Dexamethasone promotes type 2 cytokine production primarily through inhibition of type 1 cytokines

Cochlear implants with dexamethasone-eluting electrode arrays reduce foreign body response in a murine model of cochlear implantation and human subjects

The inflammatory foreign body response (FBR) following cochlear implantation (CI) can negatively impact CI outcomes, including increased electrode impedances. This study aims to investigate the long-term efficacy of dexamethasone eluting cochlear implant and locally delivered dexamethasone, a potent anti-inflammatory glucocorticoid on the intracochlear FBR and electrical impedance post-implantation in a murine model and human subjects. The left ears of CX3CR1 +/GFP Thy1 +/YFP (macrophage-neuron dual reporter) mice were implanted with dexamethasone-eluting cochlear implants (Dex-CI) or standard implant (Standard-CI) while the right ear served as unoperated control. Another group of dual reporter mice was implanted with a standard CI electrode array followed by injection of dexamethasone in the middle ear to mimic current clinical practice (Dex-local). Mouse implants were electrically stimulated with serial measurement of electrical impedance. Human subjects were implanted with either standard or Dex-CI followed by serial impedance measurements. Dex-CI reduced electrical impedance in the murine model and human subjects and inflammatory FBR in the murine model for an extended period. Dex-local in the murine model is ineffective for long-term reduction of FBR and electrode impedance. Our data suggest that dexamethasone eluting arrays are more effective than the current clinical practice of locally applied dexamethasone in reducing FBR and electrical impedance.

Dynamic changes of Th1/Th2/Th17 cytokines and hBD-2/3 in erosive oral lichen planus patients saliva before and after prednisone acetate treatment

Objective

This study aimed to investigate the expression of T helper 1 (Th1)/Th2/Th17- related cytokines and human beta defensins 2 and 3 (hBD-2 and -3) in the saliva of patients with erosive oral lichen planus (EOLP) and to explore their role in the pathogenesis of EOLP and the effects of glucocorticoids on EOLP.

Methods

A total of 30 patients with EOLP and 20 age- and sex-matched healthy individuals were included in this study. The patients were treated with prednisone at a dose of 0.4 mg/(kg·d) for 1 week and examined before and after treatment. Unstimulated whole saliva samples were collected to determine the levels of cytokines (interleukin 1 beta [IL-1β], tumour necrosis factor alpha [TNF]-α, interferon gamma [IFN-γ], IL-4, IL-6, IL-10 and IL-17) by cytometric bead array and those of hBD-2 and -3 b y enzyme-linked immunosorbent assay. In addition, oral rinse samples were collected to detect Candida load.

Results

The levels of salivary IL-1β, IL-6, hBD-2 and hBD-3 were higher and the IFN-γ/IL-4 and IL-1β/IL-6 ratios were lower in patients with EOLP than in healthy individuals. In patients with EOLP, hBD-2 levels were positively correlated with IFN-γ levels and negatively correlated with IL-17 levels, whereas hBD-3 levels were negatively correlated with IL-17 and IL-10 levels. In addition, the prevalence of EOLP was positively correlated with IL-6 levels and negatively correlated with the IFN-γ/IL-4 ratio. The levels of IL-1β, TNF-α, IFN-γ, IL-6, hBD-2 and hBD-3 and the IFN-γ/IL-4 ratio decreased after treatment with prednisone for 1 week. The levels of IL-6, hBD-2 and hBD-3 were significantly higher in EOLP patients than in healthy individuals; while TNF-α levels and the IFN-γ/IL-4 ratio were significantly lower in EOLP patients than in healthy individuals. Furthermore, the oral counts of Candida spp. (colony forming unit [CFU]) were negatively correlated with TNF-α levels. Numerical Rating Scale(NRS) and Sign scores decreased in EOLP patients after treatment. Approximately 80 % of patients were effectively treated. Salivary TNF-α levels were significantly higher in the treatment-ineffective group than in the treatment-effective group before treatment with prednisone, and differences in salivary IL-6 levels before and after treatment were significantly higher in the treatment-effective group than in the treatment-ineffective group.

Conclusions

High expression of IL-1β, IL-6, hBD-2 and Th1/Th2 imbalance in saliva may be associated with the pathogenesis of EOLP. IFN-γ/IL-4 balance may serve as a protective factor for EOLP. Glucocorticoids significantly alleviate the symptoms of EOLP and inhibit the expression of Th1/Th2 cytokines.

Beneficial Effects of Two Hydrogen Sulfide (H2S)-Releasing Derivatives of Dexamethasone with Antioxidant Activity on Atopic Dermatitis in Mice

Hydrogen sulfide (H₂S) is particularly produced in the skin, where it participates in the regulation of inflammation, pruritus, cytoprotection, scarring, and angiogenesis. In this study, we compared the effects of dexamethasone (Dex) with two H₂S-releasing Dex derivatives in a murine model of atopic dermatitis (AD) induced by topical application of 2,4-dinitrochlorobenzene (DNCB). After sensitization with DNCB, the animals were topically treated for five consecutive days with either the H₂S-releasing compounds 4-hydroxy-thiobenzamide (TBZ) and 5-(p-hydroxyphenyl)-1,2-dithione-3-thione (ADT-OH), Dex, or the derivatives Dex-TBZ or Dex-ADT. Topical treatment with equimolar doses of either Dex, Dex-TBZ, or Dex-ADT resulted in similar reductions in dermatitis score, scratching behavior, edema, eosinophilia, splenomegaly, and histological changes. In contrast with Dex, the H₂S-releasing derivatives prevented IL-4 elevation and oxidative modification of skin proteins. On an equimolar dose basis, Dex-TBZ, but not Dex-ADT, promoted the elevation of endogenous H₂S production and GPx activity. Neither Dex-TBZ nor Dex-ADT decreased GR activity or caused hyperglycemia, as observed with Dex treatment. We conclude that the presence of H₂S-releasing moieties in the Dex structure does not interfere with the anti-inflammatory effects of this corticosteroid and adds beneficial therapeutical actions to the parent compound.

Brain Versus Blood: A Systematic Review on the Concordance Between Peripheral and Central Kynurenine Pathway Measures in Psychiatric Disorders

Objective

Disturbances in the kynurenine pathway have been implicated in the pathophysiology of psychotic and mood disorders, as well as several other psychiatric illnesses. It remains uncertain however to what extent metabolite levels detectable in plasma or serum reflect brain kynurenine metabolism and other disease-specific pathophysiological changes. The primary objective of this systematic review was to investigate the concordance between peripheral and central (CSF or brain tissue) kynurenine metabolites. As secondary aims we describe their correlation with illness course, treatment response, and neuroanatomical abnormalities in psychiatric diseases.

Methods

We performed a systematic literature search until February 2021 in PubMed. We included 27 original research articles describing a correlation between peripheral and central kynurenine metabolite measures in preclinical studies and human samples from patients suffering from neuropsychiatric disorders and other conditions. We also included 32 articles reporting associations between peripheral KP markers and symptom severity, CNS pathology or treatment response in schizophrenia, bipolar disorder or major depressive disorder.

Results

For kynurenine and 3-hydroxykynurenine, moderate to strong concordance was found between peripheral and central concentrations not only in psychiatric disorders, but also in other (patho)physiological conditions. Despite discordant findings for other metabolites (mainly tryptophan and kynurenic acid), blood metabolite levels were associated with clinical symptoms and treatment response in psychiatric patients, as well as with observed neuroanatomical abnormalities and glial activity.

