Imbalanced IL-1B and IL-18 Expression in Sézary Syndrome.

Sézary syndrome (SS) is a rare and aggressive type of cutaneous T-cell lymphoma, with an abnormal inflammatory response in affected skin. The cytokines IL-1B and IL-18, as key signaling molecules in the immune system, are produced in an inactive form and cleave to the active form by inflammasomes. In this study, we assessed the skin, serum, peripheral mononuclear blood cell (PBMC) and lymph-node samples of SS patients and control groups (healthy donors (HDs) and idiopathic erythroderma (IE) nodes) to investigate the inflammatory markers IL-1B and IL-18 at the protein and transcript expression levels, as potential markers of inflammasome activation. Our findings showed increased IL-1B and decreased IL-18 protein expression in the epidermis of SS patients; however, in the dermis layer, we detected increased IL-18 protein expression. In the lymph nodes of SS patients at advanced stages of the disease (N2/N3), we also detected an enhancement of IL-18 and a downregulation of IL-1B at the protein level. Moreover, the transcriptomic analysis of the SS and IE nodes confirmed the decreased expression of IL1B and NLRP3, whereas the pathway analysis indicated a further downregulation of IL1B-associated genes. Overall, the present findings showed compartmentalized expressions of IL-1B and IL-18 and provided the first evidence of their imbalance in patients with Sézary syndrome.

Immunological imbalance in microcephalic children with congenital Zika virus syndrome.

Microcephalic children due congenital Zika virus syndrome (CZS) present neurological symptoms already well described. However, several other alterations can also be observed. Here, we aimed to evaluate the immune system of microcephaly CZS children. We showed that these patients have enlarged thymus, spleen and cervical lymph nodes, analysed by ultrasound and compared to the reference values for healthy children. In the periphery, they have an increase in eosinophil count and morphological alterations as hypersegmented neutrophils and atypical lymphocytes, even in the absence of urinary tract infections, parasitological infections or other current symptomatic infections. Microcephalic children due CZS also have high levels of IFN-γ, IL-2, IL-4, IL-5 and type I IFNs, compared to healthy controls. In addition, this population showed a deficient cellular immune memory as demonstrated by the low reactivity to the tuberculin skin test even though they had been vaccinated with BCG less than 2 years before the challenge with the PPD. Together, our data demonstrate for the first time that CZS can cause alterations in primary and secondary lymphoid organs and also alters the morphology and functionality of the immune system cells, which broadens the spectrum of CZS symptoms. This knowledge may assist the development of specific therapeutic and more efficient vaccination schemes for this population of patients.

The Role of Tumor Microenvironment in the Pathogenesis of Sézary Syndrome.

Sézary syndrome is an aggressive leukemic variant of cutaneous T-cell lymphomas, characterized by erythroderma, lymphadenopathy, and peripheral blood involvement by CD4+ malignant T-cells. The pathogenesis of Sézary syndrome is not fully understood. However, the course of the disease is strongly influenced by the tumor microenvironment, which is altered by a combination of cytokines, chemokines, and growth factors. The crosstalk between malignant and reactive cells affects the immunologic response against tumor cells causing immune dysregulation. This review focuses on the interaction of malignant Sézary cells and the tumor microenvironment.

Obesity as a risk factor for COVID-19: an overview.

The current coronavirus disease-2019 (COVID-19) pandemic presents a huge challenge for health-care systems worldwide. Many different risk factors are associated with disease severity, such as older age, diabetes, hypertension, and most recently obesity. The incidence of obesity has been on the rise for the past 25 years, reaching over 2 billion people throughout the world, and obesity itself could be considered a pandemic. In this review, we summarize aspects involved with obesity, such as changes in the immune response, nutritional factors, physiological factors, and the gut-lung axis, that impact the viral response and the COVID-19 prognosis.

Proinflammatory and regulatory mechanisms in allergic contact dermatitis caused by methylchloroisothiazolinone and methylisothiazolinone.

