Immune response modifiers--mode of action

Effects of Ultra-Weak Fractal Electromagnetic Signals on Malassezia furfur

Malassezia spp. are dimorphic, lipophilic fungi that are part of the normal human cutaneous commensal microbiome. However, under adverse conditions, these fungi can be involved in various cutaneous diseases. In this study, we analysed the effect of ultra-weak fractal electromagnetic (uwf-EMF) field exposure (12.6 nT covering 0.5 to 20 kHz) on the growth dynamics and invasiveness of M. furfur. The ability to modulate inflammation and innate immunity in normal human keratinocytes was also investigated. Using a microbiological assay, it was possible to demonstrate that, under the influence of uwf-EMF, the invasiveness of M. furfur was drastically reduced (d = 2.456, p < 0.001), while at the same time, its growth dynamic after 72 h having been in contact with HaCaT cells both without (d = 0.211, p = 0.390) and with (d = 0.118, p = 0.438) uwf-EM exposure, were hardly affected. Real-time PCR analysis demonstrated that a uwf-EMF exposure is able to modulate human-β-defensin-2 (hBD-2) in treated keratinocytes and at the same time reduce the expression of proinflammatory cytokines in human keratinocytes. The findings suggest that the underlying principle of action is hormetic in nature and that this method might be an adjunctive therapeutic tool to modulate the inflammatory properties of Malassezia in related cutaneous diseases. The underlying principle of action becomes understandable by means of quantum electrodynamics (QED). Given that living systems consist mainly of water and within the framework of QED, this water, as a biphasic system, provides the basis for electromagnetic coupling. The oscillatory properties of water dipoles modulated by weak electromagnetic stimuli not only affect biochemical processes, but also pave the way for a more general understanding of the observed nonthermal effects in biota.

The Influence of Antibiotic Resistance on Innate Immune Responses to Staphylococcus aureus Infection

Staphylococcus aureus (S. aureus) causes a broad range of infections and is associated with significant morbidity and mortality. S. aureus produces a diverse range of cellular and extracellular factors responsible for its invasiveness and ability to resist immune attack. In recent years, increasing resistance to last-line anti-staphylococcal antibiotics daptomycin and vancomycin has been observed. Resistant strains of S. aureus are highly efficient in invading a variety of professional and nonprofessional phagocytes and are able to survive inside host cells. Eliciting immune protection against antibiotic-resistant S. aureus infection is a global challenge, requiring both innate and adaptive immune effector mechanisms. Dendritic cells (DC), which sit at the interface between innate and adaptive immune responses, are central to the induction of immune protection against S. aureus. However, it has been observed that S. aureus has the capacity to develop further antibiotic resistance and acquire increased resistance to immunological recognition by the innate immune system. In this article, we review the strategies utilised by S. aureus to circumvent antibiotic and innate immune responses, especially the interaction between S. aureus and DC, focusing on how this relationship is perturbed with the development of antibiotic resistance.

Toll-Like Receptors (TLRs) as Therapeutic Targets for Treating SARS-CoV-2: An Immunobiological Perspective

INTRODUCTION

Coronavirus disease-19 (COVID-19) caused by SARS-CoV-2 is presently the biggest threat to mankind throughout the globe. Increasing reports on deaths, cases of new infection, and socioeconomic losses are continuously coming from all parts of the world. Developing an efficacious drug and/or vaccine is currently the major goal to the scientific communities. In this context, toll-like receptors (TLRs) could be the useful targets in adopting effective therapeutic approaches.

METHODS

This chapter has been written by incorporating the findings on TLR-based therapies against SARS-CoV-2 demonstrated in the recently published research papers/reviews.

RESULTS

TLRs are the essential components of host immunity and play critical roles in deciding the fate of SARS-CoV-2 by influencing the immunoregulatory circuits governing human immune response to this pathogen. Hitherto, a number of multi-subunit peptide-based vaccines and pharmacological agents developed against SARS-CoV-2 have been found to manipulate TLR function. Therefore, circumventing overt immunopathology of COVID-19 applying TLR-antagonists can effectively reduce the morality caused from "cytokine storm"-induced multiorgan failure. Similarly, pre-administration of TLR- agonists may be used as a prophylaxis to sensitize the immune system of the individuals having risk of infection. A lot of collaborative efforts are required for bench-to-bench transformation of these knowledges.

CONCLUSION

This chapter enlightens the potentials and promises of TLR-guided therapeutic strategies against COVID-19 by reviewing the major findings and achievements depicted in the literatures published till date.

Enhancement of immune responses by co-stimulation of TLR3 - TLR7 agonists as a potential therapeutics against rabies in mouse model

Rabies is always fatal, when post-exposure prophylaxis is administered after the onset of clinical symptoms. To date, there is no effective treatment of rabies once clinical symptoms has initiated. Therefore, we aimed to provide evidences which indicate the promising effects of combination treatment with TLR agonists following rabies infection. Four groups of rabies infected-mice (10-mice/group) were treated with PolyI:C 50 μg (a TLR3 agonist), Imiquimod50 μg (a TLR7 agonist), (Poly + Imi)25 μg and (Poly + Imi)50 μg respectively. The immune responses in each experimental groups were investigated in the brain through evaluation of GFAP, MAP2, CD4, HSP70, TLR3, TLR7 and apoptotic cell expression as well as determination of IFN-γ, TNF-α and IL-4, levels. The treatment with combination of agonists (Poly + Imi)50 μg/mouse resulted a 75% decrease of mortality rate and better extended survival time following street rabies virus infection. Higher number of CD4⁺T cells, TLR3 and TLR7 expression in the brain parenchyma observed in the groups receiving both combined agonist therapies at the levels of 25 μg and 50 μg. In spite of decreased number of neuronal cell, significant higher number of astrocytes was shown in the group given (Poly + Imi)25 μg. The obtained results also pointed to the dramatic decrease of HSP70 expression in all groups of infected mice whereas higher number of apoptotic cells and Caspase 8 expression were recorded in (Poly + Imi)25 μg treated group. Furthermore, the cytokine profile consisting the increased levels of TNF-α, IFN-γ and IL-4 revealed that both humoral and cellular responses were highly modulated in combination therapy of 50 μg of Imiquimod and Poly I:C. Reduced viral load as quantified by real-time PCR of rabies N gene expression in the brain also correlated with the better survival of agonist-treated groups of mice. Based on obtained results, we have presented evidences of beneficial utilization of combined agonist therapy composed of TLR3/TLR7 ligands. This treatment regimen extended survival of infected mice and decreased significantly their mortality rate. We believe that the results of synergy-inducing protection of both TLR3/TLR7 agonists lead to the enhancement of innate immune responses cells residing in the CNS which warrant the studies to further understanding of crosstalk mechanisms in cellular immunity against rabies in the future.