Conclusion

Only kynurenine and 3-hydroxykynurenine demonstrated a consistent and reliable concordance between peripheral and central measures. Evidence from psychiatric studies on kynurenine pathway concordance is scarce, and more research is needed to determine the validity of peripheral kynurenine metabolite assessment as proxy markers for CNS processes. Peripheral kynurenine and 3-hydroxykynurenine may nonetheless represent valuable predictive and prognostic biomarker candidates for psychiatric disorders.

Inflammation, HIV, and Immune Quiescence: Leveraging on Immunomodulatory Products to Reduce HIV Susceptibility

The relationship between inflammation and HIV has been a focus of research over the last decade. In HIV-infected individuals, increased HIV-associated immune activation significantly correlated to disease progression. While genital inflammation (GI) has been shown to significantly increase the risk of HIV acquisition and transmission, immune correlates for reduced risk remain limited. In certain HIV-exposed seronegative individuals, an immune quiescent phenotype characterized reduced risk. Immune quiescence is defined by specific, targeted, highly regulated immune responses that hinder overt inflammation or immune activation. Targeted management of inflammation, therefore, is a plausible strategy to mitigate HIV risk and slow disease progression. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as hydroxychloroquine and aspirin have shown encouraging preliminary results in low-risk women by reducing systemic and genital immune activation. A topical NSAID, containing ibuprofen, is effective in treating vulvovaginal inflammation. Additionally, the glucocorticoids (GCs), prednisolone, and dexamethasone are used to treat HIV-associated immune activation. Collectively, these data inform on immune-modulating drugs to reduce HIV risk. However, the prolonged use of these pharmaceutical drugs is associated with adverse effects, both systemically and to a lesser extent topically. Natural products with their reduced side effects coupled with anti-inflammatory properties render them viable options. Lactic acid (LA) has immunomodulatory properties. LA regulates the genital microbiome by facilitating the growth of Lactobacillus species, while simultaneously limiting bacterial species that cause microbial dysbiosis and GI. Glycerol monolaurate, besides being anti-inflammatory, also inhibited SIV infections in rhesus macaques. The proposed pharmaceutical and natural products could be used in combination with either antiretrovirals for treatment or preexposure prophylaxis for HIV prevention. This review provides a summary on the associations between inflammation, HIV risk, and disease progression. Furthermore, we use the knowledge from immune quiescence to exploit the use of pharmaceutical and natural products as strategic interventions to manage inflammation, toward mitigating HIV infections.

Corticosteroid inhibits chemokines production in systemic sclerosis patients

In this study, we evaluated glucocorticoids (GC) effects on cytokine/chemokine levels in serum samples and peripheral blood mononuclear cell (PBMC) production from systemic sclerosis (SSc) patients. We evaluated cytokine and chemokine levels in serum samples from SSc patients taking or not taking systemic glucocorticoids. PBMCs response to methylprednisolone (MP) was examined from 15 SSc patients and 8 healthy control subjects following PBMC stimulation with anti-CD3/CD28. Cytokine (IFN-γ, TNF, IL-2, IL-4, IL-6, IL-10, and IL-17A) and chemokine (CXCL8/IL-8, CCL5/RANTES, CXCL9/MIG, CCL2/MCP-1, and CXCL10/IP-10) levels were quantified in serum and in PBMC culture supernatants by CBA or ELISA. Compared with patients not taking corticosteroids, we did not observe any significant differences in cytokines/chemokines serum levels in patients using systemic corticosteroids. After stimulation with anti-CD3/CD28, PBMCs treated with MP (100μM), showed a significant reduction of CCL2/MCP-1 (p=0.001), CCL5/RANTES (p=0.04), and CXCL8/IL-8 (p=0.003) levels in SSc patients. In PBMC from healthy controls, we observed decreased IFN-γ, TNF, IL-2, and IL-10 levels after MP treatment, compared with stimulated condition (p<0.01 for all). However in SSc patients, we did not find any significant reduction in these cytokine levels after MP treatment. In conclusion, CCL2/MCP-1, CCL5/RANTES, and CXCL8/IL-8 are chemokines that are potentially modulated by corticosteroids in vitro in SSc patients, but no effect was observed on IL-2, IL-4, IL-6, IL-10, IL-17A, TFN, and IFN-γ secretion. These results suggest a potential effect of GCs on SSc treatment and may reflect the benefit of their use in some patients.

IL-10 Dysregulation in Acute Mountain Sickness Revealed by Transcriptome Analysis

Acute mountain sickness (AMS), which may progress to life-threatening high-altitude cerebral edema, is a major threat to millions of people who live in or travel to high altitude. Although studies have revealed the risk factors and pathophysiology theories of AMS, the molecular mechanisms of it do not comprehensively illustrate. Here, we used a system-level methodology, RNA sequencing, to explore the molecular mechanisms of AMS at genome-wide level in 10 individuals. After exposure to high altitude, a total of 1,164 and 1,322 differentially expressed transcripts were identified in AMS and non-AMS groups, respectively. Among them, only 328 common transcripts presented between the two groups. Immune and inflammatory responses were overrepresented in participants with AMS, but not in non-AMS individuals. Anti-inflammatory cytokine IL10 and inflammation cytokines IF17F and CCL8 exhibited significantly different genetic connectivity in AMS compared to that of non-AMS individuals based on network analysis. IL10 was downregulated and both IF17F and CCL8 were upregulated in AMS individuals. Moreover, the serum concentration of IL10 significantly decreased in AMS patients after exposure to high altitude (p = 0.001) in another population (n = 22). There was a large negative correlation between the changes in IL10 concentration, r(22) = −0.52, p = 0.013, and Lake Louise Score. Taken together, our analysis provides unprecedented characterization of AMS transcriptome and identifies that genes involved in immune and inflammatory responses were disturbed in AMS individuals by high-altitude exposure. The reduction of IL10 after exposure to high altitude was associated with AMS.

Glucocorticoids Suppress Antimicrobial Autophagy and Nitric Oxide Production and Facilitate Mycobacterial Survival in Macrophages

Chronic administration of glucocorticoids has been shown to render individuals highly susceptible to mycobacterial infection and lead to reactivation of latent bacilli. However, the effect of glucocorticoids on innate anti-mycobacterial defense, especially in macrophages remains largely unknown. Here, we found that glucocorticoids inhibited the innate immune response, antimicrobial nitric oxide production and autophagy in mycobacteria-challenged macrophages. Meanwhile, maturation and acidification of mycobacterial phagosomes were attenuated in RAW264.7 cells after glucocorticoids treatment. Consequently, we observed a glucocorticoid-induced increase in the survival of intracellular mycobacteria in both primary macrophages and cell lines. Glucocorticoids treatment decreased the activation of TBK1 kinase, which promotes the maturation of autophagosomes. Inhibition of TBK1 also decreased the production of nitric oxide. Furthermore, several autophagy-related genes were down-regulated, while activation of the Akt/mTOR signaling pathway was increased after glucocorticoids treatment, which may account for autophagy inhibition during mycobacterial infection. Restoration of autophagy with the agonist rapamycin abolished glucocorticoid-mediated enhancement of mycobacterial survival, suggesting that glucocorticoids blocked anti-mycobacterial defense via autophagy inhibition. Collectively, this study demonstrates that glucocorticoids impair innate antimicrobial autophagy and promote mycobacterial survival in macrophages, which is a novel mechanism for glucocorticoid-mediated immunosuppression. Our findings may provide important clues for tuberculosis prevention.

Alexithymia and Immune Dysregulation: A Critical Review

Alexithymia presents a deficit in identifying and expressing emotions, paucity of fantasies, and an externally oriented cognitive style. Numerous recent studies have documented that alexithymia is significantly related to dysregulation of immune functions. These findings implicate that stressors related to alexithymia could underlie the process of immune dysregulation that likely presents a significant risk factor in pathogenesis of several psychosomatic illnesses. In this article various findings on immune dysregulation in alexithymia are reviewed and discussed.

