Leptin favors imbalance of antigen-specific CD4+ T-cells associated with severity of cat allergy.

Introduction: Obesity can complicate IgE-mediated allergic diseases. In the present study, we aimed to investigate the ability of obesity-related concentrations of leptin to modulate the in vitro effector and regulatory Fel d1-specific CD4+ T-cell subsets in patients allergic to cat, considered the third most common cause of respiratory allergy in humans. Methods: For this study, plasma and peripheral blood mononuclear cells (PBMC) from 30 cat-allergic patients with mild, moderate and severe respiratory symptoms were obtained. The PBMC cultures were stimulated with Fel d1 antigen (10 µg/mL) in the presence or absence of obesity-related leptin dose (50 ηg/mL). After 6 days, the levels of cytokines and IgE in the supernatants were evaluated by multiplex and ELISA, respectively. The frequency of different non-follicular (CXCR5-) and follicular (CXCR5+) Fel d1-specific CD4+ T cell subsets was determined by flow cytometry. The plasma levels of leptin and IgE anti-cat titers were evaluated by ELISA and ImmunoCAP, respectively. Results and conclusions: Fel d1 induced both IgE production and release of cytokines related to Th2, Th9 and Th17 cell phenotypes. Feld1 was more efficient in increasing the frequency of TFHIL-21- cells positive for IL-4, IL-5 and IL-13 than TFHIL-21+ cell subsets. Leptin favored the expansion Th2-like and Th9-like cells and TFHIL-21- cells positive for IL-4, IL-5 and IL-13, but reduced the proportion of conventional (Treg/Tr-1) and follicular (TFR) regulatory CD4+ T-cell subsets expressing or not CD39 marker. Finally, many of the imbalances between Fel d1-specific CD4+ T-cells were also correlated with plasma leptin and anti-Fel d1 IgE titers. In summary, hyperleptinemia should negatively impact on the severity of cat allergies by favoring the expansion of pathogenic Fel d1-specific CD4+ T-cell phenotypes and damaging the functional status of regulatory CD4+ T-cell subsets.

Leptin favors Th17/Treg cell subsets imbalance associated with allergic asthma severity.

Background: Obesity has often been associated with severe allergic asthma (AA). Here, we analyzed the frequency of different circulating CD4+T-cell subsets from lean, overweight and obese AA patients. Methods: Mononuclear cells from peripheral blood were obtained from 60 AA patients and the frequency of different CD4+T-cell subsets and type 1 regulatory B cells (Br1) was determined by cytometry. The effect of obese-related leptin dose on cytokine production and Treg cell function in AA-derived CD4+ T cell cultures was evaluated by ELISA and 3H thymidine uptake, respectively. Leptin levels were quantified in the plasma by ELISA. According to the BMI, patients were stratified as lean, overweight and obese. Results: AA severity, mainly among obese patients, was associated with an expansion of hybrid Th2/Th17 and Th17-like cells rather than classic Th2-like cells. On the other hand, the frequencies of Th1-like, Br1 cells and regulatory CD4+ T-cell subsets were lower in patients with severe AA. While percentages of the hybrid Th2/Th17 phenotype and Th17-like cells positively correlated with leptin levels, the frequencies of regulatory CD4+ T-cell subsets and Br1 cells negatively correlated with this adipokine. Interestingly, the obesity-related leptin dose not only elevated Th2 and Th17 cytokine levels, but also directly reduced the Treg function in CD4+ T cell cultures from lean AA patients. Conclusion: In summary, our results indicated that obesity might increase AA severity by favoring the expansion of Th17-like and Th2/Th17 cells and decreasing regulatory CD4+T cell subsets, being adverse effects probably mediated by leptin overproduction.

Major Depressive Disorder Enhances Th2 and Th17 Cytokines in Patients Suffering from Allergic Rhinitis and Asthma.

INTRODUCTION: Major depressive disorder (MDD) can impact the severity of allergic rhinitis (AR) and asthma (AA). Here, we evaluated the cytokine production by T-cells from AR and AA patients with or without MDD. The effect of serotonin on the in vitro T-cell response was also evaluated. METHODS: The cytokines produced by activated T-cells were measured by Luminex and flow cytometry. In some cell cultures, serotonin was added. RESULTS: MDD not only enhanced the production of Th2- and Th17-related cytokines, but also, the levels of interleukin (IL)-5 and IL-17 were directly correlated with the severity of depression and anxiety symptoms. As compared with AR, the levels of IL-17 were higher and the release of IL-10 was lower in activated T-cell cultures from AA patients, mainly those with MDD. In AA/MDD patients, the severity of anxiety symptoms and lung disease was directly correlated with Th17-like and hybrid Th2/Th17 cells, but inversely correlated with IL-10-secreting CD4+ T-cells. Finally, the addition of serotonin reduced the production of Th2- and Th17-related cytokines, but elevated IL-10 secretion in cell cultures from both AR and AA patients. CONCLUSIONS: Our findings suggest that not only the occurrence of MDD but also the severity of anxiety symptoms, may adversely affect the outcome of allergic reactions by favoring the production of cytokines implicated in the pathogenesis of AR and AA, a phenomenon that was attenuated by serotonin.