Resiquimod inhibits Newcastle disease virus replication by modulating host cytokines: An understanding towards its possible therapeutics

Newcastle disease virus (NDV) infects domestic and wild avian species with high mortality and morbidity worldwide. Although this disease is mainly controlled through NDV vaccines, alternative use of antiviral compounds is increasingly under study. Resiquimod (R-848), an imidazoquinoline compound is a potent synthetic agonist of Toll-like receptor 7 (TLR7). Until now reports regarding the adjuvant potential of resiquimod is well established against human viruses but has been less explored against avian viruses. In the present study, we have analysed the anti-NDV effect of resiquimod in chicken embryo fibroblast cells (DF-1) and embryonated chicken eggs. About 70% reduction in NDV replication was observed 48 h and 72 h post-resiquimod treatment in DF-1 cells. Furthermore, differential host genes expression was observed in resiquimod treated DF-1 cells, PBMCs, and tissue sample of chicken embryos at a different time point. Among all the analyzed genes, significant up-regulation of viperin, IFNα, IFNγ, IL-1β, TNFα, IL18 were observed in its transcriptional level. Furthermore, resiquimod treatment showed NDV reduction in two weeks old chickens. About 61% and 38% reduction in NDV replication was observed 72 h post-infection in lungs and spleen, respectively. The study suggests the modulation of host innate immunity regulatory genes by resiquimod, which eventually modulates the NDV replication. The result of the study could be explored further to establish resiquimod as an alternative antiviral compound against NDV.

Efficacy of 5% imiquimod for the treatment of Vaginal intraepithelial neoplasia-A systematic review of the literature and a meta-analysis

Vaginal intraepithelial neoplasia (VaIN) is an uncommon disease associated with HPV and is considered to be a precursor of vaginal carcinoma. To date, treatment recommendations vary with no universally accepted standard of care as best treatment modality. Nevertheless, 5% imiquimod appears to be a promising, alternative, non-invasive treatment option. To ascertain the efficacy of 5% imiquimod for the treatment of this rare condition, we conducted a systematic review and meta-analysis of the proportion of women who received 5% imiquimod with their complete response, HPV clearance and recurrence rates. A literature search was carried out throughout the PubMed, EMBASE, ClinicalTrials.gov and Cochrane Databases for relevant studies. We computed the summary proportions for complete response, HPV clearance and non-recurrence following administration of 5% imiquimod by random effects meta-analysis. Six articles reporting on 94 patients were included. The summary proportions of women with complete response and HPV clearance were 76.5% (95% CI 59.4-98.5) and 52.5% (95% CI 29.5-93.6) respectively. The summary proportion of women with non-recurrence appeared high (94.3% (95% CI 67.1-132)), yet not significant. Use of 5% imiquimod for the treatment of VaIN is associated with relatively high response rate, satisfactory HPV clearance, whilst the risk for VaIN recurrence appears low.

Mushroom lectin overcomes hepatitis B virus tolerance via TLR6 signaling

Currently, chronic hepatitis B virus (HBV) infection remains a serious public health problem in the world. Recombinant HBV vaccine, as a preventive strategy against HBV infection, generates high antibody level, but it is not effective to activate innate and cellular immunity for chronic HBV infection therapy. Lectins from mushroom are natural and active proteins which have been shown important biological functions. However, little is known about the immunological mechanism engaged by mushroom lectins. Here we report that, lectin from Pleurotus ostreatus (POL) stimulated innate response by activating Toll-like receptor 6 signal pathway of dendritic cells. Subsequently POL enhanced HBV specific antibody level and follicular helper T cells response which overcame HBV tolerance in transgenic mice. This study suggests a novel mechanism for POL acting on immune response and a therapeutic approach to break HBV tolerance.

Imiquimod in cervical, vaginal and vulvar intraepithelial neoplasia: a review

Human papillomavirus (HPV) infection is in the vast majority of patients accountable for the development of vulvar, cervical and vaginal intraepithelial neoplasia (VIN, CIN, VAIN); precursors of vulvar, cervical and vaginal cancers. The currently preferred treatment modality for high grade VIN, CIN and VAIN is surgical excision. Nevertheless surgical treatment is associated with adverse pregnancy outcomes and recurrence is not uncommon. The aim of this review is to present evidence on the efficacy, safety and tolerability of imiquimod (an immune response modifier) in HPV-related VIN, CIN and VAIN. A search for papers on the use of imiquimod in VIN, CIN and VAIN was performed in the MEDLINE, EMBASE and Cochrane library databases. Data was extracted and reviewed. Twenty-one articles met the inclusion criteria and were analyzed; 16 on VIN, 3 on CIN and 2 on VAIN. Complete response rates in VIN ranged from 5 to 88%. Although minor adverse effects were frequently reported, treatment with imiquimod was well tolerated in most patients. Studies on imiquimod treatment of CIN and VAIN are limited and lack uniformly defined endpoints. The available evidence however, shows encouraging effect. Complete response rates for CIN 2-3 and VAIN 1-3 ranged from 67 to 75% and 57 to 86% respectively. More randomized controlled trials on the use of imiquimod in CIN, VAIN and VIN with extended follow-up are necessary to determine the attributive therapeutic value in these patients.

Imiquimod induces apoptosis of squamous cell carcinoma (SCC) cells via regulation of A20

Imiquimod, a nucleoside analogue of the imidazoquinoline family, is being used to treat various cutaneous cancers including squamous cell carcinoma (SCC). Imiquimod activates anti-tumor immunity via Toll-like receptor 7 (TLR7) in macrophage and other immune cells. Imiquimod can also affect tumor cells directly, regardless of its impact on immune system. In this study, we demonstrated that imiquimod induced apoptosis of SCC cells (SCC12) and A20 was involved in this process. When A20 was overexpressed, imiquimod-induced apoptosis was markedly inhibited. Conversely, knockdown of A20 potentiated imiquimod-induced apoptosis. Interestingly, A20 counteracted activation of c-Jun N-terminal kinase (JNK), suggesting that A20-regulated JNK activity was possible mechanism underlying imiquimod-induced apoptosis of SCC12 cells. Finally, imiquimod-induced apoptosis of SCC12 cells was taken place in a TLR7-independent manner. Our data provide new insight into the mechanism underlying imiquimod effect in cutaneous cancer treatment.

