Jerome Glaser lectureship. The role of food allergy and mediator release in atopic dermatitis

Food hypersensitivity in children

Adverse reactions to foods involving abnormal immune reactions to food antigens occur in 2-7% of the North American population; the numbers are perhaps higher in children. Both IgE-mediated and non-IgE-mediated allergic responses occur. IgE-mediated allergic responses to foods are the most dramatic and perhaps the most easily diagnosed type of food allergy. Non-IgE-mediated food hypersensitivity is more chronic, less acute, less obvious in its clinical presentation, and often more difficult to diagnose. It usually presents in infants between one week and three months of age with vomiting and diarrhea, although irritability, poor feeding, and failure to thrive are not uncommon. A thorough history and physical examination are often key in establishing a diagnosis of food protein hypersensitivity. In non-IgE-mediated disease, skin tests and immunological studies are not helpful. Eliminating the food allergen is the only means of dealing with a food allergy in most patients. About 85% of infants who have formula protein intolerance will outgrow their symptoms somewhere between 1 month and 3 years of age, older children and adults are somewhat less likely to lose their sensitivity, although approximately one-third will after 1-2 years of dietary restriction.

Heat treatment modifies the allergenicity of beef and bovine serum albumin

The effect of heat on the allergenicity of beef and bovine serum albumin was investigated among 10 toddlers skin prick test (SPT)-positive to raw and cooked beef. The meat-allergy diagnosis was confirmed during double-blind, placebo-controlled food challenge (DBPCFC) with 180 g of beef cooked for 5 min at 100 degrees C. SPT with homogenized and freeze-dried beef, and heated and unheated bovine serum albumin were performed. Both heated and unheated bovine serum albumin, homogenized beef, and freeze-dried beef were used in trial DBPCFC. All children were SPT-positive to unheated bovine serum albumin. Seven were positive to heated bovine serum albumin, one to freeze-dried beef, and none to homogenized beef. DBPCFCs were negative for homogenized beef and freeze-dried beef, positive for unheated bovine serum albumin in five patients, and positive for heated albumin in four children. We conclude that heating reduces sensitization to beef and bovine serum albumin but does not abolish reactivity to albumin under home conditions. However, industrially heat-treated and sterilized homogenized beef and freeze-dried beef may be suitable substitutes in beef-allergic children's diets.

Efficacy of pentoxifylline in the treatment of pruritic papular eruption of HIV-infected persons

BACKGROUND

Pruritic papular eruption (PPE) of HIV/AIDS is a common manifestation of HIV infection. Unfortunately, treatments for the unremitting pruritus have yielded only partial relief.

OBJECTIVE

Our purpose was to assess the clinical efficacy of pentoxifylline in the treatment of pruritus in HIV-infected patients with PPE while measuring its effects on HIV viral load and levels of serum triglycerides, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-4.

METHODS

Eleven of the 12 patients with PPE and HIV infection placed on a regimen of oral pentoxifylline completed the 8-week study. The degree of pruritus both before and after therapy was measured by means of a patient-reported visual analog scale (0 = none and 10 = worst experienced). A global assessment of the number and size of PPE lesions was performed by the investigator, and serum TNF-alpha, IL-4, and triglyceride levels, as well as HIV viral load, were measured.

RESULTS

The average degree of pruritus was significantly reduced (p = 0.0009) from 6.5 at baseline examination to 3.6 at the end of the study. Ten of 11 patients experienced a reduction in their pruritus, ranging from 22.6% to 87.3%. The global assessment of PPE lesions decreased from baseline in most patients and increased slightly in one patient. Serum TNF-alpha was detectable in one patient at baseline, but was undetectable at the end of the study period. Similarly, the two patients who had detectable serum IL-4 at baseline had undetectable serum IL-4 levels at the end of the study. Triglyceride levels in six patients decreased an average of 23.9% by week 8. Although when compared with baseline values, HIV viral loads in seven patients decreased, one patient had no change, and three patients had an increase in their viral load at the end of the study, the magnitude of the changes were of little clinical importance.

