The Notch1/CD22 signaling axis disrupts Treg function in SARS-CoV-2-associated multisystem inflammatory syndrome in children

Multisystem inflammatory syndrome in children (MIS-C) evolves in some pediatric patients following acute infection with SARS-CoV-2 by hitherto unknown mechanisms. Whereas acute-COVID-19 severity and outcomes were previously correlated with Notch4 expression on Tregs, here, we show that Tregs in MIS-C were destabilized through a Notch1-dependent mechanism. Genetic analysis revealed that patients with MIS-C had enrichment of rare deleterious variants affecting inflammation and autoimmunity pathways, including dominant-negative mutations in the Notch1 regulators NUMB and NUMBL leading to Notch1 upregulation. Notch1 signaling in Tregs induced CD22, leading to their destabilization in a mTORC1-dependent manner and to the promotion of systemic inflammation. These results identify a Notch1/CD22 signaling axis that disrupts Treg function in MIS-C and point to distinct immune checkpoints controlled by individual Treg Notch receptors that shape the inflammatory outcome in SARS-CoV-2 infection.

Immune modulation as a consequence of SARS-CoV-2 infection

Erroneous immune responses in COVID-19 could have detrimental effects, which makes investigation of immune network underlying COVID-19 pathogenesis a requisite. This study aimed to investigate COVID-19 related alterations within the frame of innate and adaptive immunity. Thirty-four patients clinically diagnosed with mild, moderate and severe COVID-19 disease were enrolled in this study. Decreased ILC1 and increased ILC2 subsets were detected in mild and moderate patients compared to healthy controls. NK cell subsets and cytotoxic capacity of NK cells were decreased in severe patients. Moreover, CD3⁺ T cells were reduced in severe patients and a negative correlation was found between CD3⁺ T cells and D-dimer levels. Likewise, moderate and severe patients showed diminished CD3⁺CD8⁺ T cells. Unlike T and NK cells, plasmablast and plasma cells were elevated in patients and IgG and IgA levels were particularly increased in severe patients. Severe patients also showed elevated serum levels of pro-inflammatory cytokines such as TNF-α, IL-6 and IL-8, reduced intracellular IFN-γ and increased intracellular IL-10 levels. Our findings emphasize that SARS-CoV-2 infection significantly alters immune responses and innate and acquired immunity are differentially modulated in line with the clinical severity of the disease. Elevation of IL-10 levels in NK cells and reduction of CD3⁺ and CD8⁺ T cells in severe patients might be considered as a protective response against the harmful effect of cytokine storm seen in COVID-19.

Haemophagocytic lymphohistiocytosis in a patient with familial Mediterranean fever and miliary tuberculosis: a case report

Haemophagocytic lymphohistiocytosis (HLH) is a lethal complication of several infections, especially viral origin. Mycobacterium tuberculosis infection can also lead to HLH, yet it is an uncommon trigger. Considering the role of increased cytokines in HLH, autoinflammatory conditions, such as familial Mediterranean fever (FMF), might contribute to its development. Nevertheless, the possible relationship between FMF and HLH has been suggested only in some case reports. We present a case of FMF who admitted to the hospital with consitutional symptoms and chest pain regarding to recurrent pericarditis. On a blood test, pancytopenia and elevated acute phase reactants were seen. Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography demonstrated positive FDG uptake sites on both the right and left surrenal glands, the visceral layer of pericard, and reactive lymphadenomegalies at multiple mediastinal regions. Bone marrow biopsy revealed haemophagocytosis. Methylprednisolone treatment was initiated. Despite immunosuppressive treatment, clinical and biochemical parameters deteriorated; thus, a thorax computed tomography was executed. Findings were consistent with miliary tuberculosis infection. M. tuberculosis was detected in blood culture and bronchoalveolar lavage culture material. Also, bone marrow and surrenal biopsy material revealed necrotising caseating granuloma.

The Effect of Adipose-Derived Stromal Vascular Fraction Cells to Abdominal Wall Fascia Defects in Rats: An Experimental Study

OBJECTIVE

Various synthetic and biological meshes have been developed to reduce recurrence and complications in ventral incisional hernia repairs. Adipose tissue is a rich reserve for mesenchymal stromal cells. In the present study we aimed to examine the effects of adipose-derived mesenchymal stromal cells (AD-MSCs) on abdominal incisional hernia repairs in rats.

