Molluscum Contagiosum Virus: Biology and Immune Response.

Molluscum contagiosum virus is a poxvirus belonging to the Poxviridae family, which includes Orthopoxvirus, Parapoxvirus, Yantapoxvirus, Molluscipoxvirus, Smallpox virus, Cowpox virus and Monkeypox virus. MCV belongs to the genus Molluscipoxvirus and has a tropism for skin tissue. MCV infects keratinocytes and, after an incubation period of 2 weeks to 6 weeks, causes a breakdown of the skin barrier with the development of papules of variable size depending on the proper functioning of the immune response (both adaptive and acquired). MCV only infects humans and does not cause viraemia. MCV encodes for several inhibitory proteins responsible to circumvent the immune response through different signalling pathways. Individuals who can be infected with MCV are children, immunocompromised individuals such as organ transplant recipients and Human Immunodeficiency Virus (HIV)-infected individuals. Current treatments to manage MCV-induced lesions are different and include the use of immunomodulators, which, however, do not provide an effective response.

Molecular and Cellular Substrates for the Friedreich Ataxia. Significance of Contactin Expression and of Antioxidant Administration.

In this study, the neural phenotype is explored in rodent models of the spinocerebellar disorder known as the Friedreich Ataxia (FA), which results from mutations within the gene encoding the Frataxin mitochondrial protein. For this, the M12 line, bearing a targeted mutation, which disrupts the Frataxin gene exon 4 was used, together with the M02 line, which, in addition, is hemizygous for the human Frataxin gene mutation (Pook transgene), implying the occurrence of 82-190 GAA repeats within its first intron. The mutant mice phenotype was compared to the one of wild type littermates in regions undergoing differential profiles of neurogenesis, including the cerebellar cortex and the spinal cord by using neuronal (ß-tubulin) and glial (Glial Fibrillary Acidic Protein) markers as well as the Contactin 1 axonal glycoprotein, involved in neurite growth control. Morphological/morphometric analyses revealed that while in Frataxin mutant mice the neuronal phenotype was significantly counteracted, a glial upregulation occurred at the same time. Furthermore, Contactin 1 downregulation suggested that changes in the underlying gene contributed to the disorder pathogenesis. Therefore, the FA phenotype implies an alteration of the developmental profile of neuronal and glial precursors. Finally, epigallocatechin gallate polyphenol administration counteracted the disorder, indicating protective effects of antioxidant administration.

Protective Effects of Eicosapentaenoic Acid Plus Hydroxytyrosol Supplementation Against White Adipose Tissue Abnormalities in Mice Fed a High-Fat Diet.

OBJECTIVE: Obesity induced by high-fat diet (HFD) elicits white adipose tissue dysfunction. In this study, we have hypothesized that the metabolic modulator eicosapentaenoic acid (EPA) combined with the antioxidant hydroxytyrosol (HT) attenuates HFD-induced white adipose tissue (WAT) alterations. METHODS: C57BL/6J mice were administered with a HFD (60% fat, 20% protein, 20% carbohydrates) or control diet (CD; 10% fat, 20% protein, 70% carbohydrates), with or without EPA (50 mg/kg/day), HT (5 mg/kg/day), or both for 12 weeks. Determinations in WAT include morphological parameters, EPA and docosahexaenoic acid content in phospholipids (gas chromatography), lipogenesis, oxidative stress (OS) and inflammation markers, and gene expression and activities of transcription factors, such as sterol regulatory element-binding protein-1c (SREBP-1c), peroxisome proliferator-activated receptor-gamma (PPAR-γ), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) (p65 subunit) and nuclear factor erythroid 2-related factor 2 (Nrf2) (quantitative polymerase chain reaction and enzyme linked immunosorbent assay). RESULTS: HFD led to WAT hypertrophy in relation to PPAR-γ downregulation. WAT metabolic dysfunction was characterized by upregulation of lipogenic SREBP-1c system, mitochondrial energy metabolism depression, loss of the antioxidant Nrf2 signaling with OS enhancement, n-3 long-chain polyunsaturated fatty acids depletion and activation of the pro-inflammatory NF-κB system. EPA and HT co-supplementation diminished HFD-dependent effects additively, reaching values close or similar to controls. CONCLUSION: Data presented strengthen the importance of combined protocols such as EPA plus HT to attenuate metabolic-inflammatory states triggered by obesity.

Polyphenol Effects on Splenic Cytokine Response in Post-Weaning Contactin 1-Overexpressing Transgenic Mice.