CONCLUSION

Pentoxifylline is a safe and efficacious treatment of pruritus in HIV-infected patients with PPE. Future controlled studies are needed to confirm the effectiveness of this treatment.

Randomised controlled trial of advice on an egg exclusion diet in young children with atopic eczema and sensitivity to eggs

BACKGROUND

The role of exclusion diets in the management of atopic eczema in young children is uncertain. This randomised controlled trial evaluates the effect of excluding egg from the diet in young children with atopic eczema and sensitivity to eggs. Fifty-five such children were randomised either to a 4-week regimen, in which mothers were given general advice on care of eczema and additional specific advice from a dietician about an egg exclusion diet (diet group), or to a control group in which general advice only was given. Both groups continued conventional topical treatment. Disease activity was assessed by estimates of the surface area affected by eczema and by an arbitrary severity score. Possible egg sensitivity was identified by RAST before randomisation and after the trial by double-blind placebo-controlled egg challenge.

RESULTS

The mean reduction in surface area affected by eczema was significantly greater (p = 0.02) in the group receiving dietary advice (from 19.6% to 10.9% area affected) than in the control group (from 21.9% to 18.9%). A significant improvement also occurred in severity score (p = 0.04): from 33.9 to 24.0 units for the diet group compared with a decrease from 36.7 to 33.5 in the control group. The study suggests that advice on the dietary exclusion of eggs is useful as part of the overall management of young children with atopic eczema and sensitivity to eggs.

CD4+ cells proliferate after peanut-extract-specific and CD8+ cells proliferate after polyclonal stimulation of PBMC of children with atopic dermatitis

BACKGROUND

Few studies describe in vitro food-allergen induced proliferative responses and cytokine production of PBMC of children with atopic dermatitis. This is especially true for peanut-allergen.

OBJECTIVES

To analyse the specificity of the T cell in proliferative responses, in children with atopic dermatitis with or without peanut allergy and healthy age-matched children.

METHODS

Proliferative responses were measured by [3H]-thymidine incorporation and by expression of the intracellular Ki67-antigen using flow cytometry after antigen-specific stimulation of PBMC with peanut-extract (day 7) or polyclonal stimulation with Phorbol-12myristate-13acetate and Ca-ionophore (day 3). Cytokine mRNA (Interferon-gamma (IFNgamma), IL-4) was detected by semiquantitative RT-PCR. Cytokine production (IL-4, IFNgamma) was measured by ELISA.

RESULTS

Peanut-extract induced proliferative responses of PBMC from children with atopic dermatitis and peanut allergy (AD+PA+) were significantly higher as compared with the other groups studied. Ki67-antigen double staining revealed that 80-100% of the proliferating cells were CD4+. These proliferative responses correlated significantly with the increase in IL-4 mRNA expression after peanut-extract specific stimulation. After polyclonal stimulation, however, CD8+ cells preferentially proliferated. The degree of proliferation after polyclonal stimulation correlated inversely with the ratio of IL-4/IFNgamma production.

CONCLUSIONS

The principal responding population of T cells in proliferative responses is different after peanut-extract specific and polyclonal stimulation of PBMC from AD+PA+ patients. Furthermore, we found indirect evidence that the PBMC fraction of AD+PA+ children contains increased frequencies of peanut-specific T helper-2 cells.

