Discovering adaptive features of innate immune memory

Conventionally, it was thought that innate immunity operated through a simple system of nonspecific responses to an insult. However, this perspective now seems overly simplistic. It has become evident that intricate cooperation and networking among various cells, receptors, signaling pathways, and protein complexes are essential for regulating and defining the overall activation status of the immune response, where the distinction between innate and adaptive immunity becomes ambiguous. Given the evolutionary timeline of vertebrates and the success of plants and invertebrates which depend solely on innate immunity, immune memory cannot be considered an innovation of only the lymphoid lineage. Indeed, the evolutionary innate immune memory program is a conserved mechanism whereby innate immune cells can induce a heightened response to a secondary stimulus due to metabolic and epigenetic reprogramming. Importantly, the longevity of this memory phenotype can be attributed to the reprogramming of self-renewing hematopoietic stem cells (HSCs) in the bone marrow, which is subsequently transmitted to lineage-committed innate immune cells. HSCs reside within a complex regulated network of immune and stromal cells that govern their two primary functions: self-renewal and differentiation. In this review, we delve into the emerging cellular and molecular mechanisms as well as metabolic pathways of innate memory in HSCs, which harbor substantial therapeutic promise.

Sustained Pericarditis Recurrence Risk Reduction With Long-Term Rilonacept

BACKGROUND

Rilonacept, a once-weekly interleukin-1 alpha and beta cytokine trap, reduced pericarditis recurrence in the phase 3 study, RHAPSODY (Rilonacept Inhibition of Interleukin-1 Alpha and Beta for Recurrent Pericarditis: A Pivotal Symptomatology and Outcomes Study). The RHAPSODY long-term extension further explored recurrent pericarditis natural history and treatment duration decision-making during 24 additional months of open-label rilonacept treatment.

METHODS AND RESULTS

Seventy-four patients commenced the long-term extension, with a median (maximum) total rilonacept duration of 22 (35) months. Individually, 18 months after the most proximal pericarditis recurrence, investigators decided to continue rilonacept on study, suspend rilonacept for off-treatment observation (rescue allowed), or discontinue the study. The annualized incidence of pericarditis recurrence on rilonacept up to the 18-month decision milestone was 0.04 events/patient-year versus 4.4 events/patient-year prestudy while on oral therapies. At the 18-month decision milestone, 64% (33/52) continued rilonacept, 15% (8/52) suspended rilonacept for observation, and 21% (11/52) discontinued the study. Among the 33 patients (1/33; 3.0%) continuing rilonacept (median time to recurrence could not be estimated due to too few events), a single recurrence occurred 4 weeks after a treatment interruption. Among patients suspending rilonacept, 75% (6/8) experienced recurrence (median time to recurrence, 11.8 weeks [95% CI, 3.7 weeks to not estimable]). There was a 98% reduction in risk of pericarditis recurrence among patients continuing rilonacept treatment after the 18-month decision milestone versus those suspending treatment for observation (hazard ratio, 0.02; P<0.0001).

CONCLUSIONS

In the RHAPSODY long-term extension, continued rilonacept treatment resulted in continued response; treatment suspension at the 18-month decision milestone was associated with pericarditis recurrence.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03737110.

"How to Release or Not Release, That Is the Question." A Review of Interleukin-1 Cellular Release Mechanisms in Vascular Inflammation

Cardiovascular disease remains the leading cause of death worldwide, characterized by atherosclerotic activity within large and medium-sized arteries. Inflammation has been shown to be a primary driver of atherosclerotic plaque formation, with interleukin-1 (IL-1) having a principal role. This review focuses on the current state of knowledge of molecular mechanisms of IL-1 release from cells in atherosclerotic plaques. A more in-depth understanding of the process of IL-1's release into the vascular environment is necessary for the treatment of inflammatory disease processes, as the current selection of medicines being used primarily target IL-1 after it has been released. IL-1 is secreted by several heterogenous mechanisms, some of which are cell type-specific and could provide further specialized targets for therapeutic intervention. A major unmet challenge is to understand the mechanism before and leading to IL-1 release, especially by cells in atherosclerotic plaques, including endothelial cells, vascular smooth muscle cells, and macrophages. Data so far indicate a heterogeneity of IL-1 release mechanisms that vary according to cell type and are stimulus-dependent. Unraveling this complexity may reveal new targets to block excess vascular inflammation.