BACKGROUND: In mice, postnatal immune development has previously been investigated, and evidence of a delayed maturation of the adaptive immune response has been detected. METHODS: In this study, the effects of red grape polyphenol oral administration on the murine immune response were explored using pregnant mice (TAG/F3 transgenic and wild type (wt) mice) as the animal model. The study was performed during pregnancy as well as during lactation until postnatal day 8. Suckling pups from polyphenol-administered dams as well as day 30 post-weaning pups (dietary-administered with polyphenols) were used. Polyphenol effects were evaluated, measuring splenic cytokine secretion. RESULTS: Phorbol myristate acetate-activated splenocytes underwent the highest cytokine production at day 30 in both wt and TAG/F3 mice. In the latter, release of interferon (IFN)-γ and tumor necrosis factor (TNF)-α was found to be higher than in the wt counterpart. In this context, polyphenols exerted modulating activities on day 30 TAG/F3 mice, inducing release of interleukin (IL)-10 in hetero mice while abrogating release of IL-2, IFN-γ, TNF-α, IL-6, and IL-4 in homo and hetero mice. CONCLUSION: Polyphenols are able to prevent the development of an inflammatory/allergic profile in postnatal TAG/F3 mice.

Effects of thermal water inhalation in chronic upper respiratory tract infections in elderly and young patients.

BACKGROUND: Chronic upper respiratory tract infections (cURTI) are very frequent illnesses which occur at any age of life. In elderly, cURTI are complicated by immunosenescence, with involvement of lung immune responsiveness. RESULTS: In the present study, 51 elderly (age range: 66-86) and 51 young (age range 24-58) cURTI patients underwent a single cycle (two weeks) of inhalatory therapy with salt-bromide-iodine thermal water in the thermal station "Margherita di Savoia" (Margherita di Savoia, BAT, Italy). Peripheral blood serum cytokines and clinical assessment were performed before therapy (T0) and after six months (T1) and 12 months (T2) from inhalatory treatment. In both elderly and young patients, at baseline an increased release of T helper (h)1-related cytokines [interleukin (IL)-2 and interferon-γ] and of Th2-related cytokine (IL-4) was documented. Inhalatory treatment reduced the excessive secretion of all the above-cited cytokines. IL-10 values were above normality at all times considered in both groups of patients. In addition, an increase in IL-17 and IL-21 serum levels following therapy was observed in both groups of patients. Pro-inflammatory cytokine (IL-1ß, IL-6, IL-8 and tumor necrosis factor-α) baseline values were lower than normal values at T0 in both elderly and young cURTI patients. Their levels increased following inhalatory treatment. Clinically, at T2 a dramatic reduction of frequency of upper respiratory tract infections was recorded in both groups of patients. CONCLUSION: Thermal water inhalation is able to modulate systemic immune response in elderly and young cURTI patients, thus reducing excessive production of Th1 and Th2-related cytokines, on the one hand. On the other hand, increased levels of IL-21 (an inducer of Th17 cells) and of IL-17 may be interpreted as a protective mechanism, which likely leads to neutrophil recruitment in cURTI patients. Also restoration of pro-inflammatory cytokine release following inhalatory therapy may result in microbe eradication. Quite importantly, the maintenance of high levels of IL-10 during the follow-up would suggest a consistent regulatory role of this cytokine in attenuating the pro-inflammatory arm of the immune response.

Functional foods and nutraceuticals as therapeutic tools for the treatment of diet-related diseases.

In Western societies, the incidence of diet-related diseases is progressively increasing due to greater availability of hypercaloric food and a sedentary lifestyle. Obesity, diabetes, atherosclerosis, and neurodegeneration are major diet-related pathologies that share a common pathogenic denominator of low-grade inflammation. Functional foods and nutraceuticals may represent a novel therapeutic approach to prevent or attenuate diet-related disease in view of their ability to exert anti-inflammatory responses. In particular, activation of intestinal T regulatory cells and homeostatic regulation of the gut microbiota have the potential to reduce low-grade inflammation in diet-related diseases. In this review, clinical applications of polyphenol-rich functional foods and nutraceuticals in postprandial inflammation, obesity, and ageing will be discussed. We have placed special emphasis on polyphenols since they are broadly distributed in plants.

The interaction between gut microbiota and age-related changes in immune function and inflammation.