MATERIALS AND METHODS

The study involved 32 male Wistar-Albino rats, weighing 200-250 g, which were divided into three groups. In Group 1 (control group) only an incisional hernia model was created. In Group 2, the incisional hernia model was created and 1 ml stromal vascular fraction (SVF), obtained from inguinal lipectomy material and containing mesenchymal stromal cells, was injected into the edges of the defect in the same session. In Group 3, only the incisional hernia model was created in the first stage and after 14 days, 1 ml of SVF was injected into the edges of the defect. Skin incisions of rats in Group 1 and 2 were opened on postoperative day 28 while in group 3 were opened on day 42. Peritoneal formation in abdominal wall defect was evaluated macroscopically and histopathologically.

RESULTS

Peritoneal formation was significantly superior in Groups 2 and 3 than in Group 1 (p: 0.031). In histopathological evaluation, the structural distortion and polymorphonuclear leukocyte (PMNL) levels were significantly higher in Group 1 than in Group 3 (p: 0.048 and p: 0.046, respectively). Granulation, capillary density, fibrosis and collagen organization were higher in Group 2 and 3, however this difference was not statistically significant (p > 0.05).

CONCLUSIONS

Adipose-derived stromal vascular fraction cells obtained from inguinal lipectomy material in rats positively affect the repair of abdominal incisional hernias by increasing peritoneal formation, and reducing structural distortion and PMNL infiltration.

Notch4 signaling limits regulatory T-cell-mediated tissue repair and promotes severe lung inflammation in viral infections

A cardinal feature of COVID-19 is lung inflammation and respiratory failure. In a prospective multi-country cohort of COVID-19 patients, we found that increased Notch4 expression on circulating regulatory T (Treg) cells was associated with disease severity, predicted mortality, and declined upon recovery. Deletion of Notch4 in Treg cells or therapy with anti-Notch4 antibodies in conventional and humanized mice normalized the dysregulated innate immunity and rescued disease morbidity and mortality induced by a synthetic analog of viral RNA or by influenza H1N1 virus. Mechanistically, Notch4 suppressed the induction by interleukin-18 of amphiregulin, a cytokine necessary for tissue repair. Protection by Notch4 inhibition was recapitulated by therapy with Amphiregulin and, reciprocally, abrogated by its antagonism. Amphiregulin declined in COVID-19 subjects as a function of disease severity and Notch4 expression. Thus, Notch4 expression on Treg cells dynamically restrains amphiregulin-dependent tissue repair to promote severe lung inflammation, with therapeutic implications for COVID-19 and related infections.

Differential Expression of Novel Immune Checkpoint Receptors on Tumor Infiltrating Lymphocytes in Patients with Locally Advanced Breast Cancer after Neoadjuvant Chemotherapy

Immune checkpoint receptors (ICRs) were recently found to modulate the anti-tumoral immune response. This study aimed to determine the clinical and pathological associations of ICRs expression on tumor-infiltrating lymphocytes (TILs) in patients with locally advanced breast cancer (LABC) treated with neoadjuvant chemotherapy (NAC). Expressions of ICRs including PD-1, LAG-3, TIM-3, TIGIT, and CTLA-4 on CD8+ T lymphocytes and Natural Killer (NK) cells on TILs were analyzed by flow cytometry. Patients < 50 years were more likely to express CTLA-4 on CD8+ T lymphocytes compared to those ≥ 50 years (p = 0.004). In addition, patients with ypT3-4 tumors were more likely to have increased LAG-3 expression on CD16-CD56bright NK cells (p = 0.042) and PD-1 (p = 0.014) and CTLA-4 (p = 0.018) expressions on CD8+ T cells in regard to those with ypT1-T2, respectively. Contrarily, PD-1 expression on CD16-CD56bright NK cells was found to be decreased in patients with ypN+ compared to those with ypN- (p = 0.022). Furthermore, patients with HER2+ tumors were more likely to have increased TIM-3 expression on CD8+ T cells (p = 0.043), whereas patients with a better response to NAC were more likely to express TIGIT on CD8+ T (p = 0.014) and CD16- CD56bright NK cells (p = 0.003), respectively. The new generation ICRs, TIM-3, LAG-3, and TIGIT are highly expressed in LABC following NAC in patients with poor prognostic factors. Therefore, new evolving therapies using inhibitory mAbs directed to TIM-3, LAG-3, and TIGIT could be also be considered in locally advanced breast cancers expressing these ICRs.