BACKGROUND: Methylchloroisothiazolinone (MCI) and methylisothiazolinone (MI) are the cause of an increasing number of contact allergies. Understanding the mechanisms by which MCI/MI induces proinflammatory and regulatory factors production is necessary to understand the outcome of allergic contact dermatitis (ACD). OBJECTIVES: To evaluate the dysfunction of proinflammatory cytokines and regulatory factors in the positive MCI/MI patch test at the transcriptional and protein expression levels. Moreover, to analyse the cytokines production induced by MI in peripheral blood mononuclear cells (PBMCs). MATERIALS AND METHODS: The selected patients had positive MCI/MI patch test results. The expression of proinflammatory factors was evaluated by q-PCR and immunochemistry at 48 hours of positive MCI/MI patch test. The MCI/MI- or MI- induced secretion of IL-1ß, TNF and IL-6 by PBMC was analysed by flow cytometry. RESULTS: The results showed a decreased TLR4 expression with upregulated IL6, FOXP3, IL10 and TGFß mRNA expression as assessed by q-PCR at the site of the MCI/MI skin reaction. We detected increased protein levels of TLR4, FOXP3 and IL-10 in the dermis layer in the ACD reaction by immunocitochemistry. Moreover, MCI/MI induced proinflammatory cytokine production by PBMC through the NF-κB signalling pathway. CONCLUSION: Considering the altered innate immune response triggered by MCI/MI sensitization, these findings indicate that the regulatory process at the induction phase of ACD is a crucial mechanism. Given the increase in occupational and domestic exposure to MCI/MI, the underlying immunological mechanisms should be understood.

Zika Virus Infects Newborn Monocytes Without Triggering a Substantial Cytokine Response.

Zika virus (ZIKV) is a clinically important flavivirus that can cause neurological disturbances in newborns. Here, we investigated comparatively the outcome of in vitro infection of newborn monocytes by ZIKV. We observed that neonatal cells show defective production of interleukin 1ß, interleukin 10, and monocyte chemoattractant protein 1 in response to ZIKV, although they were as efficient as adult cells in supporting viral infection. Although CLEC5A is a classical flavivirus immune receptor, it is not essential to the cytokine response, but it regulates the viral load only in adult cells. Greater expression of viral entry receptors may create a favorable environment for viral invasion in neonatal monocytes. We are the first to suggest a role for CLEC5A in human monocyte infectivity and to show that newborn monocytes are interesting targets in ZIKV pathogenesis, owing to their ability to carry the virus with only a partial triggering of the immune response, creating a potentially favorable environment for virus-related pathologies in young individuals.

Impact of Retinoic Acid on Immune Cells and Inflammatory Diseases.

Vitamin A metabolite retinoic acid (RA) plays important roles in cell growth, differentiation, organogenesis, and reproduction and a key role in mucosal immune responses. RA promotes dendritic cells to express CD103 and to produce RA, enhances the differentiation of Foxp3+ inducible regulatory T cells, and induces gut-homing specificity in T cells. Although vitamin A is crucial for maintaining homeostasis at the intestinal barrier and equilibrating immunity and tolerance, including gut dysbiosis, retinoids perform a wide variety of functions in many settings, such as the central nervous system, skin aging, allergic airway diseases, cancer prevention and therapy, and metabolic diseases. The mechanism of RA is interesting to explore as both a mucosal adjuvant and a combination therapy with other effective agents. Here, we review the effect of RA on innate and adaptive immunity with a special emphasis on inflammatory status.

Role of Histamine in Modulating the Immune Response and Inflammation.

Inflammatory mediators, including cytokines, histamine, bradykinin, prostaglandins, and leukotrienes, impact the immune system, usually as proinflammatory factors. Other mediators act as regulatory components to establish homeostasis after injury or prevent the inflammatory process. Histamine, a biogenic vasoactive amine, causes symptoms such as allergies and has a pleiotropic effect that is dependent on its interaction with its four histamine receptors. In this review, we discuss the dualistic effects of histamine: how histamine affects inflammation of the immune system through the activation of intracellular pathways that induce the production of inflammatory mediators and cytokines in different immune cells and how histamine exerts regulatory functions in innate and adaptive immune responses. We also evaluate the interactions between these effects.

Chemokine, cytokine and type I interferon production induced by Toll-like receptor activation in common variable immune deficiency.

