Lenin Pavón

CXCR5+ T helper cells mediate protective immunity against tuberculosis

One third of the worlds population is infected with Mycobacterium tuberculosis (Mtb). Although most infected people remain asymptomatic, they have a 10% lifetime risk of developing active tuberculosis (TB). Thus, the current challenge is to identify immune parameters that distinguish individuals with latent TB from those with active TB. Using human and experimental models of Mtb infection, we demonstrated that organized ectopic lymphoid structures containing CXCR5+ T cells were present in Mtb-infected lungs. In addition, we found that in experimental Mtb infection models, the presence of CXCR5+ T cells within ectopic lymphoid structures was associated with immune control. Furthermore, in a mouse model of Mtb infection, we showed that activated CD4+CXCR5+ T cells accumulated in Mtb-infected lungs and produced proinflammatory cytokines. Mice deficient in Cxcr5 had increased susceptibility to TB due to defective T cell localization within the lung parenchyma. We demonstrated that CXCR5 expression in T cells mediated correct T cell localization within TB granulomas, promoted efficient macrophage activation, protected against Mtb infection, and facilitated lymphoid follicle formation. These data demonstrate that CD4+CXCR5+ T cells play a protective role in the immune response against TB and highlight their potential use for future TB vaccine design and therapy.

Th2 cytokine response in Major Depressive Disorder patients before treatment

In Major Depressive Disorder (MDD), the neuroendocrine and immune systems interactions are impaired. We investigated the pro/anti-inflammatory Th1/Th2 cytokine balance in MDD patients and in non-depressed control group. The MDD subjects showed higher levels of cortisol and TNF-alpha, increased CD3+CD8+ and NK percentages, diminished B cell counts and no significant variations in CD3+CD4+ lymphocyte. Moreover, higher levels of IL-4 and IL-13 (Th2) and significantly lower measurements of IL-2 and IFN-gamma (Th1) cytokines were also observed in the MDD group. Overall, we propose that all these changes could be related to the elevated cortisol levels seen in the MDD patients. Further studies are necessary to explore these findings and its implication in future therapeutic approach of MDD patients.

The effects of androstenediol and dehydroepiandrosterone on the course and cytokine profile of tuberculosis in BALB/c mice

Immunity to Mycobacterium tuberculosis requires a T helper 1 (Th1) cytokine balance accompanied by tumour necrosis factor‐α (TNF‐α), and activated macrophages. These facets of the immune response are sensitive to suppression by glucocorticoids (GC), which can reactivate and exacerbate tuberculosis in man and animals. Dehydroepiandrosterone (DHEA) and its derivative, 3β,17β androstenediol (AED), are reported to have antiglucocorticoid properties in vivo. We therefore investigated the effects of predetermined optimal doses of these compounds, on the course of pulmonary tuberculosis in an established model in BALB/c mice in which an early phase of Th1‐mediated response accompanied by adrenal hyperplasia, is followed by a switch to Th2, progressive loss of TNF‐α expression and disease progression. Both compounds were protective, particularly AED which caused a fall in bacterial counts and prolonged survival. These effects correlated with the appearance within 3 days of cellular infiltrates rich in cells expressing interleukin‐2 (IL‐2), IL‐1α and TNF‐α, and with partial suppression of the switch to IL‐4 producing cells that occurred in controls. AED also caused enhanced development of granulomas at 14 days, and persistence of granuloma formation to 120 days, with a corresponding suppression of areas affected by pneumonia. Much of the therapeutic effect of AED and DHEA was obtained by treating for only the first 3 weeks, which is the phase of adrenal hyperplasia. These results suggest that the ratio of GC to anti‐GC steroids may play a role in the pathogenesis of tuberculosis, and further investigation could lead to novel treatment strategies.

Variations in circulating cytokine levels during 52 week course of treatment with SSRI for major depressive disorder

Major depressive disorder (MDD) is a psychiatric condition characterized by hypercortisolism and variations in circulatory cytokines. Previously it has been reported that administration of selective serotonin reuptake inhibitors (SSRI) in MDD patients modify cortisol and cytokine levels but these studies only evaluated changes over a short time period. This work reports the long-term effects of administration of SSRI on the cortisol levels and pro-/anti-inflammatory cytokine profile in a group of MDD patients treated for 52 weeks. A total of 31 patients diagnosed with MDD received anti depressant treatment with SSRI. HDRS and BDI were administered over a year, and levels of interleukin IL-1beta, IL-10, IL-2, IFN-gamma, IL-4, IL-13, and 24-h urine cortisol were determined at weeks (W) 0, 5, 20, 36 and 52 of treatment. Before treatment we found high levels of cortisol, IL-4, IL-13 (Th2) and IL-10 in MDD patients when compared with healthy volunteers. At W20 psychiatric scales indicated a remission of the depressive episode concomitantly with increments in IL-2 and IL-1beta but without changes in cortisol. Towards the end of the treatment (W52) we observed a significant reduction (p<0.01) in cortisol levels, with an increment in IL-1beta and IFN-gamma and a decrease in Th2 cytokines. Our results suggest that depressed patients only reach a partial reestablishment of HPA axis function after the long-term administration of SSRI.