Inflammatory status might direct ILC and NK cells to IL-17 expressing ILC3 and NK subsets in Behcet's disease

Innate lymphoid cells (ILCs) are lymphoid cells that have important effector and regulatory functions in innate immunity and tissue remodeling. Uncontrolled activation and proliferation of ILCs can contribute to inflammatory autoimmune diseases. Behcet's disease (BD) is a complex systemic inflammatory disorder of unknown etiology. It has been shown that natural killer (NK) cells may play an immunoregulatory role in BD, however the role of ILCs is unknown. In this study, the levels and functions of ILCs and NK cell subsets in BD patients were investigated. Cell surface and cytotoxic granules (perforin and granzyme) expression of NK cells and ILCs were evaluated and labeled according to whole blood lysing protocol in peripheral blood samples obtained from the patients and healthy subjects. Cytokine levels of NK cells were investigated in stimulated peripheral blood mononuclear cells. All data were analyzed by flow cytometry. Total ILC and ILC3⁺ cells were increased in active BD patients compared to inactive BD patients and healthy subjects. There was no significant difference between the patients and healthy subjects regarding NK cell surface and intracellular molecule expression. Although, an increase in IFN-γ and IL-17, and a decrease in IL-4 levels were observed in CD56^dim NK cell subset of BD patients. Recent studies showed increased neutrophilic infiltration and IL-17 secreting Th17 cells in BD patients. It is known that ILC3⁺cells are similar to Th17 subset regarding their cytokine profile and transcription factor expression patterns. Results of current study may suggest that inflammatory microenvironment in BD patients might direct ILC cells to differentiate into ILC3⁺ subset, and IL-17 released by NK cells might have a role in neutrophilic infiltration.

The Role of Natural Killer Cells in Autoimmune Diseases

Natural killer (NK) cells, the large granular lymphocytes differentiated from the common lymphoid progenitors, were discovered in early 1970’s. They are members of innate immunity and were initially defined by their strong cytotoxicity against virus-infected cells and by their important effector functions in anti-tumoral immune responses. Nowadays, NK cells are classified among the recently discovered innate lymphoid cell subsets and have capacity to influence both innate and adaptive immune responses. Therefore, they can be considered as innate immune cells that stands between the innate and adaptive arms of immunity. NK cells don’t express T or B cell receptors and are recognized by absence of CD3. There are two major subgroups of NK cells according to their differential expression of CD16 and CD56. While CD16⁺CD56^dim subset is best-known by their cytotoxic functions, CD16^-CD56^bright NK cell subset produces a bunch of cytokines comparable to CD4⁺ T helper cell subsets. Another subset of NK cells with production of interleukin (IL)-10 was named as NK regulatory cells, which has suppressive properties and could take part in immune-regulatory responses. Activation of NK cells is determined by a delicate balance of cell-surface receptors that have either activating or inhibitory properties. On the other hand, a variety of cytokines including IL-2, IL-12, IL-15, and IL-18 influence NK cell activity. NK-derived cytokines and their cytotoxic functions through induction of apoptosis take part in regulation of the immune responses and could contribute to the pathogenesis of many immune mediated diseases including ankylosing spondylitis, Behçet’s disease, multiple sclerosis, rheumatoid arthritis, psoriasis, systemic lupus erythematosus and type-1 diabetes. Dysregulation of NK cells in autoimmune disorders may occur through multiple mechanisms. Thanks to the rapid developments in biotechnology, progressive research in immunology enables better characterization of cells and their delicate roles in the complex network of immunity. As NK cells stand in between innate and adaptive arms of immunity and “bridge” them, their contribution in inflammation and immune regulation deserves intense investigations. Better understanding of NK-cell biology and their contribution in both exacerbation and regulation of inflammatory disorders is a requisite for possible utilization of these multi-faceted cells in novel therapeutic interventions.