Inhibition of interleukin‐1 with rilonacept is not effective in cold urticaria—Results of a randomized, placebo‐controlled study

Background

Cold urticaria (ColdU) is characterized by pruritic wheals following exposure of the skin to cold. Many patients show insufficient response to antihistamines, the first line treatment. Based on the high efficacy of interleukin‐1(IL‐1)‐inhibition in cold‐induced urticarial autoinflammatory diseases, we assessed the effects of rilonacept, an IL‐1 inhibitor, in ColdU patients unresponsive to standard treatment.

Methods

In this randomized, double‐blind, placebo‐controlled two‐center study, we included 20 patients with ColdU. In the first part, patients received 320 mg rilonacept or placebo (1:1) followed by weekly doses of 160 mg rilonacept or placebo for 6 weeks. In the second part, all patients received weekly 160 mg or 320 mg rilonacept for 6 weeks, open‐label. The primary endpoint was change in critical temperature threshold (CTT). Secondary endpoints included changes in quality of life impairment (Dermatology Life Quality Index, DLQI), differences of inflammatory mediators upon cold provocation and safety assessment over the study period.

Results

Baseline mean CTTs were 20.2°C (placebo) and 17.3°C (rilonacept). Mean CTTs did not change significantly during the 6‐week double‐blind treatment (placebo – 0.45°C; rilonacept +0.89°C). IL‐6, IL‐18 and HSP‐70 blood levels showed interindividual variability without significant changes during hand cold water bath provocation in placebo‐ or rilonacept‐treated patients. In contrast, DLQI significantly improved in the rilonacept (mean DLQI reduction of 3.8; p = 0.002) but not in the placebo group (mean DLQI reduction of 0). Comparing baseline with the rilonacept open‐label treatment, there were no changes in CTTs or DLQI scores.

Conclusion

IL‐1 inhibition with rilonacept did not improve ColdU, but demonstrated a good safety profile.

Clinical Trial Registration

EudraCT number: 2012‐005726‐30. ClinicalTrials.gov identifier: NCT02171416.

Interleukin-1 Trap Rilonacept Improved Health-Related Quality of Life and Sleep in Patients With Recurrent Pericarditis: Results From the Phase 3 Clinical Trial RHAPSODY

Background Recurrent pericarditis is characterized by painful flares and inflammation, which negatively impact health-related quality of life. RHAPSODY (rilonacept inhibition of interleukin-1 alpha and beta for recurrent pericarditis: a pivotal symptomatology and outcomes study) evaluated the efficacy and safety of rilonacept (IL-1α and -β cytokine trap) in recurrent pericarditis. A secondary analysis of these data evaluated the patient-reported outcome questionnaire score change during the trial. Methods and Results Participants completed 5 patient-reported outcome (PRO) questionnaires assessing pericarditis pain, health-related quality of life, general health status, sleep impact, and overall symptom severity. PRO score changes during the treatment run-in period (12 weeks) and the blinded randomized withdrawal period (up to 24 weeks) were evaluated using descriptive statistics and mixed model repeated measures analyses. Participants with PRO data from the run-in period (n=84) and the randomized withdrawal period (n=61; 30 rilonacept, 31 placebo) were included in analyses. Run-in baseline PRO scores indicated that pericarditis symptoms during pericarditis recurrence impacted health-related quality of life. All PRO scores significantly improved (P<0.001) on rilonacept treatment during the run-in period. For the randomized withdrawal period, PRO scores were maintained for participants receiving rilonacept. For those receiving placebo and who experienced a recurrence, PRO scores deteriorated at the time of recurrence and then improved following rilonacept bailout. At randomized withdrawal Week 24/End of Study, scores of participants who received bailout rilonacept were similar to those of participants who had continued rilonacept. Conclusions These results demonstrate the burden of pericarditis recurrences and the improved physical and emotional health of patients with recurrent pericarditis while on rilonacept treatment. These findings extend prior rilonacept efficacy results, demonstrating improvements in patient-reported health-related quality of life, sleep, pain, and global symptom severity while on treatment. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03737110.

Interleukin-1 pathway in active large vessel vasculitis patients with a poor prognosis: a longitudinal transcriptome analysis

Objectives

Large vessel vasculitis (LVV) is characterised by a high relapse rate. Because accurate assessment of the LVV disease status can be difficult, an accurate prognostic marker for initial risk stratification is required. We conducted a comprehensive longitudinal investigation of next‐generation RNA‐sequencing data for patients with LVV to explore useful biomarkers associated with clinical characteristics.

Methods

Key molecular pathways relevant to LVV pathogenesis were identified by examining the whole blood RNA from patients with LVV and healthy controls (HCs). The data were examined by pathway analysis and weighted gene correlation network analysis (WGCNA) to identify functional gene sets that were differentially expressed between LVV patients and HCs, and associated with clinical features. We then compared the expression of the selected genes during week 0, week 6, remission and relapse.

