Powerful anti-inflammatory action of luteolin: Potential increase with IL-38.

Luteolin belongs to the flavone family originally present in some fruits and vegetables, including olives, which decrease intracellular levels of reactive oxygen species (ROS) following the activation of various stimuli. Luteolin inhibits inflammation, a complex process involving immune cells that accumulate at the site of infectious or non-infectious injury, with alteration of the endothelium leading to recruitment of leukocytes. Cytokines have been widely reported to act as immune system mediators, and IL-1 family members evolved to assist in host defense against infections. Interleukin (IL)-1 and Toll-like receptor (TLR) are involved in the innate immunity in almost all living organisms. After being synthesized, IL-1 induces numerous inflammatory mediators including itself, other pro-inflammatory cytokines/chemokines, and arachidonic acid products, which contribute to the pathogenesis of immune diseases. Among the 11 members of the IL-1 family, there are two new cytokines that suppress inflammation, IL-37 and IL-38. IL-38 binds IL-36 receptor (IL-1R6) and inhibits several pro-inflammatory cytokines, including IL-6, through c-Jun N-terminal kinase (JNK) induction and reducing AP1 and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) activity, alleviating inflammatory diseases. Therefore, since luteolin, IL-37 and IL-38 are all anti-inflammatory molecules with different signaling pathways, it is pertinent to recommend the combination of luteolin with these anti-inflammatory cytokines in inflammation.

Luteolin, inflammation and cancer: Special emphasis on gut microbiota.

Luteolin belongs to the family of flavonoids, which have anti-inflammatory functions, potentially useful in a clinical context, particularly for patients suffering from cancer, neuropsychiatric disorders, inflammatory bowel conditions. This peculiarity has been used for centuries in traditional Chinese medicine, for many different diseases. Its anti-inflammatory effects might be particularly relevant in cancer, with some studies reporting anti-angiogenesis, anti-metastatic, and apoptotic effects on cancer cells by luteolin and other flavonoids. In this article, we analyze the anti-inflammatory role of luteolin, discussing the pathways it may act on. We will then discuss the possible role of microbiota in inflammatory modulation by luteolin. Finally, the possible therapeutic applications of luteolin's anti-inflammatory properties will be analyzed, with a particular focus on cancer.

COVID-19 and hepatic involvement: The liver as a main actor of the pandemic novel.

In the natural history of SARS-CoV-2 infection, liver injury is frequent but quite mild and it is defined as any liver damage occurring during disease progression and treatment of infection in patients with or without pre-existing liver diseases. The underlying mechanisms for hepatic injury in patients with COVID-19 are still unclear but the liver damage in SARS-CoV-2 infection seems to be directly caused by virus-induced cytopathic effects. In this review, we will summarize all data of updated literature, regarding the relationship between SARS-CoV-2 infection, acute response and liver involvement. An overview will be given on liver injury, liver transplant and the possible consequences of COVID-19 in patients with pre-existing liver diseases.

Nickel allergy in lipid transfer protein sensitized patients: Prevalence and clinical features.

Nickel (Ni), the main responsible for allergic contact dermatitis worldwide, is also involved in systemic condition called "Systemic Nickel Sulfate Allergy Syndrome (SNAS)." Likewise, IgE-mediated reactivity to Lipid Transfer Protein (LTP) represents the main cause of primary food allergy in adults of Mediterranean countries. We evaluated the prevalence of SNAS in LTP allergic patients and investigated patients' clinical features with double sensitization (LTP and Ni). A retrospective, single-center, observational study was conducted performing a complete allergological work-up including: (1) skin prick tests; (2) serum specific IgE for plant food allergens and rPru p3 (LTP); (3) patch test with 5% Ni sulfate in petrolatum. We enrolled 140 LTP allergic patients of which 36 patients (25.7% of sample) showed additional positivity to Ni patch test. Patients with double sensitization were more frequently females and reported fewer cutaneous symptoms. Higher values of sIgE for peach, apple, peanut, walnut, grain, corn, and garlic were found in LTP allergic patients, while higher values for hazelnut in the other subgroup. The prevalence of SNAS in the LTP allergic population is clinically relevant. Moreover, the clinical and immunological profiles of patients with double sensitization were different from patients monosensitized to LTP.