Cytokine responses to symbiotic and lactoferrin combination in very low birth weight neonates: a randomized control trial

INTRODUCTION

Probiotics and prebiotics, which are multifunctional agents, have potential benefits in chronic mucosal inflammation, including the prevention of necrotizing enterocolitis. However, the mechanisms and the results of these immunomodulatory effects are not clear. This study aimed to investigate the cytokine response to the combination of Lactobacillus and Bifidobacterium together with fructo- and galacto-oligosaccharides (symbiotic) and lactoferrin in very low birth weight neonates.

POPULATION AND METHODS

Infants ≤ 32 GWs and ≤ 1,500 g were randomly assigned to receive a symbiotic combination or 1 ml distilled water as placebo starting with the first feed until discharge. Blood samples were obtained at postnatal 0 ± 2, 14 ± 2, and 28 ± 2 days, and the serum levels of interferon-y, interleukin (IL)-5, IL-10, and IL-17A were measured.

RESULTS

In the study group (n = 25), the IL-10 levels decreased throughout the study period (p = 0.011) but did not change in the control group. The IL-5 levels remained steady in the first 14 days and decreased significantly thereafter (p = 0.042) in the study group, whereas they increased in the first 14 days (p = 0.019), and then decreased in 28 days (p = 0.011) in the control group (n = 25). The levels of the other cytokines did not change throughout the study period.

CONCLUSION

The combined use of probiotics with oligosaccharides and lactoferrin was associated with a decrease in IL-10 levels, but no change was observed in the other cytokines.

Abstract P5-04-24: Differential expression of novel immune checkpoint receptors expressed on tumor-infiltrating lymphocytes (TIL) in patients with early breast cancer

Introduction: High expression of immune checkpoint receptors in tumor microenvironment reduces antitumor immunity and cause immune evasion of tumor cells. In recent years, immunotherapy trials using PD-1 or PDL-1 inhibitors in advanced triple negative (TN) breast cancer evolved very rapidly. The differential expression of novel immune checkpoint receptors such as TIM-3, LAG-3 and TIGIT in addition to PD-1, and CTLA-4 on tumor infiltrating lymphocytes (TIL) in patients with early breast cancer was investigated.

Material and methods: TIL were isolated by using a Tumor Dissociation Kit from fresh tumoral tissue. Flow-cytometric analyses were performed by using CD8, CD16, CD56, PD-1, CTLA-4, TIM-3, LAG-3 and TIGIT specific monoclonal antibodies on isolated TIL. Correlations were estimated between biological and clinical characteristics of tumors and demographic features of patients and flow cytometric findings.

Results: Median age was 47 (range 28-68). There were 7 patients (35%) with HER2+ or triple negative tumors, whereas 13 patients (65%) had HER2 (-) luminal cancers. Our findings showed that patients younger than 45 years were more likely to express high levels of CTLA-4 (p=0.013) and TIGIT (p=0.007) on CD56+ natural killer (NK) cells and TIM-3 (p=0.043) on CD16+ lymphocytes (Table 1), whereas the other high expressions including LAG-3 (p=0,08) and TIM-3 (p=0.06) on CD56+ NK cells did not reach the statistical significance. Furthermore, patients with high Ki-67 proliferation index &gt;35% were found to express higher CTLA-4 (p=0.011) on CD16+ lymphocytes. Patients with Stage II disease expressed higher levels of PD-1 (p=0.018) and LAG-3 (p=0.04) on CD8+ cytotoxic T lymphocytes than patients with Stage I disease. Similarly, patients with lymph node metastasis had higher TIGIT (p=0.04) and PD-1 (p=0.05) levels on CD16+ and CD56+ lymphocytes, respectively. No other significant associations could be found between immune check receptors and other parameters.

