Anti–interleukin-6 receptor antibody therapy favors adrenal androgen secretion in patients with rheumatoid arthritis: A randomized, double-blind, placebo-controlled study

Inflammation dynamically regulates steroid hormone metabolism and action within macrophages in rheumatoid arthritis

RATIONALE

In inflammatory diseases such as rheumatoid arthritis (RA), steroid metabolism is a central component mediating the actions of immuno-modulatory glucocorticoids and sex steroids. However, the regulation and function of cellular steroid metabolism within key leukocyte populations such as macrophages remain poorly defined. In this study, the inflammatory regulation of global steroid metabolism was assessed in RA macrophages.

METHODS

Bulk RNA-seq data from RA synovial macrophages was used to assess transcripts encoding key enzymes in steroid metabolism and signalling. Changes in metabolism were assessed in synovial fluids, correlated to measures of disease activity and functionally validated in primary macrophage cultures.

RESULTS

RNA-seq revealed a unique pattern of differentially expressed genes, including changes in genes encoding the enzymes 11β-HSD1, SRD5A1, AKR1C2 and AKR1C3. These correlated with disease activity, favouring increased glucocorticoid and androgen levels. Synovial fluid 11β-HSD1 activity correlated with local inflammatory mediators (TNFα, IL-6, IL-17), whilst 11β-HSD1, SRD5A1 and AKR1C3 activity correlated with systemic measures of disease and patient pain (ESR, DAS28 ESR, global disease activity). Changes in enzyme activity were evident in inflammatory activated macrophages in vitro and revealed a novel androgen activating role for 11β-HSD1. Together, increased glucocorticoids and androgens were able to suppress inflammation in macrophages and fibroblast-like-synoviocytes.

CONCLUSIONS

This study underscores the significant increase in androgen and glucocorticoid activation within inflammatory polarized macrophages of the synovium, contributing to local suppression of inflammation. The diminished profile of inactive steroid precursors in postmenopausal women may contribute to disturbances in this process, leading to increased disease incidence and severity.

Signaling pathways involved in the biological functions of dendritic cells and their implications for disease treatment

The ability of dendritic cells (DCs) to initiate and regulate adaptive immune responses is fundamental for maintaining immune homeostasis upon exposure to self or foreign antigens. The immune regulatory function of DCs is strictly controlled by their distribution as well as by cytokines, chemokines, and transcriptional programming. These factors work in conjunction to determine whether DCs exert an immunosuppressive or immune-activating function. Therefore, understanding the molecular signals involved in DC-dependent immunoregulation is crucial in providing insight into the generation of organismal immunity and revealing potential clinical applications of DCs. Considering the many breakthroughs in DC research in recent years, in this review we focused on three basic lines of research directly related to the biological functions of DCs and summarized new immunotherapeutic strategies involving DCs. First, we reviewed recent findings on DC subsets and identified lineage-restricted transcription factors that guide the development of different DC subsets. Second, we discussed the recognition and processing of antigens by DCs through pattern recognition receptors, endogenous/exogenous pathways, and the presentation of antigens through peptide/major histocompatibility complexes. Third, we reviewed how interactions between DCs and T cells coordinate immune homeostasis in vivo via multiple pathways. Finally, we summarized the application of DC-based immunotherapy for autoimmune diseases and tumors and highlighted potential research prospects for immunotherapy that targets DCs. This review provides a useful resource to better understand the immunomodulatory signals involved in different subsets of DCs and the manipulation of these immune signals can facilitate DC-based immunotherapy.

Sex steroids and autoimmune rheumatic diseases: state of the art

In autoimmune rheumatic diseases, oestrogens can stimulate certain immune responses (including effects on B cells and innate immunity), but can also have dose-related anti-inflammatory effects on T cells, macrophages and other immune cells. By contrast, androgens and progesterone have predominantly immunosuppressive and anti-inflammatory effects. Hormone replacement therapies and oral contraception (and also pregnancy) enhance or decrease the severity of autoimmune rheumatic diseases at a genetic or epigenetic level. Serum androgen concentrations are often low in men and in women with autoimmune rheumatic diseases, suggesting that androgen-like compounds might be a promising therapeutic approach. However, androgen-to-oestrogen conversion (known as intracrinology) is enhanced in inflamed tissues, such as those present in patients with autoimmune rheumatic diseases. In addition, it is becoming evident that the gut microbiota differs between the sexes (known as the microgenderome) and leads to sex-dependent genetic and epigenetic changes in gastrointestinal inflammation, systemic immunity and, potentially, susceptibility to autoimmune or inflammatory rheumatic diseases. Future clinical research needs to focus on the therapeutic use of androgens and progestins or their downstream signalling cascades and on new oestrogenic compounds such as tissue-selective oestrogen complex to modulate altered immune responses.