The effect of 1 year of trilostane treatment on peripheral lymphocyte subsets in dogs with pituitary-dependent hyperadrenocorticism

This study investigated the changes in lymphocyte subsets during the trilostane medication of Pituitary-dependent hyperadrenocorticism (PDH) dogs. The cortisol level and lymphocyte subsets of eight dogs with PDH were monitored 0, 1, 3, 6, 9 and 12 months after the initiation of trilostane treatment. White blood cells (WBC), lymphocytes, CD3⁺ (T lymphocyte), CD4⁺ (helper T lymphocyte), CD8⁺ (cytotoxic T lymphocyte) and CD21⁺ (B lymphocyte) cells were measured. Although the post-ACTH stimulation test cortisol level was significantly lower during trilostane treatment, changes in the CD3⁺, CD4⁺, CD8⁺ and CD21⁺ counts were not observed. Meanwhile, significant decrease was observed in WBC counts during trilostane treatment. These indicate that long-term trilostane treatment has little effect on the lymphocyte subsets in PDH dogs.

Circadian Clocks, Stress, and Immunity

In mammals, molecular circadian clocks are present in most cells of the body, and this circadian network plays an important role in synchronizing physiological processes and behaviors to the appropriate time of day. The hypothalamic-pituitary-adrenal endocrine axis regulates the response to acute and chronic stress, acting through its final effectors - glucocorticoids - released from the adrenal cortex. Glucocorticoid secretion, characterized by its circadian rhythm, has an important role in synchronizing peripheral clocks and rhythms downstream of the master circadian pacemaker in the suprachiasmatic nucleus. Finally, glucocorticoids are powerfully anti-inflammatory, and recent work has implicated the circadian clock in various aspects and cells of the immune system, suggesting a tight interplay of stress and circadian systems in the regulation of immunity. This mini-review summarizes our current understanding of the role of the circadian clock network in both the HPA axis and the immune system, and discusses their interactions.

Gene polymorphisms of stress hormone and cytokine receptors associate with immunomodulatory profile and psychological measurement

OBJECTIVE

We sought to identify whether stable single nucleotide polymorphisms (SNPs) of various endocrine and immune molecules could be used as biomarkers associated with specific immune alterations and chronic stress measures in normal humans.

METHODS

A total of 207 volunteer participants answered stress questionnaire and gave peripheral blood cells for identification of SNPs in genes coding for glucocorticoid receptor (GR), beta 2 adrenergic receptor (B2AR), interferon-gamma receptors (IFNGR1, IFNGR2), and interleukin-4 receptor (IL4R). Immunoregulatory profiles were measured by flow cytometry and genotyping assays were performed by allelic discrimination real-time PCR.

RESULTS

Several significant differences were revealed in associations between stress marker and immune indicators based on SNP categories. For instance, Th1 levels of the minor alleles of GR TthIIII (AA) and IFNGR2 Q64R (Arg/Arg) groups were positively associated with chronic stress (PSS) (p = 0.024 and 0.005, respectively) compared with wild type (WT) and negatively associated with PSS in the heterozygous genotypes of GR BclI and IL4R Ile50Val (p = 0.040 and p = 0.052, respectively). Treg levels of the minor alleles of BclI (GG) and IFNGR1 T-56C (CC) groups were positively associated with PSS (p = 0.045 and p = 0.010, respectively) and negatively associated in the minor allele (Val/Val) of IL4R Ile50Va and the heterozygous genotype of IL4R Q576R (p = 0.041 and p = 0.017, respectively) compared to WT.

CONCLUSION

The data support the notion that gene polymorphisms from various components of the psychoneuroendocrine-immune network may be useful as biomarkers to categorize individual stress-associated immune responses.

Ginsenoside Rh1 Improves the Effect of Dexamethasone on Autoantibodies Production and Lymphoproliferation in MRL/lpr Mice

Ginsenoside Rh1 is able to upregulate glucocorticoid receptor (GR) level, suggesting Rh1 may improve glucocorticoid efficacy in hormone-dependent diseases. Therefore, we investigated whether Rh1 could enhance the effect of dexamethasone (Dex) in the treatment of MRL/lpr mice. MRL/lpr mice were treated with vehicle, Dex, Rh1, or Dex + Rh1 for 4 weeks. Dex significantly reduced the proteinuria and anti-dsDNA and anti-ANA autoantibodies. The levels of proteinuria and anti-dsDNA and anti-ANA autoantibodies were further decreased in Dex + Rh1 group. Dex, Rh1, or Dex + Rh1 did not alter the proportion of CD4+ splenic lymphocytes, whereas the proportion of CD8+ splenic lymphocytes was significantly increased in Dex and Dex + Rh1 groups. Dex + Rh1 significantly decreased the ratio of CD4+/CD8+ splenic lymphocytes compared with control. Con A-induced CD4+ splenic lymphocytes proliferation was increased in Dex-treated mice and was inhibited in Dex + Rh1-treated mice. Th1 cytokine IFN-γ mRNA was suppressed and Th2 cytokine IL-4 mRNA was increased by Dex. The effect of Dex on IFN-γ and IL-4 mRNA was enhanced by Rh1. In conclusion, our data suggest that Rh1 may enhance the effect of Dex in the treatment of MRL/lpr mice through regulating CD4+ T cells activation and Th1/Th2 balance.

Prospective study in a porcine model of sarcoptes scabiei indicates the association of Th2 and Th17 pathways with the clinical severity of scabies

Background

Understanding of scabies immunopathology has been hampered by the inability to undertake longitudinal studies in humans. Pigs are a useful animal model for scabies, and show clinical and immunologic changes similar to those in humans. Crusted scabies can be readily established in pigs by treatment with the glucocorticoid dexamethasone (Dex).

Methodology/ Principal Findings

Prospective study of 24 pigs in four groups: a) Scabies+/Dex+, b) Scabies+/Dex-, c) Scabies-/Dex+ and d) Scabies-/Dex-. Clinical symptoms were monitored. Histological profiling and transcriptional analysis of skin biopsies was undertaken to compare changes in cell infiltrates and representative cytokines. A range of clinical responses to Sarcoptes scabiei were observed in Dex treated and non-immunosuppressed pigs. An association was confirmed between disease severity and transcription of the Th2 cytokines IL-4 and IL-13, and up-regulation of the Th17 cytokines IL-17 and IL-23 in pigs with crusted scabies. Immunohistochemistry revealed marked infiltration of lymphocytes and mast cells, and strong staining for IL-17.

Conclusions/ Significance

While an allergic Th2 type response to scabies has been previously described, these results suggest that IL-17 related pathways may also contribute to immunopathology of crusted scabies. This may lead to new strategies to protect vulnerable subjects from contracting recurrent crusted scabies.

Scabies is a neglected tropical skin disease caused by the tiny parasitic mite Sarcoptes scabiei. Scabies is common in developing countries, and scabies outbreaks also occur in institutional settings worldwide. Scabies often underlies secondary bacterial skin infection and resulting complications, and is thus associated with considerable morbidity. Crusted scabies is a an extremely severe and debilitating clinical form of the disease, but host immune responses leading to the development of crusted or ordinary scabies are poorly understood. This is largely due to limited access to clinical samples, and the difficulty in monitoring the progression of infestation in human patients. We have overcome this challenge by using a pig model of scabies infestation, since pigs and humans with scabies display clinical and immunological similarities. In this study, we undertook longitudinal analysis of clinical, histological and molecular immunological changes in pigs experimentally infected with scabies. We confirmed that disease severity was associated with a pronounced allergic, Th2 immune response, as previously reported. In a novel finding, we showed that the Th17 associated cytokines interleukin-17 and interleukin-23 were also associated with the development of crusted scabies. This may lead to new immunotherapeutic strategies to protect vulnerable subjects from contracting recurrent crusted scabies.