Conclusion: Our results suggest TIL in patients with more advanced stages and younger than 45 years old are more likely to express higher levels of immune checkpoint receptors such as LAG-3, TIM-3, CTLA-4, TIGIT and PD-1. Interestingly, no difference could be found in immune checkpoint receptor expressions in TIL between patients with luminal and TN or HER2+, that would justify immunotherapeutical approaches in selected luminal breast cancers in future trials.

Table 1. Significant correlations between immune check point receptor expression and demographic and tumor features CD8PD1CD8LAG3CD16CTLA4CD16TIGITCD16TIM3CD56CTLA4CD56TIGITCD56PD1meanpmeanpmeanpmeanpmeanpmeanpmeanpmeanpAge&lt;45 (n:7)11.930.427120.40513.210.13212.290.3214.140.043150.01315.360.00710.290.905&gt;45 (n:13)9.739.699.049.548.548.087.8810.62Ki-67 (cut off %35)&lt;%35 (n:12)10.710.84711.710.26313.250.01110.920.69810.540.96911.920.18911.880.20312.040.153≥%35 (n:8)10.198.696.389.8810.448,388.448.19N stageN0 (n:13)10.120.69210.770.7819.810.4758.580.04710.270.8129,580.3419.960.5798.620.05N1 (n:7)11.211011.7914.0710.9312,2111.514StageStage 1 (n:5)5.10.0185.90.0447.40.17611.40.69311.20.7690.51312.50.3826.40.073Stage 2 (n:15)12.312.0311.5310.210.27119.8311.87

All statistical analyses were evaluated using the Mann Whitney U test.

Citation Format: Baran Mollavelioglu, Esin Aktas Cetin, Neslihan Cabioglu, Aykhan Abbasov, Semen Onder, Selman Emiroglu, Mustafa Tukenmez, Mahmut Muslumanoglu, Abdullah Igci, Gunnur Deniz, Vahit Ozmen. Differential expression of novel immune checkpoint receptors expressed on tumor-infiltrating lymphocytes (TIL) in patients with early breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-04-24.

Generalized Fixed Drug Eruption Induced by Fluconazole Without Cross-Reactivity to Itraconazole: Lymphocyte Transformation Test Confirms the Diagnosis

We present a rare case of generalized fixed drug eruption caused by fluconazole. A 45-year-old female patient was referred to our outpatient clinic because of suspicious drug eruptions that occurred 5 months earlier and resolved within a month. The patient had sequela of hyperpigmentation on her arms, legs, back, and abdomen after oral administration of the fourth dose of 150 mg of fluconazole once daily because of vaginal candidiasis. Patch tests with the culprit drug applied both on unaffected skin areas and over one of the lesions were negative. A lymphocyte transformation test was performed and in response to fluconazole, CD4⁺ T cells significantly proliferated. Because the patient needed a safe antifungal drug for her recurrent vaginal candidiasis symptoms, a single-blind placebo-controlled drug provocation test was performed with itraconazole and was negative. Accordingly, 200 mg of itraconazole once daily was given for 10 days safely.

CD163 levels, pro- and anti-inflammatory cytokine secretion of monocytes in children with pulmonary tuberculosis

OBJECTIVES

Childhood tuberculosis (TB) comprises an important part of the world's TB burden. Monocytes set up the early phase of infection because of innate immune responses. Understanding the changes in monocyte subsets during multisystem infectious diseases may be important for the development of novel diagnostic and therapeutic strategies. The aim of this study was to evaluate the monocyte phenotype together with the cytokine secretion profiles of children with pulmonary tuberculosis.

STUDY DESIGN

Thirteen patients with pulmonary TB were enrolled as study group, and 14 healthy subjects as control group. Surface expressions of CD16, CD14, CD62L, CD163, CCR2, and HLA-DR of monocytes were analyzed by flow cytometry. The presence of IFN-γ, TNF-α, IL-10, IL-12, IL-23, and soluble form of CD163 (sCD163) in the antigen- and LPS-stimulated whole blood culture supernatants were detected using ELISA and Luminex.