Involvement of adenosine monophosphate activated kinase in interleukin-6 regulation of steroidogenic acute regulatory protein and cholesterol side chain cleavage enzyme in the bovine zona fasciculata and zona reticularis

In bovine adrenal zona fasciculata (ZF) and NCI-H295R cells, interleukin-6 (IL-6) increases cortisol release, increases expression of steroidogenic acute regulatory protein (StAR), cholesterol side chain cleavage enzyme (P450scc), and steroidogenic factor 1 (SF-1) (increases steroidogenic proteins), and decreases the expression of adrenal hypoplasia congenita-like protein (DAX-1) (inhibits steroidogenic proteins). In contrast, IL-6 decreases bovine adrenal zona reticularis (ZR) androgen release, StAR, P450scc, and SF-1 expression, and increases DAX-1 expression. Adenosine monophosphate (AMP) activated kinase (AMPK) regulates steroidogenesis, but its role in IL-6 regulation of adrenal steroidogenesis is unknown. In the present study, an AMPK activator (AICAR) increased (P < 0.01) NCI-H295R StAR promoter activity, StAR and P450scc expression, and the phosphorylation of AMPK (PAMPK) and acetyl-CoA carboxylase (PACC) (indexes of AMPK activity). In ZR (decreased StAR, P450scc, SF-1, increased DAX-1) (P < 0.01) and ZF tissues (increased StAR, P450scc, SF-1, decreased DAX-1) (P < 0.01), AICAR modified StAR, P450scc, SF-1 and DAX-1 mRNAs/proteins similar to the effects of IL-6. The activity (increased PAMPK and PACC) (P < 0.01) of AMPK in the ZF and ZR was increased by AICAR and IL-6. In support of an AMPK role in IL-6 ZF and ZR effects, the AMPK inhibitor compound C blocked (P < 0.01) the effects of IL-6 on the expression of StAR, P450scc, SF-1, and DAX-1. Therefore, IL-6 modification of the expression of StAR and P450scc in the ZF and ZR may involve activation of AMPK and these changes may be related to changes in the expression of SF-1 and DAX-1.

Hypothalamic-Pituitary-Adrenal Hypofunction in Myalgic Encephalomyelitis (ME)/Chronic Fatigue Syndrome (CFS) as a Consequence of Activated Immune-Inflammatory and Oxidative and Nitrosative Pathways

There is evidence that immune-inflammatory and oxidative and nitrosative stress (O&NS) pathways play a role in the pathophysiology of myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS). There is also evidence that these neuroimmune diseases are accompanied by hypothalamic-pituitary-adrenal (HPA) axis hypoactivity as indicated by lowered baseline glucocorticoid levels. This paper aims to review the bidirectional communications between immune-inflammatory and O&NS pathways and HPA axis hypoactivity in ME/CFS, considering two possibilities: (a) Activation of immune-inflammatory pathways is secondary to HPA axis hypofunction via attenuated negative feedback mechanisms, or (b) chronic activated immune-inflammatory and O&NS pathways play a causative role in HPA axis hypoactivity. Electronic databases, i.e., PUBMED, Scopus, and Google Scholar, were used as sources for this narrative review by using keywords CFS, ME, cortisol, ACTH, CRH, HPA axis, glucocorticoid receptor, cytokines, immune, immunity, inflammation, and O&NS. Findings show that activation of immune-inflammatory and O&NS pathways in ME/CFS are probably not secondary to HPA axis hypoactivity and that activation of these pathways may underpin HPA axis hypofunction in ME/CFS. Mechanistic explanations comprise increased levels of tumor necrosis factor-α, T regulatory responses with elevated levels of interleukin-10 and transforming growth factor-β, elevated levels of nitric oxide, and viral/bacterial-mediated mechanisms. HPA axis hypoactivity in ME/CFS is most likely a consequence and not a cause of a wide variety of activated immune-inflammatory and O&NS pathways in that illness.

Necroinflammation in Kidney Disease

The bidirectional causality between kidney injury and inflammation remains an area of unexpected discoveries. The last decade unraveled the molecular mechanisms of sterile inflammation, which established danger signaling via pattern recognition receptors as a new concept of kidney injury-related inflammation. In contrast, renal cell necrosis remained considered a passive process executed either by the complement-related membrane attack complex, exotoxins, or cytotoxic T cells. Accumulating data now suggest that renal cell necrosis is a genetically determined and regulated process involving specific outside-in signaling pathways. These findings support a unifying theory in which kidney injury and inflammation are reciprocally enhanced in an autoamplification loop, referred to here as necroinflammation. This integrated concept is of potential clinical importance because it offers numerous innovative molecular targets for limiting kidney injury by blocking cell death, inflammation, or both. Here, the contribution of necroinflammation to AKI is discussed in thrombotic microangiopathies, necrotizing and crescentic GN, acute tubular necrosis, and infective pyelonephritis or sepsis. Potential new avenues are further discussed for abrogating necroinflammation-related kidney injury, and questions and strategies are listed for further exploration in this evolving field.

