IL-1 induces throboxane-A2 (TxA2) in COVID-19 causing inflammation and micro-thrombi: inhibitory effect of the IL-1 receptor antagonist (IL-1Ra).

IL-1 induces a significant number of metabolic and hematological changes. In experimental animals, IL-1 treatments cause hypotension due to rapid reduction of systemic blood pressure, reduced vascular resistance, increased heart rate and leukocyte aggregations. IL-1 causes endothelial dysfunction, the triggering factor of which may be of a different nature including pathogen infection. This dysfunction, which includes macrophage intervention and increased protein permeability, can be mediated by several factors including cytokines and arachidonic acid products. These effects are caused by the induction of IL-1 in various pathologies, including those caused by pathogenic viral infections, including SARS-CoV-2 which provokes COVID-19. Activation of macrophages by coronavirus-19 leads to the release of pro-inflammatory cytokines, metalloproteinases and other proteolytic enzymes that can cause thrombi formation and severe respiratory dysfunction. Patients with COVID-19, seriously ill and hospitalized in intensive care, present systemic inflammation, intravascular coagulopathy with high risk of thrombotic complications, and venous thromboembolism, effects mostly mediated by IL-1. In these patients the lungs are the most critical target organ as it can present an increase in the degradation products of fibrin, fibrinogen and D-dimer, with organ lesions and respiratory failure. It is well known that IL-1 induces itself and another very important pro-inflammatory cytokine, TNF, which also participates in hemodynamic states, including shock syndrome in COVID-19. Both IL-1 and TNF cause pulmonary edema, thrombosis and bleeding. In addition to hypotension and resistance of systemic blood pressure, IL-1 causes leukopenia and thrombocytopenia. The formation of thrombi is the main complication of the circulatory system and functionality of the organ, and represents an important cause of morbidity and mortality. IL-1 causes platelet vascular thrombogenicity also on non-endothelial cells by stimulating the formation of thromboxane A2 which is released into the inflamed environment. IL-1 is the most important immune molecule in inducing fever, since it is involved in the metabolism of arachidonic acid which increases from vascular endothelial organs of the hypothalamus. The pathogenesis of thrombosis, vascular inflammation and angigenesis involves the mediation of the activation of the prostanoid thromboxane A2 receptor. In 1986, in an interesting article (Conti P, Reale M, Fiore S, Cancelli A, Angeletti PU, Dinarello CA. In vitro enhanced thromboxane B2 release by polymorphonuclear leukocytes and macrophages after treatment with human recombinant interleukin 1. Prostaglandins. 1986 Jul;32(1):111-5), we reported for the first time that IL-1 induces thromboxane B2 (TxB2) releases in activated neutrophils and macrophages. An increase in thromboxane can induce leukocyte aggregation and systemic inflammation, which would account for the dramatic thrombi formation and organ dysfunction. Hence, IL-1 stimulates endothelial cell-leukocyte adhesion, and TxB2 production. All these events are supported by the large increase in neutrophils that adhere to the lung and the decrease in lymphocytes. Therefore, ecosanoids such as TxA2 (detected as TxB2) have a powerful action on vascular inflammation and platelet aggregation, mediating the formation of thrombi. The thrombogenesis that occurs in COVID-19 includes platelet and cell aggregation with clotting abnormalities, and anti-clotting inhibitor agents are used in the prevention and therapy of thrombotic diseases. Prevention of or induction of TxA2 avoids thrombi formation induced by IL-1. However, in some serious vascular events where TxA2 increases significantly, it is difficult to inhibit, therefore, it would be much better to prevent its induction and generation by blocking its inductors including IL-1. The inhibition or lack of formation of IL-1 avoids all the above pathological events which can lead to death of the patient. The treatment of innate immune cells producing IL-1 with IL-1 receptor antagonist (IL-1Ra) can avoid hemodynamic changes, septic shock and organ inflammation by carrying out a new therapeutic efficacy on COVID-19 induced by SARS-CoV-2.

