Identification of IgE‐reactive proteins in patients with wheat protein contact dermatitis

Background: Wheat protein and its derivatives can cause protein contact dermatitis (PCD), which mainly occurs in bakers. Few studies have attempted to identify the allergens responsible for wheat PCD. Objectives: The aim of this study was to identify allergenic wheat proteins in patients with wheat PCD. Methods: Water‐soluble and water‐insoluble wheat flour proteins were separated by 1‐ or 2‐dimensional gel electrophoresis. IgE‐binding proteins were detected by immunoblotting with sera from 3 wheat PCD patients and identified by N‐terminal amino acid sequence analysis. The IgE‐binding proteins were recombinantly expressed in Escherichia coli and tested against patients' sera. Results: IgE antibodies from the patients' sera reacted with water‐soluble proteins rather than water‐insoluble proteins, and the 2‐dimensional electrophoresis and immunoblotting produced individual IgE‐binding patterns. Analysis of the N‐terminal amino acid sequence of the IgE‐binding proteins from the 2‐dimensional gel led to the identification of three glycoproteins, wheat 27‐kDa allergen, peroxidase, and purple acid phosphatase. No specific IgE antibodies to their non‐glycosylated recombinant proteins were observed. Conclusions: We identified wheat 27‐kDa allergen, peroxidase and purple acid phosphatase as candidate allergens for wheat PCD. Our results suggest that glycan moieties in these proteins are involved in IgE binding.     

诱发儿童特应性皮炎的三疣梭子蟹过敏原研究

目的 探讨诱发儿童特应性皮炎的三疣梭子蟹过敏原。 方法 对入选的儿童特应性皮炎患儿进行血清蟹过敏原特异性IgE抗体检测或蟹过敏原皮肤点刺试验,阳性者进行三疣梭子蟹口服食物激发试验,选择出对蟹过敏的患儿33例,留取血清作为实验组;选择同期健康体检儿童30例,留取血清作为对照组。选择新鲜的三疣梭子蟹,提取总蛋白,用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）、免疫印迹检测诱发儿童特应性皮炎的蟹过敏原。 结果 三疣梭子蟹蛋白粗提液可见条带有11条,相对分子质量分别为94 000、70 000、58 000、49 000、36 000、34 000、32 000、27 000、21 000、19 000、17 000。能引起实验组免疫反应的条带有4条,相对分子质量分别为70 000、58 000、49 000、36 000,实验组阳性率分别为93.9%、45.4%、39.4%、100%;对照组无阳性条带。将实验组相对分子质量70 000、58 000、49 000及36 000免疫条带阳性率分别与健康对照组比较,χ2分别为55.483、17.898、14.891、63.000,均P < 0.05。 结论 70 000、36 000蛋白是诱发儿童特应性皮炎的三疣梭子蟹主要过敏原。     

Health outcomes in atopic dermatitis

Atopic dermatitis is a chronic inflammatory skin disease that disrupts the daily work and social lives of patients. Treatment of atopic dermatitis makes use of a variety of therapies, from medications to nutritional supplements to psychotherapy. Health outcomes research evaluates the efficacy, safety, and impact on health-related quality of life of these therapies.     

IgE‐independent atopic dermatitis is associated with a β‐2 adrenergic receptor gene polymorphism