Interleukin-6 inhibits adrenal androgen release from bovine adrenal zona reticularis cells by inhibiting the expression of steroidogenic proteins

Interleukin-6 (IL-6) is secreted by adrenocortical cells and modifies cortisol secretion. In this study, the effects of IL-6 on adrenal androgen release were investigated. The zona reticularis (ZR) was generally isolated from bovine adrenal glands by dissection. In select experiments, the intact adrenal cortex (ie, all 3 adrenocortical zones) was dissected from the adrenal glands. For androgen release experiments, ZR and intact adrenocortical cubes were dispersed into isolated cells, the cells cultured and exposed to IL-6 and/or adrenocorticotropic hormone (ACTH), and androgen release determined by radioimmunoassay. Basal and ACTH-stimulated androgen release from the ZR was inhibited by IL-6 in a concentration-dependent (10-1000 pg/mL) and time-dependent (4-24 h) manner (P < 0.01 by 1-way analysis of variance and the Bonferroni test). In contrast, IL-6 increased basal and ACTH-stimulated androgen release from mixed adrenocortical cells (P < 0.01). The mechanism of IL-6 inhibition of androgen release was investigated by exposing ZR strips to IL-6 and measuring the expression of the messenger RNA (mRNA) and protein of steroidogenic factors. Basal and ACTH-stimulated expression of the mRNA and protein for steroidogenic acute regulatory protein, cholesterol side chain cleavage enzyme, 3-β-hydroxysteroid dehydrogenase type 2, steroid 17-α-hydroxylase/17,20 lyase/17,20 desmolase, and the nuclear factor steroidogenic factor 1 (SF-1), that stimulates steroidogenesis, were decreased by IL-6 (P < 0.01). In contrast IL-6 increased the mRNA and protein for dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1 (DAX-1), a nuclear factor that inhibits steroidogenesis (P < 0.01). In summary, IL-6 decreased androgen release and the expression of steroidogenic factors in the ZR, and this decrease may be mediated in part through increasing DAX-1 and decreasing SF-1.

Anti-inflammatory effects of Crataeva nurvala Buch. Ham. are mediated via inactivation of ERK but not NF-κB

ETHNOPHARMACOLOGICAL RELEVANCE

Crataeva nurvala Buch. Ham. is an important medicinal plant in India, and its extracts and components were used to treat various inflammatory diseases, such as urinary tract infection, rheumatoid arthritis, and colitis. However, no systemic studies about anti-inflammatory effects of Crataeva nurvala Buch. Ham. and its underlying mechanisms of action have been reported. This study aimed to explore the anti-inflammatory effects of ethanol extracts of Crataeva nurvala Buch. Ham. (ECN).

MATERIALS AND METHODS

The non-cytotoxic and maximal effective concentration of ECN was determined by measuring the formation of formazan from water-soluble tetrazolium salt in living cells. The inhibitory effect of ECN on nitric oxide (NO) synthesis was measured using Griess reagent, and Enzyme-linked immunosorbent assay (ELISA) was used to measure secreted tumor necrosis factor (TNF)-α and interleukin (IL)-6 protein levels. Furthermore, reverse transcription polymerase chain reaction (RT-PCR) and Western blotting analysis were used to assess the mRNA and protein expression of each inflammatory mediator or relating signaling protein, respectively.

RESULTS

A non-cytotoxic concentration of ECN (≤200 μg/ml) significantly reduced the production of NO and IL-6, but not TNF-α, in lipopolysaccharides (LPS)-stimulated RAW 264.7 macrophages. Decreased production of NO by ECN was correlated with reduced expression of iNOS at the mRNA and protein levels. However, cyclooxygenase (COX)-2 expressions at mRNA and protein level were not regulated by ECN. The mRNA expression of IL-6 and IL-1β, but not TNF-α, was also inhibited by ECN treatment in LPS-stimulated RAW 264.7 macrophages. Reduced production of inflammatory mediators by ECN was followed by decreased activity of mitogen-activated protein kinases (MAPKs), especially extracellular signal-regulated kinase (ERK), but not nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB).

CONCLUSIONS

These results indicate that ECN inhibits LPS-induced inflammatory responses via negative regulation of ERK in murine macrophages, suggesting that ECN is a candidate for alleviating severe inflammation.

Cutting edge: circulating plasmablasts induce the differentiation of human T follicular helper cells via IL-6 production

B cells require CD4⁺ T follicular helper (Tfh) cells to progress through the germinal center and provide protective Ab responses. In this article, we reveal a reciprocal interaction whereby circulating human plasmablasts are potent inducers of the Tfh cell–differentiation program, including the expression of their key transcription factor Bcl-6. The markedly increased propensity of plasmablasts, compared with naive B cells, to induce Tfh cell differentiation was due to their increased production of IL-6. Specific targeting of IL-6 using tocilizumab therapy in patients with rheumatoid arthritis led to a significant reduction in circulating Tfh cell numbers and IL-21 production, which was correlated with reduced plasmablast formation. Our data uncover a positive-feedback loop between circulating plasmablasts and Tfh cells that could sustain autoimmunity and spread Ab-driven inflammation to unaffected sites; this represents an important therapeutic target, as well as reveals a novel mechanism of action for tocilizumab.