How to reduce the likelihood of coronavirus-19 (CoV-19 or SARS-CoV-2) infection and lung inflammation mediated by IL-1.

SARS-CoV-2, also referred to as CoV-19, is an RNA virus which can cause severe acute respiratory diseases (COVID-19), with serious infection of the lower respiratory tract followed by bronchitis, pneumonia and fibrosis. The severity of the disease depends on the efficiency of the immune system which, if it is weak, cannot stem the infection and its symptoms. The new CoV-19 spreads in the population at a rate of 0.8-3% more than normal flu and mostly affects men, since immune genes are more expressed on the X chromosome. If CoV-19 would spread with a higher incidence rate (over 10%), and affect the people who live in closed communities such as islands, it would cause many more deaths. Moreover, people from the poorest classes are most at risk because of lack of health care and should be given more assistance by the competent authorities. To avoid the aggravation of CoV-19 infection, and the collapse of the health system, individuals should remain at home in quarantine for a period of approximately one month in order to limit viral transmission. In the case of a pandemic, the severe shortage of respirators and protective clothing, due to the enormous demand and insufficient production, could lead the CoV-19 to kill a large number of individuals. At present, there is no drug capable of treating CoV-19 flu, the only therapeutic remedies are those aimed at the side effects caused by the virus, such as inflammation and pulmonary fibrosis, recognized as the first causes of death. One of the COVID-19 treatments involves inhaling a mixture of gaseous hydrogen and oxygen, obtaining better results than with oxygen alone. It was also noted that individuals vaccinated for viral and/or bacterial infectious diseases were less likely to become infected. In addition, germicidal UV radiation "breaks down" the oxygen O2 which then aggregate into O3 (ozone) molecules creating the ozone layer, capable of inhibiting viral replication and improving lung respiration. All these precautions should be taken into consideration to lower the risk of infection by CoV-19. New anti-viral therapies with new drugs should also be taken into consideration. For example, microbes are known to bind TLR, inducing IL-1, a pleiotropic cytokine, highly inflammatory, mediator of fever and fibrosis. Therefore, drugs that suppress IL-1 or IL-1R, also used for the treatment of rheumatoid arthritis are to be taken into consideration to treat COVID-19. We strongly believe that all these devices described above can lead to greater survival and. therefore, reduction in mortality in patients infected with CoV-19.

Interleukin-1 family cytokines and mast cells: activation and inhibition.

Activated mast cells (MCs) secrete a number of compounds including pro-inflammatory and anti-inflammatory cytokines. MCs are a potential source of cytokines and chemokines which participate in allergic reactions and inflammation. MCs can be activated by IgE through its receptor FceRI, but also by Toll-like receptors and/or interleukin (IL)-1. MCs can be a target for both pro-inflammatory and anti-inflammatory cytokines. IL-1 activates MCs to release inflammatory chemical mediators, and cytokines/chemokines, an effect which can be potentially inhibited by IL-37. In addition, IL-36 is also a powerful cytokine with a pro-inflammatory activity. IL-38 binds IL-36R and inhibits the pro-inflammatory activity of IL-36, thus performing a therapeutic action. In this article we review the role of MCs in relation to pro-inflammatory and anti-inflammatory IL-1 family member cytokines and a possible therapeutic effect in inflammatory disorders.

IL-33 mediates allergy through mast cell activation: Potential inhibitory effect of certain cytokines.

Mast cells (MCs) are hematopoietic immune cells commonly found in adjacent to blood vessels in the lamina propria of airway mucosa. They are important in allergic reactions since the cross-linking of their surface high affinity receptor FceRI induces activation of these cells, and provokes the synthesis, degranulation and release of inflammatory mediators including arachidonic acid-derived eicosanoids (de novo synthesized), stored enzyme mediators, and inflammatory TH1 and TH2 cytokines, and chemokines. Interleukin (IL)-33 participates in innate and adaptive immunity and inflammation and, acting on CD34+ cells, causes MC differentiation and maturation. IL-33 is generated by activated immune cells, and activates MCs which degranulate and release pro-inflammatory mediators. IL-33 is very important in mediating allergic inflammation and can be induced by IL-1 beta. It is also called "alarmin" and is an inflammatory cytokine IL-1 family member, expressed from mocytes and MCs, which binds its receptor ST2, provoking its release after cell damage. MC-derived allergic compounds in response to IL-33 is critical to innate type 2 immunity. IL-37 is expressed by immune and non-immune cells after pro-inflammatory stimulus. IL-37, an anti-inflammatory cytokine, binds IL-18Ra and suppresses pro-inflammatory IL-1 beta released by activated immune cells such as macrophages. Here, we hypothesize that pro-inflammatory IL-1 family member cytokines released by activated MCs, mediating inflammatory allergic phenomenon, can be suppressed by IL-37.

