Library

Notes: In this study we evaluated antigen-specific in vitro responses of peripheral blood lymphocytes to lipopoiysaccharide (LPS)-depleted food allergens in children who reacted to food challenge (cow's milk or hen's egg) with a deterioration of their atopic dermatitis (AD). Some ofthe children showed immediate symptoms (urticaria, bronchial asthma or gastrointestinal symptoms) as well. The proliferation of casein-stimulated lymphocytes from children reacting to cow's milk (age (0.7–5.9 years) was significantly higher (P〈0.01) than the proliferation of lymphocytes from 15 children with AD without milk allergy (age: 2.1–9.1 years). Twenty-eight T-cell clones (TCC) were established from the blood of three children sensitized to cow's milk and hen's egg who reacted to double-blind, placebo-controlled oral food challenge both with a deterioration of AD and wilh immediate symptoms. Surprisingly, 16 of 28 casein- or ovalhumin-specific TCC were CD8+. All TCC produced high amounts of IFN-γ upon stimulation with concanavalin A. In addition. 75%. of the CD4+ TCC and 44% of the CD8+ TCC secreted IL-4. Our results indicate that: (i) food-specific proliferation of blood lymphocytes can be detected in patients with clinically relevant food allergy with LPS-depleted allergens in vitro and (ii) circulating food-specific lymphocytes are CD4+ and CD8+ T cells with the capacity of producing both type 1 and type 2 cytokines.

Notes: In order to establish a noninvasive method of monitoring immediate hypersensitivity reactions in children, we studied the diurnal variation of urinary histamine and 1-methylhistamine excretion and the influence of food intake in a group of 14 healthy nonatopic children (aged 2–16 years). Histamine and 1-methylhistamine in spontaneous urine samples were determined by radioimmunoassay. Mean variation of 2–h intervals was much higher for urinary histamine than for 1-methylhistarnine (45% of base-line level versus 24%). There was no circadian rhythm or influence of food intake. The short half-life of histamine released into blood circulation may be the main reason for the higher variation of histamine excretion. In children, urinary 1-methylhistamine is less influenced by diurnal variation and is therefore more suited to monitor immediate hypersensitivity reactions than urinary histamine itself.

Notes: Background:  Double-blind, placebo-controlled food challenges are time-consuming, expensive and not without risk to patients. Therefore, an in vitro test that could accurately diagnose food allergy would be of great value.Objective:  To evaluate the utility of the ratio of specific immunoglobulin E (IgE)/total IgE compared with specific IgE (sIgE) alone in predicting symptomatic food allergy.Methods:  We retrospectively analysed 992 controlled oral food challenges performed in 501 children (median age 13 months). The ratio of sIgE/total IgE was calculated and tested for correlation with the outcome of food challenges. Receiver operator characteristics (ROC)-curves were performed; predicted probabilities and predictive decision points were calculated.Results:  A significant correlation was found between the ratio and the outcome of food challenges for cow's milk (CM), hen's egg (HE), and wheat, but not for soy. The ROC and predicted probability curves as well as sensitivity and specificity of the decision points of the ratio were similar to those of sIgE levels for CM, HE and wheat.Conclusion:  In view of the greater effort needed to determine the ratio, without benefit compared with the sIgE alone, the calculation of the ratio of sIgE/total IgE for diagnosing symptomatic food allergy offers no advantage for CM, HE, wheat or soy. For the majority of cases controlled oral food challenges still remain the method of choice.

Notes: The diagnostic work-up of suspected food allergy includes the skin prick test (SPT), the measurement of food specific immunoglobulin E (IgE) antibodies using serologic assays, and more recently the atopy patch test (APT). For specific serum IgE and the SPT, decision points have been established for some foods allowing prediction of clinical relevance in selected cases. The APT may be helpful, especially when considered in combination with defined levels of specific IgE. Controlled oral food challenges still remain the gold standard in the diagnostic work-up of children with suspected food allergy. Most food allergic children will lose their allergy over time. As there is no laboratory parameter, which can accurately predict when clinical tolerance has been developed, controlled oral food challenges are the measure of choice. In this article, the current knowledge of predictors for the outcome of oral food challenges is reviewed and proposals for the daily practical work-up in the case of suspected food related clinical symptoms are presented.

Notes: Background:  Controversial data have emerged regarding the question whether cat exposure in childhood favours or decreases the risk of sensitization and allergic airway disease. In a prospective birth-cohort study, we assessed the association between longitudinal cat allergen exposure, sensitization (immunoglobulin E, IgE), IgG antibody (ab) levels to cat and the development of asthma in children up to the age of 10 years.Methods:  Of 1314 newborn infants enrolled in five German cities in 1990, follow-up data at age 10 years were available for 750 children. Assessments included yearly measurements of specific serum IgE to cat and at age 6 and 18 months, 3, 4 and 10 years measurement of cat allergen Fel d 1 in house dust samples. Additionally, Fel d 1-specific IgG ab were determined in 378 serum samples of 207 children. Endotoxin exposure in mattress dust was measured in a subgroup of 153 children at age 10 years. From age 4 years on, International Study of Asthma and Allergy in Childhood (ISAAC) questionnaires were completed yearly in order to assess the prevalence of wheeze and asthma.Results:  Serum IgG-levels to cat showed a large variation, however, intraindividually values showed rather constant concentration over a longer time period. The IgG levels at school-age correlated with cat allergen exposure during the first 2 years of life. Specific IgE to cat was clearly associated with wheeze ever, current wheeze and bronchial hyperresponsiveness (BHR), this was also observed for children with specific IgE ab to cat (〉0.35 kU/l) plus IgG levels above 125 U/ml. A large percentage of very highly exposed children showed high IgG but no IgE responses to cat, however, not all highly exposed children were found to be protected from sensitization. Children with IgG but without IgE ab to cat showed the lowest prevalence of wheeze ever and current wheeze despite high cat allergen exposure, however, this trend did not achieve significance. While homes of cat owners showed higher Fel d 1 concentrations than homes without cats, homes of cat owners were not found to have higher endotoxin levels in carpet dust samples than homes without cats.Conclusions:  We could confirm that high cat allergen exposure in a cohort with lower community prevalence of cats is associated with higher serum IgG and IgE levels to cat in schoolchildren. Sensitization to cat allergen (IgE) is a risk factor for childhood asthma. While exposure to cat allergen during infancy is associated with sensitization (IgE), only in the very highly exposed children the likelihood of sensitization (IgE) is decreased and high IgG levels to cat without IgE were associated with low risk of wheeze. However, cat-specific IgG ab levels did not protect children with IgE-mediated sensitization from wheeze.