Cytokine-modulating strategies and newer cytokine targets for arthritis therapy

Cytokines are the key mediators of inflammation in the course of autoimmune arthritis and other immune-mediated diseases. Uncontrolled production of the pro-inflammatory cytokines such as interferon-γ (IFN-γ), tumor necrosis factor α (TNFα), interleukin-6 (IL-6), and IL-17 can promote autoimmune pathology, whereas anti-inflammatory cytokines including IL-4, IL-10, and IL-27 can help control inflammation and tissue damage. The pro-inflammatory cytokines are the prime targets of the strategies to control rheumatoid arthritis (RA). For example, the neutralization of TNFα, either by engineered anti-cytokine antibodies or by soluble cytokine receptors as decoys, has proven successful in the treatment of RA. The activity of pro-inflammatory cytokines can also be downregulated either by using specific siRNA to inhibit the expression of a particular cytokine or by using small molecule inhibitors of cytokine signaling. Furthermore, the use of anti-inflammatory cytokines or cytokine antagonists delivered via gene therapy has proven to be an effective approach to regulate autoimmunity. Unexpectedly, under certain conditions, TNFα, IFN-γ, and few other cytokines can display anti-inflammatory activities. Increasing awareness of this phenomenon might help develop appropriate regimens to harness or avoid this effect. Furthermore, the relatively newer cytokines such as IL-32, IL-34 and IL-35 are being investigated for their potential role in the pathogenesis and treatment of arthritis.

Establishment of a novel cell-based assay for screening small molecule antagonists of human interleukin-6 receptor

AIM

Blockade of interleukin-6 (IL-6) or its receptor (IL-6R) is effective in preventing the progression of autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis. In the present study, we established a novel cell-based assay for identifying small molecule IL-6R antagonists.

METHODS

HEK293A cells were transfected with recombinant plasmids pTaglite-SNAP-IL6R and pABhFc-IL6 to obtain membrane-bound IL-6R and recombinant human IL-6 coupled with human Fc fragment (rhIL-6), respectively. A novel screening assay based on the interaction between IL-6R and rhIL-6 was established, optimized and validated. The stability of the assay was also assessed by calculating the Z'-factor.

RESULTS

RhIL-6 dose-dependently bound to IL-6R expressed at HEK293A cell surface. The IC50 value of the known antagonist ab47215 was 0.38±0.08 μg/mL, which was consistent with that obtained using the traditional method (0.36±0.14 μg/mL). The value of Z'-factor was 0.68, suggesting that the novel assay was stable for high throughput screening. A total of 474 compounds were screened using the novel screening assay, and 3 compounds exhibited antagonistic activities (IC50=8.73±0.28, 32.32±9.08, 57.83±4.24 μg/mL). Furthermore, the active compounds dose-dependently inhibited IL-6-induced proliferation of 7TD1 cells, and reduced IL-6-induced STAT3 phosphorylation in U937 cells.

CONCLUSION

A novel cell-based screening assay for identifying small molecule IL-6R antagonists was established, which simplifies the procedures in traditional cellular ELISA screening and profiling and reduces the costs.

Methanol extracts of Euphorbia cooperi inhibit the production of inflammatory mediators by inhibiting the activation of c‑Jun N‑terminal kinase and p38 in murine macrophages

Numerous Euphorbiaceae plants have been used for the treatment of diseases, including liver diseases, asthma and rheumatism. The present study evaluated the effect of methanol extracts from Euphorbia cooperi (MEC), a member of the Euphorbiaceae plant family, on the production of inflammatory cytokines interleukin (IL)‑6 and tumor necrosis factor (TNF)‑α, nitric oxide (NO) as well as the activation of mitogen‑activated protein kinase and nuclear factor (NF)‑κB signaling. Non‑cytotoxic concentrations of MEC significantly reduced the production of NO and IL‑6, but not TNF‑α, in lipopolysaccharide (LPS)‑stimulated RAW 264.7 macrophages. The decreased production of NO by MEC was due to alleviated expression of inducible NO synthase. Reporter assays with cells treated with MEC demonstrated reduced activator protein‑1 (AP-1) activity, while NF‑κB activity was not reduced. Furthermore, the phosphorylation levels of c‑Jun N‑terminal kinase (JNK) and p38 were suppressed by MEC while phosphorylation levels of inhibitor of κB were not reduced by MEC, suggesting that MEC‑mediated inactivation of JNK and p38 is the underlying regulatory mechanism for inflammatory mediators in LPS‑stimulated RAW 264.7 macrophages.

Determinants of adrenal androgen hypofunction in premenopausal females with rheumatoid arthritis

The aim of our study was to investigate adrenocortical function in the context of disease activity and inflammatory status in premenopausal RA females. Adrenal glucocorticoid and androgen responses to the 1 microg ACTH 1-24 test were investigated in 23 premenopausal RA and in 15 age- and BMI-matched healthy females. Twelve RA patients were on low-dose prednisone (<8.5 mg/day). Patients with DAS28>3.2 had lower (p<0.05) total plasma cortisol, 17-hydroxyprogesterone, dehydroepiandrosterone and androstenedione responses in the ACTH test compared to healthy controls. Patients with DAS28>3.2 had lower (p<0.05) dehydroepiandrosterone response in the ACTH test compared to patients with DAS28</=3.2. C-reactive protein (CRP), DAS28, and interleukin (IL)-6 negatively correlated with androstenedione response to ACTH 1-24. Responses of all measured adrenal steroids were lower (p<0.05) in patients on low-dose glucocorticoids compared to healthy controls. RA patients not treated with glucocorticoids had lower total cortisol response (p=0.038) but did not differ in free plasma cortisol in the ACTH test. The results indicate an association of increased disease activity with a decrease in adrenal androgen production in RA and normal cortisol bioavailability in patients not treated with glucocorticoids.