Common variable immunodeficiency (CVID) is the most common symptomatic primary antibody deficiency and is associated with recurrent infections and chronic inflammatory diseases. We evaluated the ability of Toll-like receptor (TLR) ligands to induce secretion of chemokines, cytokines and type I interferons by peripheral blood mononuclear cells (PBMCs) from CVID patients. High levels of CXCL10, CCL2, CXCL9, CCL5, CXCL8, and IL-6 were detected in sera of CVID patients compared with healthy controls. Increased chemokine levels were observed in unstimulated PBMCs, but after stimulation with TLR2 and TLR4 agonists, equivalent chemokine and pro-inflammatory cytokine secretion, as in healthy controls, was observed, whereas TLR4 agonist induced a decreased secretion of CCL2 and CXCL8 and increased secretion of TNF. Decreased IFN-α secretion induced by TLR7/TLR8 activation was observed in CVID, which was recovered with TLR9 signaling. Our findings revealed that TLR9 activation has an adjuvant effect on the altered type I response in CVID.

Activation of myeloid dendritic cells, effector cells and regulatory T cells in lichen planus.

BACKGROUND: Lichen planus (LP) is a chronic mucocutaneous inflammatory disease. Evaluating the balance between regulatory T cells and effector T cells could be useful for monitoring the proinflammatory profile of LP. Therefore, this study aimed to assess populations of dendritic cells (DCs) and regulatory and effector T cells in peripheral blood samples collected from patients with LP to evaluate the polyfunctionality of T cells upon toll-like receptor (TLR) activation. METHODS: Peripheral blood mononuclear cells collected from 18 patients with LP and 22 healthy control subjects were stimulated with agonists of TLR4, TLR7, TLR7/TLR8 or TLR9. Frequencies of circulating IFN-α(+) plasmacytoid DCs (pDCs); TNF-α(+) myeloid DCs (mDCs); regulatory T cells (Tregs); and IL-17-, IL-10-, IL-22-, TNF-, and IFN-γ-secreting T cells were assessed via flow cytometry. RESULTS: The frequencies of regulatory CD4(+) and CD8(+)CD25(+)Foxp3(+)CD127(low/-) T cells and TNF-α(+) mDCs were induced following activation with TLR4, TLR7 and TLR8 agonists in the LP group. Moreover, increased baseline frequencies of CD4(+)IL-10(+) T cells and CD8(+)IL-22(+) or IFN-γ(+)T cells were found. In the LP group, TLR4 activation induced an increased frequency of CD4(+)IFN-γ(+) T cells, while TLR7/8 and staphylococcal enterotoxin B (SEB) activation induced an increased frequency of CD8(+) IL-22(+) T cells. An increased frequency of polyfunctional CD4(+) T cells that simultaneously secreted 3 of the evaluated cytokines (not including IL-10) was verified upon TLR7/8/9 activation, while polyfunctional CD8(+) T cells were already detectable at baseline. CONCLUSIONS: TLR-mediated activation of the innate immune response induced the production of proinflammatory mDCs, Tregs and polyfunctional T cells in patients with LP. Therefore, TLR activation has an adjuvant role in inducing both innate and adaptive immune responses.

Impaired CD8(+) T cell responses upon Toll-like receptor activation in common variable immunodeficiency.

