Mechanisms of allergic diseases in Otorhinolaryngology.

Allergic Rhinitis (AR) is an IgE-mediated hypersensitivity disease caused by inhalation of an allergen to which the patients is sensitized. Etiopathogenesis of AR comprises a sensitization phase, an immediate phase and a late phase. In the sensitization phase, inhaled allergens are processed in peptides and come into contact with the nasal mucosa cells. Antigen-Presenting Cells (APCs), especially represented by Dendritic Cells (DCs), capture them through the interaction with their own MHC class II complexes and migrate to lymph nodes. Then, allergenic peptides are presented to naïve CD4+ T lymphocytes and a differentiation of T cells in Th2 subset takes place. After Th2 lymphocyte induction due to allergen exposure, the most relevant cytokines that are produced are represented by IL-3, IL-4, IL-5, IL-9, IL-10, and IL-13 that are able to promote IgE synthesis and mast cell proliferation. The allergen reaction, when allergen meets its specific IgEs on mast cells surface, causes an early inflammatory reaction determined by mast cells and basophils degranulation with release of preformed mediators from the intracellular granules, resulting in symptoms such as rhinorrhea, itching and sneezing. This phase is followed by a late phase characterized by the release of newly formed mediators, like leukotrienes, chemokines and adhesion molecules, and by the recruitment of eosinophils, neutrophils, macrophages, mast cells, lymphocytes B and T in the nasal mucosa. Such mechanism is responsible for continuing inflammation sustained by chemoattractants, cytokines and adhesion receptors that induce cellular infiltration of eosinophils, basophils, Th2 lymphocytes and mast cells and is clinically mirrored by the prevalence of nasal congestion over sneezing, itching and rhinorrhea.

Periostin: The bone and beyond.

In recent years the relationship between bone, metabolism and many pathophysiologic mechanisms involving other organs and the immune system, was increasingly apparent. This observation concerns vitamin D, osteopontin and periostin (PO). PO is expressed in the periosteum of long bones but also in many other tissues and organs, including heart, kidney, skin and lungs, being enhanced by mechanical stress or injury. PO has a relevant physiological function in promoting injury repair in a large number of tissues. However, its overexpression was observed in different diseases characterized by inflammation, fibrosis and tumorigenesis. Here we review the current knowledge on the role of PO in physiologic and pathologic pathways of different diseases. A specific focus regards the correlation between the level of PO and lung diseases and the identification of PO also as an inflammatory key effector in asthma, strongly associated with airways eosinophilia. In fact PO seems to be a useful biomarker of "Th2-high" asthma compared to "Th2-low" asthma phenotype and a predictor of response to therapeutic agents. Currently, a growing number of studies suggests a possible role of PO as a new diagnostic marker and/or therapeutic target for different diseases and its usefulness in clinical practice should be supported and confirmed by further and larger studies.

Allergic rhinitis: pharmacotherapy in pregnancy and old age.

INTRODUCTION: Allergic rhinitis (AR) affects 20-30% of women in reproductive age and may worsen during pregnancy. About 10% of the elderly suffer from AR, and it could be under-diagnosed in these patients. Many drugs are currently available, however AR treatment during pregnancy and old age represents a challenging issue. AREAS COVERED: A review of the literature on the topic has been performed. Expert commentary: In pregnancy, drug avoidance should be carefully balanced with the need for AR optimal control. Topical drugs are suggested as a first approach. The safety and tolerability profile of second-generation antihistamines is well supported. If allergen immunotherapy (AIT) is ongoing and well tolerated, there is no reason for stopping it. AIT initiation in pregnancy is not recommended. For elderly patients, no specific concerns have been highlighted regarding topical treatments, except from nasal decongestionants. Second generation antihistamines are generally well tolerated. Old age should not preclude AIT.