Immunomodulatory effects mediated by serotonin.

Serotonin (5-HT) induces concentration-dependent metabolic effects in diverse cell types, including neurons, entherochromaffin cells, adipocytes, pancreatic beta-cells, fibroblasts, smooth muscle cells, epithelial cells, and leukocytes. Three classes of genes regulating 5-HT function are constitutively expressed or induced in these cells: (a) membrane proteins that regulate the response to 5-HT, such as SERT, 5HTR-GPCR, and the 5HT3-ion channels; (b) downstream signaling transduction proteins; and (c) enzymes controlling 5-HT metabolism, such as IDO and MAO, which can generate biologically active catabolites, including melatonin, kynurenines, and kynurenamines. This review covers the clinical and experimental mechanisms involved in 5-HT-induced immunomodulation. These mechanisms are cell-specific and depend on the expression of serotonergic components in immune cells. Consequently, 5-HT can modulate several immunological events, such as chemotaxis, leukocyte activation, proliferation, cytokine secretion, anergy, and apoptosis. The effects of 5-HT on immune cells may be relevant in the clinical outcome of pathologies with an inflammatory component. Major depression, fibromyalgia, Alzheimer disease, psoriasis, arthritis, allergies, and asthma are all associated with changes in the serotonergic system associated with leukocytes. Thus, pharmacological regulation of the serotonergic system may modulate immune function and provide therapeutic alternatives for these diseases.

Interactions between hormone-mediated and vaccine-mediated immunotherapy for pulmonary tuberculosis in BALB/c mice

Problems of logistics, compliance and drug resistance point to an urgent need for immunotherapeutic strategies capable of shortening the current 6‐month chemotherapy regimens used to treat tuberculosis, or of supplementing ineffective therapy. In this study we sought to define the mechanism of action of two immunotherapies, both of which have previously been shown to prolong survival. Secondly, we wished to identify any clinically useful synergy between these therapies. In BALB/c mice infected via the trachea with Mycobacterium tuberculosis H37Rv there is an initial phase of partial resistance dominated by type 1 cytokines plus tumour necrosis factor‐α (TNF‐α) and interleukin‐1 (IL‐1), followed by a phase of progressive disease. This progressive phase is accompanied by increasing expression of IL‐4, and diminished expression of IL‐1 and TNF‐α. Animals in this late progressive phase of the disease (day 60) were treated with two injections (day 60 and day 90) of 0·1 or 1·0 mg of heat‐killed Mycobacterium vaccae, or with 3β,17β‐androstenediol (AED; 25 µg subcutaneously three times/week), or with both therapies. We show here using four techniques in parallel (morphometry, immunohistochemistry with automated cell counting, semiquantitative reverse transcription–polymerase chain reaction and enzyme‐linked immunosorbent assays of cytokines in lung extracts) that treatment with M. vaccae causes a switch back towards a type 1 cytokine profile, restoration of expression of IL‐1α and TNF‐α, and a switch from pneumonia to granuloma. This is very similar to the changes previously seen after treatment with AED. However, there was no evidence for synergy between M. vaccae and AED.

Treatment with BB-94, a broad spectrum inhibitor of zinc-dependent metalloproteinases, causes deviation of the cytokine profile towards type-2 in experimental pulmonary tuberculosis in Balb/c mice.

BB‐94 (batimastat) is a broad‐ spectrum hydroxamic acid‐based zinc metalloproteinase inhibitor that inhibits both the matrix metalloproteinases (MMP) and members of the ADAM family of enzymes such as Tumour Necrosis Factor‐α Cleaving Enzyme (TACE). These enzymes are involved in the regulation of inflammatory processes in tuberculosis. Balb/c mice infected with M. tuberculosis via the intratracheal route were treated with BB‐94 for 1 month, starting on the day of infection. Immunohistochemistry, semiquantitative RT‐PCR and ELISA assays for cytokines revealed a deficit in IL‐1 and IL‐2 expression and a premature bias towards IL‐4 expression, accompanied by a delay in granuloma formation and more rapid progression of disease in BB‐94‐treated animals. This situation corrected itself after the drug was withdrawn at 28 days. In contrast, when BB‐94 was administered only after 1 month there were no significant changes apart from the presence of amyloid, and a paradoxically increased expression of IL‐1α. These results cast light on mechanisms of immunity in tuberculosis and also indicate that in patients treated with similar broad‐spectrum MMP inhibitors there may be a risk of inappropriate deviation of some immune responses towards a Type‐2 cytokine profile.

