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Psoriasis (PS) is a skin disease with autoimmune features mediated by immune cells, which typically presents inflammatory erythematous plaques, and is associated with many comorbidities. PS exhibits excessive keratinocyte proliferation, and a high number of immune cells, including macrophages, neutrophils, Th1 and Th17 lymphocytes, and mast cells (MCs). MCs are of hematopoietic origin, derived from bone marrow cells, which migrate, mature, and reside in vascularized tissues. They can be activated by antigen-provoking overexpression of proinflammatory cytokines, and release a number of mediators including interleukin (IL)-1 and IL-33. IL-1, released by activated keratinocytes and MCs, stimulates skin macrophages to release IL-36—a powerful proinflammatory IL-1 family member. IL-36 mediates both innate and adaptive immunity, including chronic proinflammatory diseases such as psoriasis. Suppression of IL-36 could result in a dramatic improvement in the treatment of psoriasis. IL-36 is inhibited by IL-36Ra, which binds to IL-36 receptor ligands, but suppression can also occur by binding IL-38 to the IL-36 receptor (IL-36R). IL-38 specifically binds only to IL-36R, and inhibits human mononuclear cells stimulated with IL-36 in vitro, sharing the effect with IL-36Ra. Here, we report that inflammation in psoriasis is mediated by IL-1 generated by MCs—a process that activates macrophages to secrete proinflammatory IL-36 inhibited by IL-38. IL-37 belongs to the IL-1 family, and broadly suppresses innate inflammation via IL-1 inhibition. IL-37, in murine models of inflammatory arthritis, causes the suppression of joint inflammation through the inhibition of IL-1. Therefore, it is pertinent to think that IL-37 can play an inhibitory role in inflammatory psoriasis. In this article, we confirm that IL-38 and IL-37 cytokines emerge as inhibitors of inflammation in psoriasis, and hold promise as an innovative therapeutic tool.

SARS-Cov-2 infection causes local and systemic inflammation mediated by pro-inflammatory cytokines and COX-2 eicosanoid products with metabolic dysfunction and tissue damage that can lead to patient death. These effects are primarily induced by IL-1 cytokines, which are involved in the elevation of hepatic acute phase proteins and fever. IL-1 has a broad spectrum of biological activities and participates in both innate and acquired immunity. In infections, IL-1 induces gene expression and synthesis of several cytokines/chemokines in both macrophages and mast cells (MCs). The activation of MCs triggers the secretion of mediators stored in the granules, and the de novo synthesis of pro-inflammatory cytokines. In microorganism infections, the release of IL-1 macrophage acts on adhesion molecules and endothelial cells leading to hypotension and septic shock syndrome. IL-1 activated by SARS-CoV-2 stimulates the secretion of TNF, IL-6 and other cytokines, a pro-inflammatory complex that can lead to cytokine storm and be deleterious in both lung and systemically. In SARS-CoV-2 septic shock, severe metabolic cellular abnormalities occur which can lead to death. Here, we report that SARS-CoV-2 induces IL-1 in macrophages and MCs causing the induction of gene expression and activation of other pro-inflammatory cytokines. Since IL-1 is toxic, its production from ubiquitous MCs and macrophages activated by SARS-CoV-2 can also provokes both gastrointestinal and brain disorders. Furthermore, in these immune cells, IL-1 also elevates nitric oxide, and the release of inflammatory arachidonic acid products such as prostaglndins and thromboxane A2. All together these effects can generate cytokine storm and be the primary cause of severe inflammation with respiratory distress and death. Although, IL-1 administered in low doses may be protective; when it is produced in high doses in infectious diseases can be detrimental, therefore, IL-1 blockade has been studied in many human diseases including sepsis, resulting that blocking it is absolutely necessary. This definitely nurtures hope for a new effective therapeutic treatment. Recently, two interesting anti-IL-1 cytokines have been widely described: IL-37 and IL-1Ra. IL-37, by blocking IL-1, has been observed to have anti-inflammatory action in rodents in vivo and in transfected cells. It has been reported that IL-37 is a very powerful protein which inhibits inflammation and its inhibition can be a valid therapeutic strategy. IL-37 is a natural suppressor of inflammation that is generated through a caspase-1 that cleaves pro-IL-37 into mature IL-37 which translocates to the nucleus and inhibits the transcription of pro-inflammatory genes; while IL-1Ra inhibits inflammation by binding IL-1 to its IL-1R (receptor). We firmly believe that blocking IL-1 with an anti-inflammatory cytokine such as IL-37 and/or IL-1Ra is an effective valid therapy in a wide spectrum of inflammatory disorders including SARS-CoV-2-induced COVID-19. Here, we propose for the first time that IL-37, by blocking IL-1, may have an important role in the therapy of COVID-19.