Intestinal microbiota and gut immune systems interact each other, maintaining a condition of homeostasis in the context of the intestinal habitat. However, both systems undergo modifications in elderly, thus accounting for a low grade inflammatory status which, in turn, may evolve toward more severe pathological conditions such as inflammatory bowel disease and colon rectal cancer. In addition, in western societies dietary habits may negatively influence the microbiota composition, also altering gut immune response which is per se impaired in elderly. In order to prevent the outcome of aged-related disease, supplementation of nutraceuticals able to correct abnormalities of both immune system and microbiota has become more frequent than in the past. In this respect, a better identification of components of the aged microbiota as well as a deeper analysis of gut mucosal immunity function should be pursued.

Healthy effects exerted by prebiotics, probiotics, and symbiotics with special reference to their impact on the immune system.

Pre-, pro-, and symbiotics are endowed with a broad spectrum of beneficial effects when administered to animals and humans. A series of experimental and clinical studies have clearly demonstrated that prebiotics, probiotics, or their combination are very effective in attenuating chronic inflammatory conditions such as inflammatory bowel disease or obesity. In addition, these natural products are able to prevent or arrest tumor development, acting on the intestinal microbiota as well as potentiating the immune response.Aging is characterized by a dramatic reduction of both innate and adaptive immune responses, the so-called immunosenescence. This leads to an increased incidence of infections, autoimmune diseases, and cancer in the elderly. Pre-, pro-, and symbiotic administration has been shown to ameliorate the immune response in aging. In particular, administration of a symbiotic to free-living elderly was able to potentiate the release of interleukin-8, thus increasing neutrophils in the host, perhaps explaining the reduced frequency of winter infections in the elderly.

The Role of Nutrition During the COVID-19 Pandemic: What We Know.

BACKGROUND: Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) (COVID-19) infection provokes serious clinical consequences, which in many situations need hospitalization of the patient in Intensive Care Unit. Additionally, SARS-COV-2 infection can indirectly cause deaths in aged individuals as well as in patients with co-morbidities. OBJECTIVE: To evaluate the effects of nutrition during the COVID-19 pandemic in both hospitalized patients and the general population. METHODS: Authors searched Medline (PubMed), Web of Science, EMBASE, Cochrane Library, Google, and Institutional websites for medical subheadings terms and free full text referred to "SARS-CoV-2", COVID-19", "nutrition", "immune system", before 31st July 2020. RESULTS: A total of 20 articles describing different nutritional interventions for patients with SARS-- CoV-2 infection focusing on the general population have been included. Of these, 6 studies are dealing with nutritional interventions for patients with SARS-CoV2 infection. The others are focalized on a potential beneficial effect exerted by a Mediterranean diet (MD), related to the supplementation of micronutrients and vitamins. CONCLUSION: A correct lifestyle, including the consumption of nutrients largely present in MD, may be beneficial for preventing or improving prognosis in the SARS-CoV-2 infection.

Taking Advantage of Plant Defense Mechanisms to Promote Human Health. Exploitation of Plant Natural Products for Preventing or Treating Human Disease: Second of Two Parts.

BACKGROUND: Plants have been regarded as essential source of food for human beings, as confirmed by archeological studies that have revealed the presence of proteins from cereals and legumes on old pottery. SPECIFIC AIMS: In this review, major health effects derived from the consumption of plant fibers, polyunsaturated fatty acids (PUFAs) and polyphenols, respectively, will be described with special emphasis on their mechanisms of action, both at cellular and molecular levels. Dietary Compounds: Fibers exhibit a prevalent prebiotic effect, acting on the intestinal microbiota with the production of protective metabolites, such as short chain fatty acids. Plant PUFAs include α-linolenic and stearidonic acids, which are the precursors of other two major PUFAs, namely, eicosapentaenoic and docosahexaenoic acids. Some clinical trials demonstrated the ability of PUFAs to lower the risk of coronary disease, while other trials did not confirm such a finding. Polyphenols are endowed with anti-oxidant and anti-inflammatory activity in view of their property to inhibit NF-κB activation, to induce the anti-inflammatory T regulatory cells and to normalize the intestinal microbiota. The beneficial effects of polyphenols on obesity/diabetes, allergic/autoimmune and inflammatory disease are elucidated. CONCLUSION: Plants are one of the major sources of healthy dietary products, whose exploitation may promote prevention of chronic disease.

Platelets: Angels and Demons Dancing on the Immune Stage. Nutrition Conducts the Orchestra.