Effect of Perceived Stress on Cytokine Production in Healthy College Students

Chronic psychological stress impairs antibody synthesis following influenza vaccination. Chronic stress also increases circulating levels of proinflammatory cytokines and glucocorticoids in elders and caregivers, which can impair antibody synthesis. The purpose of this study was to determine whether psychological stress increases ex vivo cytokine production or decreases glucocorticoid sensitivity (GCS) of peripheral blood leukocytes from healthy college students. A convenience sample of Reserve Officer Training Corps (ROTC) students completed the Perceived Stress Scale (PSS). Whole blood was incubated in the presence of influenza vaccine and dexamethasone to evaluate production of interleukin-6 (IL-6), interleukin-1-beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and interferon-gamma (IFN-γ). Multiple regression models controlling for age, gender, and grade point average revealed a negative relationship between PSS and GCS for vaccine-stimulated production of IL-1β, IL-6, and TNF-α. These data increase our understanding of the complex relationship between chronic stress and immune function.

Effects of strenuous exercise on Th1/Th2 gene expression from human peripheral blood mononuclear cells of marathon participants

Physical stressors, such as strenuous exercise, can have numerous effects on the human body including the immune system. The aim of this study was to evaluate the gene expression profile of Th1/Th2 cytokines and related transcription factor genes in order to investigate possible immune imbalances before and after a marathon. Blood samples were collected from 16 normal volunteers 24-48 h before and one week after completing a marathon race. Gene expression of Th1 and Th2 related cytokines from human peripheral blood mononuclear cells (PBMC) was analyzed using Human Th1-Th2-Th3 RT(2) Profiler PCR Array and qRT-PCR that measured the transcript levels of 84 genes related to T cell activation. We found that PBMC express a characteristic Th2-like gene profile one week post-marathon compared to pre-marathon. The majority of genes up-regulated one week post-marathon such as IL-4, GATA3, and CCR4 were Th2 associated. For Th1-related genes, CXCR3 and IRF1 were up-regulated one week post-marathon. There was a trend of down-regulation of two Th1 related genes, T-bet and STAT1. Th3-related gene expression patterns did not change in the study. The ratios of both IFN-γ/IL-4 and T-bet/GATA3 gene expressions were significantly lower one week after marathon. These findings suggest that a Th1/Th2 immune imbalance persisted at least 1 week after completion of a marathon which offers a mechanistic rationale for the increased risk of upper respiratory tract infections often reported after strenuous exercise.

Immunomodulatory effects of dexamethasone on gene expression of cytokine and stress hormone receptors in peripheral blood mononuclear cells

Glucocorticoid (GC) such as cortisol in humans is a major stress hormone and can influence immunomodulation through various mechanisms including impact on regulatory T-cell (RTC) elements and changes in Th1/Th2 cytokine balance. In this study, we sought to determine the immunomodulatory effects of GC equivalent dexamethasone (DEX) at various concentrations (10(-7), 10(-8), and 10(-9) M) on gene expression of RTC, cytokine receptors and stress hormone receptors from normal human peripheral blood mononuclear cells (PBMC) in an in vitro stress model in 24 h (acute stress) vs 11-day (chronic stress) cultures. Results revealed that the mRNA of forkhead box P3 (FoxP3) was significantly decreased at 24 h with 10(-7) and 10(-8) M DEX. After 11 days, FoxP3 expression in the 10(-8) M DEX cultures had returned to baseline but was still down-regulated with 10(-7) M DEX. GC receptor (GR) mRNA decreased and β2 adrenergic receptor (β 2AR) mRNA increased significantly after 24 h exposure to DEX. These changes had returned to baseline in the 11-day cultures. The IFN-γR/IL-4R ratio, an alternative marker for Th1/Th2 balance, was significantly increased at 24 h and decreased after 11-day cultures with 10(-7) and 10(-8) M DEX compared to control cultures. These findings further contribute to our understanding of the mechanisms associated with the effects of acute vs. chronic stress on normal immune balance.

Oral administration of poly-γ-glutamate ameliorates atopic dermatitis in Nc/Nga mice by suppressing Th2-biased immune response and production of IL-17A

Atopic dermatitis (AD) is a chronic inflammatory skin disease that is closely related to dysregulation of the T helper type 1 and 2 (Th1)/Th2 balance. A previous study showed that high molecular mass poly-γ-glutamate (γ-PGA) isolated from Bacillus subtilis sp. Chungkookjang induces the production of IL-12 from dendritic cells (DCs). Here, we investigated the effect of γ-PGA on AD-like skin disease using an Nc/Nga mouse model. In vitro, γ-PGA activated DCs and induced IL-12 production in mice. In vivo, oral administration of γ-PGA markedly reduced the AD symptoms, similar to the response seen in the dexamethasone (Dex)-treated group. Treatment with γ-PGA also decreased the serum levels of IgG1, the skin levels of Th2 cytokines, the extent of skin inflammation, and the accumulation of mast cells. Furthermore, γ-PGA was effective against established AD, significantly decreasing serum IgE and Th2 cytokines in the inflamed tissue. Interestingly, the production of IL-17A in splenocytes was also suppressed by γ-PGA, indicating that it inhibits both Th2 and Th17 immune responses. Collectively, these results suggest that oral administration of γ-PGA could be a therapeutic strategy for treating AD via the modulation of Th2-biased immune responses in an Nc/Nga mouse model.

Glucocorticoid receptor BclI polymorphism associates with immunomodulatory response to stress hormone in human peripheral blood mononuclear cells

Glucocorticoid receptor (GR) variants have been found to be associated with stress-related disorders. Our previous in vivo study revealed that the CC allele of GR BclI single-nucleotide polymorphism (SNP) was more common in the high-stress group, which had lower levels of both regulatory T cells (Treg) and Th1 cytokine. The current study was to investigate the associations between GR BclI polymorphism and immunomodulatory response to stress hormone in vitro in human peripheral blood mononuclear cells (PBMC). Blood samples were collected from 18 normal volunteers including 9 subjects with BclI polymorphism GG allele and 9 with wild-type (WT) CC allele. PBMC were cultured with 10(-8) m dexamethasone (DEX), which mimics the plasma cortisol level observed during periods of psychological stress for 24 h and 11 days. Gene expressions of transcription factors, stress hormone and cytokine receptors were analysed by real-time RT-PCR. FoxP3 mRNA was significantly altered in the BclI WT (decreased at 24 h and increased at 11 days) but not in the GG allele. GR mRNA was up-regulated at 24 h and down-regulated at 11 days in CC alleles (P < 0.01 and P < 0.05), rather than in GG alleles. The expression of β-2 adrenergic receptor (β2AR) was increased at 24 h in both CC and GG alleles (P < 0.01 and P < 0.001), but decreased significantly at 11 days in only GG alleles. Expression of T-bet and GATA-3 was altered simultaneously in 24-h culture with DEX from both groups. The BclI polymorphism of GR identifies different immunomodulatory responses to corticosteroids, which may explain, at least in part, the variability in individual sensitivity to stressors.

