS. Our data also suggests that population-scale HS genetic research will yield valuable insights into disease pathology.

IL-27 mediates the response to IFN-ß therapy in multiple sclerosis patients by inhibiting Th17 cells.

Interferon (IFN)-ß is a commonly used therapy for relapsing remitting multiple sclerosis (RRMS). However its protective mechanism is still unclear and the failure of many patients to respond has not been explained. We have found that IFN-ß suppressed IL-23 and IL-1ß production and increased IL-10 production by human dendritic cells (DC) activated with the TLR2 and dectin-1 agonist zymosan. Furthermore, IFN-ß impaired the ability of DC to promote IL-17 production by CD4(+) T cells, but did not affect IFN-γ production. IFN-ß induced IL-27 expression by DC, and neutralisation of IL-27 abrogated the suppressive effects of IFN-ß on zymosan-induced IL-1 and IL-23 production and the generation of Th17 cells in vitro. Complementary in vivo studies in a mouse model showed that treatment with IFN-ß enhanced expression of IL-27, and reduced IL-17 in the CNS and periphery and attenuated the clinical signs of experimental autoimmune encephalomyelitis (EAE). In addition, the significant suppressive effect of IFN-ß on the ability of DC to promote Th17 cells was lost in cells from IL-27 receptor deficient mice. Finally, we showed that PBMC from non-responder RRMS patients produced significantly less IL-27 in response to IFN-ß than patients who responded to IFN-ß therapy. Our findings suggest that IFN-ß mediates its therapeutic effects in MS at least in part via the induction of IL-27, and that IL-27 may represent an alternative therapy for MS patients that do not respond to IFN-ß.

Naturally derived Heme-Oxygenase 1 inducers attenuate inflammatory responses in human dendritic cells and T cells: relevance for psoriasis treatment.

Psoriasis is a chronic autoimmune disease mediated by dysregulated immune responses in dendritic cells (DC) and T cells. The stress-response enzyme heme oxygenase-1 (HO-1) has been described as protective in animal models of psoriasis, however, implementation of HO-1-based therapies is hindered by the lack of clinically-suitable HO-1 inducers. The plant-derived polyphenols, carnosol and curcumin, have been identified as candidate HO-1 inducers however there has been little investigation into their effects on human immune cells. We demonstrate that treatment of human DC with these polyphenols limits DC maturation, reduces pro-inflammatory cytokine production, and prevents induction of allospecific T cell responses, in a manner partially dependent on carbon monoxide (CO). We also characterised their effects in ex-vivo psoriasis PBMC and report that curcumin, but not carnosol, strongly reduces T cell proliferation and cytokine poly-functionality, with reduced expression of psoriatic cytokines IFNγ, IL-17, GM-CSF and IL-22. This study therefore supports reports highlighting the therapeutic potential of curcumin in psoriasis by providing insight into its immunological effects on healthy human DC and psoriasis PBMC. We also demonstrate, for the first time, the anti-inflammatory effects of carnosol in human immune cells.

Adipokines, psoriasis, systemic inflammation, and endothelial dysfunction.

Adipokines are secreted by white adipose tissue, an active endocrine organ, and play a role in the regulation of metabolic functions such as lipid metabolism, inflammation, and vascular homeostasis. Adipokines are secreted in excess in obesity and contribute to the development of associated comorbidities such as metabolic syndrome and atherosclerosis. Psoriasis, a chronic immune-mediated skin disease, is associated with obesity and increased cardiovascular risk. Understanding the role of adipokines in psoriasis may in part explain the association between psoriasis and cardiovascular disease. This review summarizes the data regarding key adipokines in patients with psoriasis and the change in adipokine profiles with psoriasis therapy. Adipokines may be mediators of cutaneous inflammation suggesting a role in the pathophysiology of psoriasis and the development of comorbidities.

Hidradenitis Suppurativa Is Characterized by Dysregulation of the Th17:Treg Cell Axis, Which Is Corrected by Anti-TNF Therapy.

Hidradenitis suppurativa (HS) is a chronic, inflammatory, and debilitating disease of hair follicles with 1-4% prevalence and high morbidity. There is a dearth of information on the pathogenesis and immune dysregulation underlying HS; therefore, we carried out a detailed analysis of skin-infiltrating T cells. Cells isolated from skin biopsy samples and blood from HS patients and healthy control subjects were analyzed by 16-parameter flow cytometry to provide detailed profiles of CD4 T-cell subsets. We observed substantial infiltration of inflammatory T cells with a striking T helper (Th) type 17-skewed cytokine profile in HS skin; these cells expressed the Th17 lineage marker CD161 and IL-17, as well as proinflammatory cytokines GM-CSF, IL-22, IFN-γ, and tumor necrosis factor. Regulatory T cells were also enriched in HS lesional skin; however, the ratio of Th17 to regulatory T cells was nonetheless highly dysregulated in favor of Th17 cells. In contrast, lesional skin from anti-tumor necrosis factor-treated HS patients who showed substantial clinical improvement exhibited a significant reduction in the frequency of Th17 cells and normalization of the Th17 to regulatory T cell ratio. These data suggest that inhibition of pathogenic IL-17 via tumor necrosis factor blockade is associated with improvement in immune dysregulation in HS and may provide a rationale for targeting IL-17 in the disease.