Impact of mold on mast cell-cytokine immune response.

Molds include all species of microscopic fungi, the spores of which are small molecules, ubiquitous, mostly found in soil with higher rainfall and high humidity, in the atmosphere of urban and rural settings and in decaying vegetation. They originate from pathogenic fungi and have a crucial role in inflammatory response, causing a broad range of diseases. Immune suppressed subjects may develop mycoses caused by opportunistic common pathogenic fungi. Mast cells (MCs) are immune cells involved in the pathophysiology of infected skin, lung, and organs, where there is an increase of angiogenesis. Airways fungi infections can induce allergic lung disease mediated by MCs and other immune cells. In addition, fungal infection may cause and/or aggravate asthma inflammation. Spores are able to navigate in the airways of the lung and can be recognized trough toll-like receptor (TLR) signaling by the innate immune cells including MCs. Activated MCs release preformed mediators including histamine, proteases (tryptase, chimase), pro-inflammatory cytokines/chemokines and they also generate arachidonic acid products. MCs activated by fungi provoke an increases of PGD2 levels and lead to hypersensitivity diseases which present signs such as irritation of the respiratory tract and eyes, recurrent sinusitis, bronchitis, cough and neurological manifestations including fatigue, nausea, headaches and brain fog. Therefore, fungi activate the innate immune response through the TLRs, leading to the release of myeloid differentiation factor 88 (MyD88) which, with a series of cascade reactions, induces the stimulation of AP-1 and NF-kB with subsequent activation of inflammatory IL-1 family members. Here, we report that fungi can activate MCs to secrete pro-inflammatory cytokines which may be inhibited by IL-37, a new anti-inflammatory IL-1 family member.

Diagnosis of a neonatal ophthalmic discharge, Ophthalmia neonatorum, in the molecular age: investigation for a correct therapy.

An early double case of acute Ophthalmia neonatorum in 3-day-old twins is reported. Culture of eye swabs showed a wide bacterial polymorphism, in which common bacteria, such as Klebsiella pneumoniae, Streptococcus pneumoniae, Corynebacterium ulcerans and other Enterobacteriaceae, coexisted with atypical Mycoplasmataceae and Chlamydiaceae from resident cervical-vaginal maternal microbiota. The neonates were in an apparently healthy state, but showed red eyes with abundant greenish-yellow secretion, mild chemosis and lid edema. The maternal cervical-vaginal ecosystem resulted differently positive to the same common cultivable, atypical bacteria culturally and molecularly determined. This suggested a direct maternal-foetal transmission or a further foetal contamination before birth. An extended culture analysis for common bacteria to atypical ones was decisive to describe the involvement of Mycoplasmas (M. hominis and U. urealyticum) within the scenario of the Ophthalmia neonatorum in a Caucasian couple. The introduction of a routine PCR molecular analysis for Chlamydiaceae and N. gonorrhoeae allowed to establish which of these were present at birth, and contributed to determine the correct laboratory diagnosis and to define an adequate therapeutic protocol obtaining a complete resolution after one year for culture and atypical bacteria controls. This study suggests to improve the quality of laboratory diagnosis as unavoidable support to a correct clinical diagnosis and therapy, in a standardized modality both for swabbing and scraping, to check the new-born microbial programming starting in uterus, overtaking the cultural age to the molecular age, and to revise the WHO guidelines of SAFE Strategy for trachoma eye disease, transforming it into SAFES Strategy where the S letter is the acronym of Sexual ecosystem and behavioural valuation/education.