Results

The whole‐transcriptome gene expression data for 108 samples obtained from LVV patients (n = 27) and HCs (n = 12) were compared. The pathway analysis and WGCNA revealed that molecular pathway related to interleukin (IL)‐1 was significantly upregulated in LVV patients compared with HCs, which correlated with the positron emission tomography vascular activity score, a disease‐extent score based on the distribution of affected arteries. Further analysis revealed that the expression levels of genes in the IL‐1 signalling pathway remained high after conventional treatment and were associated with disease relapse.

Conclusion

Upregulation of the IL‐1 signalling pathway was a characteristic of LVV patients and was associated with the extent of disease and a poor prognosis.

Hypothesis: Febrile infection-related epilepsy syndrome is a microglial NLRP3 inflammasome/IL-1 axis-driven autoinflammatory syndrome

FIRES (febrile infection-related epilepsy syndrome) is a protracted neuroinflammatory condition of obscure cause. It mainly afflicts school-age children and often leads to permanent neurological sequelae. Most treatments to date have been of limited efficacy, while ketogenic diet and anti-interleukin-1 therapy appear beneficial for some patients. Research into this clinical entity is hampered by its rarity and complexity. Nonetheless, accumulating evidence derived from basic investigations and clinical observations converges to implicate the autoinflammatory nature of this syndrome. A closer analysis of current literature suggests that microglia and the NLRP3 inflammasome might be the pivotal cellular and molecular players in FIRES pathogenesis, respectively. Through evidence synthesis, herein we formulate the working hypothesis of overactivation of microglial NLRP3 inflammasome/interleukin-1 axis as the driving event in FIRES by creating a proinflammatory and proconvulsive milieu. The reverberation between neuroinflammation and seizure forms a vicious cycle. The unique properties of microglia might also contribute to unopposed IL-1 signalling and incessant sterile neuroinflammation in this context. The potential therapeutic relevance of the proposed conceptual framework is discussed.

Interleukin-1 Blockade Inhibits the Acute Inflammatory Response in Patients With ST-Segment-Elevation Myocardial Infarction

Background

ST‐segment–elevation myocardial infarction is associated with an intense acute inflammatory response and risk of heart failure. We tested whether interleukin‐1 blockade with anakinra significantly reduced the area under the curve for hsCRP (high sensitivity C‐reactive protein) levels during the first 14 days in patients with ST‐segment–elevation myocardial infarction (VCUART3 [Virginia Commonwealth University Anakinra Remodeling Trial 3]).

Methods and Results

We conducted a randomized, placebo‐controlled, double‐blind, clinical trial in 99 patients with ST‐segment–elevation myocardial infarction in which patients were assigned to 2 weeks treatment with anakinra once daily (N=33), anakinra twice daily (N=31), or placebo (N=35). hsCRP area under the curve was significantly lower in patients receiving anakinra versus placebo (median, 67 [interquartile range, 39–120] versus 214 [interquartile range, 131–394] mg·day/L; P<0.001), without significant differences between the anakinra arms. No significant differences were found between anakinra and placebo groups in the interval changes in left ventricular end‐systolic volume (median, 1.4 [interquartile range, −9.8 to 9.8] versus −3.9 [interquartile range, −15.4 to 1.4] mL; P=0.21) or left ventricular ejection fraction (median, 3.9% [interquartile range, −1.6% to 10.2%] versus 2.7% [interquartile range, −1.8% to 9.3%]; P=0.61) at 12 months. The incidence of death or new‐onset heart failure or of death and hospitalization for heart failure was significantly lower with anakinra versus placebo (9.4% versus 25.7% [P=0.046] and 0% versus 11.4% [P=0.011], respectively), without difference between the anakinra arms. The incidence of serious infection was not different between anakinra and placebo groups (14% versus 14%; P=0.98). Injection site reactions occurred more frequently in patients receiving anakinra (22%) versus placebo (3%; P=0.016).

Conclusions

In patients presenting with ST‐segment–elevation myocardial infarction, interleukin‐1 blockade with anakinra significantly reduces the systemic inflammatory response compared with placebo.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT01950299.