TLR Agonists as Modulators of the Innate Immune Response and Their Potential as Agents Against Infectious Disease

Immunotherapies that can either activate or suppress innate immune responses are being investigated as treatments against infectious diseases and the pathology they can cause. The objective of these therapies is to elicit protective immune responses thereby limiting the harm inflicted by the pathogen. The Toll-like receptor (TLR) signaling pathway plays critical roles in numerous host immune defenses and has been identified as an immunotherapeutic target against the consequences of infectious challenge. This review focuses on some of the recent advances being made in the development of TLR-ligands as potential prophylactic and/or therapeutic agents.

Anti-inflammatory effects of Z-ligustilide nanoemulsion

The Z-ligustilide (LIG) was studied for its anti-inflammatory activities with prepared LIG nanoemulsions (LIGNE). Healthy male adult Wistar rats were used in the study. Endotoxin-induced uveitis (EIU) was induced by a footpad injection of 200 μg lipopolysaccharide. EIU rats were administered orally with saline, LIG (20 mg/kg/day), and LIGNE (20 mg LIG /kg/day), respectively. Twenty-four hours later, rats were euthanized, and blood was collected from either right marginal ear vein to estimate inflammatory cells and inflammatory mediators. The drug dissolution profiles of LIGNE in both phosphate buffer pH 6.8 and 0.1 N HCl showed complete dissolution within 20 min. Pharmacokinetic studies suggested a significant increase (P < 0.0001) in the C pmax and AUC0→24 h were observed in the LIGNE group when compared with the LIG group. LIGNE significantly reduced the levels of tumor necrosis factor alpha, interleukin 1 beta, vascular endothelial growth factor alpha, and interleukin-17. The anti-inflammatory animal testing revealed that LIGNE led to an improvement in oral bioavailability.

Use of PD biomarkers to drive dose selection and early clinical decision making

A major challenge facing the development of new therapies is the high level of compound attrition in late-stage clinical studies. A key factor in reducing these unsustainable levels of attrition is the successful evaluation of the level of drug effect on its target pathway in early development, otherwise known as testing the compound mechanism. Incorporation of PD biomarkers into Phase I/II trials to demonstrate compound binding to its molecular target and the subsequent modulation of downstream pathways enables early testing of compound mechanism and provides a data-driven framework for decisions on compound progression. This review will discuss the identification and validation of such 'fit-for-purpose' PD biomarkers, and case studies illustrating their use and value in dose selection and accelerating the clinical development of small-molecule drugs will be described.

Efficacy evaluation of two synthetic lysine lipidated tripeptides as vaccine adjuvants against HBsAg

In the present investigation, adjuvant potential of two novel lipidated tripeptide lysine derivatives (KKSM and KKSMB) was evaluated using various in vitro and animal-derived models of humoral and cell-mediated immune events in response to hepatitis B surface antigen (HBsAg). The results were compared with alum adjuvanted with HBsAg. Both these molecules were found to stimulate anti-HBsAg IgG and neutralizing (IgG1 and IgG2a) antibody titres in mice sera. The two molecules stimulated the proliferation of T-lymphocyte sub-sets (CD4/CD8) as well as the production of soluble mediators of Th1 (IL-2 and IFN-γ) and Th2 response (IL-4) in spleen cell culture supernatant. Furthermore, the two lipidated tripeptides enhanced the CD4, CD8, CD3 and CD19 cell populations as well as CD4/CD8 derived IL-2, IL-4, IFN-γ and TNF-α in whole blood of treated mice. There was found to be the significant enhancement in the release of IL-12, IFN-γ and nitrite content in macrophage supernatant. Moreover, the two lipidated tripeptides enhanced the population of CD80 and CD86 in spleen-derived macrophages and did not show any hemolytic effect on rabbit RBCs. Taken together, these results suggest that both these molecules are the potent enhancers of anti-HBsAg immune response via augmenting Th1/Th2 response in a dose dependent manner.

Adult recurrent respirator papillomatosis: a new therapeutic approach with pegylated interferon alpha 2a (Peg-IFNα-2a) and GM-CSF

OBJECTIVE

To determine a new therapeutic approach using granulocyte monocyte-colony-stimulating factor (GM-CSF) and pegylated interferon alpha 2a (Peg-IFNα-2a) as adjuvant therapy in patients with adult recurrent respiratory papillomatosis.

STUDY DESIGN

Descriptive observational clinical trial.

SETTING

Departments of Otolaryngology and Immunology.

METHODS

Fourteen patients with adult recurrent respiratory papillomatosis were examined regarding medical history and number of operations before and after treatment. Voice disorder and glottal stop were evaluated using the Voice-Related Quality-of-Life instrument. Papilloma staging was determined using the Coltera/Derkay diagram. The patients received Peg-IFNα-2a at 180 mcg weekly for 6 months. In the third month, the patients began GM-CSF treatment at 400 mcg weekly for 2 months. The patients were observed for 12 months after treatment ended.

RESULTS

Eleven patients met the study criteria; 3 patients had tracheotomies before treatment, and they were decannulated after treatment. Before treatment, the scale of voice quality ranged from 34 to 45 points (mean, 38.31). After treatment, the range was 12 to 35 points (mean, 21.09; P < .001). Prior to therapy, the glottal stop ranged from 50% to 90% (average, 62.27%). After therapy, the range decreased to 0% to 15% (mean, 4.63%; P < .001). The number of surgical interventions decreased. Two patients each had 1 surgical intervention after treatment began.

CONCLUSION

A new adjuvant treatment based on immunogenetic mechanisms against human laryngeal papilloma virus, with expectations of reducing disease aggressiveness and the number of operations, avoids the risks of surgery.

IMPLICATION FOR PRACTICE

Peg-IFNα-2a and GM-CSF is an adjuvant therapy for treating adult recurrent respiratory papillomatosis.

Nanovectorized radiotherapy: a new strategy to induce anti-tumor immunity

Recent experimental findings show that activation of the host immune system is required for the success of chemo- and radiotherapy. However, clinically apparent tumors have already developed multiple mechanisms to escape anti-tumor immunity. The fact that tumors are able to induce a state of tolerance and immunosuppression is a major obstacle in immunotherapy. Hence, there is an overwhelming need to develop new strategies that overcome this state of immune tolerance and induce an anti-tumor immune response both at primary and metastatic sites. Nanovectorized radiotherapy that combines ionizing radiation and nanodevices, is one strategy that could boost the quality and magnitude of an immune response in a predictable and designable fashion. The potential benefits of this emerging treatment may be based on the unique combination of immunostimulatory properties of nanoparticles with the ability of ionizing radiation to induce immunogenic tumor cell death. In this review, we will discuss available data and propose that the nanovectorized radiotherapy could be a powerful new strategy to induce anti-tumor immunity required for positive patient outcome.