IgE levels are not elevated in about 20% of patients with atopic dermatitis (AD). In this intrinsic AD (IAD), allergic mechanisms are not very important and pathogeny could be mainly neurogenic. β2-adrenergic receptors are localized on cells involved in AD: Langerhans' cells, keratinocytes and lymphocytes. We wondered whether IAD could be associated with gene polymorphisms 16 and 27 of this receptor. We studied 98 healthy subjects and 83 subjects suffering from DA (UKWP criteria). IgE levels were normal in 12 of them and elevated in 71 (EAD). After DNA extraction, the genotyping was done by PCR and Direct Sequencing of candidate gene. Statistical analysis was performed with EPI-INFO 6.04 for χ² test. We found a significant association of Gln27Glu polymorphism with IAD ( P  = 0.00071 and χ² = 14.51). There was no difference between healthy subjects and EAD patients. Adrenergic receptor agonists are known to attenuate the proliferative response of human lymphocytes after activation, through the inhibition of interleukin-2 release. It is known that catecholamines inhibit the antigen-presenting capability of epidermal Langerhans' cells. Long-term agonist-promoted downregulation of receptor number is absent when glu is at position 27. We suggest that the suppression of inhibiting effects of catecholamines could be involved in IAD pathogeny. Dichotomic nature of AD (EAD and IAD) is also associated with polymorphisms (SNP) of the interleukin-4/interleukin-13 receptor gene and the differences of cutaneous variables (transepidermal water loss, capacitance and pH). Altogether, these findings indicate that IAD patients exhibit phenotypic and also genotypic features which differ from those patients with EAD. Otherwise, the presence of this polymorphism could provide an explication of rarity of hypertension with AD, because Glu27Gln has been identified as a susceptibility polymorphism for HTA.     

The sweat of patients with atopic dermatitis contains specific IgE antibodies to inhalant allergens

We have investigated levels of total and specific against inhalant allergens in the sweat of 15 patients with atopic dermatitis, 10 patients with allergic rhinitis and high levels of specific IgE in the serum, and five patients with psoriasis without atopy as controls, by means of various commercial methods such as fluorescence immunoassay, nephetometry, chemiluminescence assay, enzyme immunoassay and the radioallergosorbent lest. Total IgE and specific IgE antibodies were detectable in the sweat of patients with atopic dermatitis as well as of patients with allergic rhinitis alone. These levels of total IgE in the sweat correlated with the severity of the skin disease (P < 0·05). By means of the Ciba Corning assay (P < 0·001), the fluorescence immunoassay (P < 0·05) and the nephelometry assay (P < 0·05), positive correlations were then established between the levels of total IgE in the serum and the sweat. Moreover, specific IgE antibodies to birch pollen and Dermatophagoides pteronyssinus were detectable in the sweat and correlated positively with these specific IgE levels in the serum (P < 0·05). Further, the specific IgE levels against these allergens in the sweat also correlated with the severity of dermatitis (P < 0·05). It is suggested that these specific IgE antibodies against certain inhalant allergens in the sweat of patients with atopic dermatitis may play a role in allergen trapping in the skin.     

Interactions between FLG mutations and allergens in atopic dermatitis

Filaggrin gene (FLG) mutations and sensitization in patients with atopic dermatitis (AD) have been well documented. However, whether an interaction exists between these mutations and specific sensitization in AD patients is still unknown. The aim of the study was to explore the interaction between FLG mutations and specific sensitization in AD patients. A total of 249 AD outpatients were recruited in the current study. Skin prick tests were conducted to assess the patient??s sensitization to specific allergens. FLG mutations were analyzed through comprehensive sequencing. Logistic regression analyses were conducted to determine the interactions between FLG mutations and sensitization present. The mean age of the patients was 3.5?years, and the mean age of onset of AD was 9.6?months. The mean SCORAD of the patients was 25.8. Fourteen types of mutations were identified in the FLG of 64 patients. A total of 24 (9.6?%) and 29 (11.6?%) cases were mutated with 3321delA and K4671X, respectively. Sensitization to at least one type of allergen was detected in 118 patients (47.4?%). Logistic regression analyses showed that FLG mutations presented an interaction with sensitization to peanut and did not interact with the other detected allergens among AD patients. Sensitization to peanut allergens would have an interaction with the mutation of K4671X and the combined mutations in FLG in patients with atopic dermatitis. However, sensitization to the other common allergens might not interact with FLG mutations in the development of atopic dermatitis.     