Interleukin-6 in Rheumatoid Arthritis.

The role of interleukin (IL)-6 in health and disease has been under a lot of scrutiny in recent years, particularly during the recent COVID-19 pandemic. The inflammatory pathways in which IL-6 is involved are also partly responsible of the development and progression of rheumatoid arthritis (RA), opening interesting perspectives in terms of therapy. Anti-IL-6 drugs are being used with variable degrees of success in other diseases and are being tested in RA. Results have been encouraging, particularly when anti-IL-6 has been used with other drugs, such as metothrexate (MTX). In this review we discuss the main immunologic aspects that make anti-IL-6 a good candidate in RA, but despite the main therapeutic options available to target IL-6, no gold standard treatment has been established so far.

New insight into systemic mastocytosis mediated by cytokines IL-1ß and IL-33: Potential inhibitory effect of IL-37.

Systemic mastocytosis in various forms is characterized by mast cell (MC) infiltration of the bone marrow and other internal organs. The most common form is the indolent one with life expectancy similar to the normal population, while the systemic aggressive myeloproliferative type presents serious damage to various organs and is associated with mature and immature atypical mast cells. In systemic mastocytosis patients, MCs could be activated with consequent severe anaphylactic reactions, along with other symptoms. MCs, which are reactive to a variety of external factors such as allergens or other inflammatory or physical stimuli, derive from pluripotent cellular progenitor CD34+ which leaves the bone marrow as CD34+/CD17+ for implantation in the tissues where they reach maturation. MCs participate in the innate and adaptive immune system where they play a role in host defense. Activation of MCs occurs through the binding of IgE to FcεRI receptor, and initiates the phosphorylation and activation of the p38 tyrosine MAP kinase. After various reactions there is a subsequent translation and generation of pro-inflammatory cytokines which are strongly linked to allergic inflammation and mastocytosis. Human cytokine interleukin-37 (IL-37), a unique IL-1ß family member, has strong protective and anti-inflammatory properties, influencing cellular metabolism. We investigated the effect of IL-37 on inflammation in mastocytosis and report that the hematopoietic expression of IL-37 can reduce the inflammatory state in this disease. IL-37 limits excessive inflammation, which suggests that IL-37 may be beneficial to the metabolic and inflammatory process and is a candidate as a potential new therapeutic agent.

Mast Cells Mediate Rheumatoid Arthritis-Inhibitory Role of IL-37.

Rheumatoid arthritis (RA) is an autoimmune, chronic inflammatory, disabling arthropathy that severely affects the quality of life. This disease involves several proinflammatory cytokines, including interleukin (IL)-1ß and tumor necrosis factor (TNF). IL-1 induces TNF and vice versa, causing joint damage and cartilage degradation. Current antirheumatic drugs may be effective, but they possess many unwanted side effects. In recent years, inhibitors of proinflammatory cytokines have increasingly entered mainstream clinical practice. Recent evidence indicates that IL-37, which has anti-inflammatory properties, is increased in the serum and is released from white blood cells in patients with RA. Mast cells (MCs), stimulated by the neuropeptide substance P (SP) and IL-33, release IL-1ß and TNF. Recent evidence indicates that large amounts of IL-1ß and TNF can be released from human MCs, which also secrete CXCL8, which promotes migration of immune cells, causing erosion of the bone and cartilage. Treatment with IL-37 can block the MC stimulation and release of inflammatory compounds, attenuating the severity of the disease and/or altering its progression.

Impact of Fungi on Immune Responses.