Platelets are cellular fragments derived from bone-marrow megacaryocytes and they are mostly involved in the haemostasis and coagulation. However, according to recent data, platelets are able to perform novel immune functions. In fact, they possess a receptorial armamentarium on their membrane for interacting with innate and adaptive immune cells. In addition, platelets also secrete granules which contain cytokines and chemokines for activating and recruiting even distant immune cells. The participation of platelets in inflammatory processes will also be discussed in view of their dual role in terms of triggering or resolving inflammation. Involvement of platelets in disease will be illustrated, pointing to their versatile function to either up- or down-regulate pathological mechanisms. Finally, despite the availability of some anti-platelet agents, such as aspirin, dietary manipulation of platelet function is currently investigated. In this regard, special emphasis will be placed on dietary omega-3 polyunsaturated fatty acids (PUFAs) and polyphenol effects on platelets. Platelets play a dual role in inflammatory-immune-mediated diseases either activating or deactivating immune cells. Diet based on substances, such as omega-3 PUFAs and polyphenols, may act as a modulator of platelet function, even if more clinical trials are needed to corroborate such a contention.

Taking Advantage of Plant Defense Mechanisms to Promote Human Health. The Plant Immune System. First of Two Parts.

Despite the evidence that plants do not possess sessile cells, they are able to mount a vigorous immune response against invaders or under stressful conditions. Plants are endowed with pattern recognition receptors (PPRs) which perceive damage-associated molecular patterns and microbe- associated molecular patterns or pathogen-associated molecular patterns (PAMPs), respectively. PPR activation leads to either the initiation of PAMP-triggered immunity (PTI) (early response) or the effector-triggered immunity (ETI). Both PTI and ETI contribute to plant systemic acquired resistance as an expression of immunological memory or trained immunity. PTI is initiated by activation of both receptor-like kinases and receptor-like proteins, while ETI depends on nucleotide- binding leucine-rich-repeat protein receptors for microbe recognition. Plant chloroplasts contribute to both PTI and ETI through the production of peptides, which act as hormones or phytocytokines. Salicylic acid, jasmonic acid and ethylene are the major compounds involved in plant defense. The interaction between plant receptors and/or their products and bacterial components will be discussed. Also, emphasis will be placed on plant microbiome for its contribution to plant immune response. Finally, the mutual interplay between insects and plants will also be illustrated. A better knowledge of plant immunity may pave the way for the exploitation of plant derivatives in the field of agriculture and medicine, as well.

Exploitation of Some Natural Products for the Prevention and/or Nutritional Treatment of SARS-CoV2 Infection.

Dietary habits strongly influence our health status, mostly in terms of maintenance of the inflammatory/anti-inflammatory homeostasis. High fat and high sugar diets account for the development of a low-grade inflammation, which is the pathogenic common denominator of various chronic diseases. Severe Acute Respiratory Syndrome Coronavirus (SARS)-CoV2 (COVID-19) infection affects all ages and especially frail elderly people and a nutritional intervention seems to be crucial in the course of this pandemic. The present review describes the properties of some vegetal products and their derivatives, such as Lupin sp., garlic, salvia and extra virgin olive oil (EVOO) that can be exploited for their beneficial effects, as preventive and/or nutritional treatment of coronavirus disease SARS-CoV2. Lupin, salvia, garlic and EVOO share overlapping properties, such as anti-oxidant, anti-inflammatory and anti-viral activities. Quite importantly, these products and their derivatives are able to recover the expression of angiotensin converting enzyme expression 2 on cell membrane, otherwise suppressed by COVID-19 binding and entry into cytoplasm. Dietary administration of the above nutraceuticals or their extracts may play a preventive or nutritional role in the course of SARS-CoV2 infection, even including the effects of the lockdown and the condition of inflamm-ageing.

Red Grape Polyphenol Oral Administration Improves Immune Response in Women Affected by Nickel-Mediated Allergic Contact Dermatitis.

BACKGROUND: Our previous findings demonstrated that in vitro supplementation of polyphenols, extracted from seeds of red grape (Nero di Troia cultivar), to peripheral lymphomonocytes from patients affected by allergic contact dermatitis (ACD) to nickel (Ni) could reduce the release of proinflammatory cytokines and nitric oxide (NO), while increasing the levels of interleukin (IL)-10, an anti-inflammatory cytokine. OBJECTIVE: To assess whether an intervention with oral administration of polyphenols leads to a reduction of peripheral biomarkers in ACD patients. METHODS: At T0, 25 patients affected by ACD to Ni were orally administered with 300 mg polyphenols prodie extracted from seeds of red grape (Nero di Troia cultivar) (NATUR-OX®) for 3 months (T1). The other 25 patients affected by ACD to Ni received placebo only for the same period of time. Serum biomarkers were analyzed at T0 and T1. In both groups, seven dropouts were recorded. RESULTS: At T1 in comparison to T0, in treated patients, values of interferon-γ, IL-4, IL-17, pentraxin 3 and NO decreased, while IL-10 levels increased when compared with T0 values. Conversely, in placebo- treated patients, no modifications of biomarkers were evaluated at T1. CONCLUSION: Present laboratory data rely on the anti-oxidant, anti-inflammatory and anti-allergic properties of polyphenols.