Role of neuroendocrine and neuroimmune mechanisms in chronic inflammatory rheumatic diseases--the 10-year update

BACKGROUND

Neuroendocrine immunology in musculoskeletal diseases is an emerging scientific field. It deals with the aspects of efferent neuronal and neurohormonal bearing on the peripheral immune and musculoskeletal systems. This review aims to add new information that appeared since 2001.

SEARCH STRATEGY

The following PubMed search sentence was used to find a total of 15,462 references between 2001 and March 2013: "(rheum* OR SLE OR vasculitis) AND (nerve OR hormone OR neurotransmitter OR neuropeptide OR steroid)." In a continuous process, year by year, this search strategy yielded relevant papers that were screened and collected in a database, which build the platform of this review.

RESULTS

The main findings are the anti-inflammatory role of androgens, the loss of androgens (androgen drain), the bimodal role of estrogens (support B cells and inhibit macrophages and T cells), increased conversion of androgens to estrogens in inflammation (androgen drain), disturbances of the gonadal axis, inadequate amount of HPA axis hormones relative to inflammation (disproportion principle), biologics partly improve neuroendocrine axes, anti-corticotropin-releasing hormone therapies improve inflammation (antalarmin), bimodal role of the sympathetic nervous system (proinflammatory early, anti-inflammatory late-most probably due to catecholamine-producing local cells), anti-inflammatory role of alpha melanocyte-stimulating hormone, vasoactive intestinal peptide, and the Vagus nerve via α7 nicotinergic receptors. Circadian rhythms of hypothalamic origin are responsible for circadian rhythms of symptoms (neuroimmune link revealed). Important new pain-sensitizing immunological pathways were found in the last decade.

CONCLUSIONS

The last decade brought much new information that gave birth to the first therapies of chronic inflammatory diseases on the basis of neuroendocrine immune targets. In addition, a new theory linked evolutionary medicine, neuroendocrine regulation of distribution of energy-rich fuels, and volume regulation that can explain many disease sequelae in patients with chronic inflammatory diseases.

Autoimmune diseases and reproductive aging

As the population ages, more individuals with autoimmune diseases are experiencing reproductive senescence. Understanding the impact of menopause and age-related androgen decline on disease onset and course, as well as the potential for hormonal interventions, is critically important. In men, lupus erythematosis (SLE), rheumatoid arthritis (RA), and multiple sclerosis (MS) are associated with lower androgen levels. However, the impact of age-related declines in testosterone, as well as of testosterone replacement, on disease course remains underexplored. In women, the course of all three diseases with onset after the age of menopause differs from that with onset before menopause. Early age at menopause is associated with increased disease risk, and after menopause, disease course changes in SLE and RA. Less is known about MS. This article summarizes what is known about the relationship between reproductive aging and autoimmune diseases in men and women, and highlights areas for further investigation.

IL-6 receptor is a possible target against growth of metastasized lung tumor cells in the brain

In the animal model of brain metastasis using human lung squamous cell carcinoma-derived cells (HARA-B) inoculated into the left ventricle of the heart of nude mice, metastasized tumor cells and brain resident cells interact with each other. Among them, tumor cells and astrocytes have been reported to stimulate each other, releasing soluble factors from both sides, subsequently promoting tumor growth significantly. Among the receptors for soluble factors released from astrocytes, only IL-6 receptor (IL-6R) on tumor cells was up-regulated during the activation with astrocytes. Application of monoclonal antibody against human IL-6R (tocilizumab) to the activated HARA-B cells, the growth of HARA-B cells stimulated by the conditioned medium of HARA-B/astrocytes was significantly inhibited. Injecting tocilizumab to animal models of brain metastasis starting at three weeks of inoculation of HARA-B cells, two times a week for three weeks, significantly inhibited the size of the metastasized tumor foci. The up-regulated expression of IL-6R on metastasized lung tumor cells was also observed in the tissue from postmortem patients. These results suggest that IL-6R on metastasized lung tumor cells would be a therapeutic target to inhibit the growth of the metastasized lung tumor cells in the brain.

Novel treatments for systemic lupus erythematosus

There are many new therapeutic directions for the disease systemic lupus erythematosus (SLE). Despite this, the US Food and Drug Administration (FDA) has approved only one biological agent and it involves B cells, now thought to play a significant role in the pathogenesis of SLE. The name of the drug is belimumab, which is an agent that removes the B-cell cytokine called B lymphocyte stimulation factor (BLyS). Rituximab did not achieve its primary endpoints, even though the consensus is that it may be effective in some forms of SLE including renal disease. The anticytokine therapies against interleukin (IL)-6, IL-10, IL-17 and tumor necrosis factor (TNF) are effective in their own ways and phase II and III trials are in progress. Of particular interest to immunologists are the anti-interferon alpha and gamma drugs, which show promise in the animal models. Modulation of costimulatory molecules; specifically, the anti CD40, CTLA-***Ig and ICOS/B7RP blockade agents offer possibilities for the future using new pathways heretofore limited to rheumatoid arthritis. Finally, the use of tyrosine kinase inhibitors is another direction that has been successful in the inhibition of SLE in the murine model; early trials in human SLE have begun.

Tocilizumab for rheumatoid arthritis

BACKGROUND

Tocilizumab, a new biologic that inhibits interleukin-6, is approved for treatment of rheumatoid arthritis (RA) in Europe, Japan and the US.