Mast cell in innate immunity mediated by proinflammatory and antiinflammatory IL-1 family members.

Innate immunity consists of physical and chemical barriers which provide the early defense against infections. Innate immunity orchestrates the defense of the host with cellular and biochemical proteins. Mast cells (MCs) are involved in innate and adaptive immunity and are the first line of defense which generates multiple inflammatory cytokines/chemokines in response to numerous antigens. MC-activated antigen receptor Fc-RI provokes a number of important biochemical pathways with secretion of numerous vasoactive, chemoattractant and inflammatory compounds which participate in allergic and inflammatory diseases. MCs can also be activated by Th1 cytokines and generate pre-formed and de novo inflammatory mediators, including TNF. IL-37 is an anti-inflammatory cytokine which binds IL-18R-alpha chain and reduces the production of inflammatory IL-1 family members. IL-37 down-regulates innate immunity by inhibiting macrophage response and its accumulation and reduces the cytokines that mediate inflammatory diseases. Here, we discuss the relationship between MCs, innate immunity, and pro-inflammatory and anti-inflammatory cytokines.

Cytokine expression profile and blood parameter evaluation of patients undergoing cardiac surgery.

Cardiac surgery is accompanied by an important immune response that is poorly understood. This inflammatory response is caused by several stimuli: surgical trauma, cardiopulmonary bypass apparatus, aortic-cross clamping, reperfusion injury and hypothermia. The aim of the present study is to investigate the cytokine level profile involved in the inflammatory pathway of patients undergoing cardiac surgery. One hundred and two patients undergoing elective cardiac surgery utilizing cardiopulmonary bypass (CPB) apparatus were enrolled in the study. In the hematological and biochemical profiles investigated, we observed a significant increase of WBC and blood glucose concentration and a strong decrease of RBC, HB, HCT and PLT 24 h post-surgery compared to baseline and immediately after surgery groups. Furthermore, we found a modulation of cytokine levels mostly for IL-10 and an increase of IL-6, detected at 6 h post-surgery, IL-8 at 6 and 24 h, and TNFα only at 24 h post-surgery. In conclusion, these findings evidence a time course profile on cytokine levels and a balance between pro- and anti-inflammatory cytokine activation during and after cardiac surgery. In fact, IL-6 and IL-10, a pro- and an anti-inflammatory cytokine, respectively, increased immediately after surgery. The plasma level of TNF-α could be inhibited by the high concentration of IL-10 up to 6 h post-surgery. An IL-10 reduction at baseline level, after 24 h post-surgery, could explain a rise of TNF-α plasma concentration. On the other hand, considering the dual role of IL-6 on inflammation acting both as an activator of inflammatory cascade or an anti-inflammatory agent, the increased IL-6 levels 24 h after surgery could be related to the negative feedback action on TNFα activity.

Activation and inhibition of adaptive immune response mediated by mast cells.

Adaptive immune response plays an important role against bacteria and parasites, a reaction that also involves mast cell (MC) activation which participates in innate and adaptive immunity. In allergic reactions there is a TH2 immune response with generation of allergen-specific IgE antibodies. In MCs, IgE cross-link FcRI high affinity receptor and activate tyrosine kinase proteins, leading to stimulation of NF-κB and AP-1 resulting in the release of a number of cytokines/chemokines and other compounds. Through their proteolytic pathways, MCs may process the antigen for presentation to CD4+ cells which release TH2 cytokines and growth factors, which play an important role in asthma, allergy, anaphylaxis and inflammation. Thus, MCs can contribute to adaptive immunity. MCs may also be activated though the TLR-dependent pathway which is controlled by several proteins including myeloid differentiation factor 88 (MyD88) which can be inhibited by interleukin (IL)-37. Here, we describe the participation of MCs in adaptive immunity and inflammation, an effect that may be inhibited by IL-37.