BACKGROUND: Infections caused by bacteria or viruses are frequent in common variable immunodeficiency (CVID) patients due to antibody deficiencies, which may be associated with altered T cell function. CVID patients are frequently in contact with pathogen-associated molecular patterns (PAMPs), leading to the activation of innate immunity through Toll-like receptors (TLR) affecting T cell activation. We evaluated the effect of TLR activation on T cells in CVID patients undergoing intravenous immunoglobulin (IVIg) replacement using synthetic ligands. METHODS: Expression of exhaustion, activation and maturation markers on T cells from peripheral blood as well as regulatory T cells and follicular T cells in peripheral blood mononuclear cells (PBMCs) from CVID and healthy individuals were evaluated by flow cytometry. PBMCs cultured with TLR agonists were assessed for intracellular IFN-γ, TNF, IL-10, IL-17a or IL-22 secretion as monofunctional or polyfunctional T cells (simultaneous cytokine secretion) by flow cytometry. RESULTS: We found increased expression of the exhaustion marker PD-1 on effector memory CD4(+) T cells (CD45RA(-)CCR7(-)) in the peripheral blood and increased expression of CD38 in terminally differentiated CD8(+) T cells (CD45RA(+)CCR7(-)). Furthermore, a decreased frequency of naïve regulatory T cells (CD45RA(+)Foxp3(low)), but not of activated regulatory T cells (CD45RA(-)Foxp3(high)) was detected in CVID patients with splenomegaly, the non-infectious manifestation in this CVID cohort (43.7 %). Moreover, the frequency of peripheral blood follicular helper T cells (CD3(+)CD4(+)CXCR5(+)PD-1(+)ICOS(+)) was similar between the CVID and control groups. Upon in vitro TLR3 activation, a decreased frequency of CD8(+) T cells secreting IFN-γ, IL-17a or IL-22 was detected in the CVID group compared to the control group. However, a TLR7/TLR8 agonist and staphylococcal enterotoxin B induced an increased Th22/Tc22 (IL-22(+), IFN-γ(-), IL-17a(-)) response in CVID patients. Both TLR2 and TLR7/8/CL097 activation induced an increased response of CD4(+) T cells secreting three cytokines (IL-17a, IL-22 and TNF)in CVID patients, whereas CD8(+) T cells were unresponsive to these stimuli. CONCLUSION: The data show that despite the unresponsive profile of CD8(+) T cells to TLR activation, CD4(+) T cells and Tc22/Th22 cells are responsive, suggesting that activation of innate immunity by TLRs could be a strategy to stimulate CD4(+) T cells in CVID.

Immunity in the spleen and blood of mice immunized with irradiated Toxoplasma gondii tachyzoites.

Toxoplasma gondii infection induces a strong and long-lasting immune response that is able to prevent most reinfections but allows tissue cysts. Irradiated, sterilized T. gondii tachyzoites are an interesting vaccine, and they induce immunity that is similar to infection, but without cysts. In this study, we evaluated the cellular immune response in the blood and spleen of mice immunized with this preparation by mouth (v.o.) or intraperitoneally (i.p.) and analyzed the protection after challenge with viable parasites. BALB/c mice were immunized with three i.p. or v.o. doses of irradiated T. gondii tachyzoites. Oral challenge with ten cysts of the ME-49 or VEG strain at 90 days after the last dose resulted in high levels of protection with low parasite burden in the immunized animals. There were higher levels of specific IgG, IgA and IgM antibodies in the serum, and the i.p. immunized mice had higher levels of the high-affinity IgG and IgM antibodies than the orally immunized mice, which had more high-affinity IgA antibodies. B cells (CD19(+)), plasma cells (CD138(+)) and the CD4(+) and CD8(+) T cell populations were increased in both the blood and spleen. Cells from the spleen of the i.p. immunized mice also showed antigen-induced production of interleukin-10 (IL-10), interferon gamma (IFN-γ) and interleukin 4 (IL-4). The CD4(+) T cells, B cells and likely CD8(+) T cells from the spleens of the i.p. immunized mice proliferated with a specific antigen. The protection was correlated with the spleen and blood CD8(+) T cell, high-affinity IgG and IgM and antigen-induced IL-10 and IL-4 production. Immunization with irradiated T. gondii tachyzoites induces an immune response that is mediated by B cells and CD4(+) and CD8(+) T cells, with increased humoral and cellular immune responses that are necessary for host protection after infection. The vaccine is similar to natural infection, but free of tissue cysts; this immunity restrains infection at challenge and can be an attractive and efficient model for vaccine development in toxoplasmosis.

Up-regulation of Proinflammatory Genes and Cytokines Induced by S100A8 in CD8+ T Cells in Lichen Planus.

Lichen planus (LP) is a chronic inflammatory mucocutaneous disease. The inflammatory status of LP may be related to S100A8 (myeloid-related protein 8; MRP8) activation of cytotoxic cells. The aims of this study were to evaluate S100A8 expression in skin lesions and the in vitro effects of S100A8 on CD8+ T cells and natural killer (NK) cells in LP. Increased levels of S100A8/S100A9 were detected in the skin lesions as well as in the sera of subjects with LP. S100A8 expression induced an increased cytotoxic response by peripheral blood CD8+CD107a+ T cells as well as by NK CD56bright cells in patients with LP. Increased expression of interleukin (IL)-1ß, tumour necrosis factor (TNF) and IL-6 in the CD8+ T cells of patients with LP was induced by S100A8, in contrast to the control group that produced IL- 10 and interferon (IFN) type I genes. These data suggest that, in individuals with LP, S100A8 may exert distinct immunomodulatory and cytotoxicity functions.