In vitro effects of dexamethasone on bovine CD25+CD4+ and CD25-CD4+ cells

This paper investigates the in vitro effect of dexamethasone on bovine CD25highCD4+, CD25lowCD4+ and CD25-CD4+ T cells. Only a small percentage of bovine CD25highCD4+ (2-4%) and CD25lowCD4+ (1-2%) cells expressed Foxp3. Dexamethasone caused considerable loss of CD25-CD4+ cells, but it increased the relative and absolute numbers of CD25highCD4+ and CD25lowCD4+ lymphocytes, while at the same time reducing the percentage of Foxp3+ cells within the latter subpopulations. Considering all these, as well as the intrinsically poor Foxp3 expression in bovine CD25+CD4+, it can be concluded that the drug most probably increased the number of activated non-regulatory CD4+ lymphocytes. It has been found that changes in cell number were at least partly caused by proapoptotic effect of the drug on CD25-CD4+ cells and antiapoptotic effect on CD25highCD4+ and CD25lowCD4+ cells. The results obtained from this study indicate that the involvement of CD4+ lymphocytes in producing the anti-inflammatory and immunosuppressive effect of dexamethasone in cattle results from the fact that the drug had a depressive effect on the production of IFN-γ by CD25-CD4+ cells. Secretion of TGF-β and IL-10 by CD4+ lymphocytes was not involved in producing these pharmacological effects, because the drug did not affect production of TGF-β and, paradoxically, it reduced the percentage of IL-10+CD4+ cells.

Favorable response of chronic refractory immune thrombocytopenic purpura to mesenchymal stem cells

Seven patients with chronic refractory immune thrombocytopenic purpura (ITP) received adipose tissue-derived mesenchymal stem cells (AMSC) from haplo-identical family donors. The AMSC dose was 2.0×10(6)/kg. No side effects were noted after the AMSC infusions. Overall responses were reached in all patients and sustained response rate was 57.1% (4/7). The serum levels of transforming growth factor β1 (TGF-β1), interleukin (IL)-4, and IL-10 were significantly elevated, whereas those of interferon-γ (IFN-γ) and IL-2 were significantly decreased after AMSC administration, compared with those in the patients with active ITP. During follow-up, the cytokine profiles in patients maintaining sustained response remained stable compared with the post-treatment level, but IFN-γ and IL-2 levels were significantly increased, and those of TGF-β1, IL-4, and IL-10 were significantly reduced again in relapsed patients. AMSC therapy seems to represent reasonable salvage treatment in severe, chronic refractory ITP by causing a shift in the Th1/Th2 cytokine balance to the same levels as normal controls.

Neuroendocrine effects of stress on immunity in the elderly: implications for inflammatory disease

Age-related changes in immune function leave older adults at risk for a host of inflammatory diseases. Immune-mediated inflammatory processes are regulated by neuroendocrine hormones, including glucocorticoids, dehydroepiandrosterone, and the catecholamines, epinephrine, and norepinephrine. This regulation, however, becomes impaired in older adults in light of age-related changes in endocrine function. Chronic stress shows similarly harmful effects on neuroendocrine and immune function and may, therefore, combine with age to further increase disease risk in older adults. This article highlights evidence for the impact of age and stress on neuroendocrine regulation of inflammatory processes that may substantially increase risk for inflammatory disease at older ages.

Effects of hydrocortisone on the differentiation of human T helper 2 cells

We investigated the effects of the neuroendocrine modulator hydrocortisone (HC) on Th2 differentiation of human naive CD4+ T cells with and without CD28 co-stimulation. Human naive CD4+ T cells were isolated and purified from umbilical cord blood mononuclear cells from full-term newborn infants. CD4+ T cells were treated with different concentrations of HC under Th0 or Th2 culture conditions. Th0 conditions included stimulation by immobilized monoclonal antibodies (mAbs) against CD3 and CD28; Th2 conditions were the same + rhIL-4. Parallel cultures excluded the CD28 mAb. Th1 (IL-2, INF-γ)- and Th2 (IL-4, IL-5)-type cytokines were quantified in culture supernatants by ELISA and within cells by flow cytometry. For both Th0 and Th2 culture conditions, HC significantly inhibited Th1 cytokines' release (IL-2 and INF-γ). For Th0 culture conditions, HC slightly increased IL-4 expression (Th2 cytokine). However, for Th2 culture conditions, HC inhibited the IL4-induced production of IL-4. Although the absolute cytokine amounts were decreased, absence of CD28 co-stimulation did not alter these 'trends'. Our findings indicate that HC can alter the Th1/Th2 balance by inhibiting the production of Th1-type cytokines. HC can also diminish the extensive Th2 differentiation induced by IL-4.

Immune function in hypopituitarism: time to reconsider?

Hypopituitarism is not currently considered as a potential cause of immune disruption in humans. Accumulating data from in vitro and animal models support a role for the pituitary gland in immune regulation. Furthermore, the increased mortality risk noted in patients with adult hypopituitarism remains poorly explained and immune dysfunction could conceivably contribute to this observation. In a recent issue of Clinical & Experimental Immunology, we presented new data relating to immune status in adults with treated, severe hypopituitarism. We observed humoral immune deficiency in a significant proportion, despite stable pituitary replacement, including growth hormone (GH). This was especially evident in those with low pretreatment IGF-I levels and appeared independent of anticonvulsant use or corticosteroid replacement. These observations require substantiation with future studies. In this short review, we summarize existing data relating to the effects of pituitary hormones on immune function and discuss potential clinical implications surrounding the hypothesis of immune dysregulation in severe hypopituitarism.

Infection, immunity and the neuroendocrine response

The Central Nervous (CNS) and Immune Systems (IS) are the two major adaptive systems which respond rapidly to numerous challenges that are able to compromise health. The defensive response strictly linking innate to acquired immunity, works continuously to limit pathogen invasion and damage. The efficiency of the innate response is crucial for survival and for an optimum priming of acquired immunity. During infection, the immune response is modulated by an integrated neuro-immune network which potentiates innate immunity, controls potential harmful effects and also addresses metabolic and nutritional modifications supporting immune function. In the last decade much knowledge has been gained on the molecular signals that orchestrate this integrated adaptive response, with focus on the systemic mediators which have a crucial role in driving and controlling an efficient protective response. These mediators are also able to signal alterations and control pathway dysfunctions which may be involved in the persistence and/or overexpression of inflammation that may lead to tissue damage and to a negative metabolic impact, causing retarded growth. This review aims to describe some important signalling pathways which drive bidirectional communication between the Immune and Nervous Systems during infection. Particular emphasis is placed on pro-inflammatory cytokines, immunomodulator hormones such as Glucocorticoids (GCs), Growth hormone (GH), Insulin-like Growth Factor-1 (IGF-1), and Leptin, as well as nutritional factors such as Zinc (Zn). Finally, the review includes up-to-date information on this neuroimmune cross-talk in domestic animals. Data in domestic animal species are still limited, but there are several exciting areas of research, like the potential interaction pathways between mediators (i.e. cytokine-HPA regulation, IL-6-GCS-Zn, cytokines-GH/IGF-1, IL-6-GH-Leptin and thymus activity) that are or could be promising topics of future research in veterinary medicine.

Modulation of lung inflammation by vessel dilator in a mouse model of allergic asthma

BACKGROUND

Atrial natriuretic peptide (ANP) and its receptor, NPRA, have been extensively studied in terms of cardiovascular effects. We have found that the ANP-NPRA signaling pathway is also involved in airway allergic inflammation and asthma. ANP, a C-terminal peptide (amino acid 99-126) of pro-atrial natriuretic factor (proANF) and a recombinant peptide, NP73-102 (amino acid 73-102 of proANF) have been reported to induce bronchoprotective effects in a mouse model of allergic asthma. In this report, we evaluated the effects of vessel dilator (VD), another N-terminal natriuretic peptide covering amino acids 31-67 of proANF, on acute lung inflammation in a mouse model of allergic asthma.