OBJECTIVES

To assess the efficacy and safety of tocilizumab in patients with RA using the data from published randomized or quasi-randomized controlled trials (RCTs).

SEARCH STRATEGY

We performed a search of the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL) up to issue 3, 2009; OVID MEDLINE(1966 to 1 October 2009); CINAHL(1982 to 2009); EMBASE (1980 to week 39, 2009); Science Citation Index (Web of Science) (1945 to 2009) and Current Controlled Trials.

SELECTION CRITERIA

Tocilizumab alone or in combination with disease-modifying anti-rheumatic drugs (DMARDs) or biologics compared to placebo or other DMARDs or biologics.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted all data including major (ACR50, adverse events, serious adverse events, withdrawals, specific adverse events) and secondary outcomes. We calculated the risk ratio for dichotomous outcomes and mean difference for continuous outcomes.

MAIN RESULTS

Eight RCTs were included in this systematic review with 3334 participants; 2233 treated with tocilizumab and 1101 controls. Of the 2233, 1561 were treated with tocilizumab 8 mg/kg every four weeks, which is the approved dose. In patients taking concomitant methotrexate, compared to placebo, tocilizumab-treated patients were four times more likely to achieve ACR50 (absolute %, 38.8% versus 9.6%), 11 times more likely to achieve Disease Activity Score (DAS) remission (absolute %, 30.5% versus 2.7%), 1.8 times more likely to achieve clinically meaningful decrease in Health Assessment Questionnaire (HAQ/mHAQ) scores (absolute %, 60.5% versus 34%), 1.2 times more likely to have any adverse event (absolute %, 74% versus 65%) and 0.6 times less likely to withdraw from therapy for any reason (absolute %, 8.1% versus 14.9%). With the limitation that none of the studies were powered for safety as primary outcome, there were no statistically significant differences in serious adverse effects, or withdrawals due to adverse events. A significant increase in total, HDL and LDL cholesterol and triglyceride level was seen in the tocilizumab treated patients.

AUTHORS' CONCLUSIONS

Tocilizumab is beneficial in decreasing RA disease activity and improving function. Tocilizumab treatment was associated with significant increase in cholesterol levels and in total adverse events. Larger safety studies are needed to address these safety concerns.

Tocilizumab in systemic lupus erythematosus: data on safety, preliminary efficacy, and impact on circulating plasma cells from an open-label phase I dosage-escalation study

OBJECTIVE

To assess the safety of interleukin-6 receptor inhibition and to collect preliminary data on the clinical and immunologic efficacy of tocilizumab in patients with systemic lupus erythematosus (SLE).

METHODS

In an open-label phase I dosage-escalation study, 16 patients with mild-to-moderate disease activity were assigned to receive 1 of 3 doses of tocilizumab given intravenously every other week for 12 weeks (total of 7 infusions): 2 mg/kg in 4 patients, 4 mg/kg in 6 patients, or 8 mg/kg in 6 patients. Patients were then monitored for an additional 8 weeks.

RESULTS

The infusions were well tolerated. Tocilizumab treatment led to dosage-related decreases in the absolute neutrophil count, with a median decrease of 38% in the 4 mg/kg dosage group and 56% in the 8 mg/kg dosage group. Neutrophil counts returned to normal after cessation of treatment. One patient was withdrawn from the study because of neutropenia. Infections occurred in 11 patients; none was associated with neutropenia. Disease activity showed significant improvement, with a decrease of > or =4 points in the modified Safety of Estrogens in Lupus Erythematosus National Assessment version of the Systemic Lupus Erythematosus Disease Activity Index score in 8 of the 15 evaluable patients. Arthritis improved in all 7 patients who had arthritis at baseline and resolved in 4 of them. Levels of anti-double-stranded DNA antibodies decreased by a median of 47% in patients in the 4 mg/kg and 8 mg/kg dosage groups, with a 7.8% decrease in their IgG levels. These changes, together with a significant decrease in the frequency of circulating plasma cells, suggest a specific effect of tocilizumab on autoantibody-producing cells.

CONCLUSION

Although neutropenia may limit the maximum dosage of tocilizumab in patients with SLE, the observed clinical and serologic responses are promising and warrant further studies to establish the optimal dosing regimen and efficacy.

Recent advances in neutralizing the IL-6 pathway in arthritis

Recent advances in understanding the mechanism(s) of how IL-6 trans-signaling regulates immune cell function and promotes inflammation in autoimmune arthritis are critically reviewed. Serum and/or synovial fluid (SF) IL-6 is markedly elevated in adult and juvenile rheumatoid arthritis (RA), psoriatic arthritis (PsA), ankylosing spondylitis (AS) and osteoarthritis (OA). IL-6, in concert with IL-17, determines the fate of CD4⁺ lymphocytes and therefore TH₁₇ cell differentiation. IL-6 also plays a critical role in modulating B-lymphocyte activity. The recognition that IL-6 trans-signaling regulates inflammation resulted in the development of tocilizumab, a fully humanized monoclonal antibody that neutralizes the biological activity of the IL-6-receptor (IL-6R). Significant clinical benefit was demonstrated as well as reduced serum IL-6 levels with suppression of X-ray progression of disease in several clinical trials in which juvenile or adult RA patients were treated with tocilizumab monotherapy or tocilizumab plus methotrexate. However, levels of serum and/or SF IL-6 cytokine protein superfamily members, adiponectin, oncostatin M, pre-B-cell colony enhancing factor/visfatin and leukemia inhibitory factor are also elevated in RA. Additional studies will be required to determine if anti-IL-6 trans-signaling inhibition strategies with tocilizumab or recombinant soluble IL-6R reduce the level of these cytokines.