Soy allergy is not common in atopic children: a multicenter study

The aim of the present study was to evaluate the prevalence of soy allergy (positive skin test and positive challenge test) in a large cohort of atopic children, many of them soy fed early in life for several months. In order to investigate the prevalence of soy allergy, two groups of children were enrolled into the study. The first group comprised a cohort of 505 children with personal history suggestive of food allergy. The second group included 243 children born of atopic parents, who had been soy protein formula fed for the first six months of life for the prevention of cow's milk allergy and who had been prospectively followed up, from birth to 5 years. As regards the prevalence of soy allergy in the cohort of children suffering from allergic disease: 31/505 children (6%) had positive skin prick test to soy, however only six of the 31 children with positive skin prick test to soy had positive challenge test to soy. With regard to the prevalence of soy allergy in the children who had been soy protein formula fed in the first six months of life (second group): 14/243 children (6%) had positive skin prick test to soy, but the double blind placebo control oral food challenge to soy was positive in only one of these 14 children. In conclusion documented soy allergy is not common in atopic children.

Comparison of specificity between IgG, IgE and T cells to three casein components: implication for the role of circulating allergen-specific T cells in food allergy

In order to investigate the role of food antigen-specific T cells circulating in the blood of patients with food allergy, we compared T cell response to three casein components (alpha s-, beta- and, kappa-casein) with specificities of IgG and IgE binding to the casein components in four milk-allergic patients (P1-4) with atopic dermatitis. In all patients the binding activities of IgG antibodies to alpha s-casein were most dominant, followed by those to beta- and to kappa-casein. The major component of casein bound by IgE antibodies was alpha s-casein in P1 and P3, kappa-casein in P2, and alpha s-casein as well as kappa-casein in P4; the order of casein components bound by IgE antibodies was different from that by IgG antibodies. Proliferative responses of peripheral blood mononuclear cells (PBMC) to casein components were so low that the dominance of casein recognition could not be clearly demonstrated. However, short-term T cell lines that specifically respond to casein were successfully established from PBMC of the four patients and the proliferative responses of the T cell lines to the three components of casein were in accord with the IgE antibody specificity to casein components but not with that of IgG antibody specificity. When taken together, these results indicate that casein-specific T cells circulating in the blood are involved in or reflect an allergic reaction against casein.

Natural history of soy allergy and/or intolerance in children, and clinical use of soy-protein formulas

Atopic diseases of infants and children are common, debilitating, chronic and sometimes even life-threatening. Several well-conducted studies in high risk babies have demonstrated a significant reduction in the prevalence and severity of atopic diseases with dietary and environmental manipulations. The currently available cow's milk (CM) substitutes for infants are soy protein (SP) formulas (SPFs), hydrolyzed formulas (HF), and home-made meat-based formulas. Soybeans have been cultivated in Eastern countries for many centuries and were first used to feed US babies with CM allergy (CMA) in 1929. Since then, SPFs containing purified SP, a mixture of vegetable oils, and purified carbohydrate have been developed. From a nutritional point of view, SPFs are adequate, support normal growth, protein status, bone mineralization, are well accepted, and economical. SPFs are used for different conditions including CMA, lactose and galactose intolerance and in the management of severe gastroenteritis, and some studies show that feeding SPFs for the first six months of life significantly reduces the prevalence of atopic diseases in high risk babies. Although gastrointestinal symptoms and atopic dermatitis (AD) may occur in some SPF-fed children, anaphylaxis following the ingestion of soybean is extremely rare in children. However, in the past few years the antigenicity/allergenicity of SPFs has been over-emphasized in the medical literature. In this paper on the natural history of soy antigenicity/allergenicity we discuss all the pros and cons of SPFs, their composition and nutritional value, the basic immune definitions, chemistry and characterization of SPs. We then discuss the antigenicity and allergenicity of SPFs in animals, recent data on the use of SPFs and the incidence of soy allergy in children, clinical reactions to SPFs, and the clinical relevance of skin testing and IgE antibodies to soy, challenge test procedure, clinical indication of SPFs, and their relevance in the prevention of atopy. We have meta-analyzed 17 different studies and conclude that history-based SPF allergy incidence totals 27%, in skin prick tests (SPT) RAST-oral food challenge (OFC)/double-blind food challenge (DBFC)-based epidemiological studies attains 3%, and in challenge test studies 4%. We suggest that double-blind placebo-controlled food challenge (DBPCFC) studies in larger cohorts of babies may establish a more reliable prevalence of SPF allergy in different disorders associated with CMA.