Anti-inflammation effects of corn silk in a rat model of carrageenin-induced pleurisy

Pleurisy is an inflammation of the pleural layers that surround the lungs. Despite much research into inflammatory diseases, no drugs with favorable safety profiles are available yet for their treatment. Corn silk has been used in many parts of the world for the treatment of edema, cystitis, gout, kidney stones nephritis, and prostitutes. However, no scientific reports on the anti-inflammatory effects of corn silk were so far available. To test the anti-inflammatory efficacy of corn silk extract (CSEX) in a rat model of carrageenin (Cg)-induced pleurisy, exudate formation, and cellular infiltration, tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), vascular endothelial growth factor alpha (VEGF-α), interleukin-17 (IL-17), C3 and C4 complement protein levels, adhesion molecule (ICAM-1) and inducible nitric oxide synthase (iNOS) levels, nuclear factor kappa B (NF-κB) activation, and total antioxidant activity were studied, respectively. Pretreatment with CSEX reduced Cg-induced pleurisy exudate, number of leukocytes, oxidative stress, C3 protein level, and O (2)(-) levels at the inflammatory site. Pretreatment with CSEX also inhibited TNF-α, IL-1β, VEGF-α, and IL-17A and blocked inflammation-related events (ICAM-1 and iNOS) by activation of NF-κB. Supplementation with CSEX may be a promising treatment for inflammatory diseases that involve oxidative stress.

Developing Phytocompounds from Medicinal Plants as Immunomodulators

Imbalance or malfunction of the immune systems is associated with a range of chronic diseases including autoimmune diseases, allergies, cancers and others. Various innate and adaptive immune cells that are integrated in this complex networking system may represent promising targets for developing immunotherapeutics for treating specific immune diseases. A spectrum of phytochemicals have been isolated, characterized and modified for development and use as prevention or treatment of human diseases. Many cytotoxic drugs and antibiotics have been developed from phytocompounds, but the application of traditional or new medicinal plants for use as immunomodulators in treating immune diseases is still relatively limited. In this review, a selected group of medicinal herbs, their derived crude or fractionated phytoextracts and the specific phytochemicals/phytocompounds isolated from them, as well as categorized phytocompound groups with specific chemical structures are discussed in terms of their immunomodulatory bioactivities. We also assess their potential for future development as immunomodulatory or inflammation-regulatory therapeutics or agents. New experimental approaches for evaluating the immunomodulatory activities of candidate phytomedicines are also discussed.

Toll-like receptor 7 stimulation by imiquimod induces macrophage autophagy and inflammation in atherosclerotic plaques

Atherosclerotic plaques tend to rupture as a consequence of a weakened fibrous cap, particularly in the shoulder regions where most macrophages reside. Macrophages express Toll-like receptors to recognize pathogens and eliminate intracellular pathogens by inducing autophagy. Because Toll-like receptor 7 (TLR7) is thought to be expressed in macrophages but not in smooth muscle cells (SMCs), we investigated whether induction of macrophage autophagic death by TLR7 ligand imiquimod can affect the composition of atherosclerotic plaques in favor of their stability. Immunohistochemical staining of human carotid plaques as well as Western blotting of cultured macrophages and SMCs confirmed that TLR7 was expressed in macrophages, but not in SMCs. In vitro experiments showed that only TLR7 expressing cells underwent imiquimod-induced cell death, which was characterized by autophagosome formation. Imiquimod-treated macrophages activated nuclear factor-κB (NF-κB) and released pro-inflammatory cytokines and chemokines. This effect was inhibited by the glucocorticoid dexamethasone. Imiquimod-induced cytokine release was significantly decreased in autophagy-deficient macrophages because these cells died by necrosis at an accelerated pace. Local in vivo administration of imiquimod to established atherosclerotic lesions in rabbit carotid arteries induced macrophage autophagy without induction of cell death, and triggered cytokine production, upregulation of vascular adhesion molecule-1, infiltration of T-lymphocytes, accumulation of macrophages and enlargement of plaque area. Treatment with dexamethasone suppressed these pro-inflammatory effects in vivo. SMCs and endothelial cells in imiquimod-treated plaques were not affected. In conclusion, imiquimod induces macrophage autophagy in atherosclerotic plaques, but stimulates plaque progression through cytokine release and enhanced infiltration of inflammatory cells.

Isolation and biological activity of triglycerides of the fermented mushroom of Coprinus Comatus

BACKGROUND

Although many physiological functions of Coprinus comatus have been reported, there has been no report on the antinociceptive activity of Coprinus comatus. Therefore, the objective of the present study is to demonstrate the production, isolation, and biological properties of triglycerides (TFC) of the fermented mushroom of Coprinus comatus.

METHODS

The effects of TFC on cytokines levels, total antioxidant activity, antinociceptive effects in vivo, LD50 and tactile hyperalgesia were analyzed respectively.

RESULTS

TFC treatment decreased the levels of cytokines and total antioxidant status (TAOS) and inhibited the acetic acid-induced abdominal constrictions in mice. In addition, TFC reduced CFA-induced tactile hyperalgesia in a dose-dependent manner and the LD50 of TFC was determined to be 400 mg/kg. However, TFC did not significantly inhibit the reaction time to thermal stimuli in the hot-plate test.

CONCLUSIONS

TFC showed anti-inflammatory, antioxidant, peripheral antinociceptive and antihyperalgesic activity in various models of inflammatory pain. The data suggest that TFC may be a viable treatment option for inflammatory pain.

Use of modelling and simulation techniques to support decision making on the progression of PF-04878691, a TLR7 agonist being developed for hepatitis C

AIM

To use non-linear mixed effects modelling and simulation techniques to predict whether PF-04878691, a toll-like receptor 7 (TLR7) agonist, would produce sufficient antiviral efficacy while maintaining an acceptable side effect profile in a 'proof of concept' (POC) study in chronic hepatitis C (HCV) patients.