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 (

Acute severe respiratory syndrome coronavirus-2 (SARS-CoV-2) caused a global pandemic coronavirus disease 2019 (COVID-19). In humans, SARS-CoV-2 infection leads to acute respiratory distress syndrome which presents edema, hemorrhage, intra-alveolar fibrin deposition, and vascular changes characterized by thrombus formation, micro-angiopathy and thrombosis. These clinical signs are mediated by pro-inflammatory cytokines. In recent studies it has been noted that COVID-19 pandemic can affect patients of all ages, including children (even if less severely) who were initially thought to be immune. Kawasaki disease is an autoimmune acute febrile inflammatory condition, which primarily affects young children. The disease can present immunodeficiency with the inability of the immune system to fight inflammatory pathogens and leads to fever, rash, alterations of the mucous membranes, conjunctiva infection, pharyngeal erythema, adenopathy, and inflammation. In the COVID-19 period, virus infection aggravates the condition of Kawasaki disease, but it has also been noted that children affected by SARS-V-2 may develop a disease similar to Kawasaki's illness. However, it is uncertain whether the virus alone can give Kawasaki disease-like forms. As in COVID-19, Kawasaki disease and its similar forms are mediated by pro-inflammatory cytokines produced by innate immunity cells such as macrophages and mast cells (MCs). In light of the above, it is therefore pertinent to think that by blocking pro-inflammatory cytokines with new anti-inflammatory cytokines, such as IL-37 and IL-38, it is possible to alleviate the symptoms of the disease and have a new available therapeutic tool. However, since Kawasaki and Kawasaki-like diseases present immunodeficiency, treatment with anti-inflammatory/immunosuppressant molecules must be applied very carefully.

Sjögren’s syndrome (SS) is a chronic autoimmune inflammatory disease that affects primarily older women and is characterized by irreversible damage of the exocrine glands, including tear (xerophthalmia) and salivary glands (xerostomia). Secretory glands lose their functionality due to the infiltration of immune cells, which produce cytokines and cause inflammation. Primary SS is characterized by dry syndrome with or without systemic commitment in the absence of other pathologies. Secondary SS is accompanied by other autoimmune diseases with high activation of B lymphocytes and the production of autoantibodies, including the rheumatoid factor. Other cells, such as CD4+ T cells and mast cells (MCs), participate in SS inflammation. MCs are ubiquitous, but are primarily located close to blood vessels and nerves and can be activated early in autoimmune diseases to express a wide variety of cytokines and chemokines. In the SS acute phase, MCs react by generating chemical mediators of inflammation, tumor necrosis factor (TNF), and other pro-inflammatory cytokines such as interleukin (IL)-1 and IL-33. IL-33 is the specific ligand for ST2 capable of inducing some adaptive immunity TH2 cytokines but also has pro-inflammatory properties. IL-33 causes impressive pathological changes and inflammatory cell infiltration. IL-1 family members can have paracrine and autocrine effects by exacerbating autoimmune inflammation. IL-37 is an IL-1 family cytokine that binds IL-18Rα receptor and/or Toll-like Receptor (TLR)4, exerting an anti-inflammatory action. IL-37 is a natural inhibitor of innate and acquired immunity, and the level is abnormal in patients with autoimmune disorders. After TLR ligand activation, IL-37 mRNA is generated in the cytoplasm, with the production of pro-IL-37 and later mature IL-37 caspase-1 mediated; both precursor and mature IL-37 are biologically active. Here, we discuss, for the first time, the current knowledge of IL-37 in autoimmune disease SS and propose a new therapeutic role.

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.

Chimeric antigen receptor (CAR) T cells are genetically modified T cells that act against cancer. When CAR-T cells are administered they can trigger inflammatory cytokines and increase toxicity. Interleukin (IL)-1 is the classic cytokine that mediates inflammatory reactions including those that occur in CAR-T-cell therapy. IL-1 also induces IL-33 in mast cells (MCs), amplifying the allergic reaction. IL- 37 (ILF7) is an IL-1 family member which binds IL-18 receptor alpha (IL-18Rα) chain and suppresses innate and acquired immunity. IL-37 is an anti-inflammatory cytokine which inhibits pro-inflammatory cytokines including IL-1 and IL-33. Here, we hypothesize that inflammation and toxicity generated in tumor CAR-T therapy could be inhibited by IL-37, contributing to an improvement in the treatment of tumors with CAR-T therapy.

It is now well-known that interleukins (ILs) play a pivotal role in shaping innate immunity: inflammatory ILs are responsible for all innate aspects of immune response, from the very first vascular reactions to the chronic non-specific response to inflammation; while anti-inflammatory ILs are responsible for keeping adaptive immunity at bay. The interactions between ILs and adaptive immunity have been long considered secondary to the effects on the innate immune system, but in recent years it has appeared more clearly that IL direct interactions with adaptive immunity are extremely important both in physiologic and pathologic immune response. In the present review we analyze the role of inflammatory ILs (IL-1, IL-6, IL-33 and IL-37) on adaptive immunity and briefly discuss the possible therapeutic perspectives of IL-blockade in adaptive immunity disorders.