Serum leptin levels correlate negatively with the capacity of vitamin D to modulate the in vitro cytokines production by CD4+ T cells in asthmatic patients.

Both obesity and low vitamin D levels have been associated with allergic asthma (AA) severity. In the present study, severity of AA was associated with obesity but to the in vitro IgE production. In those patients, higher levels of IL-5, IL-6 and IL-17 were quantified in CD4+ T-cell cultures as compared with patients with mild and moderate AA. In addition, the lowest IL-10 levels were detected in the cell cultures from patients with a worse prognosis. Interestingly, the occurrence of AA elevates the plasma levels of leptin, and this adipokine was positively correlated with the release of IL-5, IL-6 and IL-17, but inversely correlated with IL-10 production, by CD4+ T-cells from patients. In AA-derived CD4+ T-cell cultures, 1,25(OH)2D3 was less efficient at inhibiting IL-5, IL-6 and IL-17 production, and up regulating IL-10 release, as those from healthy subjects. Interestingly, the in vitro immunomodulatory effects of vitamin D were inversely correlated with serum leptin levels. In summary, our findings suggested that obesity, probably due to the overproduction of leptin, negatively impacts AA as it favors imbalance between Th2/Th17 and regulatory phenotypes. The deleterious effects of leptin may also be due to its ability to counter-regulate the immunosuppressive effects of vitamin D.

Endogenous interleukin-6 amplifies interleukin-17 production and corticoid-resistance in peripheral T cells from patients with multiple sclerosis.

Interleukin-6 (IL-6) has been implicated in the induction of pathogenic IL-17-producing T cells in autoimmune diseases, and studies evaluating the role of this cytokine in T-cell function in patients with multiple sclerosis (MS) are lacking. Our objective was to evaluate the role of IL-6 receptor (IL-6R) signalling on in vitro functional status of T cells from patients with relapsing-remitting MS during clinical remission. Our results demonstrated that, even during the remission phase, activated T cells from patients produce higher levels of IL-17, and this cytokine was positively correlated with disease severity, as determined by Expanded Disability Status Scale score. In the MS group, the blockade of IL-6R signalling by anti-IL-6R monoclonal antibody reduced IL-17 production and elevated IL-10 release by activated CD4(+) T cells, but it did not alter the production of these cytokines by activated CD8(+) T cells. Blockade of IL-6R signalling also reduced the ability of monocytes to up-regulate T helper type 17 phenotype in patients with MS. Finally, both cell proliferation and IL-17 release by CD4(+) and, mainly, CD8(+) T cells from patients with MS were less sensitive to hydrocortisone inhibition than control group. Interestingly, IL-6R signalling blockade restored the ability of hydrocortisone to inhibit both T-cell proliferation and IL-17 production. Collectively, these results suggest that IL-6 might be involved in MS pathogenesis by enhancing IL-17 production and reducing corticoid inhibitory effects on activated T cells.

High in vitro immune reactivity to Escherichia coli in neuromyelitis optica patients is correlated with both neurological disabilities and elevated plasma lipopolysaccharide levels.

The pathogenesis of neuromyelitis optica (NMO) is influenced by a combination of genetic and environmental factors, including infectious agents. Several infectious diseases can both trigger or exacerbate autoimmunity. The objective of the present work was to evaluate the in vitro immune responsiveness to Escherichia coli (EC), Staphylococcus aureus (SA) and Candida albicans (CA) in remittent-recurrent NMO patients, and correlate it with the level of neurological disability. Our results revealed that the extent of lymphoproliferation and cytokine profile in response to SA- and CA-stimulated PBMC cultures was similar between NMO patients and healthy individuals. Nevertheless, a higher in vitro CD4(+) T cell proliferation associated with elevated IL-1ß, IL-6 and IL-17 release was observed in NMO-derived EC-stimulated cell cultures. Additionally, in these last cultures, the IL-10 production was significantly lower as compared with control group. The in vitro EC-induced levels of IL-6 and IL-17 were positively related with neurological disabilities. This higher tendency to produce Th17-related cytokines was proportional to the production of IL-23 and IL-6 by LPS-activated monocytes. Interestingly, elevated LPS levels were quantified in the plasma of NMO patients. The results suggest that a higher Th17-responsiveness to E. coli could be involved in the NMO pathogenesis.

The ex vivo production of IL-6 and IL-21 by CD4+ T cells is directly associated with neurological disability in neuromyelitis optica patients.