Mapping and mutational analysis of the IgE-binding epitopes on Ara h 1, a legume vicilin protein and a major allergen in peanut hypersensitivity

Peanut allergy is a significant health problem because of the prevelance and potential severity of the allergic reaction. Serum IgE from patients with documented peanut hypersensitivity reactions and overlapping peptides were used to identify the IgE-binding epitopes on the major peanut allergen, Ara h 1. At least twenty-three different linear IgE-binding epitopes, located throughout the length of the Ara h 1 protein, were identified. All of the epitopes were 6-10 amino acids in length, but there was no obvious sequence motif shared by all peptides. Four of the peptides appeared to be immunodominant IgE-binding epitopes in that they were recognized by serum from more than 80% of the patients tested and bound more IgE than any of the other Ara h 1 epitopes. Mutational analysis of the immunodominant epitopes revealed that single amino acid changes within these peptides had dramatic effects on IgE-binding characteristics. The identification and determination of the IgE-binding capabilities of core amino acids in epitopes on the Ara h 1 protein will make it possible to address the pathophysiologic and immunologic mechanisms regarding peanut hypersensitivity reactions specifically and food hypersensitivity in general.

Soy allergy in atopic children

BACKGROUND

Although soy is considered a major food allergen (along with milk, egg, peanut, fish, and wheat), the prevalence of soy allergy in the pediatric population is not well defined.

OBJECTIVE

To determine the prevalence of soy allergy in atopic children attending the Allergy Clinic at the Pediatric Department of Milan University.

METHODS

Seven hundred four patients with allergic signs and symptoms, aged 1 month to 18 years, were recruited between December, 1991 and April, 1992. The subjects with positive skin prick tests to soy were tested using a DBPCFC with powdered soy formula in fruit juice, and rice or corn flour as placebo. In children who refused the liquid challenge, capsules containing dehydrated soy flour or talcum powder as placebo were administered. An age-matched and sex-matched group of subjects with negative skin prick tests to soy were tested using an open challenge with soy formula.

RESULTS

A positive skin prick test to soy was found in 148/704 patients (21%); 131 out of 148 children with positive skin prick test (group A) and 131 out of 556 children with negative skin prick test to soy (group B) were challenged with soy: 8/131 (6%) in group A had a positive soy challenge while no clinical reactions were observed in children in group B. A younger median age, a positive past and current personal history of cow milk allergy, and a previous history of soy allergy were found most often in children with positive soy skin prick test and positive soy challenge than in children with positive skin prick test and negative soy challenge. The eight soy-allergic children reacted to the soy challenge mostly with cutaneous and gastrointestinal symptoms; symptoms were immediate in six and late in two children. The eliciting dose of soy was very small in the immediate reaction; higher and repeated doses were necessary for the onset of late reactions.

CONCLUSION

The prevalence of clinical soy allergy in our children with positive skin prick tests to soy is 6.1% (8/131), while none of 131 children with negative skin prick test to soy reacted to the challenge.

Interferon-gamma and interleukin-4 production of ovalbumin-stimulated lymphocytes in egg-sensitive children

BACKGROUND

The causal relation between egg allergy and cytokines derived from lymphocytes is unknown.

OBJECTIVE

Interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) production of ovalbumin-stimulated and interleukin-2 (IL-2)-stimulated peripheral blood mononuclear cells from egg-sensitive patients was investigated and compared with that of stimulated peripheral blood mononuclear cells from nonatopic healthy children.

METHODS

Peripheral blood mononuclear cells from egg-sensitive patients and nonatopic healthy children were cultured with ovalbumin and IL-2 for seven days. The IFN-gamma and IL-4 concentrations in culture supernatants of the peripheral blood mononuclear cells were investigated.