RESULTS

Higher percentages of CD14⁺⁺ CD16⁺ and CD14⁺ CD16⁺⁺ monocyte subsets, and CCR2, CD62L and CD163 expression on circulating monocytes in children with pulmonary tuberculosis were obtained. Diminished levels of ESAT-6/CFP-10-induced IL-10 and increased levels of TB-antigen and LPS-stimulated sCD163 were found in childhood with pulmonary TB.

CONCLUSIONS

High expression of CD14⁺⁺ CD16⁺ , CD14⁺ CD16⁺⁺ , CD14⁺ CCR2⁺ , and CD14⁺ CD62L⁺ cells in childhood TB, and monocyte-derived cytokines reflected both pro- and anti-inflammatory profiles. Higher sCD163 and CD14⁺ CD163⁺ monocytes might help physicians in the differential diagnosis of pulmonary TB in children. Pediatr Pulmonol. 2017;52:675-683. © 2016 Wiley Periodicals, Inc.

Natural Killer Cell Subsets and Their Functional Activity in Behçet's Disease

BACKGROUND

Behçet's disease (BD) is a rare, chronic autoinflammatory disorder of unknown origin. Natural killer (NK) cells are one of the major immunoregulatory cell groups of the innate immune system, but their role in BD pathogenesis is not well documented.

OBJECTIVES

We aimed to investigate the role of NK cell subsets and their cytokine secretion and cytotoxic activity in patients with BD.

PATIENTS AND METHODS

The study group consisted of BD patients who had only mucocutaneous involvement, and they were compared with healthy subjects. BD patients were divided into two groups according to their frequencies of oral ulcerations. NK cell cytotoxicity was determined using CD107a expression and a CFSE-based cytotoxicity test. Expression of NK cell receptors and surface markers and the intracellular IL-5, IL-10, IL-17, and IFN-γ levels in CD16⁺ NK cells were assessed by flow cytometry.

RESULTS

Although the cytokine secretion pattern was different, no difference was obtained in cytotoxic activity, expression of activatory receptors, or degranulation of NK cells.

CONCLUSION

Increases in NK1/NK2 ratio and CD16⁺IFN-γ⁺ NK1 cells might support the idea of a biased IFN-γ dominant immune response in the mucocutaneous involvement of BD pathogenesis. Although the cytokine secretion pattern was different, no difference was obtained in cytotoxic activity, expression of activatory receptors, or degranulation of NK cells.

Elevated plasma concentrations of S100 calcium-binding protein B and tumor necrosis factor alpha in children with autism spectrum disorders

Objective:

To investigate plasma concentrations of S100B (a calcium-binding protein derived primarily from the glia) and inflammatory cytokines in children with autism and the relationship between S100B and cytokine concentrations.

Methods:

Plasma levels of S100B, tumor necrosis factor alpha (TNF-α), interferon gamma, interleukin (IL)-1β, IL-4, IL-6, IL-10, and IL-17A were measured in 40 unmedicated children with autism and 35 normally developing healthy children. The severity of autism was assessed using the Childhood Autism Rating Scale (CARS).

Results:

Concentrations of both S100B and TNF-α were higher in children with autism before and after adjusting for a priori-selected confounders (age, sex, and body mass index). S100B concentrations were higher in children with severe autism compared to children with mild-moderate autism. However, this association remained as a trend after adjusting for confounders. S100B concentrations correlated positively with TNF-α concentrations.

Conclusion:

Our findings showing an increase in peripheral concentrations of S100B and TNF-α provide limited support to the hypothesis about the roles of altered immune function and S100B in autism spectrum disorder (ASD). Studies of larger numbers of well-characterized individuals with ASD are needed to clarify the potential role of the immune system in the pathophysiology of this disorder.

Peripheral blood NK cells expressing HLA-G, IL-10 and TGF-β in healthy donors and breast cancer patients

Human natural killer (NK) cells are not only professional cytotoxic cells integrated into effector branch of innate immunity, but they are also regulatory cells, managing different immune processes. Immunoregulatory NK cells, expressing HLA-G and IL-10, have been generated in vitro from human hematopoietic progenitors and found in vivo among decidual NK cells of pregnant women. Human peripheral blood NK cells have been shown to acquire suppressive properties after HLA-G uptake during trogocytosis. Moreover, it has been shown that circulating NK cells contain a trace amount of cells producing TGF-β and IL-10, which exert a suppressive influence upon innate and adaptive immunity. In this study, we report on a minor subset of peripheral blood HLA-G(+) NK cells possessing suppressive activity toward effector functions of NK cells. Further we demonstrate an increased number of circulating HLA-G(+), IL-10(+), and TGF-β(+) NK cells in breast cancer patients which might impair efficiency of anti-tumor immunity.