Spores and fungal fragments found in indoor and outdoor environments originate from opportunistic fungi and they can contribute to inflammatory responses, causing a broad range of symptoms. Papers were selected and reviewed with an emphasis on the molecular mechanisms involved in the effect of fungi on immune cells, especially mast cells (MCs). Fungi can bind to antibodies and complement them, allowing them to be recognized by cells of the innate immune system, including macrophages, dendritic cells, and MCs, which are then stimulated via Toll-like receptor signaling. Fungi can cause diseases mediated by MCs and aggravate allergic inflammation. Immunosuppressed subjects can be particularly susceptible to developing diseases caused by opportunistic fungi. Mold also liberates mycotoxins that could be on volatile spores and stimulate MCs to secrete pro-inflammatory cytokines/chemokines, but this mechanism is not known. Fungi can activate the immune system directly or through mycotoxins, leading to stimulation of immune cells and chronic neuroinflammatory symptoms. Some of these processes may be inhibited by the new anti-inflammatory cytokine interleukin 37.

Association between IgH enhancer hs1.2 and type 1 diabetes.

AIM: To investigate the association of alleles of the 3' immunoglobulin heavy-chain regulatory region 1 (3'RR-1) enhancer hs1.2 in patients with type 1 diabetes (T1D). METHODS: Eighty-one patients with T1D [among which 12 had concomitant coeliac disease (CD) and 25 an autoimmune thyroid disease (AITD)] were compared to 248 healthy individuals. All subjects were recruited from the same geographical area. Blood samples were collected from all patients and a nested PCR was performed to amplify the core of the 3'RR-1 and detect the alleles of the hs1.2 enhancer. RESULTS: Allele distribution in healthy individuals was significantly different when compared to that of patients with T1D (p < 0.01). Even greater differences were detected comparing allele distribution of patients with T1D alone versus those with concomitant CD, but not versus those with concomitant AITD. The frequency of *2 allele is increased by 23% in patients with T1D and CD. CONCLUSIONS: The present study establishes that the multiallelic hs1.2 enhancer of the 3'RR-1 is associated with T1D, with higher frequency when there is co-occurrence of CD. This evidence has been previously observed in other immune diseases.

Integrins: Integrating the Biology and Therapy of Cell-cell Interactions.

PURPOSE: Although the role of integrins has been described in a variety of diseases, these roles seem to be distinct. To date, no study has attempted to provide links to the various pathways by which such integrins can be involved in these diverse disease settings. The purpose of this review was to address this gap in our knowledge with the hypothesis that there is, in fact, a common pathway by which integrins may function. METHODS: This article provides an in-depth perspective on the discovery, development, and design of therapeutics that modulate cellular function by targeting integrin:ligand interactions by reviewing the literature on this subject; the review included the most recent results of clinical and subclinical studies. A MEDLINE search was conducted for articles pertaining to the various issues related to integrins, and the most relevant articles are discussed (ie, not only those published in journals with a higher impact factor). FINDINGS: It seems that the ligation of the integrins with their cognate ligands plays a major role in translating membrane dialogue into biological function. In addition, they also seem to play a major regulatory role that can enhance or inhibit biological function depending on the context within which such receptor:ligand interactions occur and the organ and tissues at which interactions occurs and is manipulated. Those studies that used statistical analyses have been included where appropriate. IMPLICATIONS: Our findings show that anti-integrin treatment has the potential to become a valid coadjuvant in the treatment of several diseases including cancer, inflammatory diseases, HIv infection and cardiovascular diseases.

Immune Modulation by Vitamin D: Special Emphasis on Its Role in Prevention and Treatment of Cancer.

PURPOSE: Vitamin D has been known to be involved in mineral and bone homeostasis for many years. In the past its main use was in treating osteoporosis and rickets. In recent years it was found that vitamin D is an immune-modulating agent and may also have a role in several diseases, including autoimmune diseases. The immune-modulating effects appear to be mediated by vitamin D interaction with the vitamin D receptor (VDR) that has transcriptional effects and is expressed on various cell types, especially those of the immune system. Immunologic and rheumatologic diseases were the first to be studied, but at the moment the spotlight is on the interactions between tumor cells and vitamin D. This review focuses on four forms of cancer that apparently benefit from a vitamin D supplementation during treatment: prostate, breast, and colorectal cancers and melanoma. Several studies reported that differences exist between white and black patients, which we discuss in the review. METHODS: We systematically searched PubMed for studies published in English. The search terms included vitamin D, cancer, breast, colorectal, prostate, and melanoma. FINDINGS AND IMPLICATIONS: Our findings show that vitamin D has the potential to become a valid coadjuvant in the treatment of cancer.