RESULTS

The levels of IFN-gamma production of only IL-2-stimulated or both ovalbumin-stimulated and IL-2-stimulated peripheral blood mononuclear cells from egg-sensitive patients with atopic dermatitis was significantly higher than that of healthy children and that of egg-sensitive patients with immediate allergic symptoms.

CONCLUSIONS

Increased IFN-gamma production by lymphocytes after IL-2 and antigen stimulation has important implications for the mechanism of food-sensitive atopic dermatitis.

Effects of a dietary and environmental prevention programme on the incidence of allergic symptoms in high atopic risk infants: three years' follow-up

A prospective case-control study is presented to assess an allergy prevention programme in children up to 36 months of age. Infants born at three maternity hospitals were followed from birth: 279 infants with high atopic risk (intervention group) were compared with 80 infants with similar atopic risk but no intervention (non-intervention group). The intervention programme included dietary measures (exclusive and prolonged milk feeding diet followed by a hypoantigenic weaning diet) and environmental measures (avoidance of parental smoking in the presence of the babies, day care > 2 years of life). Mothers in this group who had insufficient breast milk were randomly assigned to one of two coded formulas: either a hydrolysed milk formula (Nidina HA, Nestlé) or a conventional adapted formula (Nan, Nestlé). Other environmental measures remained the same as for the breastfeeding mothers. The non-intervention group were either breastfed or received the usual Italian milk feeding and weaning diet, without environmental advice. The main outcome measures were anthropometric measurements and allergic disease manifestations. Normal anthropometric data were observed both in the intervention group and in the non-intervention group. The incidence of allergic manifestations was much lower in the intervention group than in the non-intervention group at 1 year (11.5 versus 54.4%, respectively) and at 2 years (14.9 versus 65.6%) and 3 years (20.6 versus 74.1%). Atopic dermatitis and recurrent wheezing were found in both the intervention group and the non-intervention group from birth up to the second year of life, while urticaria and gastrointestinal disorders were only present in the non-intervention group in the first year of life. Conjunctivitis and rhinitis were present after the second year in both the intervention group and the non-intervention group. Relapse of the same allergic symptom was less in the intervention group (13.0%) than in the non-intervention group (36.9%). In comparison to the non-intervention group, there were fewer intervention group cases with two or more different allergic symptoms (8.7 versus 32.6%), and they were more likely to avoid steroid treatment (0 versus 10.8%) and hospital admission (0 versus 6.5%). Babies in the non-intervention group fed with adapted formula were more likely to develop allergies than breastfed babies in the same group. In the intervention group the breastfed infants had the lowest incidence of allergic symptoms, followed by the infants fed the hydrolysed formula (ns). Infants in the intervention group fed the adapted formula had significantly more allergies than the breastfed and hydrolysed milk fed infants, although less than their counterparts in the non-intervention group. Of the affected subjects in the intervention group, 80.4% were RAST and/or Prick positive to food or inhalant allergens. Total serum IgE values detected at birth in the intervention group were not predictive, but at 1 and 2 years of age, IgE values more than 2 SD above the mean in asymptomatic babies were found to predictive for later allergy. In breastfed babies the total IgE level at 1 and 2 years of age was lower than in the other two feeding groups. Of the various factors tested in the non-intervention group, the following were the most important in the pathogenesis of allergic symptoms: (i) formula implementation begun in the first week of life; (ii) early weaning (< 4 months); (iii) feeding beef (< 6 months); (iv) early introduction of cow's milk (< 6 months); and (v) parental smoking in the presence of the babies and early day care admission (< 2 years of life). All the preventive measures used in this study (exclusive breastfeeding and/or hydrolysed milk feeding, delayed and selective introduction of solid foods, and environmental advice) were effective at the third year of follow-up, greatly reducing allergic manifestations in high atopic risk babies in comparison with those not receiving these interventions

Atopic dermatitis: is it an allergic disease?