HLA-G expressing NK cell subset with suppressive properties is expanded in breast cancer (TUM10P.1043)

NK cells were considered traditionally as cytotoxic effector cells rapidly killing infected and transformed cells. Recently, NK cells have been shown to act as potential regulatory cells interacting with various components of the immune system. HLA-G is an important immune-regulatory molecule.There is evidence that HLA-G expression contributes to escape of malignant cells from immune recognition and destruction by down-regulation of the immune response. Immunosuppressive T cells expressing HLA-G have been recently reported. In healthy donors, we have found a subset of circulating NK cells that constitutively express HLA-G (4.5±1.3, n=11), which occurs more frequently among CD57- than CD57+ NK cells. They are enhanced in response to PHA stimulation and enriched with IL-10- and TGF-β-producing NK cells. HLA-G+ NK do not show cytotoxic activity and strongly decrease both cytotoxicity and expression of perforin, granzyme B and CD107a of HLA-G- NK cells, but do not affect IFN-γ production. HLA-G neutralization antagonized the suppressive effects, leading to a 88% restoration of cytotoxic capacity of HLA-G- NK cells. In breast cancer patients, an increased number of circulating HLA-G+NK cells compared to healthy women (6.8±1.8, n=21; 4.0±1.1, n=6; p=0.001) has been detected. Obtained data suggest that increased number of suppressive HLA-G+ NK cells may be included into cohort of immunosuppressive cells mediating escape of NK-sensitive tumor cells from cytolysis.

IL-22-secreting Th22 and IFN-γ-secreting Th17 cells in Behçet's disease

OBJECTIVE

Behçet's disease (BD) is a systemic inflammatory disease with unknown etiology. Studies have shown that some T helper (Th) 1-associated cytokines have role in the inflammation of BD. The CD4(+) Th cells can be differentiated into Th1, Th2, Th17 and Th22 secrete different cytokines to regulate immune system. In this study, cytokine secretion of Th subsets in BD was investigated.

METHODS

The study group consisted of 26 BD patients with mucocutaneous involvement and 12 healthy subjects. Lymphocyte subpopulations, IL-5, IL-10, IL-17, IL-22 and IFN-γ secretion of CD4(+) T and Foxp3(+) Treg cells were determined by flow cytometry.

RESULTS

Compared with healthy subjects, Th1 (IL-17A(-)IL-22(-)IFN-γ(+)), Th22 (IL-17A(-)IL-22(+)IFN-γ) and IL-17A(+)IFN-γ(+)-secreting cells were significantly increased, and the percentage of Treg cells were dramatically reduced in BD patients. The frequency of recurrent oral ulcers was associated with increased Th22 cells.

CONCLUSIONS

Our study describes an association between Th22 cell subset and IL-17A(+) IFNγ(+)-secreting cells with mucocutaneous BD. These findings revealed that reduced levels of Tregs and increased levels of Th1 and Th22 cells as well as Th17/Th1 cells might be associated with the pathogenesis of BD.

Evidence for an association between tumor necrosis factor-alpha levels and lithium response

BACKGROUND

The role of inflammation in bipolar disorder has recently emerged as a potential pathophysiological mechanism. Tumor necrosis factor-alpha (TNF-α) modulation may represent a pathogenic molecular target and a biomarker for staging bipolar disorder. In this context, the possible association between lithium response and TNF-α level was examined.

METHODS

Sixty euthymic bipolar patients receiving lithium therapy were recruited for assessment of TNF-α level. The ALDA lithium response scale (LRS) was used to evaluate longitudinal lithium response in bipolar patients, using cut-offs of poor response, partial response and good response. TNF-α level was assessed using enzyme-linked immunosorbent assay.