Effects of endogenous and exogenous hypercortisolemia on low-dose adrenocorticotropin test outcome in humans

BACKGROUND

The results of low-dose ACTH testing may be impaired during endogenous or exogenous hypercortisolemia in various clinical situations.

AIM

The hypothesized inhibitory effects of hypercortisolemia on adrenal responsiveness to low-dose ACTH were tested in two model situations in healthy humans.

SUBJECTS AND METHODS

Nine young healthy women underwent low-dose ACTH test in 5 modifications. In ACTH-ACTH test, ACTH (1 microg iv) was given at 09:00 h and 10:00 h. Two control tests consisted of single ACTH bolus at 09:00 h or at 10:00 h. In hydrocortisone (HC)-ACTH test, HC (20 mg po) was given at 08:30 h and ACTH was injected at 10:00 h. Control test consisted of single HC administration at 08:30 h.

RESULTS

Cortisol response after the 2nd ACTH test was significantly lower vs the 1st ACTH bolus (Deltamax: 166+/-32 nmol/l vs 276+/-15 nmol/l, p<0.05) in ACTH-ACTH test. Responses of other steroids after both ACTH injections were comparable. ACTH bolus during HC-induced hypercortisolemia caused a slight increase in cortisol level and prevented its decrease, seen after HC administration alone. Adrenal cortisol production in response to ACTH bolus under different incipient conditions (baseline, physiological, and pharmacological hypercortisolemia; 180+/-16, 173+/-21, and 177+/-53 nmol.min.l-1, respectively) did not significantly differ (p=0.8).

CONCLUSIONS

Endogenous and exogenous hypercortisolemia did not influence adrenal cortisol response to low-dose ACTH test indicating lack of its negative feedback at adrenal level.

Cytokine signalling via gp130 in gastric cancer

Cytokine signalling pathways that depend on gp130 are dysregulated in several epithelial cancers including gastric cancer. It has been established that blockade of SHP2 activation of MAPK signalling results in hyperactivation of STAT3 resulting in increased cell proliferation, angiogenesis, inflammation and inhibition of both immunocyte and epithelial cell apoptosis. Additionally, key genes regulated downstream of gp130 via MAPK activation such as the stomach-specific tumor suppressor gene tff1 are suppressed, contributing to the oncogenic outcome. The main cytokine driver of gp130 signalling in the stomach is IL-11, with IL-6 having little activity in the antral stomach in which most pathology initiates. IL-11 is up-regulated in both mouse and human gastric cancer and in pre-neoplastic mucosa. A characteristic gene signature specifically associated with IL-11 drive has been observed, although the prognostic value of the signature has not yet been assessed. Infection of human or mouse stomach with Helicobacter pylori, especially that expressing the CagA cytotoxin, produces constitutive MAPK activation, but also activated STAT3 and increases IL-11 expression. The possibility of designing and utilising small molecule inhibitors of either IL-11 or STAT3 activation may be worthwhile in developing new cancer therapeutics.

Pre-analytical and biological variability in circulating interleukin 6 in healthy subjects and patients with rheumatoid arthritis

Interleukin (IL)-6, a key player in the inflammatory response, may be a useful biomarker in rheumatoid arthritis (RA). The aim was to determine analytical variability, a reference interval in healthy subjects, and long- and short-term variation in serum and plasma IL-6 in healthy subjects and RA patients. An enzyme-linked immunosorbent assay from R&D was used for determination of serum and plasma IL-6. The IL-6 concentration did not depend on the type of anticoagulant used or the 3-h time delay between sampling and processing or repeated freeze-thaw cycles. The median plasma and serum IL-6 in 318 healthy subjects were 1.3 pg ml(-1) (range 0.33-26) and 1.4 pg ml(-1) (range 0.25-23), respectively. The median coefficient of variation in plasma IL-6 in 27 healthy subjects during 1 month, and repeated after 6 and 12 months were 27%, 31% and 26%, respectively. No significant long-term changes were observed in serum IL-6 over a 3-year period (14%, p = 0.33). Exercise (cycling) increased serum IL-6 in healthy subjects but not in RA patients. In conclusion, circulating IL-6 is stable regarding sample handling and shows little variation over time. Changes in IL-6 concentrations > 60% (2 times the biological variation) are likely to reflect changes in disease activity and not only pre-analytical or normal biological variability.