Notes: Not too long ago, physicians took ‘compliance’ or ‘adherence’ to mean the strict obedience of patients and parents – doing what the physician said, suggesting that the success or failure of the treatment lay entirely in the hands of the patient. But it is preferable to improve compliance rather than enforce it. As there is no single solution that will ensure compliance, several steps should be taken: (i) ‘exploration’ includes open questions, and allows admission of non-compliance, e.g. in terms of failure to take drugs, or smoking; (ii) ‘education’ means explaining pathomechanisms, and reducing corticophobia; (iii) ‘tailoring’ is reached by focussing therapeutic options on individual requirements, and simplifying treatment regimens; (iv) ‘contracting’ involves negotiating a realistic therapeutic regimen on an individual basis; (v) ‘reminders’ are practical tips, which may help to overcome reluctance, e.g. by placing drugs in the toothbrush glass, and on the breakfast table, or in the sports bag; (vi) ‘follow-up’ ensures long-term compliance, with regular visits to the physician, and self-management programmes. In conclusion, non-compliance of patients and parents is a challenging problem in daily practice. Including the aspects of the abovementioned factors can help build up a relation of trust and partnership, which is the prerequisite of any therapeutic success. However, this is an ongoing process, which has to be continuously reviewed.

Notes: Background:  Severe anaphylactic reactions are medical emergencies requiring immediate recognition and treatment. Despite this, little is known on their clinical features, especially in infants and children.Objective:  To evaluate trigger factors, patterns of clinical reaction, site of occurrence and treatment modalities of reported reaction in infants and children below 12 years of age in Germany.Methods:  Paediatricians throughout Germany were asked by questionnaire to report accidental anaphylactic reactions over the previous 12 months. Severity of reported reactions was classified in grades I–IV according to reported symptoms.Results:  Hundred and three cases of anaphylaxis were evaluated. Median age was 5 years, 58% were boys. Site of occurrence was the child's home in the majority of cases (58%). Foods were the most common causative allergen (57%), followed by insect stings (13%) and immunotherapy (SIT) (12%); in 8% anaphylactic agent was unknown. Among foods, peanuts and tree nuts were the most frequent allergens (20% of food allergens in each case). Severe reactions with cardiovascular involvement occurred in 24% of cases. No fatal reaction was observed. Recurrent episodes of anaphylaxis were reported in 27% of cases, half of these caused by the same allergen again. For treatment, 20% of children received adrenaline, in 8% of cases intravenously. Thirty-six per cent of patients with grade-IV reactions received adrenaline, 24% intravenously. In 17% of all children an adrenaline self-injector was prescribed after the episode.Conclusion:  Our data: (i) shows an uncertainty of physicians in diagnosing anaphylaxis, (ii) reveals remarkable under-treatment of the majority of children with anaphylaxis, (iii) reflects the need for guidelines and training for physicians in managing children with anaphylaxis and (iv) should encourage the development of self-management programmes for patients and families.

Notes: The diagnosis of food allergy in infants and children is still a challenging task for the pediatrician. While immediate-type allergic reactions to foods can be diagnosed quite easily, late-phase reactions, e.g. in atopic dermatitis, often represent a diagnostic challenge. Once classical diagnostic procedures such as history, skin prick tests, atopy patch test, and specific immunoglobulin E in serum have been exhausted, double-blind, placebo-controlled food challenges represent the state of the art. After an oligo-allergenic diet, suspected foods or placebo are given in a titrated manner until a clear clinical reaction or the highest dose. The observation period should be 48 h in the case of atopic dermatitis. Constant clinical monitoring is mandatory. Dietetic recommendations are given for 12 months. The effort involved in such a procedure is justified because it can help to avoid clinically relevant food allergens in some cases and in others can prevent children from being exposed unnecessarily to diets that may be harmful to them.

Notes: A considerable body of literature on therapeutic aspects of complementary and alternative medicine has been published in recent years, but little is known on diagnostic procedures. This short review lists complementary and alternative diagnostic procedures for the diagnosis of allergic diseases and presents an assessment of their usefulness for the daily practice. The review of the literature revealed that neither the determination of specific immunoglobulin G-antibodies in serum, the hair-analysis, the cytotoxic test, kinesiology, iridology, or electrodermal testing represent useful tests for the daily practice. To date, no complementary or alternative diagnostic procedure can be recommended as a meaningful element in the diagnostic work-up of allergic diseases. This is especially true for food allergy: properly performed oral food challenges still represent the gold standard for implementing specific diets in food allergic individuals. Ineffective diagnostic approaches may be costly for the consumer and delay appropriate therapy.