Fetuin-A aggravates lipotoxicity in podocytes via interleukin-1 signaling

Sterile inflammation is considered critical in the pathogenesis of diabetic nephropathy (DN). Here we show that Fetuin-A (FetA) or lipopolysaccharide (LPS) exacerbate palmitic acid-induced podocyte death, which is associated with a strong induction of monocyte chemoattractant protein-1 (MCP-1) and keratinocyte chemoattractant (KC). Moreover, blockage of TLR4 prevents MCP-1 and KC secretion and attenuates podocyte death induced by palmitic acid alone or combined with FetA. In addition, inhibition of interleukin-1 (IL-1) signaling by anakinra, a recombinant human IL-1Ra, or a murinized anti-IL-1β antibody attenuates the inflammatory and ultimate cell death response elicited by FetA alone or combined with palmitic acid. In vivo short-term therapy of diabetic DBA/2J mice with an anti-IL1-β antibody for 4 weeks prevented an increase in serum FetA and considerably decreased urinary tumor necrosis alpha (TNF-α), a known risk factor for DN progression. In summary, our results suggest that FetA similarly to LPS leads to an inflammatory response in podocytes, which exacerbates palmitic acid-induced podocyte death and our data imply a critical role for IL-1β signaling in this process. The study offers the rational for prolonged in vivo studies aimed at testing anti-IL-1β therapy for prevention and treatment of DN.

AAO: Autoimmune and Autoinflammatory (Disease) in Otology: What is New in Immune-Mediated Hearing Loss

OBJECTIVES

Autoinflammatory diseases are a family of immune-mediated, rare diseases, some of which, exhibit sensorineural hearing loss (SNHL), suggesting potentially similar mechanisms of molecular pathogenesis between autoinflammatory-mediated hearing loss and autoimmune inner ear disease (AIED) may exist. The purpose of this review is to compare the clinical features of autoimmune and autoinflammatory diseases that affect hearing, discuss the limitations of our knowledge, and highlight potential new disease mechanisms and therapeutics.

DATA SOURCES

Pubmed Literature Review; Google Scholar Literature review.

REVIEW METHODS

A focused comparison of AIED with a number of autoinflammatory diseases that manifest with sensorineural hearing loss was performed. The pathogenesis of these diseases is reviewed in the context of the innate and adaptive immune system, cytokine expression and genetic polymorphisms.

RESULTS

AIED, since first described by Cogan and Lehnhardt and first clinically characterized by McCabe, has remained an enigmatic disease, with limited advances in both new diagnostics and new therapeutics. Since the discovery of autoinflammatory diseases, a number of systemic autoimmune diseases have either been re-classed as autoinflammatory diseases or identified to have features of autoinflammatory disease.

CONCLUSION

AIED has clinical features of both autoimmune and autoinflammatory disease. It is critical that autoinflammatory diseases be correctly identified, as failure to do so may result in systemic amyloidosis and kidney damage.

Interleukin-1 inhibitors for acute gout

BACKGROUND

Acute gout flares cause significant pain and disability and it is important to provide quick and effective pain relief. Traditional options for managing acute flares include colchicine, non-steroidal anti-inflammatory drugs (NSAIDs) and glucocorticoids.

OBJECTIVES

To assess the benefits and harms of interleukin-1 inhibitors (anakinra, canakinumab, rilonacept) in acute gout.

SEARCH METHODS

We searched The Cochrane Library, MEDLINE and EMBASE on 19 June 2013. We applied no date or language restrictions. We performed a handsearch of the abstracts from the European League Against Rheumatism (EULAR) (2009 to 2012) and American College of Rheumatology (ACR) (2009 to 2011) conferences and of the references of all included trials. We also screened the Clinical Trials Registry Platform of the World Health Organization and Clinical Trials Registry Platform of the US National Institutes of Health.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-randomised clinical trials (controlled clinical trials (CCTs)) assessing an interleukin-1 inhibitor (anakinra, canakinumab or rilonacept) against placebo or another active treatment (colchicine, paracetamol, NSAIDs, glucocorticoids (systemic or intra-articular), adrenocorticotropin hormone, a different interleukin-1 blocking agent or a combination of any of the above) in adults with acute gout.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed the risk of bias and extracted the data. If appropriate, we pooled data in a meta-analysis. We assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