Diurnal secretion of growth hormone, cortisol, and dehydroepiandrosterone in pre- and perimenopausal women with active rheumatoid arthritis: a pilot case-control study

Rheumatoid arthritis (RA) is associated with neuroendocrine and immunologic dysfunction leading to rheumatoid cachexia. Although excess proinflammatory cytokines can decrease somatotropic axis activity, little is known about the effects of RA on growth hormone/insulin-like growth factor-1 (GH/IGF-I) axis function. We tested the hypothesis that patients with active RA exhibit decreased GH/IGF-I axis activity. To do so, we conducted a pilot case-control study at a clinical research center in 7 pre- and perimenopausal women with active RA and 10 age- and body mass index-matched healthy women. Participants underwent blood sampling every 20 minutes for 24 hours (8 a.m. to 8 a.m.), and sera were assayed for GH, cortisol, and dehydroepiandrosterone (DHEA). Sera obtained after overnight fasting were assayed for IGF-I, IGF-binding protein (IGFBP)-1, IGFBP-3, C-reactive protein (CRP), interleukin-6 (IL-6), glucose, insulin, and lipids. Body composition and bone mineral density were evaluated by DEXA (dual emission x-ray absorptiometry) scans. In patients with RA, mean disease duration was 7.6 ± 6.8 years, and erythrocyte sedimentation rate, CRP, and IL-6 were elevated. GH half-life was shorter than in control subjects (p = 0.0037), with no other significant group differences in GH deconvolution parameters or approximate entropy scores. IGF-I (p = 0.05) and IGFBP-3 (p = 0.058) were lower, whereas IGFBP-1 tended to be higher (p = 0.066), in patients with RA, with nonsignificantly increased 24-hour total GH production rates. There were no significant group differences in cortisol or DHEA secretion. Lean body mass was lower in patients with RA (p = 0.019), particularly in the legs (p = 0.01). Women with active RA exhibit a trend toward GH insensitivity and relatively diminished diurnal cortisol and DHEA secretion for their state of inflammation. Whether these changes contribute to rheumatoid cachexia remains to be determined.

NCT00034060.

Treatment with anti-gamma-glutamyl transpeptidase antibody attenuates osteolysis in collagen-induced arthritis mice

The effectiveness of a new antibody treatment on arthritis-associated osteolysis was studied by using CIA mice. GGT, a newly identified bone-resorbing factor, was upregulated in arthritic joints. We generated monoclonal antibodies against GGT and injected them into CIA mice. Mice treated with antibodies showed a reduction in osteoclast number and bone erosion.

INTRODUCTION

Gamma-glutamyl transpeptidase (GGT) acts as a bone-resorbing factor that stimulates osteoclast formation. GGT expression has been detected in active lymphocytes that accumulate at inflammation sites, such as rheumatoid arthritis (RA). We hypothesize that GGT is an effective target for suppression of arthritis-related osteoclastogenesis and joint destruction. Here, we describe the therapeutic effect of neutralizing antibodies against GGT on joint destruction using a collagen-induced arthritis (CIA) mouse model.

MATERIALS AND METHODS

GGT expression in the synovium of RA patients and CIA mice was determined by immunohistochemistry and RT-PCR. Monoclonal antibodies were generated against recombinant human GGT (GGT-mAbs) using BALB/c mice. Antibody treatment was performed by intraperitoneal injections of GGT-mAbs into CIA mice. Effects of antibody treatment on arthritis and bone erosion were evaluated by incidence score, arthritis score, and histopathological observations. The role of GGT in osteoclast development was examined by using the established osteoclastogenic culture system.

RESULTS

GGT expression was significantly upregulated in inflamed synovium. Immunohistochemistry revealed that GGT was present in lymphocytes, plasma cells, and macrophages, as well as capillaries. Injection of GGT-mAbs significantly decreased the number of osteoclasts and attenuated the severity of joint destruction in CIA mice. In vitro examination showed that GGT enhanced RANKL-dependent osteoclast formation. GGT stimulated the expression of RANKL in osteoblasts and its receptor RANK in osteoclast precursors, respectively.

CONCLUSIONS

This study indicates that inflamed synovial tissue-derived GGT acts as a risk factor for joint destruction and that the antibody-mediated inhibition of GGT significantly decreases osteoclast number and bone erosion in CIA mice. GGT antagonists might be novel therapeutic agents for attenuating joint destruction in RA patients.

Conversation galante: how the immune and the neuroendocrine systems talk to each other

The generation of endogenous adjuvants and the clearance of apoptotic cells occur at the intersection between the neuroendocrine and the immune systems. Recent data suggest that autoimmunity associates with a communication breakdown between the two systems and that events taking place in lymphoid organs and in peripheral inflamed tissues shape the response to tissue damage. Autonomic nerve endings release norepinephrine and acetylcholine, whereas sensitive fibers release neuropeptides. Moreover, nervous endings in the tissues control the secretory activity of neuroendocrine cells, which are distributed in the gut, the pancreas, the lung, the thyroid, the liver, the prostate, the skin. Intracellular enzymes, and in particular the 11 beta-hydroxysteroid dehydrogenase type 1, regulate the availability of active glucocorticoids in inflammatory macrophages and maturing dendritic cells; in turn the rate of active glucocorticoids determine the efficiency of phagocytes in clearing apoptotic cells, possibly influencing the availability of autoantigens. Immune cells release cytokines, which, in turn signal to the central and peripheral nervous system. We learnt from cytokine-neutralizing therapies that the sustained production of pro-inflammatory signals interferes with various neuro-endocrine axes. A better molecular dissection of this finely regulated inter-system cross-talk, in physiological conditions and during self-sustaining inflammatory diseases, might enable more rational therapeutic approaches.