Mast cell, pro-inflammatory and anti-inflammatory: Jekyll and Hyde, the story continues.

IL-1 family members include inflammatory and anti-inflammatory cytokines. They can be beneficial or detrimental, not only in cancer, but also in inflammatory conditions. Mast cells (MCs) originate from CD34+/CD117+/CD13+ pluripotent hematopoietic stem cells, express c-Kit receptor (c-Kit-R), which regulates the proliferation and sustain the survival, differentiation and maturation of MCs. They are immune cells involved in innate and adaptive immunity, allergy, autoimmunity, cancer and inflammation. MCs along with T cells and macrophages release interleukin (IL)-10, which is a pleiotropic immunoregulatory cytokine with multiple biological effects. IL-10 inhibits Th1 inflammatory cells, in particular TNF mostly generated by macrophages and MCs, and down-regulates IFN-γ, IL-1 and IL-6. IL-37 is a family member cytokine which binds IL-18 receptor α chain and inhibits inflammatory mediators including TNF, IL-1, IL-6, IL-33 and nitric oxide (NO). IL-37 similar to IL-10 inhibits MC inflammatory cytokines in several disorders, including asthma, allergy, arthrtitis and cancer. Here we report a study comparing IL-10 with IL-37, two anti-inflammatory cytokines.

Cytokine modulation in patients with idiopathic pulmonary fibrosis undergoing treatment with steroids, immunosuppressants, and IFN-γ 1b.

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease of unknown etiology and pathogenic mechanisms. From an etiopathogenic point of view, alveolar macrophages play a key role in accumulation of fibroblasts and deposition of collagen and extracellular matrix by releasing specific cytokines and inflammatory mediators. IPF seems to be also associated with circulating fibrocytes, which might be involved with an abnormal pulmonary vascular repair and remodeling. Based on its hypothesized pathologic mechanisms, anti-inflammatory, anti-fibrotic and immunosuppressive therapies are often used. For these reasons, Interferon-g (IFN-g) has been used to exploit its activity on macrophages and fibroblasts. The aim of this study was to investigate the response to corticosteroids and/or IFN-g 1b treatments based on pulmonary function tests and on inflammatory cytokine patterns of expression on bronchoalveolar lavage (BAL), at baseline and during and after the therapies. Unlike previous studies, we analyzed a period of therapy longer than 1 year. Our results demonstrated the effectiveness of IFN-γ in a group of IPF patients in whom the treatment was prolonged for over a year. These data suggest a positive role of IFN-γ; treatment in patients in the initial stage of the disease.

ENOX2 (or tNOX): a new and old molecule with cancer activity involved in tumor prevention and therapy.

Cancer includes a number of related diseases due to abnormal cell proliferation that spreads to nearby tissues. Many compounds (physical, chemical and biological) have been used to try to halt this abnormal proliferation, but the therapeutic results are poor, due also to the side effects. It has been reported that ecto-nicotinamide adenine dinucleotide oxidase di-sulfide-thiol exchanger 2 (ENOX2), also known as tumor-associated nicotinamide adenine dinucleotide oxidase (tNOX), was found to be located on the cancer cell surface, essential for cancer cell growth. Capsaicin and other anti-oxidants are capable of inhibiting tNOX, causing apoptosis of cells, exerting anti-tumor activity. It is interesting that some authors reported that ENOX2 is present in the serum of cancer patients several years before the clinical symptoms of the tumor. However, this result has to be confirmed. In this article we discuss ENOX2 and its inhibition as a hope of improving cancer therapy.

Endocrinology of the skin: intradermal neuroimmune network, a new frontier.