We included four studies (806 participants) in the review. The studies had an unclear risk of selection bias and low risk of performance and attrition biases. One study each had an unclear risk of detection and selection bias.Three studies (654 participants) compared subcutaneous canakinumab compared with intramuscular triamcinolone acetonide 40 mg in the treatment of acute gout flares of no more than five days' duration. Doses of canakinumab were varied (10 to 150 mg), but most people (255/368) were treated with canakinumab 150 mg. None of the studies provided data on participant-reported pain relief of 30% or greater. Moderate-quality evidence indicated that canakinumab 150 mg was probably superior to triamcinolone acetonide 40 mg in terms of pain relief, resolution of joint swelling and in achieving a good treatment response at 72 hours following treatment, but was probably associated with an increased risk of adverse events.Mean pain (0- to 100-mm visual analogue scale (VAS), where 0 mm was no pain) was 36 mm after triamcinolone acetonide treatment; pain was further reduced by a mean of 11 mm with canakinumab treatment (mean difference (MD) -10.6 mm, 95% confidence interval (CI) -15.2 to -5.9). Forty-four per cent of participants treated with canakinumab had resolution of joint swelling at 72 hours compared with 32% of participants treated with triamcinolone (risk ratio (RR) 1.39, 95% CI 1.11 to 1.74, number needed to treat for an addition beneficial outcome (NNTB) 9); 65% of participants treated with canakinumab assessed their response to treatment as good or excellent compare with 47% of participants treated with triamcinolone acetonide (RR 1.37, 95% CI 1.16 to 1.61, NNTB 6). Function or health-related quality of life were not measured. In both groups, 0.7% of participants withdrew from treatment (RR 1.1, 95% CI 0.2 to 7.2); there was one death and one alteration of laboratory results in each of the treatment groups. Adverse events were more frequent in participants receiving canakinumab (61%) compared with triamcinolone acetonide (51%; RR 1.2, 95% CI 1.1 to 1.4, number needed to treat for an addition harmful outcome (NNTH) 10).Low-quality evidence from one study (152 participants with an acute gout flare of no more than 48 hours' duration and affecting fewer than four joints) comparing rilonacept 320 mg with indomethacin (50 mg three times a day for three days followed by 25 mg three times a day for up to nine days) indicated that indomethacin may improve pain more than rilonacept at 24 to 72 hours, and there may be no evidence of a difference in withdrawal rates or adverse events. The mean change (improvement) in pain from baseline with indomethacin was 4.3 points (measured on a 0 to 10 numerical rating scale, where 0 was no pain); pain was improved by a mean of only 2.5 points with rilonacept (MD 2.52, 95% CI 0.29 to 4.75, 25% less improvement in absolute pain with rilonacept). Inflammation, function health-related quality of life and participant global assessment of treatment success were not measured. Rates of study withdrawals due to adverse events were low in both groups: 1/75 (1%) participants in the rilonacept group compared with 2/76 (3%) participants in the indomethacin group (RR 0.5, 95% CI 0.05 to 5.5). Adverse events were reported in 27/75 (36%) participants in the rilonacept group and 23/76 (30%) in the indomethacin group (RR 1.2, 95% CI 0.8 to 1.9).

AUTHORS' CONCLUSIONS

Moderate-quality evidence indicated that compared with a single suboptimal 40-mg dose of intramuscular injection of triamcinolone acetonide, a single subcutaneous dose of 150 mg of canakinumab probably results in better pain relief, joint swelling and participant-assessed global assessment of treatment response in people with an acute gout flare but is probably associated with an increased risk of adverse events. The cost of canakinumab is over 5000 times higher than triamcinolone acetonide; however, there are no data on the cost-effectiveness of this approach. We found no studies comparing canakinumab with more commonly used first-line therapies for acute gout flares such as NSAIDs or colchicine. Low-quality evidence indicated that compared with maximum doses of indomethacin (50 mg three times a day), 320 mg of rilonacept may provide less pain relief with a similar rate of adverse events.

Effect of anti-IL-1β antibody (canakinumab) on insulin secretion rates in impaired glucose tolerance or type 2 diabetes: results of a randomized, placebo-controlled trial

AIMS

Evaluate anti-interleukin-1β (IL-1β) antibody, canakinumab, in patients with type 2 diabetes and impaired glucose tolerance (IGT) in whom hyperglycaemia may trigger IL-1β-associated inflammation leading to suppressed insulin secretion and β-cell dysfunction.

METHODS

This 4-week, parallel-group study randomized 190 patients with type 2 diabetes 2 : 1, canakinumab versus placebo, into the following treatment arms: metformin monotherapy, metformin + sulfonylurea, metformin + sulfonylurea + thiazolidinedione or insulin ± metformin. IGT population (n = 54) was randomized 1 : 1, canakinumab versus placebo. Primary efficacy assessment was change from baseline in insulin secretion rate (ISR) relative to glucose 0-2 h.