Key Role of DAMP in Inflammation, Cancer, and Tissue Repair.

PURPOSE: This review aimed to take stock of the current status of research on damage-associated molecular pattern (DAMP) protein. We discuss the Janus-faced role of DAMP molecules in inflammation, cancer, and tissue repair. The high-mobility group box (HMGB)-1 and adenosine triphosphate proteins are well-known DAMP molecules and have been primarily associated with inflammation. However, as we shall see, recent data have linked these molecules to tissue repair. HMGB1 is associated with cancer-related inflammation. It activates nuclear factor kB, which is involved in cancer regulation via its receptor for advanced glycation end-products (RAGE), Toll-like receptors 2 and 4. Proinflammatory activity and tissue repair may lead to pharmacologic intervention, by blocking DAMP RAGE and Toll like receptor 2 and 4 role in inflammation and by increasing their concentration in tissue repair, respectively. METHODS: We conducted a MEDLINE search for articles pertaining to the various issues related to DAMP, and we discuss the most relevant articles especially (ie, not only those published in journals with a higher impact factor). FINDINGS: A cluster of remarkable articles on DAMP have appeared in the literature in recent years. Regarding inflammation, several strategies have been proposed to target HMGB1, from antibodies to recombinant box A, which interacts with RAGE, competing with the full molecule. In tissue repair, it was reported that the overexpression of HMGB1 or the administration of exogenous HMGB1 significantly increased the number of vessels and promoted recovery in skin-wound, ischemic injury. IMPLICATIONS: Due to the bivalent nature of DAMP, it is often difficult to explain the relative role of DAMP in inflammation versus its role in tissue repair. However, this point is crucial as DAMP-related treatments move into clinical practice.

How the Intricate Interaction among Toll-Like Receptors, Microbiota, and Intestinal Immunity Can Influence Gastrointestinal Pathology.

The gut is able to maintain tolerance to microbial and food antigens. The intestine minimizes the number of harmful bacteria by shaping the microbiota through a symbiotic relationship. In healthy human intestine, a constant homeostasis is maintained by the perfect regulation of microbial load and the immune response generated against it. Failure of this balance may result in various pathological conditions. Innate immune sensors, such as Toll-like receptors (TLRs), may be considered an interface among intestinal epithelial barrier, microbiota, and immune system. TLRs pathway, activated by pathogens, is involved in the pathogenesis of several infectious and inflammatory diseases. The alteration of the homeostasis between physiologic and pathogenic bacteria of intestinal flora causes a condition called dysbiosis. The breakdown of homeostasis by dysbiosis may increase susceptibility to inflammatory bowel diseases. It is evident that environment, genetics, and host immunity form a highly interactive regulatory triad that controls TLR function. Imbalanced relationships within this triad may promote aberrant TLR signaling, critically contributing to acute and chronic intestinal inflammatory processes, such as in IBD, colitis, and colorectal cancer. The study of interactions between different components of the immune systems and intestinal microbiota will open new horizons in the knowledge of gut inflammation.

Heat shock protein-90 inhibitors enhance antigen expression on melanomas and increase T cell recognition of tumor cells.