METHODS

A549 cells were transfected with pVD or the pVAX1 control plasmid and cells were collected 24 hrs after transfection to analyze the effect of VD on inactivation of the extracellular-signal regulated receptor kinase (ERK1/2) through western blot. Luciferase assay, western blot and RT-PCR were also performed to analyze the effect of VD on NPRA expression. For determination of VD's attenuation of lung inflammation, BALB/c mice were sensitized and challenged with ovalbumin and then treated intranasally with chitosan nanoparticles containing pVD. Parameters of airway inflammation, such as airway hyperreactivity, proinflammatory cytokine levels, eosinophil recruitment and lung histopathology were compared with control mice receiving nanoparticles containing pVAX1 control plasmid.

RESULTS

pVD nanoparticles inactivated ERK1/2 and downregulated NPRA expression in vitro, and intranasal treatment with pVD nanoparticles protected mice from airway inflammation.

CONCLUSION

VD's modulation of airway inflammation may result from its inactivation of ERK1/2 and downregulation of NPRA expression. Chitosan nanoparticles containing pVD may be therapeutically effective in preventing allergic airway inflammation.

[Cutaneous leishmaniasis in rheumatoid arthritis]

INTRODUCTION

Cutaneous leishmaniasis is a protozoal infection. Its prevalence is increasing, especially in immunocompromised subjects.

CASE REPORTS

We report four patients with rheumatoid arthritis, treated with methotrexate and prednisone who developed cutaneous leishmaniasis. Clinical outcome was favorable after institution of antimony therapy in three cases despite the continuation of methotrexate and prednisone. One patient failed to respond to therapy.

DISCUSSION

The frequency of cutaneous leishmaniasis is increasing especially in immunocompromised subjects. In our patients, rheumatoid arthritis, corticosteroid therapy and methotrexate were predisposing factors of cutaneous leishmaniasis.

Failure of antibody response to polysaccharide antigen in treated panhypopituitary adults

Although pituitary hormones are known to affect immune function, treated hypopituitarism is not a recognized cause of immune deficiency in humans. We set out to assess integrity of baseline and stimulated immune function in severely hypopituitary adults. Twenty-one panhypopituitary adults (group 1), on stable pituitary replacement including growth hormone, and 12 healthy volunteers (group 2) were studied. Lymphocyte subsets, pneumococcal antibody levels pre- and 1 month after polysaccharide vaccination, T cell numbers and in-vitro interferon (IFN)-gamma response were studied. There were no significant differences in T cell numbers or IFN-gamma secretion. B cell numbers were lower in group 1, especially those with low prolactin levels. Independent of this finding, nine of 21 patients in this group had low antibody response to polysaccharide antigen. This was most striking in those with low insulin-like growth factor 1 levels and appeared to be independent of the use of anti-convulsants or corticosteroid replacement. Significant humoral immune deficiency is seen in panhypopituitarism and may contribute to morbidity.

Targeting the CD134-CD134L interaction using anti-CD134 and/or rhCD134 fusion protein as a possible strategy to prevent lupus nephritis

Lupus nephritis (LN) is characterized by an increased upregulation of Th1. This study was undertaken to evaluate the role of CD134 in cytokine production in peripheral blood mononuclear cells (PBMCs) from subjects with LN. Percentages of IFN-gamma- (Th1), IL-4-, and IL-10- (Th2) producing cells within the PBMC CD4+ T cell population of LN subjects were found to be higher than those of healthy subjects. Stimulation of PBMC from LN subjects with anti-CD3 epsilon mAb/rIL-2 resulted in further increases in cytokine production. Stimulation in the presence of anti-CD134 mAb resulted in reduced IL-4 and IL-10 production; however, it also resulted in increased IFN-gamma production. Stimulation in the presence of the fusion protein rhCD134:Fc resulted in decreased production of all three cytokines. The possibilities that anti-CD134 therapy may control the extent of IL-4- and IL-10-mediated damage in active LN and that rhCD134:Fc therapy may prevent occurrence of LN are discussed.

Posttraumatic stress and immune dissonance

Stress or neuroendocrine response usually occurs soon after trauma, which is central to the maintenance of post-traumatic homeostasis. Immune inflammatory response has been recognized to be a key element both in the pathogenesis of post-traumatic complications and in tissue repair. Despite the existence of multiple and intricate interconnected neuroendocrine pathways, the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system have been considered to be the most important in trauma. Although the short-term and appropriate activation of these stress responses is vital to the host's adaptation, prolonged duration and exaggerative magnitude of their activity leads to deleterious effects on immune function in trauma, causing immune dissonance. The overall appropriate and controlled activation and termination of the neuroendocrine responses that mediate the necessary physiological functions involved in maintaining and restoring homeostasis in the event of trauma are of critical importance. This review will describe the effects of some important neuroendocrine responses on immune system. Present evidences indicate that the neuroendocrine and immune systems form a cohesive and integrated early host response to trauma, and identify areas for further research to fully elucidate the regulatory role of neuroendocrine system in trauma.

Natural glucocorticoids induce expansion of all developmental stages of murine bone marrow granulocytes without inhibiting function

Natural glucocorticoids (Gc) produced during stress have profound effects on the immune system. It is well known that Gc induce apoptosis in precursor T and B cells, markedly altering lymphopoiesis. However, it has been noted that marrow myeloid cells expanded both in proportion and absolute numbers in the mouse after Gc exposure. Mice were implanted with a corticosterone (CS) tablet that increased serum Gc and caused atrophied thymuses, both classic signs of activation of the stress axis. Blood neutrophil counts were elevated (4.8x), whereas lymphocyte counts declined. Flow cytometric analysis of the marrow revealed that the phenotypic distribution of the various major classes of cells was shifted by Gc exposure. As expected, marrow lymphocyte numbers declined >40% after 3 days of exposure to Gc. Conversely, in the myeloid compartment, both monocytes and granulocytes increased in number by >40%. Further, all granulocyte developmental stages showed large increases in both total number and percentage of cells. To investigate the functional capacity of mature granulocytes from Gc-treated mice, an improved granulocyte isolation method was developed. Gc exposure had little effect on the ability of granulocytes to produce superoxide or undergo chemotaxis or phagocytose bacteria. These results indicate that Gc treatment shifts bone marrow composition and provides evidence that granulocytes and their progenitors are selectively preserved under stressful conditions without losing function.

Randomized clinical trial of the effects of methylprednisolone on renal function after major vascular surgery

BACKGROUND

Perioperative renal dysfunction following abdominal aortic aneurysm (AAA) repair is multifactorial and may involve hypotension, hypoxia and ischaemia-reperfusion injury. Studies of cardiac and hepatic transplant surgery have demonstrated beneficial effects on renal function of high-dose methylprednisolone administered before surgery.

METHODS

Twenty patients undergoing elective open AAA repair were randomized to receive either methylprednisolone 10 mg/kg or dextrose (control) before induction of anaesthesia. Blood was analysed for a panel of cytokines representative of T helper cell type 1 and 2 subsets. Urine was analysed for subclinical markers of renal dysfunction (albumin, alpha(1)-microglobulin and N-acetyl-beta-D-glucosaminidase).

RESULTS

Data from 18 patients were analysed. Both groups demonstrated glomerular and proximal convoluted tubular dysfunction that was unaffected by steroid treatment. Steroid administration increased serum levels of urea and creatinine (both P < 0.001). The steroid group had increased interleukin 10 levels (P = 0.005 compared to controls). There were no differences between groups in overall surgical complications, length of intensive care unit (P = 0.821) and hospital (P = 0.719) stay, or 30-day mortality.

CONCLUSION

Methylprednisolone administration altered the cytokine profile favourably but adversely affected postoperative renal function.