RESULTS

Mean changes from baseline to week 4 in ISR relative to glucose at 0-2 h or other time points were not statistically significant for canakinumab versus placebo across groups. ISR (relative to glucose) at 0-0.5 h (first-phase insulin secretion) numerically favoured canakinumab versus placebo in insulin-treated patients {difference in mean change from baseline [point estimate (PE)] 3.81 pmol/min/m(2)/mmol/l; p = 0.0525} and in the IGT group (PE 3.92 pmol/min/m(2)/mmol/l; p = 0.1729). Mean change from baseline in fasting plasma glucose favoured canakinumab in the type 2 diabetes/metformin group and the IGT group; however, differences were not statistically significant. Mean change from baseline in peak insulin level and insulin AUC 0-4 h were statistically significantly higher in the canakinumab group in IGT patients. Canakinumab was well tolerated and consistent with known safety experience.

CONCLUSIONS

The trend towards improving ISR relative to glucose 0-0.5 h in patients treated with insulin supports the hypothesis that insulin secretion can be improved by blocking IL-1β.

Epileptic encephalitis: the role of the innate and adaptive immune system

Seizures are a prominent clinical feature of encephalitis. Recent data suggest the adaptive as well as innate immune system to be involved directly in the pathomechanism of epileptogenesis. Cytotoxic T-cells and antibody-mediated complement activation are major components of the adaptive immune system, which can induce neurodegeneration, thereby probably contributing to epileptic encephalitis. The innate immune system operates via interleukin-1 and toll-like receptor-associated mechanisms and was shown to play a direct role in epileptogenesis. Here, we review neuropathology hallmarks of various encephalitis conditions such as Rasmussen encephalitis (RE) but also introduce the more recently discovered antibody-associated voltage-gated potassium channel complex (VGKC), N-methyl-D-aspartate receptor (NMDAR) or glutamic acid decarboxylase (GAD) 65 encephalitides. Neuropathological investigations are used to determine specific cellular components and molecular mechanisms used by the immune system to provoke neurodegeneration and to promote epileptogenesis. Based on recent findings, we propose concepts for the stratification of epileptic encephalitis. Knowledge of the role of the innate immunity has already translated into clinical treatment strategies and may help to discover novel drug targets for these epileptic disorders.

Inflammatory mechanisms associated with brain damage induced by kainic acid with special reference to the interleukin-1 system

The evidence of inflammatory processes in the clinical manifestations and neuropathological sequelae of epilepsy have accumulated in the last decade. Administration of kainic acid, an analogue of the excitatory amino acid glutamate, induces a characteristic behavioural syndrome and a reproducible pattern of neurodegeneration in several brain areas, closely resembling human temporal lobe epilepsy. Results from studies using the kainic acid model indicate that manipulation of pro- and anti-inflammatory cytokines can modify the outcome with regard to the behavioural syndrome as well as the neuropathological consequences. Interleukin-1 is one of the most important cytokines and has several actions in the brain that are critical for the host defense against injury and infection, and it is involved in the initiation of early stages of inflammation. It is believed that interleukin-1 plays a pivotal role in the neuroinflammation associated with certain forms of neurodegeneration, including cerebral ischemia, trauma and excitotoxic brain injury. In this review, we have summarized the experimental data available with regard to the involvement of the interleukin-1 system in kainic acid-induced changes in the brain and emphasized the modulatory role of interleukin-1beta in this model of epilepsy

Interleukin-1 induces sleep-like behavior and alters call structure in juvenile rhesus macaques

To date, there have been no investigations of the behavioral effects of interleukin-1 (IL-1) in nonhuman primates. In this study the locomotor behavior and vocalizations of juvenile rhesus monkeys were monitored for 45 minutes following intravenous injections of recombinant human IL-1 alpha. In addition, their reaction to a broadcasted recording of infant monkey distress calls was determined 20 minutes after the beginning of each test session. IL-1 induced sleep-like inactivity and significantly diminished the monkey's behavioral and vocal responses to the broadcasted calls. The coo calls uttered by the monkeys following IL-1 treatment also had a longer duration and lower fundamental frequency than calls during the control condition. As several studies have indicated that behavioral effects of IL-1 may be mediated by corticotropin-releasing hormone (CRH), a second group of rhesus monkeys was given injections of CRH. CRH did not alter behavior or call structure at the dose administered. These results extend previous research on the behavioral effects of IL-1 to include the nonhuman primate and provide the first evidence that cytokines can affect vocal communication in rhesus monkeys. © 1995 Wiley-Liss, Inc.