Endocrinology systems exert an important effect on vascular function and have direct actions on blood vessels. Estrogens provoke an increase in skin elasticity, epidermal hydration, skin thickness, reduce skin wrinkles and augment the content of collagen and the level of vascularisation. Therefore, there is an intricate cross-talk between skin conditions and stress. In stress, ß2--adrenoreceptor (ß2AR) pathway, cortisol, epinephrine and norepinephrine increase DNA damage and interfere with the regulation of the cell cycle, contributing to aging and skin diseases. Substance P is a neuropeptide released in the skin from the peripheral nerve and is related to stress and inflammation. SP provokes infiltration of inflammatory cells in the skin and induces a variety of cytokines/chemokines. Corticotropin-releasing hormone (CRH), produced by mast cells, is a neuropeptide also expressed in skin and responds to stress. CRH initiates diverse intracellular signaling pathways, including cAMP, protein kinase C, and mitogen-activated protein kinases (MAPK). Under stress, CRH, glucocorticoids, epinephrine and cytokines are generated. Moreover, the release of ACTH binds the receptor MC2-R and stimulates the generation of glucocorticoids such as corticosterone and cortisol, which interact with the transcription factors AP-1 and NF-kB. In skin keratinocytes, ACTH promotes the generation of pro-inflammatory cytokines, which enhances T-cell activity. Cortisol is immunosuppressive by inhibiting Th1 and Th2 cell response, antigen presentation, antibody and cytokine/chemokine production. However, glucocorticoids are certainly helpful in Th1-mediated autoimmune disorders. On the other hand, cytokines, such as TNF, IL-1 and IL-6, stimulate the generation of CRH and activate HPA axis in inflammatory states. Here, we describe for the first time a cross-talk between endocrinology and skin, including pro-inflammatory cytokines and neurogenic inflammatory pathways.

Effect of low energy light irradiation by light emitting diode on U937 cells.

Photobiomodulation (PBM) can induce a set of different biological modulators either in vitro or in vivo. Experimental evidence has highlighted the role of light effects on the mechanisms related to inflammation, apoptosis and autophagy. The goal of this project was the evaluation of PBM on U937, an established cell line of histiocytic lymphoma origin. Several aspects of modulation of proinflammatory pathways were analyzed and autophagic and proapoptotic mechanisms related to low laser light exposure of cells were studied. As a source of low energy light emission, we used an NIR-LED device, characterized by an 880 nm-wavelength as light source. Flow cytometry analysis was performed on supernatants of controls and treated U937 cells to detect inflammatory cytokine levels. In order to evaluate NF-kB and caspase3 expressions, Western blot analysis was performed according to standard procedures. In this report, we show the effect of PBM on a monocyte/macrophage established tumor cell line (U-937). We demonstrate that LED exposure, in the presence or absence of lipopolysaccharide (LPS), activates cell degranulation, increased expression of Interleukin-8 (IL-8) and modulation of beta galactosidase activity. Evidence shows that the well-known pro-inflammatory nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and the apoptotic marker (caspase3/cleaved-caspase3 ratio) are up-regulated in response to a proinflammatory biochemical pathway.

Comparative molecular analysis of bacterial species associated with periodontal disease.

Periodontal disease is an inflammatory disorder affecting the supporting teeth structures, including gingiva, periodontal ligament and alveolar bone, causing loss of connective tissue, reabsorption of alveolar bone and formation of periodontal pockets. The aim of this study is to find a correlation between bacterial growth and periodontal disease. Fifty-seven patients aged between 21 and 65 years, median age 46 years, were enrolled. According to gingival pocket depth, ranging from 3 to 7 mm, patients were divided into two groups: the first (30 patients, 53%) with deep pockets ³ 5 mm and the second (27 patients, 47%) less than 5 mm. The samples taken were processed for microbiological analysis by absolute quantitative real-time Taq-Man technique. Patients affected by periodontal disease were 32 (56%) and patients with gingival bleeding were 35 (61%). This data showed that the presence, the type and the bacterial load in gingival pockets were strongly correlated with gingival depth, periodontal disease and gingival bleeding. Quantitative microbiological analysis is a key point to improve patient compliance, allowing to choose the specific antibiotic treatment. avoiding antibiotic resistance and ensuring the successful outcome of therapy for periodontal disease.

IMMUNOMODULATORY EFFECTS OF VITAMIN D ON SKIN INFLAMMATION.