RESULTS

There was a significant increase in TNF-α level in patients with poor lithium response compared to those with good response, also after controlling for a range of potential confounders (adjusted effect size: 0.47, p=0.011). Partial response showed a directionally similar, but attenuated and statistically inconclusive association (adjusted effect size: 0.16, p=0.326).

LIMITATIONS

Assessment of response was retrospective and natural course cannot be separated easily from treatment response in an observational design. Selection of additional inflammatory markers could provide for a better understanding of underlying immune changes.

CONCLUSIONS

This study strengthens the hypothesis that TNF-α level may mark or mediate lithium response, and that continuous immune imbalance in poor lithium responders may occasion treatment resistance. Further investigation of immune alterations in treatment-resistant bipolar patients may be productive.

Plasma concentrations of soluble cytokine receptors in euthymic bipolar patients with and without subsyndromal symptoms

BACKGROUND

Current evidence suggests that high concentrations of pro-inflammatory markers are associated with bipolar disorder characterized by severe impairment during inter-episodic periods, reduced treatment response and persistent subsyndromal symptoms. We tested whether persistent subsyndromal symptoms in euthymic bipolar patients were associated with markers of an ongoing chronic pro-inflammatory process.

METHODS

Forty-five euthymic bipolar patients (22 with subsyndromal symptoms (BD+) and 23 without subsyndromal symptoms (BD-) and 23 well controls (WC) were recruited for assessment of soluble tumor necrosis factor receptor-1 (sTNF-R1), soluble interleukin-6 receptor (sIL-6R) and soluble interleukin-2 receptor (sIL-2R) concentrations. Soluble cytokine receptor concentrations were assessed using enzyme-linked immunosorbent assay.

RESULTS

In comparison to WC, sTNF-R1 concentration was higher in both BD- and BD+ (age and sex adjusted standardized β, respectively: β = 0.34, p = 0.012 and β = 0.41, p = 0.003). Similarly, compared to WC, sIL-6R concentration was higher in both BD- and BD+ (age and sex adjusted standardized β, respectively: β = 0.44, p = 0.001 and β = 0.37, p = 0.008). There was no difference between BD- and BD+ in the concentration of either sTNF-R1 or sIL-6R; plasma concentration of sIL-2R was not analyzed as 75% percent of the samples were non-detectable.

CONCLUSIONS

Although bipolar patients present with a pro-inflammatory shift compared to well controls, subsyndromal symptoms are not associated with additive increasing effects. Longitudinal studies with larger samples are required to clarify the relationship between illness course and inflammatory markers in bipolar disorder.

Cytokine levels in euthymic bipolar patients

BACKGROUND

The pathophysiology of bipolar disorder is not thoroughly understood. Several studies have investigated the possible role of cytokines in psychiatric disorders, based on their role in neuro-immune modulation; however, findings in studies on bipolar disorder remain limited and contradictory, and most studies have focused on either manic or depressive episodes. These studies suggest that both manic and depressive episodes could be pro-inflammatory states. The present study aimed to determine whether there are enduring differences in cytokine levels-unrelated to the effects of medication-between euthymic bipolar patients and healthy controls.

METHODS

The study included 31 euthymic bipolar patients-16 medication-free (MF) and 15 on lithium monotherapy (LM) and 16 healthy volunteers in whom serum cytokine levels were measured. The 3 groups were homogenous in terms of age, gender, and ethnicity. IFN-γ, TNF-α, IL-2, IL-4, IL-5, and IL-10 levels were measured in all groups using flow cytometry.

RESULTS

There were no differences in cytokine levels between MF euthymic bipolar patients and healthy controls. TNF-α and IL-4 levels in LM euthymic bipolar patients were higher than in both the MF euthymic bipolar patients and controls.

LIMITATIONS

The small and strictly selected study sample could limit the generalizability of the findings.

CONCLUSIONS

Cytokine production in MF euthymic bipolar patients was similar to that in healthy controls. The present study shows that the pro-inflammatory state resolves in euthymia and that lithium had an influence on the cytokine profile, which could create a confounding factor while investigating disease- related immunopathology of bipolar disorder.