For many years controversy has surrounded the relation between allergy and atopic dermatitis. We critically review the evidence for the contribution of allergy, or IgE-mediated hypersensitivity reactions, to the pathogenesis of this disease. We conclude that, at present, there is scant evidence that allergy is central to the development of atopic dermatitis, although it may be an aggravating factor in a few patients. Hence there is little rationale for the routine use of allergy testing or dietary and environmental manipulation in the management of this disease.

Meat allergy: I--Specific IgE to BSA and OSA in atopic, beef sensitive children

OBJECTIVE

The use of lamb meat products has been suggested as an alternative diet for polyallergic children, although until now this clinical practice has not been supported by in-depth biochemical/immunological studies. The aims of this research were: to evaluate cross-reactivity between lamb and beef; to evaluate the role of BSA and OSA as allergens in beef allergic children; and to evaluate cross-reactivity between BSA and OSA.

METHODS

16 children suffering from atopic dermatitis (AD), aged 12 months-8 8 years (mean age 2.61 +/- 1.93 years) were found skin prick test (SPT)--positive to bovine meat; all of them were also SPT-positive to ovine meat and to milk. After a period of restricted diet, the selected 16 children were recalled; 12 AD-free children (8 males and 14 females, aged 12 months-4.33 years (mean age 2.21 +/- 1.05 years) were evaluated by SPT and radioallergosorbent test (RAST) for the following allergens: bovine meat, ovine meat, BSA 1 mg/ml, OSA 1 mg/ml. Double-blind, placebo-controlled food challenge (DBPCFC) with bovine serum albumin (BSA) and ovine serum albumin (OSA) were performed. For SPT, the results were expressed in mm of wheal, and 3 mm was considered as the end point; correlation between wheal diameters was calculated by Spearman rank test. For DBPCFC, according to the Sampson's experimental procedure, BSA and OSA were given in pear juice (the dermal negative response to the pear juice was verified by fresh food SPT before starting the oral challenge test). The total dose administered to the children corresponded to the amount of albumin present in 180 g of calf or lamb meat (90 and 63 mg respectively, as calculated by Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SPS-PAGE). The administration of pear juice (containing placebo or albumin) and symptom evaluation were entrusted to medical people who did not know what the child received.

RESULTS

All children tested SPT positive to bovine and ovine meat, and to BSA and OSA. Significant correlations were observed between the following diameters of wheal: BSA vs OSA (R = 0.846, p < 0.0001); ovine meat vs OSA (R = 0.769, p < 0.005); b.meat vs o.meat (R = 0.771, p < 0.005); and ovine meat vs BSA (R = 0.594, p < 0.043). In RAST, 6 of 12 children were positive to bovine meat, 3 to lamb meat, 4 to BSA and 3 to OSA. DBPCFC showed an immediate reaction to BSA or OSA in 2 and 3 children, respectively. One other child developed severe dyspnea, cough and asthma 3 hours after OSA challenge.

CONCLUSIONS

BSA and OSA are important beef and lamb allergens; they share not only proteic sequences, but also allergenic properties. Clinical tolerance to BSA and OSA can be present in beef and lamb SPT-positive children.

The role of eosinophils and eosinophil cationic protein in monitoring oral challenge tests in children with food-sensitive atopic dermatitis

To investigate the role of peripheral blood eosinophils and eosinophil cationic protein as parameters in monitoring oral food challenges, we monitored 25 infants and children with atopic dermatitis for up to 48 hours after 47 placebo-controlled oral food challenges with cow's milk, hen's egg, cow's milk and hen's egg, or placebo for up to 48 hours. Six healthy young nonatopic adult volunteers served as control subjects. Compared with baseline values, peripheral blood eosinophils decreased significantly immediately after clinical reaction in positive challenges (p < 0.0004), independent of the kind of reaction. Eosinophil cationic protein increased significantly 8 hours after provocation, with a maximum at 24 hours (p < 0.03). This increase was predominantly related to eczematous reactions (p < 0.005). Blood sampling immediately after clinical reaction (for eosinophils) and at 24 hours (for eosinophil cationic protein) seems to be useful in monitoring oral food challenges in children with atopic dermatitis.