Vitamin D has a major role in calcium absorption and maintenance of healthy bones. Vitamin D is also involved in cancer, cardiovascular system, allergic diseases, immune regulation and immune disor¬ders. Irradiation of food as well as animals produces vitamin D and more than 90% of previtamin D3 synthesis in the skin occurs in the epidermis. Vitamin D receptor has been found in many cells including T and B lymphocytes, macrophages, mast cells, NK cells and Tregs, and it selectively binds with high affinity to its ligand. Vitamin D binds its receptor VDR, resulting in transcription of a number of genes playing a role in inhibition of MAPK. Its effect may be also mediated by the direct activation of PKC. Vitamin D has the ability to suppress inflammatory cytokines such as TNF, IL-1, IFN-gamma and IL-2; while it increases the generation of anti-inflammatory cytokines IL-4 and IL-10. In B cells, vitamin D3 have also been shown to suppress IgE antibody class switch partly through the inhibition of NF-kB. Here we discuss the relationship between vitamin D, immunity and skin disorders.

Impact of mast cells on the skin.

When through the skin a foreign antigen enters it provokes an immune response and inflammatory reaction. Mast cells are located around small vessels that are involved in vasaldilation. They mature under the influence of local tissue to various cytokines. Human skin mast cells play an essential role in diverse physiological and pathological processes and mediate immediate hypersensitive reaction and allergic diseases. Injection of anti-IgE in the skin or other agents that directly activate mast cells may cause the decrease in vascular tone, leakage of plasma and may lead to a fall in blood pressure with fatal anaphylactic shock. Skin mast cells are also implicated as effector cells in response to multiple parasites such as Leishmania which is primarily characterized by its tissue cutaneous tropism. Activated macrophages by IFNgamma, cytotoxic T cells, activated mast cells and several cytokines are involved in the elimination of the parasites and immunoprotection. IL-33 is one of the latest cytokines involved in IgE-induced anaphylaxis and in the pathogenesis of allergic skin disorders. IL-33 has been shown in epidermis of patients with psoriasis and its skin expression causes atopic dermatitis and it is crucial for the development of this disease. Here we review the impact of mast cells on the skin.

Mast cell involvement in rheumatoid arthritis.

Autoimmunity is a failure of self-tolerance resulting in immune reactions against autologous antigen. Rheumatoid arthritis is characterized by inflammation of synovium associated with destruction of the join cartilage and bone. A role of mast cell-mediated inflammation and antibodies are involved in this disease. Numerous cytokines such as IL-1, TNF, IL-8, IL-33 and IFN gamma have been implicated in rheumatoid arthritis and in particular in the synovial joint fluid. Since TNF is believed to activates resident synovial cells to produce collagenase that mediate destruction of cartilage, antagonists against the inflammatory cytokine TNF have a beneficial effects in this disease. Here we review the interrelationship between rheumatoid arthritis and mast cell activation.

Impact of capsaicin on mast cell inflammation.

Mast cells are inflammatory cells, and they are prominent in inflammatory diseases such as allergy and asthma. Mast cells possess high-affinity receptors for IgE (FcERI) and the cross-linking of these receptors is essential to trigger the secretion of granules containing arachidonic acid metabolism (such as prostaglandin (PG) D2, leukotriene (LT) B4, and LTC4), histamine, cytokines, chemokines, and proteases, including mast cell-specific chymases and tryptases. Activation of mast cells provokes the secretion of cytokines and mediators that are responsible for the pathologic reaction of immediate hypersensitivity. Sensory nerve stimulation by irritants and other inflammatory mediators provokes the release of neuropeptides, causing an increase in vascular permeability, plasma extravasation and edema. Trigeminal nerve stimulation actives dura mast cells and increases vascular permeability, effects inhibited by capsaicin. Capsaicin causes release of sensory neuropeptide, catecholamines and vasodilation. Several studies have reported that capsaicin is effective in relief and prevention of migraine headaches, improves digestion, helps to prevent heart disease, and lowers blood cholesterol and blood pressure levels. The findings reported in these studies may have implications for the pathophysiology and possible therapy of neuroinflammatory disorders.