In an effort to enhance antigen-specific T cell recognition of cancer cells, we have examined numerous modulators of antigen-expression. In this report we demonstrate that twelve different Hsp90 inhibitors (iHsp90) share the ability to increase the expression of differentiation antigens and MHC Class I antigens. These iHsp90 are active in several molecular and cellular assays on a series of tumor cell lines, including eleven human melanomas, a murine B16 melanoma, and two human glioma-derived cell lines. Intra-cytoplasmic antibody staining showed that all of the tested iHsp90 increased expression of the melanocyte differentiation antigens Melan-A/MART-1, gp100, and TRP-2, as well as MHC Class I. The gliomas showed enhanced gp100 and MHC staining. Quantitative analysis of mRNA levels showed a parallel increase in message transcription, and a reporter assay shows induction of promoter activity for Melan-A/MART-1 gene. In addition, iHsp90 increased recognition of tumor cells by T cells specific for Melan-A/MART-1. In contrast to direct Hsp90 client proteins, the increased levels of full-length differentiation antigens that result from iHsp90 treatment are most likely the result of transcriptional activation of their encoding genes. In combination, these results suggest that iHsp90 improve recognition of tumor cells by T cells specific for a melanoma-associated antigen as a result of increasing the expressed intracellular antigen pool available for processing and presentation by MHC Class I, along with increased levels of MHC Class I itself. As these Hsp90 inhibitors do not interfere with T cell function, they could have potential for use in immunotherapy of cancer.

Uncomplicated diverticular disease: innate and adaptive immunity in human gut mucosa before and after rifaximin.

BACKGROUND/AIM: Uncomplicated diverticular disease (UDD) is a frequent condition in adults. The pathogenesis of symptoms remains unknown. Bacteria are able to interact with Toll-like receptors (TLRs) and to induce inflammation through both innate immunity and T-cell recruitment. We investigated the pattern of TLRs 2 and 4 and the intestinal homing in patients with UDD before and after a course of Rifaximin. METHODS: Forty consecutive patients with UDD and 20 healthy asymptomatic subjects were enrolled. Among UDD patients, 20 were assigned to a 2-month course of treatment with Rifaximin 1.2 g/day for 15 days/month and 20 received placebo. Blood sample and colonic biopsies were obtained from patients and controls. The samples were collected and analyzed at baseline and at the end of treatment. Flow cytometry was performed using monoclonal antibodies (CD3, CD4, CD8, CD103, TCR-gamma/delta, CD14, TLR2, and TLR4). RESULTS: In UDD, TLR2 and TLR4 expression on immune cell subpopulations from blood and mucosa of the affected colon are altered as compared with controls. Rifaximin treatment induced significant modifications of altered conditions. CONCLUSIONS: Our data show the role of TLRs in the development of inflammation in UDD. TLRs distribution is altered in UDD and these alterations are reversed after antibiotic treatment. This trial is registered with ClinicalTrials.gov: NCT02068482.

Adequate patient's outcome achieved with short immunoglobulin replacement intervals in severe antibody deficiencies.

PURPOSE: The optimal immune globulin replacement dosages required over time to minimize infection risks in patients with Primary Antibody Deficiencies are not definitely established. As with many interventions, there may be specific subgroups of patients who are more likely to benefit from treatment with higher or lower dosages. The aim of the study was to verify the efficacy of a rationale for individualized immune globulin utilization and to elucidate the effects of care on patient outcome. METHODS: Single centre interventional study on 108 patients with Primary Antibody Deficiencies. The objective was to determine for each patient the best interval between immune globulins administration in order to: • Keep IgG trough levels >500 mg/dL, • Minimize of major infections (pneumonias and infections requiring hospitalization), • Minimize of adverse events (AE). RESULTS: Ninthly eight per cent of patients achieved the objective of the study. Patients who had low switched memory B cells and low IgA serum levels and/or are affected by bronchiectasis and/or enteropathy and/or continued to experience adverse events despite pre-medications, achieved the study objective by shortening the administration intervals to 2-weeks or to 1-week without the need to increase the monthly cumulative immunoglobulin dosage and its relative cost. The adverse events were reduced by administrating low Ig dosages in a single setting. Patients without risk factors achieved the study objective with immune globulin replacement administered with the widely used interval of 3 or 4 weeks. CONCLUSIONS: The exact timing and optimal immunoglobulin prophylaxis regimen might be tailored according to clinical and immunological markers.

The role of IL-15 in gastrointestinal diseases: a bridge between innate and adaptive immune response.