Worse progression of COVID-19 in men: Is testosterone a key factor?

BACKGROUND: The novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) disease 2019 (COVID-19) seems to have a worse clinical course among infected men compared with women, thus highlighting concerns about gender predisposition to serious prognosis. Therefore, androgens, particularly testosterone (T), could be suspected as playing a critical role in driving this excess of risk. However, gonadal function in critically ill men is actually unknown, mainly because serum T concentration is not routinely measured in clinical practice, even more in this clinical context. OBJECTIVE: To overview on possible mechanisms by which serum T levels could affect the progression of COVID-19 in men. METHODS: Authors searched PubMed/MEDLINE, Web of Science, EMBASE, Cochrane Library, Google, and institutional websites for medical subject headings terms and free text words referred to "SARS-CoV-2," "COVID-19," "testosterone," "male hypogonadism," "gender" "immune system," "obesity," "thrombosis" until May 19th 2020. RESULTS: T, co-regulating the expression of angiotensin-converting enzyme 2 and transmembrane protease serine 2 in host cells, may facilitate SARS-CoV-2 internalization. Instead, low serum T levels may predispose to endothelial dysfunction, thrombosis and defective immune response, leading to both impaired viral clearance and systemic inflammation. Obesity, one of the leading causes of severe prognosis in infected patients, is strictly associated with functional hypogonadism, and may consistently strengthen the aforementioned alterations, ultimately predisposing to serious respiratory and systemic consequences. DISCUSSION AND CONCLUSION: T in comparison to estrogen may predispose men to a widespread COVID-19 infection. Low serum levels of T, which should be supposed to characterize the hormonal milieu in seriously ill individuals, may predispose men, especially elderly men, to poor prognosis or death. Further studies are needed to confirm these pathophysiological assumptions and to promptly identify adequate therapeutic strategies.

Editorial on the Occasion of the 20th Anniversary of Endocrine Metabolic Immune Disorders-Drug Targets Journal with a Kaleidoscopic Vision of Selected Publications.

Over the past 20 years, Endocrine Metabolic Immune Disorders-Drug Targets (EMIDDT) journal has been covering a broad field of intertwined topics related to pathogenesis, diagnosis, and therapy of endocrine, metabolic, and immune diseases. At first, the journal publications were restricted to reviews only and, then, original article submissions have also been accepted. EMIDDT represents as a successful journal in continuous expansion with 10 issues in 2020 and a current impact factor (IF) equal to 1.973. Moreover, since 2019, EMIDDT is the official journal of the Italian AME (Associazione Medici Endocrinologi), also linked to the American Association of Endocrinologists. Such a connection has given more impetus to the journal in terms of additional higher-quality submissions. In order to celebrate the 20th anniversary of EMIDDT, the content of some original representative articles published by the journal in the past and current years will be illustrated with special emphasis on cellular and molecular bases of drug targeting.

Eosinophils, a Jack of All Trades in Immunity: Therapeutic Approaches for Correcting Their Functional Disorders.