Neuromyelitis optica (NMO), also known as Devic's disease, is an autoimmune, inflammatory disorder of the central nervous system (CNS) in which the immune system attacks myelin of the neurons located at the optic nerves and spinal cord, thus producing a simultaneous or sequential optic neuritis and myelitis. The objective of this study was evaluated the background T-cell function of patients suffering from neuromyelitis optica (NMO), an autoimmune disorder of the central nervous system. In our study, the in vitro T cell proliferation and the production of Th1 cytokines were significantly lower in cell cultures from NMO patients, as compared with healthy individuals. In contrast, a dominant Th17-like phenotype, associate with higher IL-23 and IL-6 production by LPS-activated monocytes, was observed among NMO patients. The release of IL-21 and IL-6 by polyclonally activated CD4+ T cells was directly correlated to neurological disability. In addition, the in vitro release of IL-21, IL-6 and IL-17 was significantly more resistant to glucocorticoid inhibition in NMO patients. In conclusion, the results indicate dominant Th17-related response in NMO patients that was directly proportional to neurological disability. Furthermore, our results can help to explain why NMO patients trend to be more refractory to corticoid treatment.

Dopamine up-regulates Th17 phenotype from individuals with generalized anxiety disorder.

Our objective was to evaluate the effect of stress-related dose of dopamine (DA) on the in vitro proliferation and cytokine production in polyclonally-activated T cells from healthy individuals or individuals with generalized anxiety disorder (GAD). Our results demonstrated that cell cultures from GAD group proliferated less following T cell activation, as compared with control group. The addition of DA reduced the proliferative response in cell cultures from healthy but not from GAD individuals. The cytokine profile in GAD individuals revealed Th1 and Th2 deficiencies associated with a dominant Th17 phenotype, which was enhanced by DA. A similar DA-induced immunomodulation was also observed in PPD-activated cell cultures from GAD individuals. Unlike the control, DA-enhanced Th17 cytokine production in GAD individuals was not affected by glucocorticoid. In conclusion, our results show that the T cell functional dysregulation in GAD individuals is significantly amplified by DA. These immune abnormalities can have impact in increasing the susceptibility of individuals with anxiety disorders to infectious diseases and inflammatory/autoimmune disorders.

Enhanced Th17 phenotype in individuals with generalized anxiety disorder.

The generalized anxiety disorder (GAD) is often a debilitating chronic condition, characterized by long-lasting anxiety that is not focused on any object or situation. Besides being clearly linked to increased susceptibility to infectious diseases, anxiety is also known to contribute to the pathogenesis of many inflammatory/autoimmune disorders. The present work aimed to explore the T cell profile following in vitro activation in cultures obtained from a group of individuals with GAD, comparing them with healthy control individuals. Our results demonstrated that cell cultures from GAD group proliferated less following T cell activation as compared with the control group. The analysis of the cytokine profile revealed Th1 and Th2 cytokine deficiencies in the anxious group, as compared with the control subjects. On the other hand, this cellular and humoral immune damage was followed by enhanced production of Th17-derived cytokines. In particular, the levels of TNF-α and IL-17 were significantly higher in cell cultures containing activated T cells from GAD individuals. Therefore, besides a deficiency on Th1 phenotype, an elevated proinflammatory status of these individuals might be related to both glucocorticoid immune resistance and lower IL-10 levels produced by activated T cells. In conclusion, our results demonstrated a T cell functional dysregulation in individuals with GAD, and can help to explain the mechanisms of immune impairment in these subjects and their relationship with increased susceptibility to infections and autoimmune diseases.

IL-10-secreting T cells from HIV-infected pregnant women downregulate HIV-1 replication: effect enhanced by antiretroviral treatment.

OBJECTIVE: This study aimed to evaluate the impact of pregnancy-related immune events on the HIV-1 replication and to analyze their relationship with the risk of vertical transmission. METHODS: The peripheral blood from HIV-1-infected pregnant women who controlled (G1) or not controlled (G2) their plasma viral load was drawn, and the plasma and the T cells were obtained. The T-cell cultures were activated in vitro with anti-CD3 and anti-CD28, and the proliferation and cytokine production profile were evaluated after 3 days of incubation. The in-vitro HIV-1 replication was measured in culture supernatants in the seventh day following stimulation. The cytokines were also analyzed in the plasma. RESULTS: Our results demonstrated a lower T-cell proliferation and a lower interleukin-1beta, tumor necrosis factor-alpha and interferon-gamma production in polyclonally activated T-cell cultures from G1 patients, when compared with G2. Furthermore, high levels of interleukin-10 were produced both systemically and by activated T-cell cultures from G1 patients. Interestingly, the neutralization of endogenous interleukin-10 by anti-interleukin-10 monoclonal antibody elevated both the inflammatory cytokines' release and the HIV-1 replication in the polyclonally activated T-cell cultures from G1 patients. Additionally, the maternal antiretroviral treatment significantly enhanced the systemic interleukin-10 production. Finally, the higher systemic interleukin-10 levels were inversely correlated with vertical virus transmission risk. CONCLUSION: These results indicate that a high tendency of pregnant women to produce interleukin-10 can help them control the HIV-1 replication, and this can reduce the risk of vertical transmission. Furthermore, our data suggest a role for maternal antiretroviral treatment in enhancing this phenomenon.