Skin tests are important in children with ß-lactam hypersensitivity, but may be reduced in number.

BACKGROUND: There is no perfect agreement on how to perform an allergy workup in suspected beta-lactam (BL)-allergic children, since skin test (ST)-induced pain is often a limitation. The aim of the study was to assess the possibility of reducing the number of ST in children when performing a complete allergy workup for BL hypersensitivity reactions. METHODS: A retrospective analysis of all patients referring to the Allergy Unit of the University Hospital of Montpellier (France) with positive responses in immediateand non-immediate-reading ST to a BL over a 16-year period was performed, to determine the positive predictive value (PPV) of ST. All pediatric patients with a suspected BL hypersensitivity were skin-tested with the suspected drug only, during the following 54 months. RESULTS: A total of 319 patients reporting 328 BL reactions were included in the retrospective study. The PPV of ST for the reported drug was of 99.4%. Based on the results, the number of patients to include in the prospective study was estimated to be 101. In the prospective study, 229 children were included. We diagnosed a BL hypersensitivity in 12 children (5.2%): Diagnosis was reached in 6 (50.0%) through ST (delayed reading for all) and in 6 through drug provocation test (DPT). CONCLUSION: ST with BL should therefore be performed as a screening test, before DPT, and testing only the suspected drug may be sufficient when dealing with children.

Autoimmunity in atopic dermatitis: biomarker or simply epiphenomenon?

The idea that a mechanism of autoimmunity could play a role in the pathogenesis of atopic dermatitis gained support from the observation that patients with atopic dermatitis display IgE reactivity to a variety of human protein antigens, several of which have been characterized at molecular level. A broad spectrum of at least 140 IgE-binding self-antigens associated with atopic dermatitis has been demonstrated; they might promote, perpetuate, or both, skin inflammation by binding IgE antibodies or activating specific T cells. Even if the presence of autoreactivity seems to be associated with the severity of the disease and may be used as a parameter reflecting chronic tissue damage, at the state of art the role of autoimmunity in atopic dermatitis is far from clear. Data from the literature show that the use of autoantibodies as biomarkers of atopic dermatitis are still limited by the evidence that the epiphenomenon of autoreactivity is detectable only in a percentage of patients and that the involved self-allergens often are not the same; further longitudinal case-control studies are needed to investigate and to clarify the pathogenethic role of autoimmunity in the course of atopic dermatitis.

Microbiota in healthy skin and in atopic eczema.

The Italian interest group (IG) on atopic eczema and urticaria is member of the Italian Society of Allergology and Immunology. The aim of our IG is to provide a platform for scientists, clinicians, and experts. In this review we discuss the role of skin microbiota not only in healthy skin but also in skin suffering from atopic dermatitis (AD). A Medline and Embase search was conducted for studies evaluating the role of skin microbiota. We examine microbiota composition and its development within days after birth; we describe the role of specific groups of microorganisms that colonize distinct anatomical niches and the biology and clinical relevance of antimicrobial peptides expressed in the skin. Specific AD disease states are characterized by concurrent and anticorrelated shifts in microbial diversity and proportion of Staphylococcus. These organisms may protect the host, defining them not as simple symbiotic microbes but rather as mutualistic microbes. These findings reveal links between microbial communities and inflammatory diseases such as AD and provide novel insights into global shifts of bacteria relevant to disease progression and treatment. This review also highlights recent observations on the importance of innate immune systems and the relationship with normal skin microflora for the maintenance of healthy skin.

Probiotics and food allergy.

The exact prevalence of food allergy in the general population is unknown, but almost 12% of pediatric population refers a suspicion of food allergy. IgE mediated reactions to food are actually the best-characterized types of allergy, and they might be particularly harmful especially in children. According to the "hygiene hypothesis" low or no exposure to exogenous antigens in early life may increase the risk of allergic diseases by both delaying the development of the immune tolerance and limiting the Th2/Th1 switch. The critical role of intestinal microbiota in the development of immune tolerance improved recently the interest on probiotics, prebiotics, antioxidants, polyunsaturated fatty acid, folate and vitamins, which seem to have positive effects on the immune functions.Probiotics consist in bacteria or yeast, able to re-colonize and restore microflora symbiosis in intestinal tract. One of the most important characteristics of probiotics is their safety for human health. Thanks to their ability to adhere to intestinal epithelial cells and to modulate and stabilize the composition of gut microflora, probiotics bacteria may play an important role in the regulation of intestinal and systemic immunity. They actually seem capable of restoring the intestinal microbic equilibrium and modulating the activation of immune cells.Several studies have been recently conducted on the role of probiotics in preventing and/or treating allergic disorders, but the results are often quite contradictory, probably because of the heterogeneity of strains, the duration of therapy and the doses administered to patients. Therefore, new studies are needed in order to clarify the functions and the utility of probiotics in food allergies and ion other types of allergic disorders.

Impact of child obesity on adipose tissue physiology: assessment of adipocytokines and inflammatory cytokines as biomarkers of obesity.

Obesity could be interpreted as a low grade inflammatory state. The role of cytokines for innate and acquired immune response and adipocytokines in pathogenesis of obesity is not completely understood. The aim of the study was to evaluate anthropometric parameters, adipocytokines and inflammatory cytokine levels as biomarkers of childhood obesity. This investigation was designed as a longitudinal observational study. Forty-seven obese children (19 males and 28 females) were enrolled by Pediatric Clinic of the Foundation IRCCS Policlinico San Matteo, Pavia, Italy. For each patients a blood sample, used for other biochemical evaluations, was collected. Cytokines and adipocytokines plasmatic levels were determined using an ELISA method. Plasma leptin levels are in correlation with age (r=0.5; P<0.001) and BMI-z score (r=0.36; P<0.001), particularly in girls; plasma resistin levels are in inverse correlation with age, particularly in boys (r=-0.67; P<0.001) and in correlation with BMI-z score (r=0.52; P=0.002). Plasma leptin and resistin levels show a good correlation with antrophometric parameters of child obesity (sex and BMI z score). This study suggests that leptin and resistin can be considered as biomarker of childhood obesity and its comorbility. We observed a statistically significant correlation between plasma leptin and resistin levels and antrophometric parameters of child obesity (sex and BMI z score). This study suggests that adipocytokines, such as leptin and resistin, can be considered as biomarkers of childhood obesity.