Characterization of mice bearing subclones of colon 26 adenocarcinoma disqualifies interleukin-6 as the sole inducer of cachexia

A subclone (clone 20) of chemically induced, murine colon adenocarcinoma with a potent ability to induce cachexia and another subclone (clone 5) without such an activity were transplanted to syngeneic mice (CDF1) and their tissue weights, blood components and cytokine levels in sera were compared. Mice transplanted with clone 20 showed a profound body-weight loss by 15 days after inoculation when the tumor accounted for less than 1% of the body weight, along with marked reduction of food and water intakes. Thereafter, they transiently gained in body weight with restoration of food and water intakes. Thus, the change in body weight was biphasic and not proportional to the tumor size. Body fat was lost preferentially, accompanied with a decrease in plasma triglyceride levels. The thymus contracted remarkably, and the peripheral lymphocyte count decreased extensively. Mice transplanted with clone 5, in contrast, did not show any of these changes characteristic of cachexia. Serum concentration of interleukin-6, which has been proposed as the principal inducer of cachexia in mice with colon 26, increased in mice with clone 5 to levels comparable to those in mice with clone 20. The changes in mice bearing clone 20 could not all be explained in terms of known biological activities of interleukin-6. Additional unknown factors, therefore, are presumed to contribute to cachexia in mice with clone 20. Identification of them should be helpful in the care of cachectic patients.

Interaction of interleukin-1 and interferon-gamma on fibroblast growth factor-induced angiogenesis

The interaction of interleukin-1 (IL-1) and interferon-gamma (IFN-gamma) actions on several aspects of angiogenesis in vitro and in vivo was studied. The proliferation and migration of human umbilical vein endothelial cells cultured with basic fibroblast growth factor (bFGF) were synergistically inhibited by cotreatment with IL-1 and IFN-gamma. Endothelial cell adhesion to collagen was suppressed by IL-1 and the effect was slightly enhanced by the combination of IL-1 and IFN-gamma. Local administration of IL-1 (10,000 U) and IFN-gamma (1,000 U) inhibited bFGF-induced angiogenesis in the skin of mice, and synergistic inhibitory activity of the combination was demonstrated. Expression of FGF receptors was strongly downregulated by the combination, whereas expressions of epidermal growth factor (EGF) receptors, integrin beta 1 and integrin beta 3 were not. EGF partially abrogated the growth-inhibitory effects of IL-1 and IFN-gamma. These findings indicate that IL-1 and IFN-gamma are each able to act an angiogenesis inhibitor in a situation where FGF plays a major role in angiogenesis, and the activity is synergistically enhanced when they are used in combination.

Antitumor effector mechanism of interleukin-1 beta at a distant site in the double grafted tumor system

Recombinant human interleukin-1 beta (IL-1 beta) inhibited the growth of not only the right, but also the left non-treated tumor in a double grafted tumor system. Since the antitumor activity of IL-1 beta against the right and left tumors was not seen in nude mice, lymphocytes have a key role in the antitumor effect of intratumoral administration of IL-1 beta. TIL (tumor-infiltrating leukocytes) obtained from left and right side tumors treated with IL-1 beta were examined by Winn assay for their antitumor activity against Meth-A sarcoma in BALB/c mice. TIL from the right side clearly inhibited the growth of admixed Meth-A cells, but control TIL did not. Spleen cells and right and left regional lymph node cells prepared from IL-1-treated mice were examined for Lyt-1, Lyt-2 and L3T4 phenotypes. The number of Lyt-1-positive lymphocytes increased in the spleen and in the right regional lymph nodes after intratumoral administration of IL-1. Isolated tumor cells obtained from the right tumor treated with IL-1 beta and the left side tumor on day 6 were cultured in RPMI 1640 with 10% fetal calf serum for 24 h. The culture supernatants were harvested and tested for the presence of chemotactic activity for neutrophils or macrophages. Significant neutrophil chemotactic factor and macrophage chemotactic factor activities were detected in the culture media from IL-1-treated tumor tissues cultured for 24 h. Neither significant neutrophil nor macrophage chemotactic activity was detected in the media from untreated tumor tissues. These results suggest that intratumoral administration of IL-1 first induces neutrophils and macrophages in the right tumor, then Lyt-1-positive cells in the right regional lymph nodes and in the spleen, and subsequently induces macrophages in the left, non-treated tumor.