BACKGROUND AND OBJECTIVE: Eosinophils are primitive myeloid cells derived from bonemarrow precursors and require the intervention of interleukin (IL)-5 for their survival and persistence in blood and tissues. Under steady-state conditions, they contribute to immune regulation and homeostasis. Under pathological circumstances, eosinophils are involved in host protection against parasites and participate in allergy and inflammation. DISCUSSION: Mostly, in asthma, eosinophils provoke airway damage via the release of granule contents and IL-13 with mucus hypersecretion and differentiation of goblet cells. Then, tissue remodeling follows with the secretion of transforming growth factor-ß. Eosinophils are able to kill helminth larvae acting as antigen-presenting cells with the involvement of T helper (h)-2 cells and subsequent antibody response. However, they also exert pro-worm activity with the production of suppressive cytokine (IL- 10 and IL-4) and inhibition of nitric oxide. Eosinophils may play a pathogenic role in the course of chronic and autoimmune disease, e.g., inflammatory bowel disease and eosinophilic gastroenteritis, regulating Th2 responses and promoting a profibrotic effect. In atopic dermatitis, eosinophils are commonly detected and may be associated with disease severity. In cutaneous spontaneous urticaria, eosinophils participate in the formation of wheals, tissue remodeling and modifications of vascular permeability. With regard to tumor growth, it seems that IgE can exert anti-neoplastic surveillance via mast cell and eosinophil-mediated cytotoxicity, the so-called allergo-oncology. From a therapeutic point of view, monoclonal antibodies directed against IL-5 or the IL-5 receptors have been shown to be very effective in patients with severe asthma. Finally, as an alternative treatment, polyphenols for their anti-inflammatory and anti-allergic activities seem to be effective in reducing serum IgE and eosinophil count in bronchoalveolar lavage in murine asthma. CONCLUSION: Eosinophils are cells endowed with multiple functions and their modulation with monoclonal antibodies and nutraceuticals may be effective in the treatment of chronic disease.

Impact of Heavy Metals on Host Cells: Special Focus on Nickel-Mediated Pathologies and Novel Interventional Approaches.

BACKGROUND: Heavy metals [arsenic, aluminium, cadmium, chromium, cobalt, lead, nickel (Ni), palladium and titanium] are environmental contaminants able to impact with host human cells, thus, leading to severe damage. OBJECTIVE: In this review, the detrimental effects of several heavy metals on human organs will be discussed and special emphasis will be placed on Ni. In particular, Ni is able to interact with Toll-like receptor-4 on immune and non-immune cells, thus, triggering the cascade of pro-inflammatory cytokines. Then, inflammatory and allergic reactions mediated by Ni will be illustrated within different organs, even including the central nervous system, airways and the gastrointestinal system. DISCUSSION: Different therapeutic strategies have been adopted to mitigate Ni-induced inflammatoryallergic reactions. In this context, the ability of polyphenols to counteract the inflammatory pathway induced by Ni on peripheral blood leukocytes from Ni-sensitized patients will be outlined. In particular, polyphenols are able to decrease serum levels of interleukin (IL)-17, while increasing levels of IL- 10. These data suggest that the equilibrium between T regulatory cells and T helper 17 cells is recovered with IL-10 acting as an anti-inflammatory cytokine. In the same context, polyphenols reduced elevated serum levels of nitric oxide, thus, expressing their anti-oxidant potential. Finally, the carcinogenic potential of heavy metals, even including Ni, will be highlighted. CONCLUSION: Heavy metals, particularly Ni, are spread in the environment. Nutritional approaches seem to represent a novel option in the treatment of Ni-induced damage and, among them, polyphenols should be taken into consideration for their anti-oxidant and anti-inflammatory activities.

Mast Cells as a Double-Edged Sword in Immunity: Their Function in Health and Disease. First of Two Parts.

Mast cells (MCs) have recently been re-interpreted in the context of the immune scenario in the sense that their pro-allergic role is no longer exclusive. In fact, MCs even in steady state conditions maintain homeostatic functions, producing mediators and intensively cross-talking with other immune cells. Here, emphasis will be placed on the array of receptors expressed by MCs and the variety of cytokines they produce. Then, the bulk of data discussed will provide readers with a wealth of information on the dual ability of MCs not only to defend but also to offend the host. This double attitude of MCs relies on many variables, such as their subsets, tissues of residency and type of stimuli ranging from microbes to allergens and food antigens. Finally, the relationship between MCs with basophils and eosinophils will be discussed.

Mast Cells as a Double Edged Sword in Immunity: Disorders of Mast Cell Activation and Therapeutic Management. Second of Two Parts.

Mast cells (MCs) bear many receptors that allow them to respond to a variety of exogenous and endogenous stimuli. However, MC function is dual since they can initiate pathological events or protect the host against infectious challenges. The role of MCs in disease will be analyzed in a broad sense, describing cellular and molecular mechanisms related to their involvement in auto-inflammatory diseases, asthma, autoimmune diseases and cancer. On the other hand, their protective role in the course of bacterial, fungal and parasitic infections will also be illustrated. As far as treatment of MC-derived diseases is concerned, allergen immunotherapy as well as other attempts to reduce MC-activation will be outlined according to the recent data. Finally, in agreement with current literature and our own data polyphenols have been demonstrated to attenuate type I allergic reactions and contact dermatitis in response to nickel. The use of polyphenols in these diseases will be discussed also in view of MC involvement.