Food allergy in infancy

This article discusses the current understanding of the mechanisms of food hypersensitivity and presents a practical approach to the condition. Skin testing is a useful technique if properly applied and interpreted; however, double-blind placebo-controlled food challenge is the standard for accurate diagnosis against which all other tests should be compared. Treatment still consists of avoidance of the offending food allergens; however, most children lose their reactivity, and thus regular challenges are important.

Identification of monocyte chemotactic factors in supernatants of ovalbumin-stimulated lymphocytes from patients with atopic dermatitis who are sensitive to hen's egg

Monocyte chemotactic activities in supernatants of ovalbumin (OA)-stimulated peripheral blood mononuclear cell (PBMC) cultures were studied in patients with atopic dermatitis (AD) who were sensitive to hen's egg. The monocyte chemotactic activities in hen's egg-sensitive AD patients were significantly higher than those of non-atopic healthy controls and patients with immediate allergic symptoms. However, the monocyte chemotactic activities were not detected in bovine serum albumin-stimulated PBMC culture supernatants in patients with AD who were sensitive to hen's egg, but not to cow's milk. Furthermore, there was significant correlation between the monocyte chemotactic activities and proliferative responses of PBMCs to OA in hen's egg-sensitive AD patients, whereas there was no significant correlation between the monocyte chemotactic activities and radioallergosorbent test values. These results suggest that PBMCs stimulated with food antigens produce monocyte chemotactic factors which relate to the pathogenesis of AD in food-sensitive AD patients and that the pathogenesis of AD may be related to cell-mediated immune responses.

Production and secretion of interferon-gamma (IFN-gamma) in children with atopic dermatitis

IFN-gamma is known to be a major inhibitor of IgE synthesis in vitro. Recent studies demonstrating reduced production of IFN-gamma in children and adults with atopic dermatitis and elevated serum IgE suggest a similar role for this cytokine in vivo. The reasons for this reduced IFN-gamma production are not known. One possibility is that atopic individuals have a reduced population of cells producing IFN-gamma in vivo. Using a fluorescence-labelled antibody to detect intracellular IFN-gamma, the percentage of IFN-gamma-producing cells was determined in children with atopic dermatitis and in non-atopic controls. Children with atopic dermatitis had a greater percentage of IFN-gamma-producing cells in unstimulated cultures compared with controls, indicating in vivo activation of lymphocytes in the atopic group. This could reflect the significant degree of inflammation present in these children, or the presence of bacterial infection or colonization. Although secretion of IFN-gamma after stimulation with phorbol myristate acetate (PMA)/Ca was significantly lower in children with atopic dermatitis compared with controls, the percentage of IFN-gamma-producing cells in the stimulated cultures from this group was equivalent to controls. This demonstrates that the reduced ability of atopic children to secrete IFN-gamma in vitro does not relate to a lack of IFN-gamma-producing cells, but to a difference in the regulation of IFN-gamma production beyond the stage of signal transduction.

Diet and dermatology. The role of dietary manipulation in the prevention and treatment of cutaneous disorders

The role of dietary manipulation and vitamins in the prevention and treatment of certain skin diseases is reviewed. Manipulation of nutrition by either diet restriction or supplementation can effect cutaneous disorders such as skin cancer, wound healing, atopic dermatitis, psoriasis, and dermatitis herpetiformis.