IL-15 is a member of the IL-2 family of cytokines whose signaling pathways are a bridge between innate and adaptive immune response. IL-15 is part of the intestinal mucosal barrier, and functions to modulate gut homeostasis. IL-15 has pivotal roles in the control of development, proliferation and survival of both innate and adaptive immune cells. IL-15 becomes up-regulated in the inflamed tissue of intestinal inflammatory disease, such as IBD, Celiac Disease and related complications. Indeed, several studies have reported that IL-15 may participate to the pathogenesis of these diseases. Furthermore, although IL-15 seems to be responsible for inflammation and autoimmunity, it also may increase the immune response against cancer. For these reasons, we decided to study the intestinal mucosa as an 'immunological niche', in which immune response, inflammation and local homeostasis are modulated. Understanding the role of the IL-15/IL-15R system will provide a scientific basis for the development of new approaches that use IL-15 for immunotherapy of autoimmune diseases and malignancies. Indeed, a better understanding of the complexity of the mucosal immune system will contribute to the general understanding of immuno-pathology, which could lead to new therapeutical tools for widespread immuno-mediated diseases.

Tissue-infiltrating lymphocytes analysis reveals large modifications of the duodenal "immunological niche" in coeliac disease after gluten-free diet.

OBJECTIVES: The role of T lymphocytes in the pathogenesis of Celiac disease (CD) is well established. However, the mechanisms of T-cell involvement remain elusive. Little is known on the distribution of T subpopulations: T-regulatory (Treg), Th17, CD103, and CD62L cells at disease onset and after gluten-free diet (GFD). We investigated the involvement of several T subpopulations in the pathogenesis of CD. METHODS: We studied T cells both in the peripheral blood (PB) and the tissue-infiltrating lymphocytes (TILs) from the mucosa of 14 CD patients at presentation and after a GFD, vs. 12 controls. RESULTS: Our results extend the involvement of Treg, Th1, and Th17 cells in active CD inflammation both in the PB and at the TILs. At baseline, Tregs, Th1, and Th17 cells are significantly higher in active CD patients in TILs and PB. They decreased after diet. Moreover, CD62L+ TILs were increased at diagnosis as compared with GFD patients. CONCLUSIONS: Our data show significant modifications of the above-mentioned subpopulations both in the PB and TILs. The increase of suppressive Tregs in active CD both in the PB and TILs is intriguing. T lymphocytes are known to have a crucial role in the pathogenesis of CD. We have shown that gluten trigger results in systemic recruitment of T lymphocytes, the unbalance between pro-inflammatory and anti-inflammatory populations and the increase of CD62L+ T cells in TILs. Our results delineate a more complete picture of T-cell subsets in active vs. GFD disease. Our data of T-cell subpopulations, combined with known data on cytokine production, support the concept that duodenal micro-environment acts as an immunological niche and this recognition may have an important role in the diagnosis, prognosis and therapeutical approach of CD.

Recent insights in primary immunodeficiency diseases: the role of T-lymphocytes and innate immunity.

In recent years, the field of primary immunodeficienciency diseases (PID) has experienced remarkable progress with the identification of a number of new genes associated with specific diseases. Yet the diagnosis of PID remains difficult. In fact, this field requires continuous updating because once a novel molecule related to the immune function is discovered, the corresponding PID will soon be described. Since comprehensive reviews on the classification of PID are available, we concentrate here on reviewing some controversial and new issues, mainly those related to the role of T-cells and innate immunity. We will consider common variable immunodeficiency as an example of a PID where several immune pathways are impaired. We will also discuss the restricted usage of the T-cell receptor repertoire in PID. Innate immunity and Toll-like receptors (TLR) are new major players in this field. We will therefore discuss the association of TLR with the function of Bruton tyrosine kinase (Btk) that is essential in the development of B-cells and in the pathogenesis of X-linked agammaglobulinemia. Finally, we will discuss the role of mast-cells. These cells were once thought to be relevant almost exclusively to the pathogenesis of allergy. Now we know that mast cells are involved in initiating the adaptive response and may contribute to ineffective immune responses.