State of the Art on the Role of Staphylococcus aureus Extracellular Vesicles in the Pathogenesis of Atopic Dermatitis.

Atopic dermatitis (AD) is a chronic and relapsing inflammatory cutaneous disease. The role of host defense and microbial virulence factors in Staphylococcus aureus skin colonization, infection, and inflammation perpetuation in AD remains an area of current research focus. Extracellular vesicles (EV) mediate cell-to-cell communication by transporting and delivering bioactive molecules, such as nucleic acids, proteins, and enzymes, to recipient cells. Staphylococcus aureus spontaneously secretes extracellular vesicles (SA-derived EVs), which spread throughout the skin layers. Previous research has shown that SA-derived EVs from AD patients can trigger cytokine secretion in keratinocytes, shape the recruitment of neutrophils and monocytes, and induce inflammatory AD-type lesions in mouse models, in addition to their role as exogenous worsening factors for the disease. In this review article, we aim to examine the role of SA-derived EVs in AD physiopathology and its progression, highlighting the recent research in the field and exploring the potential crosstalk between the host and the microbiota.

Methotrexate for refractory adult atopic dermatitis leads to alterations in cutaneous IL-31 and IL-31RA expression.

BACKGROUND: Methotrexate (MTX) is an alternative treatment for patients with moderate/severe atopic dermatitis (AD). OBJECTIVE: The authors evaluated the effect of MTX on the cutaneous expression of cytokines and chemokines that are involved in the inflammatory response in adult AD patients who received treatment with methotrexate for 24 weeks. METHODS: The authors conducted a prospective single-institution cohort study with 12 adults with moderate/severe AD who received oral MTX (15 mg/wk for 24 wks) and 10 non-atopic matched controls. The comparison was made of skin biopsies of lesional and non-lesional skin, pre- and post MTX treatment. The authors analyzed mean epidermal thickness and expression of IL-31, IL-31RA, OSMR, TSLP, Ki67, IL-4 mRNA, IL-6, IL-10, TNF-α, IFN-γ, TARC, and CCL-22. RESULTS: There was a reduction in mean epidermal thickness (p = 0.021), an increase in IL-31RA expression (immunohistochemistry) in the epidermis (p = 0.016) and a decrease in IL-31 gene expression (p = 0.019) on lesional AD skin post-MTX treatment. No significant changes in the cutaneous expression of the other evaluated markers were identified. STUDY LIMITATIONS: Small sample size and limited length of follow-up. CONCLUSIONS: Treatment with MTX in adults with moderate/severe AD reduced epidermal hyperplasia and changed the cutaneous expression of inflammatory cytokines and receptors that are mainly related to pruritus, including IL-31 and IL-31RA. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03327116.

Cutaneous inflammasome driving ASC / gasdermin-D activation and IL-1ß-secreting macrophages in severe atopic dermatitis.