METHODS

A population pharmacokinetic-pharmacodynamic (PKPD) model was developed using available 'proof of pharmacology' (POP) clinical data to describe PF-04878691 pharmacokinetics (PK) and its relationship to 2',5'-oligoadenylate synthetase (OAS; marker of pharmacology) and lymphocyte levels (marker of safety) following multiple doses in healthy subjects. A second model was developed to describe the relationship between change from baseline OAS expressed as fold change and HCV viral RNA concentrations using clinical data available in HCV patients for a separate compound, CPG-10101 (ACTILON™), a TLR9 agonist. Using these models the antiviral efficacy and safety profiles of PF-04878691 were predicted in HCV patients.

RESULTS

The population PKPD models described well the clinical data as assessed by visual inspection of diagnostic plots, visual predictive checks and precision of the parameter estimates. Using these relationships, PF-04878691 exposure and HCV viral RNA concentration was simulated in HCV patients receiving twice weekly administration for 4 weeks over a range of doses. The simulations indicated that significant reductions in HCV viral RNA concentrations would be expected at doses > 6 mg. However at these doses grade ≥ 3 lymphopenia was also predicted.

CONCLUSIONS

The model simulations indicate that PF-04878691 is unlikely to achieve POC criteria and support the discontinuation of this compound for the treatment of HCV.

Imiquimod clears tumors in mice independent of adaptive immunity by converting pDCs into tumor-killing effector cells

Imiquimod is a synthetic compound with antitumor properties; a 5% cream formulation is successfully used to treat skin tumors. The antitumor effect of imiquimod is multifactorial, although its ability to modulate immune responses by triggering TLR7/8 is thought to be key. Among the immune cells suggested to be involved are plasmacytoid DCs (pDCs). However, a direct contribution of pDCs to tumor killing in vivo and the mechanism of their recruitment to imiquimod-treated sites have never been demonstrated. Using a mouse model of melanoma, we have now demonstrated that pDCs can directly clear tumors without the need for the adaptive immune system. Topical imiquimod treatment led to TLR7-dependent and IFN-α/β receptor 1-dependent (IFNAR1-dependent) upregulation of expression of the chemokine CCL2 in mast cells. This was essential to induce skin inflammation and for the recruitment of pDCs to the skin. The recruited pDCs were CD8α+ and induced tumor regression in a TLR7/MyD88- and IFNAR1-dependent manner. Lack of TLR7 and IFNAR1 or depletion of pDCs or CD8α+ cells from tumor-bearing mice completely abolished the effect of imiquimod. TLR7 was essential for imiquimod-stimulated pDCs to produce IFN-α/β, which led to TRAIL and granzyme B secretion by pDCs via IFNAR1 signaling. Blocking these cytolytic molecules impaired pDC-mediated tumor killing. Our results demonstrate that imiquimod treatment leads to CCL2-dependent recruitment of pDCs and their transformation into a subset of killer DCs able to directly eliminate tumor cells.

Evidence of an anti-inflammatory effect of mycophenolate mofetil in a murine model of pleurisy

A promising therapeutic approach to reducing inflammation is to inhibit the production of proinflammatory cytokines (e.g., tumor necrosis factor alpha [TNF-α], interleukin 1 beta [IL-1β], vascular endothelial growth factor alpha (VEGF-α), and, as shown more recently, interleukin-17 [IL-17]). In the present study, the authors have demonstrated the anti-inflammatory effects of mycophenolate mofetil (MMF) in in vivo experiments and have investigated the mechanism of action underlying those effects. Oral administration of MMF significantly inhibited leukocyte influx during the first (4 hours) and second (48 hours) phases of inflammation in a mouse model of pleurisy caused by carrageenan (P < .01). As expected, MMF suppressed protein levels of TNF-α, IL-1β, VEGF-α, and IL-17A (P < .01). This inhibitory effect was due to down-regulation of mRNA expression for these proinflammatory cytokines (P < .01). These results provide evidence of MMF-mediated inhibition of proinflammatory cytokines, and these anti-inflammatory effects are assumed to result mainly from the inhibition of the synthesis and release of TNF-α, IL-1β, VEGF-α, and IL-17A from activated leukocytes. These findings suggest that MMF might be an applicable therapeutic in the regulation of the inflammatory response-a response in which the humoral system plays a pivotal role.

Advances in the use of topical imiquimod to treat dermatologic disorders

Imiquimod (IQ) is an immune-response modifying agent, first approved by FDA for the topical treatment of external genital and perianal warts in 1997. It induces, through stimulation of Toll-like receptors (TLRs) localized on the surface of antigen-presenting cells, synthesis and release of several endogenous pro-inflammatory cytokines such as interferon-α (IFN-α), tumor necrosis factor-α (TNF-α) and interleukins (IL) 6 and 12, which in turn stimulate both the innate and acquired immune pathways, resulting in upregulation of natural antiviral and antitumor activity. IQ 5% cream has been used for the treatment of a wide variety of dermatologic conditions in which the immune system is thought to play a role in regression of the disease. In some disorders, such as genital and perianal warts, actinic keratoses, basal cell carcinomas, Bowen’s disease and molluscum contagiosum, relative safety and efficacy are supported by randomized controlled trials of IQ. However, it is common for patients to experience local skin reactions, which can range from mild to severe in intensity, but usually resolve 1–2 weeks after interrupting treatment. Additional randomized trials are encouraged to assess safety and efficacy of IQ in the treatment of an even wider range of cutaneous disorders.

Nonsteroidal anti-inflammatory drugs do not interfere with imiquimod treatment for usual type vulvar intraepithelial neoplasia

Imiquimod has been shown to be an effective treatment for usual type vulvar intraepithelial neoplasia (uVIN). Since local inflammation and burning are common side effects, patients often use nonsteroidal anti-inflammatory drugs (NSAIDs). Our study investigated whether NSAID-use, which has been documented to inhibit the cell-mediated immune response, interferes with the outcome of imiquimod treatment. Monocyte-derived dendritic cells (moDCs) and Langerhans cells (moLCs) were cultured in the presence of NSAIDs. The expression of relevant surface markers (CD80, CD86, CD40, HLA-DR, CCR6 and CCR7), stimulatory function, and cytokine production were evaluated. Furthermore, we analyzed in uVIN patients whether frequent NSAID-use had an effect on the clinical response and on immunocompetent cell counts before and after imiquimod treatment. Although an effect was observed on the expression of moDC and moLC maturation markers, NSAIDs did not affect the ability of moDCs and moLCs to stimulate allogeneic T-cell proliferation, or the production of cytokines in an allogeneic T-cell stimulation assay. In agreement with this, in uVIN patients treated with imiquimod, no interference of frequent NSAID-use with clinical outcome was observed. However, we did notice that high CD1a(+) and CD207(+) cell counts in frequent NSAID-users before treatment seemed to predict a favourable response to imiquimod treatment. Our data indicate that NSAID-use does not seem to interfere with moDC and moLC function and does not interfere with immunomodulatory properties of imiquimod in uVIN patients. Therefore, NSAIDs can safely be used to reduce imiquimod side effects in uVIN patients during treatment.