Dipeptidyl peptidase-4 inhibition and narrow-band ultraviolet-B light in psoriasis (DINUP): study protocol for a randomised controlled trial.

BACKGROUND: Moderate to severe psoriasis is a systemic inflammatory disease associated with insulin resistance, obesity and type 2 diabetes (T2DM). Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor that improves glycaemia and has a marketing authorisation for the treatment of T2DM. Non-immunosuppressive therapies that are effective for psoriasis and its associated comorbidities would be a significant advance in the treatment of this chronic disease. METHODS/DESIGN: This is a single centre, 39-week, prospective, randomised, open label, clinical trial of oral sitagliptin (Januvia(®)) in psoriasis patients who are due to undergo a course of narrow-band ultraviolet-B (NB-UVB) phototherapy. We plan to enrol 120 participants and allocate participants on a random and 1:1 basis to receive sitagliptin 100 mg daily for 24 weeks combined with NB-UVB or NB-UVB monotherapy. Participants will be followed up for 12 weeks after sitagliptin therapy is discontinued. The primary endpoint is the change in Psoriasis Area and Severity Index (PASI) 24 weeks after treatment initiation. Secondary endpoints include cumulative NB-UVB dose, number of NB-UVB treatments required to clear psoriasis, proportions of participants who achieve PASI-50 (50 % reduction in PASI from baseline), PASI-75, PASI-90 and the proportion of participants who relapse in each group. We will also analyse changes in cardiovascular disease risk factors, serum cytokine and hormone levels and peripheral blood mononuclear expression of immune proteins at 24 and 36 weeks. A subgroup of participants will have skin biopsies taken and analysed for skin levels and expression of immune cells, receptors, hormones and immune proteins. The genetic or epigenetic profile that predicts best response to DPP-4 inhibitor therapy will be analysed. The safety endpoints include the rate and severity of adverse events. DISCUSSION: This is the first randomised clinical trial assessing dipeptidyl peptidase-4 inhibition therapy in psoriasis. We hypothesise that sitagliptin therapy in combination with NB-UVB improves psoriasis severity compared to NB-UVB monotherapy. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02347501 (Date of registration: 27 January 2015).

Hidradenitis suppurativa: the role of immune dysregulation.

Hidradenitis suppurativa (HS) is a chronic relapsing inflammatory disease of follicular occlusion characterized by boils, sinus tracts, fistulae, and scarring. It has a significant underestimated morbidity. Antimicrobial, immunosuppressive, anti-androgenic, and surgical approaches have been used with varying results. Knowledge of the pathogenesis of HS is fragmented, and treatment choices have hitherto been empiric without an exact understanding of the scientific basis for their use. Tumor necrosis factor-α inhibitors have shown promise in the treatment of HS in recent years, and the concept of HS as an immunological condition has come to the fore. The focus of this review is to discuss the immunological abnormalities underpinning HS as elucidated to date.

Innate immunity in the pathogenesis of psoriasis.

Psoriasis is a common, immune-mediated inflammatory skin disorder. T helper(h)1 and Th17 lymphocytes contribute to the pathogenesis of psoriasis through the release of inflammatory cytokines that promote further recruitment of immune cells, keratinocyte proliferation and sustained inflammation. The innate immune system is the first line of defence against infection and plays a crucial role in the initiation of the adaptive immune response. The presence of innate immune cells and their products in psoriatic skin plaques suggests a role for innate immunity in this disease. In addition, the innate immune system can direct the development of pathogenic Th cells in psoriasis. In this article, we will summarise the role of the innate immune system in psoriasis with particular emphasis on the role of cytokines, signalling pathways and cells of the innate immune system.

Attenuating regulatory T cell induction by TLR agonists through inhibition of p38 MAPK signaling in dendritic cells enhances their efficacy as vaccine adjuvants and cancer immunotherapeutics.

TLR ligands are potent adjuvants and promote Th1 responses to coadministered Ags by inducing innate IL-12 production. We found that TLR ligands also promote the induction of IL-10-secreting regulatory T (Treg) cells through p38 MAPK-induced IL-10 production by dendritic cells (DC). Inhibition of p38 suppressed TLR-induced IL-10 and PGE(2) and enhanced IL-12 production in DC. Incubation of Ag-pulsed CpG-stimulated DC with a p38 inhibitor suppressed their ability to generate Treg cells, while enhancing induction of Th1 cells. In addition, inhibition of p38 enhanced the antitumor therapeutic efficacy of DC pulsed with Ag and CpG and this was associated with an enhanced frequency of IFN-gamma-secreting T cells and a reduction of Foxp3(+) Treg cells infiltrating the tumors. Furthermore, addition of a p38 inhibitor to a pertussis vaccine formulated with CpG enhanced its protective efficacy in a murine respiratory challenge model. These data demonstrate that the adjuvant activity of TLR agonists is compromised by coinduction of Treg cells, but this can be overcome by inhibiting p38 signaling in DC. Our findings suggest that p38 is an important therapeutic target and provides a mechanism to enhance the efficacy of TLR agonists as vaccine adjuvants and cancer immunotherapeutics.