Novel insights in the pathogenesis of congenital immunodeficiencies”

The immune system is a complex integrated network of chemical and cellular mediators that developed during evolution to defend the body from any form of chemical, traumatic or infective insult to their integrity. A proper immune response relies on the innate immunity, that is responsible for a first line of defense against aggression and the aspecific recognition of a limited repertoire of antigens, and, later, on the adaptative immunity which includes chemical and cellular mediators responsible for a more powerful and specific defensive response from any form of antigen. Alterations of any part of the immune response results in failure of host defense and, in particular, of immunodeficiency, autoimmunity and cancer predisposition. Recent evidence highlights that the skin participates in a host defenses either acting as a primary boundary for germs, as the principal site of environment–host interactions, or directly in the developmental process of the immune system. As a matter of fact, skin and skin annexa abnormalities, such as skin dryness, brittleness of hair, nail abnormalities and abnormal dentition, can be not infrequently associated with distinct forms of immunodeficiency and may be a warning sign of immunodeficiency, since both epidermal and thymic epithelium have ectodermal origin. Severe combined immunodeficiency diseases (SCIDs) represent a heterogeneous group of rare genetic syndromes responsible for severe dysfunctions of the immune system, which share similar clinical manifestations. SCID is the most severe form of inherited primary immunodeficiency (PID) and its prevalence is approximately 1:100,000 live births, with a higher prevalence in males (1). SCIDs are difficult to recognize clinically because so many different infectious scenarios can occur. Without a functional cellular and humoral immune system SCID patients are susceptible to recurrent infections such as severe bacterial, viral, or fungal infections early in life and often present with interstitial lung disease, chronic diarrhea, and ...