Correction of Th1-dominant Cytokine Profiles by High-dose Dexamethasone in Patients with Chronic Idiopathic Thrombocytopenic Purpura

To investigate the possible correcting of T helper (Th) cytokine profiles by high-dose dexamethasone (HD-DXM) therapy in chronic idiopathic thrombocytopenic purpura (ITP) with active disease, we determined the plasma levels of IFN-gamma, IL-2, IL-4, IL-10, and TGF-beta1 in 52 patients before and after oral administration of 40 mg/day DXM for four consecutive days. The cytokine levels were measured by enzyme-linked immunosorbent assay. The results showed that initial responses were reached in all patients and sustained response (SR) rate is 46.15%. The pretreatment plasma levels of both IFN-gamma and IL-2 were significantly increased and those of IL-4, IL-10, and TGF-beta1 significantly decreased, compared with those of the normal controls (P < 0.01), indicating a Th1-dominant cytokine profile typically found in ITP. After HD-DXM treatment, IFN-gamma and IL-2 were decreased (P < 0.01), whereas IL-4 and IL-10 were increased (P < 0.05). There was no significant difference between the HD-DXM-treated patients and the normal controls (P > 0.05). TGF-beta1 was also increased (P < 0.01) after HD-DXM treatment, but still lower than that of the normal controls (P < 0.05). During following-up, the cytokine profiles in the SRs remained stable compared to the posttreatment level (P > 0.05), but IFN-gamma and IL-2 levels raised up, and IL-4, IL-10, and TGF-beta1 levels reduced again in the relapsed patients (P < 0.01). Our data demonstrate that HD-DXM is an effective initial therapy for ITP, and the Th1 cytokine dominance could be corrected by HD-DXM.

Changes in immune regulation in response to examination stress in atopic and healthy individuals

BACKGROUND

Stress can aggravate the allergic inflammation, but determinants of disturbed immune regulation are largely unknown.

OBJECTIVE

To determine systemic immunological, local inflammatory and functional airway responses to stress in healthy and atopic individuals.

METHODS

Forty-one undergraduate students, 22 with allergy of whom 16 had asthma, and 19 healthy controls, were studied in a low-stress period and in association with a large exam. Subjects completed questionnaires on stress and health behaviours, underwent lung function tests, bronchial methacholine challenge, measurements of exhaled nitric oxide and urine cortisol. Blood cells were phenotyped, and cytokines from mononuclear blood cells were analysed.

RESULTS

Perceived stress and anxiety increased in both groups during the exam period while cortisol increased only in the atopy group. Cytokine production decreased broadly in response to stress in both groups, which was paralleled by an increase in the proportion of regulatory T cells (CD4(+)CD45RO(+)CD25(bright)). Interestingly, atopic individuals, but not controls, reacted with a decreased T-helper type 1/T-helper type 2 (Th1/Th2) ratio and a decrease in natural killer (NK) cell numbers in response to stress. In control subjects only, exhaled nitric oxide decreased and forced expiratory volume in one second increased during stress.

CONCLUSION

Atopic and non-atopic subjects shared some immune changes in response to stress, such as a dramatic decline in cytokines and an increase in the number of regulatory T cells in peripheral blood. However, other stress-induced immune changes were unique to atopic individuals, such as a skewed Th1/Th2 ratio and reduced NK cell numbers, indicating that some pathogenic mechanisms in atopics may be more strongly affected by stress than others.

Psychologic stress, reduced NK cell activity, and cytokine dysregulation in women experiencing diagnostic breast biopsy

The purpose of this study was to evaluate a woman's psychological and immunological response to breast biopsy before and after the procedure. Women were enrolled into the study when notified of the need for breast biopsy. Psychological and immunological assessments were made at enrollment, on the day of breast biopsy, as well as 1 month and 4 months after notification of biopsy results. Psychological assessments demonstrated that perceived stress, anxiety, and mood disturbance were heightened before biopsy and remained elevated after biopsy regardless of the diagnosis. Immunologically, the women exhibited reduced natural killer cell activity and INF gamma production before biopsy with reductions significant 1 month after the procedure. In contrast, IL-4, IL-6, and IL-10 production were increased before and after the procedure with most significant increases prior to the procedure and continuing 1 month after the procedure. These results demonstrate that undergoing biopsy of the breast for cancer diagnosis is an emotional experience, characterized by increased perceived stress, anxiety, and mood disturbance. This emotional distress is accompanied by reduced NK cell activity and cytokine dysregulation. The psychological and immunological impact of breast biopsy is not transient, but persists well beyond the actual experience of the biopsy procedure. Noteworthy is the observation that women with benign or malignant biopsy results experienced similar psycho-immune consequences. Hence, these observations are of relevance not only to women diagnosed with malignancy, who face the challenges of cancer treatment and adaptation to illness, but also to women with benign biopsy findings.

Leishmaniose cutanée au cours d'une polymyosite

INTRODUCTION

The prevalence of cutaneous leishmaniasis is increasing, especially in immunocompromized subjects.

CASE RECORD

We report a case of particular interest, where a patient with steroid refractory polymyositis developed cutaneous leishmaniasis. Clinical outcome was favorable after institution of intralesional antimony therapy.

DISCUSSION

Cutaneous leishmaniasis is still recognized to be an opportunistic infection. Its frequency is indeed higher in immunocompromized subjects, mainly HIV-infected patients. In our patient, both polymyositis and steroid therapy were predisposing factors of cutaneous leishmaniasis onset; prednisone therapy has been postulated to be associated with immune dysfunction leading to: reduced blood T cells' levels (CD4 et CD8) as well as decreased cytokine synthesis (e.g. interferon gamma).

Neural regulation of innate immunity: a coordinated nonspecific host response to pathogens

The central nervous system (CNS) regulates innate immune responses through hormonal and neuronal routes. The neuroendocrine stress response and the sympathetic and parasympathetic nervous systems generally inhibit innate immune responses at systemic and regional levels, whereas the peripheral nervous system tends to amplify local innate immune responses. These systems work together to first activate and amplify local inflammatory responses that contain or eliminate invading pathogens, and subsequently to terminate inflammation and restore host homeostasis. Here, I review these regulatory mechanisms and discuss the evidence indicating that the CNS can be considered as integral to acute-phase inflammatory responses to pathogens as the innate immune system.

Sleep-like concentrations of growth hormone and cortisol modulate type1 and type2 in-vitro cytokine production in human T cells

Slow wave sleep (SWS) is characterized by maximum release of growth hormone (GH) and minimum release of cortisol. We hypothesized that this hormonal pattern during SWS leads, in addition to generally increased T cell cytokine production, to a shift towards type1 cytokines. To test this hypothesis, blood was sampled from 8 humans during SWS, and whole blood cultures were activated in-vitro with ionomycin and phorbol-myrestate-acetate (PMA) in the absence and presence of GH neutralizing antibody (Ab) or physiological concentrations of cortisol. Production of interferon-gamma (IFN-gamma), interleukin-2 (IL-2), IL-4, and tumor necrosis factor-alpha (TNF-alpha) was measured using multiparametric flow cytometry. GH Ab decreased IFN-gamma+CD4+ cells but had no effect on other cytokines. Cortisol alone and in combination with GH Ab decreased CD4+ and CD8+ cells producing IFN-gamma, TNF-alpha and IL-2. Simultaneously, these two reactants reduced IL-4+CD4+ cells, so that the ratio of IFN-gamma/IL4 producing CD4+ cells indicated an unexpected shift towards type1 dominance. Results support the view that release of GH by increasing particularly production of IFN-gamma can contribute to the shift in type1/type2 balance towards type1 activity characterizing SWS. Suppression of cortisol during this sleep period enhances both type1 and type2 activity. Yet, our finding of predominant type1 activity after cortisol administration, rules out any relevance of this suppression for the shift towards type1 activity during SWS.