Imiquimod-induced clearance of HPV is associated with normalization of immune cell counts in usual type vulvar intraepithelial neoplasia

Recently, we reported on the efficacy of imiquimod for treatment of usual type vulvar intraepithelial neoplasia (uVIN). A histologic regression of uVIN to normal tissue was observed in 58% of patients. As success of treatment is related to clearance of high-risk human papilloma virus (HPV), the aim of our study was to assess differences in immune cell counts and in the expression of p16(INK4a) in VIN tissue before and after imiquimod treatment, in relation to HPV clearance and clinical response. Vulvar tissue samples taken prior to imiquimod treatment and 4 weeks after treatment were tested for the presence of HPV. Previously determined immune cell counts (CD1a, CD207, CD208, CD123/CD11c, CD94, CD4, CD8 and CD25/HLA-DR) in epidermis and dermis of 25 VIN patients and 19 healthy controls were completed with the counts for CD14 and CD68. The expression of p16(INK4a) was investigated by immunohistochemistry in 15 patients. Before imiquimod treatment, both HPV cleared and HPV noncleared patients showed mainly in the dermis significantly upregulated immune cell counts compared to healthy controls. However, in patients that cleared HPV and showed histologic regression already 4 weeks after imiquimod treatment, immune cell counts and p16(INK4a) expression were normalized. In conclusion, our data indicate that imiquimod-induced clearance of HPV results in normalization of counts for certain immune cells and is strongly correlated with histologic regression of the disease.

The innate immune response, clinical outcomes, and ex vivo HCV antiviral efficacy of a TLR7 agonist (PF-4878691)

Hepatitis C virus (HCV) infection is an issue of global concern, and studies are ongoing to identify new therapies that are both effective and safe. PF-4878691 is a Toll-like receptor 7 (TLR7) agonist modeled so as to dissociate its antiviral activities from its inflammatory activities. In a proof-of-mechanism study in healthy volunteers who received doses of 3, 6, and 9 mg of PF-4878691 twice a week for 2 weeks, PF-4878691 induced biomarkers of the immune and interferon (IFN) responses in a dose-dependent and dose-frequency-related manner. A novel finding was induction of TLR7 expression in vivo in response to PF-4878691, leading to an amplified biomarker response. A nonresponder at the 9-mg dose had a polymorphism in the IFN-α receptor 1 subunit (Val168Leu). Two subjects who had received 9-mg doses experienced serious adverse events (SAEs), characterized by flu-like symptoms, hypotension, and lymphopenia, leading to early termination of the study. TLR7 stimulation results in a pharmacologic response at levels commensurate with predicted antiviral efficacy, but these doses are associated with SAEs, raising concerns about the therapeutic window of this class of compounds for the treatment of HCV infection.

Treatment of vulvar intraepithelial neoplasia with topical imiquimod: seven years median follow-up of a randomized clinical trial

OBJECTIVE

Recently we reported on the efficacy of imiquimod for treating vulvar intraepithelial neoplasia (VIN) in a placebo-controlled, double-blinded randomized clinical trial (RCT). Four weeks after treatment, a complete response was observed in 35% of patients and a partial response in 46%. All complete responders remained disease-free at 12 months follow-up. In the current investigations, we assessed long-term follow-up at least 5 years after the initial RCT.

METHODS

Twenty-four of 26 imiquimod-treated patients who had participated in the initial RCT were seen for follow-up. Primary endpoint was durability of clinical response to imiquimod assessed by naked eye vulvar examination and histology. Long-term clinical response was correlated to lesion size before start of the initial RCT. Secondary endpoints were mental health, global quality of life, body image and sexual function in relation with long-term clinical response.

RESULTS

Median follow-up period was 7.2 years (range 5.6-8.3 years). VIN recurred in one of nine complete responders. Of the initial partial responders, two became disease-free after additional imiquimod treatment. In the other partial responders, VIN recurred at least once after the initial RCT. In long-term complete responders, lesion size at study entry was smaller and these patients had a significantly better global quality of life at follow-up than patients with residual disease and/or recurrence after imiquimod treatment.

CONCLUSIONS

In case of a complete response, imiquimod is effective in the long-term. Furthermore, patients with a long-term complete response had a significantly better global quality of life than patients who recurred after imiquimod treatment.

TLR-activated dendritic cells enhance the response of aged naive CD4 T cells via an IL-6-dependent mechanism

The most effective immunological adjuvants contain microbial products, such as TLR agonists, which bind to conserved pathogen recognition receptors. These activate dendritic cells (DCs) to become highly effective APCs. We assessed whether TLR ligand-treated DCs can enhance the otherwise defective response of aged naive CD4 T cells. In vivo administration of CpG, polyinosinic-polycytidylic acid, and Pam(3)CSK(4) in combination with Ag resulted in the increased expression of costimulatory molecules and MHC class II by DCs, increased serum levels of the inflammatory cytokines IL-6 and RANTES, and increased cognate CD4 T cell responses in young and aged mice. We show that, in vitro, preactivation of DCs by TLR ligands makes them more efficient APCs for aged naive CD4 T cells. After T-DC interaction, there are enhanced production of inflammatory cytokines, particularly IL-6, and greater expansion of the aged T cells, resulting from increased proliferation and greater effector survival with increased levels of Bcl-2. TLR preactivation of both bone marrow-derived and ex vivo DCs improved responses. IL-6 produced by the activated DCs during cognate T cell interaction was necessary for enhanced aged CD4 T cell expansion and survival. These studies suggest that some age-associated immune defects may be overcome by targeted activation of APCs by TLR ligands.

Toll-like receptor-7 agonist administered subcutaneously in a prolonged dosing schedule in heavily pretreated recurrent breast, ovarian, and cervix cancers

BACKGROUND

The primary objective was to study the antitumor activity of prolonged subcutaneous dosing of systemic 852A, a Toll-like receptor-7 agonist (TLR-7), in recurrent breast, ovarian and cervix cancer. Secondary objectives included assessment of safety and immune system activation.

METHODS

Adults with recurrent breast, ovarian or cervix cancer failing multiple therapies received 0.6 mg/m(2) of 852A subcutaneously twice weekly for 12 weeks. Doses increased by 0.2 mg/m(2)/week to a maximum of 1.2 mg/m(2). Serum was collected to assess immune activation.