Proinflammatory cytokine levels in fibromyalgia patients are independent of body mass index

BackgroundFibromyalgia (FM) is characterized by chronic, widespread muscular pain and tenderness and is generally associated with other somatic and psychological symptoms. Further, circulatory levels of proinflammatory cytokines (IL-1β, TNF-α, and IL-6) may be altered in FM patients, possibly in association with their symptoms. Recently, rises in BMI have been suggested to contribute to increased circulating levels of proinflammatory cytokines in FM patients. Our aim was to measure the circulatory levels of proinflammatory cytokines to determine the influence of BMI on these levels in FM patients and healthy volunteers (HVs). In Spanish FM patients (n = 64) and HVs (n = 25), we measured BMI and serum concentrations of proinflammatory cytokines by capture ELISA.FindingsThere were significant differences in BMI levels between FM patients (26.40 ± 4.46) and HVs (23.64 ± 3.45) and significant increase in IL-6 in FM patients (16.28 ± 8.13 vs 0.92 ± 0.32 pg/ml) (P < 0.001). IL-1β and TNF-α decreased in FM patients compared with HVs. By ANCOVA, there was no significant association between BMI and TNF-α (F = 0.098, p = 0.75) or IL-6 (F = 0.221, p = 0.63) levels in FM patients.ConclusionsOur analysis in FM patients of BMI as a covariate of proinflammatory cytokines levels showed that serum TNF-α and IL-6 levels are independent of BMI. Further studies are necessary to dissect these findings and their implication in future therapeutic approaches for FM patients.

Evaluation of the effect of selective serotonin-reuptake inhibitors on lymphocyte subsets in patients with a major depressive disorder

To date, only the effect of a short-term antidepressant treatment (<12 weeks) on neuroendocrinoimmune alterations in patients with a major depressive disorder has been evaluated. Our objective was to determine the effect of a 52-week long treatment with selective serotonin-reuptake inhibitors on lymphocyte subsets. The participants were thirty-one patients and twenty-two healthy volunteers. The final number of patients (10) resulted from selection and course, as detailed in the enrollment scheme. Methods used to psychiatrically analyze the participants included the Mini-International Neuropsychiatric Interview, Hamilton Depression Scale and Beck Depression Inventory. The peripheral lymphocyte subsets were measured in peripheral blood using flow cytometry. Before treatment, increased counts of natural killer (NK) cells in patients were statistically significant when compared with those of healthy volunteers (312+/-29 versus 158+/-30; cells/mL), but no differences in the populations of T and B cells were found. The patients showed remission of depressive episodes after 20 weeks of treatment along with an increase in NK cell and B cell populations, which remained increased until the end of the study. At the 52nd week of treatment, patients showed an increase in the counts of NK cells (396+/-101 cells/mL) and B cells (268+/-64 cells/mL) compared to healthy volunteers (NK, 159+/-30 cells/mL; B cells, 179+/-37 cells/mL). We conclude that long-term treatment with selective serotonin-reuptake inhibitors not only causes remission of depressive symptoms, but also affects lymphocyte subset populations. The physiopathological consequence of these changes remains to be determined.

Effect of Selective Serotonin Reuptake Inhibitors and Immunomodulator on Cytokines Levels: An Alternative Therapy for Patients with Major Depressive Disorder

Major depressive disorder (MDD) is a psychiatric illness that presents as a deficit of serotonergic neurotransmission in the central nervous system. MDD patients also experience alterations in cortisol and cytokines levels. Treatment with selective serotonin reuptake inhibitors (SSRIs) is the first-line antidepressant regimen for MDD. The aim of this study was to determine the effect of a combination of SSRIs and an immunomodulator—human dialyzable leukocyte extract (hDLE)—on cortisol and cytokines levels. Patients received SSRIs or SSRIs plus hDLE. The proinflammatory cytokines IL-1β, IL-2, and IFN-γ; anti-inflammatory cytokines IL-13 and IL-10; and 24-h urine cortisol were measured at weeks (W) 0, 5, 20, 36, and 52 of treatment. The reduction in cortisol levels in the SSRI-treated group was 30% until W52, in contrast, the combined treatment induced a 54% decrease at W36. The decline in cortisol in patients who were treated with SSRI plus hDLE correlated with reduction of anti-inflammatory cytokines and increases levels of proinflammatory cytokines at the study conclusion. These results suggest that the immune-stimulating activity of hDLE, in combination with SSRIs, restored the pro- and anti-inflammatory cytokine balance and cortisol levels in depressed patients versus those who were given SSRIs alone.