Lymphocyte functions in dairy cows in hot environment

This study was carried out to ascertain the effects of intense high environmental temperatures (HET) on lymphocyte functions in periparturient dairy cows. The study was undertaken from the beginning of March through the end of July 2003 in a commercial dairy unit located approximately 40 km north of Rome. Thirty-four Holstein cows were utilised in the study. Twenty-two of these cows gave birth in spring (SP cows), from 28 March to 30 April. The remaining 12 cows gave birth in summer (SU cows), between 15 June and 2 July. The two groups of cows were balanced for parity and were fed the same rations. Blood samples were taken 4, 3, 2 and 1 week before calving, and 1, 2 and 4 weeks after calving, in order to evaluate peripheral blood mononuclear cell (PBMC) function in vitro, and to determine plasma cortisol concentrations. After isolation, the PBMC were stimulated with mitogens and their response in terms of DNA synthesis and IgM secretion was measured. During spring, either the day (9-20 h) or the night (21-8 h) temperature humidity index (THI) was below the upper critical THI (72) established for dairy cows. During summer, the mean daily THI values were 79.5+/-2.9 during the day and 70.1+/-4.7 during the night. Furthermore, during summer, three heat waves (a period of at least 3 consecutive days during which there were less than 10 recovery hours) occurred. Recovery hours were intended hours with a THI below 72. The first heat wave lasted 5 days, the second 6 days, and the third 15 days. Compared to the SP cows, over the entire periparturient period the extent of DNA synthesis and IgM secretion levels were lower (P ranging from <0.01 to 0.0001) and higher (P<0.01) respectively, in the SU cows. Before calving, the SU cows also presented higher (P<0.01) concentrations of plasma cortisol compared to the SP cows. This study indicates that the effects of HET on the immune response depend on the specific immune function under consideration, and that neuroendocrinal changes due to HET may play a role in the perturbation of immune functions.

Increased GILZ expression in transgenic mice up-regulates Th-2 lymphokines

GILZ (glucocorticoid-induced leucine zipper), a gene induced by dexamethasone, is involved in control of T lymphocyte activation and apoptosis. In the present study, using Gilz transgenic mice (TG), which overexpress GILZ in the T-cell lineage, we demonstrate that Gilz is implicated in T helper-2 (Th-2) response development. After in vitro stimulation by CD3/CD28 antibodies, peripheral naive CD4+ T cells from TG mice secrete more Th-2 cytokines such as interleukin-4 (IL-4), IL-5, IL-13, and IL-10, and produce less Th-1 cytokines such as interferon-gamma (IFN-gamma) than wild-type mice (WT). CD4+ TG lymphocytes up-regulated Th-2 cytokine expression in the specific response to ovalbumin chicken egg (OVA) antigen immunization. Up-regulation correlated with increased expression of GATA-3 and signal transducer and activator of transcription 6 (Stat6), Th-2-specific transcription factors and decreased expression of T-bet, a transcription factor involved in Th-1 differentiation. Finally, in TG mice delayed-type hypersensitivity, a Th-1 response, was inhibited and bleomycin-induced pulmonary fibrosis, a Th-2 mediated disease, was more severe. These results indicate that Gilz contributes to CD4+ commitment toward a Th-2 phenotype and suggest this contribution may be another mechanism accounting for glucocorticoid immunomodulation.

Inhibition of HIV-1-specific T-cells and increase of viral load during immunosuppressive treatment in an HIV-1 infected patient with Chlamydia trachomatis induced arthritis

BACKGROUND

Studies in HIV-1 infected long-term non-progressors could demonstrate a strong HIV-1-specific CTL response, but it is difficult to prove that this strong CTL response actually is the cause of the efficient control of HIV-1 and not the consequence of low HIV-1 replication in these patients.

OBJECTIVE

Studies of HIV-1-specific immunity and viral replication in patients undergoing immunosuppressive therapy provide important opportunities to understand the role of HIV-1-specific T-cells.

RESULTS

In this report we describe an HLA B27 positive patient with normal CD4 counts and a low viral load of 200 copies/ml without antiretroviral therapy who exhibited a very strong HIV-1-specific CTL response. He had to be treated with steroids, NSAIDS and hydroxchloroquine because of a severe inflammatory reactive arthritis triggered by an acute Chlamydia trachomatis infection. Analysis of HIV-1 specific T-cells by gamma-IFN-ELISPOT revealed a high frequency of HIV-1 gag-specific CTL both in blood and synovial fluid, whereas gag-specific CD4-cells could be detected only in the peripheral blood. Further analysis revealed that the gag-specific T-cells were predominantly targeting the HLA B27-restricted CTL epitope KRWIILGLNK (KK10). Immunosuppressive therapy by prednisone was associated with a moderate increase of HIV-1 viremia and a decrease both in the number and in the gamma-IFN production of KK10-specific CTL indicating that inhibition of CTL function contributed to the increase of viral load.

CONCLUSIONS

This study is suggesting that HIV-1 specific CTL play an important role in the control of HIV-1, at least in this patient. Inhibition of CTL function by immunosuppressive therapy with prednisone may enhance viral replication. In addition, we could demonstrate for the first time the migration of HIV-1 specific T-cells into the synovial fluid.

Involvement of human natural killer cells in asthma pathogenesis: natural killer 2 cells in type 2 cytokine predominance

BACKGROUND

T H 2 cells play a pivotal role in the pathogenesis of human asthma. Natural killer (NK) cells are also thought to divide into NK1 and NK2 subsets.

OBJECTIVE

Whether NK1 or NK2 cells are involved in asthma remains unclear.

METHODS

Triple-color flow cytometry for detecting intracellular cytokine and NK cell surface phenotype from asthmatic patients was used. The NK cell cloning and analysis with RT-PCR for cytokine expression and Western blotting for signal transducer and activator of transcription activation were performed.

RESULTS

For the first time, we observed that the ratio of IL-4 + CD56 + NK2 cells in PBMCs of 8 asthmatic patients were higher than in healthy individuals. NK cell clones were then obtained by means of limited dilution, and the average mean of the relative intensity of PCR products for type 2 cytokines significantly increased in the asthmatic patients. Signal transducer and activator of transcription 6, a key transcript factor of type 2 phenotype, was constitutively activated in NK2 clones from asthmatic patients. We cocultured freshly purified NK cells from asthmatic patients with IFN-gamma and anti-IL-4 antibody in the presence of IL-15 and found that the content of IL-4 + NK2 cells significantly decreased after treatment. Interestingly, NK2-biased status in asthmatic patients was reversed when patients recovered from regular therapy.

CONCLUSION

The results suggest that the NK2 cell subset is involved in the pathogenesis of asthma.

Multi-dysfunctional pathophysiology in ITP

Idiopathic thrombocytopenic purpura (ITP) is an organ-specific autoimmune disorder characterized by a low platelet count and mucocutaneous bleeding. The decrease of platelets is caused by increased autoantibodies against self-antigens, particularly IgG antibodies against GPIIb/IIIa. The production of these autoantibodies by B cells depends on a number of cellular mechanisms that form a network of modulation, with T cells playing a pivotal role in pathophysiology. Delineation of the dysfunction of cellular immunity has recently been attempted. This review will focus on these recent advances applicable to ITP and to highlight how these may translate into novel approaches to treatment in the future. Multi-dysfunction in these networks may include a failure of self-antigen recognition and tolerance, involvement of abnormal cell surface molecules, altered Th1/Th2 cytokine profiles, impaired megakaryocytopoiesis and impaired cell-mediated cytotoxicity. In ITP, multi-step dysfunctions in these networks may take place that finally lead to the occurrence of the disease. Therefore, unveiling these dysfunctions is vital in understanding the pathophysiology of ITP and will finally lead to the development of new therapies to fight the disease.