Severity strata for five patient‐reported outcomes in adults with atopic dermatitis

Atopic dermatitis (AD, also known simply as eczema) is a skin disease that can cause itching (pruritus), sleep disturbance and impaired quality of life (QoL), often affecting everyday activities such as school and work, resulting in impaired mental health. During studies into eczema or when treating patients, doctors use a variety of systems that record how severe the person's eczema is. Some of these look at the physical symptoms, such as how severe the skin lesions (areas of affected skin) are. However, as mentioned above, many of the symptoms of the disease can't be measured by looking at the skin, and for these, different measurements of ‘Patient Reported Outcomes’ (PRO) are used, in which the patient answers questions about, for example, their quality of life, mood or itch severity. These measures are not always specific to eczema, and can be used across a range of skin disorders. Each PRO has a different numbers of questions, response options, and scoring systems, which can make it difficult to interpret the results across different PROs. Severity strata have been developed for some PROs, which attribute levels of severity to the results of the scores, so for example, in a PRO called POEM, a score of 0 to 7 is mild, 8 to 16 is moderate and 17 to 28 is severe. This study sought to confirm whether previously reported strata for the PRO's called POEM and DLQI are indeed accurate for adults with AD. They also sought to develop severity strata for PRO's that don't already have them: NRS‐itch, mean ItchyQOL and 5‐D itch scale. The authors confirm that existing strata for POEM and DLQI perform well in adult AD and suggested amendments and new strata for certain other PRO's.     

Skin prick testing to food allergens in breast-fed young infants with moderate to severe atopic dermatitis

SUMMARY The role of food allergy in atopic dermatitis is controversial. This study presents results of skin prick tests to 31 different food allergens in a selected population of predominantly breast-fed young infants who had moderate to severe generalized atopic dermatitis. Of the 59 infants (22 female, mean age 26.5 weeks) tested, 54 infants (91.5%) had positive responses to one or more foods, 53 infants (90%) were positive to one or more of the five common food allergens (egg white, cow's milk, peanuts, wheat or soy) and 80% were positive to egg white, which was by far the most common positive test. A total of 37 infants had strongly positive responses to one or more foods, with 33 of these 37 having strongly positive responses to egg white. The significance of these responses is discussed. It is concluded that positive skin prick tests to foods, particularly to egg white, are very common in this selected population of breast-fed infants with moderate to severe atopic dermatitis.     

Pediatric atopic dermatitis: the importance of food allergens

Food allergy and atopic dermatitis often occur in the same patients. Food-induced eczema may be perceived as a controversial topic because the immunologic mechanisms have yet to be fully elucidated. Nevertheless, published clinical studies have clearly demonstrated that foods can induce symptoms in a subset of patients with atopic dermatitis. Those at greatest risk are young children in whom eczematous lesions are severe or recalcitrant to therapy. Allergy testing can be helpful but must be applied judiciously. A medical history obtained by a skilled and knowledgeable health care provider is of paramount importance to interpret test results appropriately. Finally, the implementation of proper dietary avoidance can improve symptoms and provide safety from potentially fatal anaphylaxis. However, if inappropriate prescribed, elimination diets can have significant negative nutritional and social consequences.     

Sensitization to cockroach allergens evaluated by skin tests in children with atopic dermatitis

INTRODUCTION: Cockroach and house dust mites (Dermatophagoides pteronyssinus, Dp and farinae, Df) are the most often implicated aeroallergens in severe asthma, hay fever and conjunctivitis. Cockroach allergy is still unknown in atopic dermatitis.PATIENTS AND METHOD: 146 children with atopic dermatitis-aged 6 months to 15 years- have been patch tested with the European standard series and some aeroallergens. We have studied the sensitisation to cockroach allergens and compared to Dp and Df.RESULTS: 113 children reacted positively at least to one of the 3 aeroallergens (77 p. 100), 61 children had a positive reaction to cockroach (42 p. 100) and 29 simultaneously to the 3 allergens.DISCUSSION: Delayed hypersensitivity to house dust mites in young children with atopic dermatitis suggests early epicutaneous sensitization due to an altered epidermal barrier. For us, cockroach could also be implicated in some flare-ups of atopic dermatitis. Eviction of cockroach and house dust mite should be proposed for children with a positive patch test to cockroach.