Murine tumor cells metastasizing selectively in the liver: ability to produce hepatocyte-activating cytokines interleukin-1 and/or -6

Increasing evidence suggests that an intimate correlation may exist between the production of a cytokine, granulocyte-macrophage colony-stimulating factor (GM-CSF) and the ability to metastasize spontaneously in the lungs in murine transplantable tumors. In the present study, we further examined the cytokine production by tumor cells with the ability to metastasize in the liver. Four out of 8 test tumors, which produced metastasis in the lungs but not in the liver, exhibited the ability to produce GM-CSF activity in culture. Three other tumors produced metastasis in the liver but not in the lungs. These tumor cells exhibited no ability to produce GM-CSF, but two of them expressed an interleukin-6 (IL-6) mRNA and also produced IL-6 activity in the culture fluids. One of the two IL-6-producing tumors and the remaining liver metastatic tumor produced interleukin-1 (IL-1) as revealed by bioassay and neutralization test. In the tumor cells producing pulmonary metastasis, neither IL-6 gene expression nor IL-1 production could be detected. The last test tumor, which produced no metastasis either in the lungs or liver, produced neither GM-CSF, IL-1 nor IL-6. Furthermore, injection of antisera reactive to recombinant murine IL-6 caused a marked decrease of the number of liver metastases of an IL-6-producing tumor, but not lung metastases of a GM-CSF-producing tumor, which could be markedly inhibited by injection of anti-recombinant murine GM-CSF sera. These results suggest the possibility that there may be a correlation between the cytokines produced by tumor cells and their organ specificity in spontaneous metastasis, and also indicate that these tumor models may provide a useful tool for studies on the role of cytokines in tumor metastasis.

Co-production of interleukin-1 and interleukin-6 in tumor cell lines elaborating colony-stimulating factors

Six carcinoma cell lines elaborating colony-stimulating factors (CSFs) were examined by enzyme-linked immunosorbent assay and Northern blotting to determine whether or not they co-produced interleukin-1 alpha (IL-1 alpha), IL-1 beta and IL-6. All 6 cell lines were co-producers; IL-1 alpha was produced in all 6, IL-6 in 5 and IL-1 beta in 3 of them. These results indicate that IL-1 and IL-6 are commonly co-produced in CSF-producing tumors.

Antitumor activity of recombinant human interleukin-1 against heterotransplanted human non-Hodgkin lymphomas in nude mice

Antitumor activity of recombinant human interleukin 1 alpha (IL-1) against seven human non-Hodgkin lymphomas grown in athymic nude mice was studied. Growth of the lymphomas was markedly inhibited after an injection of 0.4 mg/kg IL-1. The growth inhibition of Burkitt lymphoma was found to be dose-dependent up to 0.4 mg/kg, reaching a plateau thereafter. The loss of colony-forming ability of the cells and the loss of cell viability showed the same type of dose-dependence and progressed during 24 h following an injection of IL-1. In accordance with these observations, histopathologic examination revealed progressively spreading coagulative necrosis without bleeding. Little infiltration of inflammatory cells into the tumor tissue was observed. IL-1 growth inhibition of T lymphoma in beige nude mice having low natural killer activity was similar to that in nude mice. These findings suggested that the antitumor effects might not be produced through cell-mediated antitumor actions. Immunocytological examination with anti-IL-1 antibody revealed that administered IL-1 was bound to the lymphoma cells, suggesting that IL-1 receptor is probably expressed on these cells in vivo. The antitumor action of IL-1 on the lymphomas may be exerted directly through the IL-1 receptor.

Antitumor effect of interleukin-1 beta in the double grafted tumor system

The antimetastatic effect of recombinant human interleukin-1 beta (rIL-1 beta) in a new experimental mouse model was studied. Intratumoral administration of IL-1 beta strongly inhibited the growth of Meth-A solid tumors in male BALB/c mice and led to a complete regression of tumors and resistance to reinoculated tumor. Subsequently, the anti-metastatic effect of IL-1 beta was examined in the double grafted tumor system, in which mice first received simultaneous intradermal inoculations of Meth-A in both right (10(6) cells) and left (2 X 10(5) cells) flanks and were then injected with 0.2 micrograms of IL-1 beta in the right tumor on days 3, 4 and 5. IL-1 beta significantly inhibited the growth of the left, non-treated tumor. When mice received only an inoculation of Meth-A (2 X 10(5) cells) in the left flank and were injected subcutaneously with IL-1 beta into the right flank on day 3 (single tumor system), there was no inhibition of the growth of the left, non-treated tumor. These findings suggest that intratumoral IL-1 beta immunotherapy in one region has an effect on tumor growth in another region. Immunized spleen cells were taken from mice which had been cured by the intratumoral administration of IL-1 beta. Adoptive transfer of the immunized spleen cells caused the complete regression of Meth-A tumors. These results suggest that intratumoral administration of IL-1 beta might induce cytotoxic cells in the left non-treated tumor of the double grafted tumor system and bring about the regression of metastatic tumors.(ABSTRACT TRUNCATED AT 250 WORDS)