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.

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.

The activation of brain nociceptors and neurons may lead to neurogenic inflammation, an event that involves immune cells including mast cells (MCs). Microglia are similar to macrophages and secrete pro-inflammatory IL-1 family members and TNF. TNF is rapidly released (first 10 minutes from MC granules) and is subsequently secreted along with other pro-inflammatory cytokines with a new synthesis after several hours. MC-derived TNF is a very powerful pro-inflammatory cytokine which mediates sensitization of the meningeal nociceptors. Here, we report the involvement of MCs in neuroinflammation, the role of inflammatory cytokine IL-1 family members, and of TNF, as well as the potential inhibition of IL-37.

Background Fibrosis involves the activation of inflammatory cells, leading to a decrease in physiological function of the affected organ or tissue. Aims To update and synthesize relevant information concerning fibrosis into a new hypothesis to explain the pathogenesis of fibrosis and propose potential novel therapeutic approaches. Materials and methods Literature was reviewed and relevant information is discussed in the context of the pathogenesis of fibrosis. Results A number of cytokines and their mRNA are involved in the circulatory system and in organs of patients with fibrotic tissues. The profibrotic cytokines are generated by several activated immune cells, including fibroblasts and mast cells (MCs), which are important for tissue inflammatory responses to different types of injury. MC-derived TNF, IL-1, and IL-33 contribute crucially to the initiation of a cascade of the host defence mechanism(s), leading to the fibrosis process. Inhibition of TNF and inflammatory cytokines may slow the progression of fibrosis and improve the pathological status of the affected subject. IL-37 is generated by various types of immune cells and is an IL-1 family member protein. IL-37 is not a receptor antagonist; it binds IL-18 receptor alpha (IL-18Rα) and delivers the inhibitory signal by using TIR8. It has been shown that IL-37 can be protective in inflammation and injury, and inhibits both innate and adaptive immunity. Discussion IL-37 may be useful for suppression of inflammatory diseases induced by inhibiting MyD88-dependent TLR signalling. In addition, IL-37 downregulates NF-κB induced by TLR2 or TLR4 through a mechanism dependent on IL-18Rα. Conclusion This review summarizes current knowledge on the role of MC in inflammation and tissue/organ fibrosis, with a focus on the therapeutic potential of IL-37-targeting cytokines.

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.

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.

The major aim of this study is to provide a review of the research studies regarding the clinical link between alexithymia and interleukins (IL). We performed a search for the relevant literature by using search terms as "alexithymia" combined with "interleukin or IL". A total of 9 original research studies were identified and included. Alexithymia was found to be prevalent in inflammatory response and associated with inflammatory cytokines. Our review emphasized for the first time the relationships of alexithymia with inflammatory response mediated by IL-1 family members. Therefore, the screening of alexithymic traits and the administration of appropriate psychological and psychotherapeutical interventions should be integral parts of disease management programs. Supplying such interventions will probably help with prevention of the development of the disease and/or its exacerbation by improving the quality of life of alexithymic individuals.

Mast cells (MCs) are mediators of allergy and inflammation and participate in the growth of cancer cells. MCs can promote both neoangiogenesis and tumor growth. They increase in the stroma of certain tumors where they can be recruited by tumor-derived chemoattractants, such as monocyte chemotactic protein-1 (MCP-1), RANTES and stem cell factor (SCF) to selectively secrete inflammatory molecules including chemical mediators and cytokines (TNF, IL-6 and IL-1). However, MC differentiation pathways and heterogeneity in cancer are still poorly understood. Human interleukin 1 (IL-1) plays a pivotal role in the pathogenesis of many diseases and functions, including host response to microbial invasion, injury inflammatory processes, immunologic challenges and cancer. Inflammation around the tumor includes the infiltration of mast cells and facilitates cancer growth. MCs are activated by IL-1 which can be produced by certain cancer cells and stimulate the stromal cells to selectively release IL-6, contributing to the development of Th-17 cells and increasing inflammation. IL-37, mainly generated by macrophage cell line, is an IL-1 family member which binds IL-18 receptor α (IL-18Rα) chain, and acts as a natural inhibitor of immune responses. IL-37 down-regulates cJun induced by IL-1, pro-inflammatory signals and reduces the expression of the mitogen-activated protein kinase (MAPK) p38α, STAT transcription factors and p53, affecting cellular differentiation and proliferation. In the present study we report the relationship between inflammatory mast cells, cancer and the beneficial effect of IL-37.