RESULTS

Fifteen patients enrolled: 10 ovarian, 2 cervix and 3 breast. Three completed all 24 injections. There were two grade 2 (decreased ejection fractions), nine grade 3 (1 cardiovascular, 1 anorexia, 3 dehydration, 2 infections, 2 renal) and two grade 4 (hepatic and troponin elevation) unanticipated toxicities. Cardiac toxicities included three cardiomyopathies (2 asymptomatic) and one stress-related non-ST elevated myocardial infarction. Five patients discontinued therapy due to possibly associated side effects. One who had stable disease (SD) following 24 doses received 17 additional doses. A cervix patient with SD following 24 doses received chemotherapy after progressing 3 months later, and remains disease free at 18 months. Immune activation, as evidenced by increased IP-10 and IL-1ra, was observed.

CONCLUSIONS

In this first human experience of a TLR-7 agonist delivered subcutaneously using a prolonged dosing schedule, 852A demonstrated sustained tolerability in some patients. Clinical benefit was modest, but immune activation was seen suggesting further study of antitumor applications is warranted. Because of cardiac toxicity; 852A should be used cautiously in heavily pretreated patients.

Lupus erythematosus-like imiquimod reaction: a diagnostic pitfall

Imiquimod (AldaraTM), a Toll-like receptor 7 agonist (TLR7), is known for its unique properties of being an immune response modifier and stimulator. Upon topical application, this TLR7 agonist triggers a cell-mediated immune response predominantly expressed by dendritic cells and monocytes. Local skin irritation at the application site involving erythema, pain, crusting and erosions is common and well documented. On the contrary, the specific histopathologic features associated with these treatment site reactions is not. Herein reported is a case where historical omission of imiquimod use for actinic keratosis complicated the histologic interpretation. We highlight a lupus erythematosus-like microscopic pattern and explore histopathologic features that could help in avoiding a diagnostic pitfall, as well as the relationship between TLR activation, cell-mediated immunity and skin histology.

Effectiveness of cross polarized light and fluorescence diagnosis for detection of sub-clinical and clinical actinic keratosis during imiquimod treatment

BACKGROUND

During treatment of actinic keratosis (AK) lesions with imiquimod sub-clinical lesions often become visible. It is, however, unclear whether these sub-clinical lesions would be detectable beforehand.

OBJECTIVE

The aim of this pilot study was to compare two techniques, cross polarized light photography (CPL) and fluorescence diagnosis (FD) using methyllevulinic acid and illumination with Wood's lamp for their ability to detect sub-clinical lesions. These findings were also compared with biopsy results taken before and after treatment with imiquimod 5% cream or vehicle.

METHODOLOGY

Twelve patients with at least five clinically visible AK lesions in a single contiguous 20 cm(2) area on the head were recruited. Patient eligibility was determined at the screening visit, when they were randomized to treatment. The randomization was 3:1, active to vehicle (nine treated with imiquimod, three with vehicle cream) for a total duration of 24 weeks (six clinic visits). Patients were assessed for baseline AK lesion counts (clinical and sub-clinical) at the screening visit and final counts at week 20.

RESULTS

The number of clinically observed AK lesions was significantly lower at week 12 and week 20 compared with baseline following imiquimod treatment versus vehicle. The number of counted lesions were significantly higher using the CPL method compared with clinical counting with imiquimod treatment at baseline (8.3 +/- 3.4 vs 5.8 +/- 1.3; P = 0.027) and week 20 (4.8 +/- 2.4 vs 3.0 +/- 1.7; P = 0.02) but not in the vehicle group. The FD lesion counting method did not show a significant increase in the number of detected lesions compared with clinical analysis in the imiquimod and placebo groups but when comparisons were performed using pooled data (treatments and visits combined) the results were significant.

CONCLUSION

The number of sub-clinical and clinical AK lesions detected during treatment with imiquimod can be better demonstrated using the methods of CPL and FD, but statistical significance was reached only using the CPL method. This is only a preliminary study with a small number of patients and as a result it is difficult to conclude both statistical and clinical significance. However, results were encouraging and indicate that larger studies are needed to demonstrate the relevance of these two new methods for improved detection of clinical and especially sub-clinical AK lesions.

Immunogenicity and safety of different injection routes and schedules of IC41, a Hepatitis C virus (HCV) peptide vaccine

BACKGROUND

An effective vaccine would be a significant progress in the management of chronic HCV infections. This study was designed to examine whether different application schedules and injection routes may enhance the immunogenicity of the HCV peptide vaccine IC41.

METHODS

In this randomized trial 54 healthy subjects received either subcutaneous (s.c.) or intradermal (i.d.) vaccinations weekly (16 injections) or every other week (8 injections). One group additionally received imiquimod, an activator of the toll-like receptor (TLR) 7. The T cell epitope-specific immune response to IC41 was assessed using [(3)H]-thymidine CD4+ T cell proliferation, interferon-gamma (IFN-gamma) CD8+ and CD4+ ELIspot and HLA-A*0201 fluorescence-activated cell sorting (FACS) tetramer-binding assays.

RESULTS

More than 60% of vaccinees responded in the CD4+ T cell proliferation assay in all groups. An HLA-A*0201 FACS tetramer-binding assay and IFN-gamma CD8+ ELIspot class I response of more than 70% was induced in four and three groups, respectively. IC41 induced significant immunological responses in all groups with responder rates of up to 100%. Interestingly, topical imiquimod was not able to enhance immunogenicity but was associated with a lower immune response. Local injection site reactions were mostly transient. Intradermal injections caused more pronounced reactions compared to s.c., especially erythema and edema.

CONCLUSION

Compared to a previous study intensified dosing and/or i.d. injections enhanced the response rates to the vaccine IC41 in three assays measuring T cell function. Immunization with IC41 was generally safe in this study. These results justify testing IC41 in further clinical trials with HCV-infected individuals.

Herpes simplex virus-1 infection causes the secretion of a type I interferon-antagonizing protein and inhibits signaling at or before Jak-1 activation

Host cells respond to viral infection by the production of type I interferons (IFNs), which induce the expression of antiviral genes. Herpes simplex virus I (HSV-1) encodes many mechanisms that inhibit the type I IFN response, including the ICP27-dependent inhibition of type I IFN signaling. Here we show inhibition of Stat-1 nuclear accumulation in cells that express ICP27. ICP27 expression also induces the secretion of a small, heat-stable type I IFN antagonizing protein that inhibits Stat-1 nuclear accumulation. We show that the inhibition of IFN-induced Stat-1 phosphorylation occurs at or upstream of Jak-1 phosphorylation. Finally, we show that ISG15 expression is induced after IFNalpha treatment in mock-infected cells, but not cells infected with WT HSV-1 or ICP27(-) HSV-1. These data suggest that HSV-1 has evolved multiple mechanisms to inhibit IFN signaling not only in infected cells, but also in neighboring cells, thereby allowing for increased viral replication and spread.