Atopic dermatitis (AD) is an inflammatory skin disease with intense pruritus, and chronic skin colonization by Staphylococcus aureus. To understand the inflammatory status in AD, we investigated the inflammasome complex, that activates ASC (Apoptosis-associated speck-like protein containing a CARD), caspase-1 and GSDMD (gasdermin-D), and production of IL-1ß and IL-18. We aimed to evaluate the expression of the inflammasome pathway in the skin of adults with AD. Thirty patients with moderate to severe AD and 20 healthy controls were enrolled in the study. We performed the analysis of the inflammasome components NLRP1, NLRP3, AIM-2, IL-1ß, IL-18, Caspase-1, ASC, GSDMD, and CD68 expression (macrophage marker) by immunohistochemistry and immunofluorescence. The main findings included increased expression of NLRP3, NLRP1 and AIM-2 at dermal level of severe AD; augmented IL-18 and IL-1ß expression at epidermis of moderate and severe patients, and in the dermis of severe AD; augmented expression of ASC, caspase-1 and GSDMD in both epidermis and dermis of moderate and severe AD. We detected positive correlation between caspase-1, GSDMD and IL-1ß (epidermis) and caspase-1 (dermis) and AD severity; NLRP3, AIM-2 and IL-1ß, and NLRP3 with IL-18 in the epidermis; ASC, GSDMD and IL-1ß, and NLRP3, AIM-2, caspase-1, and IL-18 in the dermis. We also evidenced the presence of CD68+ macrophages secreting GSDMD, ASC and IL-1ß in moderate and severe AD. Cutaneous macrophages, early detected in moderate AD, have its role in the disease inflammatory mechanisms. Our study indicates a canonical activation pathway of inflammasomes, reinforced by the chronic status of inflammation in AD. The analysis of the inflammasome complex evidenced an imbalance in its regulation, with increased expression of the evaluated components, which is remarkably in severe AD, emphasizing its relevance as potential disease biomarkers and targets for immunomodulatory interventions.

Outlining the skin-homing and circulating CLA+NK cells in patients with severe atopic dermatitis.

Atopic dermatitis (AD) is a complex, multifactorial skin disease, characterized by pruritus and predominant Th2 inflammation. Innate immune cells may play a role in AD development and are composed of granulocytes, macrophages, innate-like T cells, and innate lymphoid cells. This study investigates the phenotypic and functional profile of circulating CLA+ natural killer (NK) cells and its role in the skin-homing to NK cells infiltrated in adults' skin with AD. We selected 44 AD patients and 27 non-AD volunteers for the study. The results showed increased frequencies of both CLA+CD56bright and CLA+CD56dim NK cell populations in the peripheral blood, mainly in severe AD patients. Upon SEB stimulation, we observed an augmented percentage of CLA+CD56dim NK cells expressing CD107a, IFN-γ, IL-10, and TNF, reinforcing the role of staphylococcal enterotoxins in AD pathogenesis. Additionally, we demonstrated increased dermal expression of both NK cell markers NCAM-1/CD56 and pan-granzyme, corroborating the skin-homing, mostly in severe AD. Further studies are necessary to elucidate the potential role of NK cells in the chronification of the inflammatory process in AD skin, as well as their possible relationship with staphylococcal enterotoxins, and as practicable therapeutic targets.

Enhanced immunogenicity and protective efficacy in mice following a Zika DNA vaccine designed by modulation of membrane-anchoring regions and its association to adjuvants.

Zika virus (ZIKV) is a re-emerging pathogen with high morbidity associated to congenital infection. Despite the scientific advances since the last outbreak in the Americas, there are no approved specific treatment or vaccines. As the development of an effective prophylactic approach remains unaddressed, DNA vaccines surge as a powerful and attractive candidate due to the efficacy of sequence optimization in achieving strong immune response. In this study, we developed four DNA vaccine constructs encoding the ZIKV prM/M (pre-membrane/membrane) and E (envelope) proteins in conjunction with molecular adjuvants. The DNA vaccine candidate (called ZK_ΔSTP), where the entire membrane-anchoring regions were completely removed, was far more immunogenic compared to their counterparts. Furthermore, inclusion of the tPA-SP leader sequence led to high expression and secretion of the target vaccine antigens, therefore contributing to adequate B cell stimulation. The ZK_ΔSTP vaccine induced high cellular and humoral response in C57BL/6 adult mice, which included high neutralizing antibody titers and the generation of germinal center B cells. Administration of ZK-ΔSTP incorporating aluminum hydroxide (Alum) adjuvant led to sustained neutralizing response. In consistency with the high and long-term protective response, ZK_ΔSTP+Alum protected adult mice upon viral challenge. Collectively, the ZK_ΔSTP+Alum vaccine formulation advances the understanding of the requirements for a successful and protective vaccine against flaviviruses and is worthy of further translational studies.

Corrigendum: Enhanced immunogenicity and protective efficacy in mice following a Zika DNA vaccine designed by modulation of membrane-anchoring regions and its association to adjuvants.

[This corrects the article DOI: 10.3389/fimmu.2024.1307546.].