Induction of novel CD8+ T-cell responses during chronic untreated HIV-1 infection by immunization with subdominant cytotoxic T-lymphocyte epitopes

OBJECTIVE

To investigate the potential to induce additional cytotoxic T-lymphocyte (CTL) immunity during chronic HIV-1 infection.

DESIGN

We selected infrequently targeted or subdominant but conserved HLA-A*0201-binding epitopes in Gag, Pol, Env, Vpu and Vif. These relatively immune silent epitopes were modified as anchor-optimized peptides to improve immunogenicity and delivered on autologous monocyte-derived dendritic cells (MDDCs).

METHODS

Twelve treatment-naïve HLA-A*0201 HIV-1-infected Danish individuals received 1 x 10 MDDCs subcutaneously (s.c.) (weeks 0, 2, 4 and 8), pulsed with seven CD8 T-cell epitopes and three CD4 T-cell epitopes. Epitope-specific responses were evaluated by intracellular cytokine staining for interferon-gamma, tumor necrosis factor alpha and interleukin-2 and/or pentamer labeling 3 weeks prior to, 10 weeks after and 32 weeks after the first immunization.

RESULTS

Previously undetected T-cell responses specific for one or more epitopes were induced in all 12 individuals. Half of the participants had sustained CD4 T-cell responses 32 weeks after immunization. No severe adverse effects were observed. No overall or sustained change in viral load or CD4 T-cell counts was observed.

CONCLUSION

These data show that it is possible to generate new T-cell responses in treatment-naive HIV-1-infected individuals despite high viral loads, and thereby redirect immunity to target new multiple and rationally selected subdominant CTL epitopes. Further optimization could lead to stronger and more durable cellular responses to selected epitopes with the potential to control viral replication and prevent disease in HIV-1-infected individuals.

In vivo characterization of the inflammatory infiltrate and apoptotic status in imiquimod-treated basal cell carcinoma

BACKGROUND

Imiquimod use in the treatment of basal cell carcinoma (BCC) has proven to be successful in a large percentage of cases, inducing tumor regression; however, the exact cellular mechanism has not been fully clarified.

AIM

To measure the morphological changes in the tumor microenvironment and the markers of apoptosis in skin biopsies from patients with BCC before and after imiquimod treatment.

METHODS

In this open label study, skin biopsies obtained from 11 patients with BCC were evaluated before and after imiquimod treatment for: (i) morphological changes in the tumor microenvironment, with specific emphasis on the immunophenotype of inflammatory cells around the tumor; and (ii) markers of apoptosis, including expression of death receptors.

RESULTS

Imiquimod treatment induced a significant increase in the mononuclear inflammatory response. In the majority of cases, the cellular infiltrate was predominantly composed of CD3(+)/CD4(+) T cells, suggesting that the effector response is mediated by CD3(+)/CD4(+) lymphocytes, with a minor cytotoxic and natural killer (NK) component. An increase in the cytotoxic CD3(+)/CD8(+) T-cell population was also observed. Imiquimod treatment was associated with a marked increased in CD20(+) B cells, and a less pronounced enhancement in cells of monocyte-macrophage origin (CD68(+)) surrounding, or within, the tumor. This finding indicates either that macrophages play a minor role in the imiquimod-induced response, or the recruitment of these cells is related to time and dose. Imiquimod treatment decreased CD1A(+) Langerhans cells in the epidermis and increased the number of CD1A(+) dendritic cells within the tumor aggregates. Imiquimod reduced Bcl-2 expression, but no difference was found in Bax, Fas/FasL, and p53 expression in BCC cells.

CONCLUSIONS

Our results support the hypothesis that imiquimod activity in the treatment of BCC is partly a result of a pro-inflammatory action mediated by CD3(+)/CD4(+) lymphoid cells and of a pro-apoptotic activity associated with decreased Bcl-2 expression.

Dendritic cells--why can they help and hurt us

Dendritic cells (DCs) show a Janus-like functional behavior. They help us by their orchestration of numerous immune responses to defend our body against invading pathogenic micro-organisms and also induce regulatory T cells to inhibit immune reactions against autoantigens as well as diverse harmless environmental antigens. However, DCs can also be of harm to us when misguided by their microenvironment as in allergic and autoimmune diseases or when DCs are targeted and exploited by microbes and cancer cells to evade the immune defense. This huge and diverse functional repertoire of DCs requires complex decision-making processes and the integration of multiple stimulatory and inhibitory signals. Although a given DC type has an extensive functionally plasticity, DCs are heterogeneous and individual DC subtypes are differentially distributed in tissues, express distinct sets of pattern recognition receptors and differ in their capacity to program naive T cells. With the help of transgenic mouse models and selective ablation of individual DC subtypes, we are just at the beginning of understanding the DC system in its complexity. Obtaining a more detailed knowledge of the DC system in mice and men holds strong promise for the successful induction of immunity and tolerance in therapeutic trials. This review presents the recent advances in the understanding of DC biology and discusses why and how DC can help and hurt us.

Topical treatments in psoriasis: today and tomorrow

Topical therapy in psoriasis is of use in mild cases. It is also applied as an adjunct to phototherapy and systemic treatments in moderate to severe cases. Long-established pharmaceuticals such as cignolin, tar preparations, and glucocorticoids are still in use. Newer topical agents such as vitamin A and D derivatives are gradually replacing them. Combining a vitamin D derivative and a strong glucocorticoid now seems to be the most efficient way to treat psoriasis when topical agents are indicated. There is a growing list of "alternative" treatment options, where evidence is generally absent. Rewarding investments should perhaps be directed at intervening with molecules of innate immunity. Superfluous activation of natural immune system cascades is now in view as the major culprit in psoriasis, replacing the T-cell hypothesis of the disease. Agents directed at tumor necrosis factor alpha, Toll-like receptors, and neutrophils may have great impact in future topical therapy of psoriasis. Finally, innovations in the development of more targeted glucocorticoids and vitamin A and D derivatives, where desired effects are better separated from undesired side effects, may lead to an increased benefit/risk ratio of these nuclear receptor-directed therapies.