Food allergies in children

Ingested food represents the greatest foreign antigenic load that confronts the human immune system. In most individuals tolerance develops to food antigens that are continually gaining access to the body. When tolerance fails to develop, the immune system may react with a hypersensitivity reaction. Allergies to food affect up to 8% of children less than 3 years of age and 1% to 2% of the general population. Symptoms include the gastrointestinal, cutaneous, and respiratory symptoms, as well as systemic anaphylaxis with shock. Clinical investigations in the past have characterized the food hypersensitivity disorders, but our understanding of the basic immunopathologic mechanism remains incomplete. Current progress in allergen characterization and the rigorous scientific methods now being applied to this field by many investigators provide hope that new information regarding the pathogenesis of these disorders and new forms of therapy will soon become available. For now, practicing physicians must carefully diagnose specific food sensitivities and educate patients and their families in the elimination of the responsible food allergen.

Cutaneous late-phase response in food-allergic children and adolescents with atopic dermatitis

Food hypersensitivities contribute to disease exacerbation in a sub-group of children with atopic dermatitis (AD). It has been shown that only selected foods are capable of causing clinical reactions when ingested, whereas other foods, to which the patient is equally sensitive by skin-prick testing, may be tolerated. The purpose of this study was to examine the cutaneous late-phase response (LPR) to food antigens in food-allergic patients with AD and to determine if the skin reacted differently to 'relevant foods' (foods eliciting positive skin-prick tests and positive oral challenges) than to 'non-relevant foods' (foods eliciting positive skin tests but negative oral challenges). Using blister chambers adfixed to the skin, six children with AD were challenged epicutaneously with foods to which they had previously been shown to be sensitive. Histamine and PGD2 were measured hourly for 10-12 hr in parallel with quantitation of the cellular traffic. There appeared to be no difference in any of the measured parameters between relevant foods and non-relevant foods, and the patterns of the LPR cells and mediators were similar to those previously described with aero-allergens in patients with respiratory allergy. Histamine rose to 13.0 +/- 24 ng/ml (P < 0.005) during the first hours, declined to < 1 ng/ml by the fifth hour, and then rose a second time to 6.72 +/- 3.4 ng/ml (P < 0.05) during the 12th hour. PGD2 rose to an average of 312 pg/ml (P < 0.05) during the first 3 hr followed by a decline to baseline.(ABSTRACT TRUNCATED AT 250 WORDS)

Atopic dermatitis: correlation of peripheral blood T cell activation, eosinophilia and serum factors with clinical severity

In the first part of this study peripheral blood lymphocyte subpopulations, their activation state and various serum parameters were measured in extrinsic and intrinsic atopic dermatitis (AD) patients compared to normal individuals. Beside the characteristic eosinophilia, significantly increased numbers of CD4+ T cells with increased expression of IL-2 receptors (IL-2R) and HLA-DR were noted in the AD patients. In addition, extrinsic AD patients showed increased numbers of CD23+ B cells and decreased numbers of CD16+ natural killer cells. Moreover, increased serum levels of eosinophil cationic protein (ECP) and soluble IL-2R as well as soluble factors that prolong survival of eosinophils in vitro could be demonstrated. In the second section of this study we determine how these blood immunological parameters relate to the clinical severity of the skin lesions of AD, by weekly analysis of 12 AD patients attending a high altitude clinic for 3 to 6 weeks. The patients were divided into two groups on the basis of treatment with topical steroids, but during the observation period a significant improvement in clinical status was observed in all AD patients independent of topical steroid therapy. A progressive decrease in eosinophil and activated T cell numbers, soluble IL-2R levels and serum eosinophil survival prolonging activity could be demonstrated, which closely correlated with the clinical severity of the AD.

Improvement of food-sensitive atopic dermatitis accompanied by reduced lymphocyte responses to food antigen following natural measles virus infection

Five patients with atopic dermatitis (AD) who were sensitive to hen's egg were observed before and after natural measles virus infection. Within 4 weeks of natural measles virus infection, the eczematous lesions clearly improved in four of the five patients in whom neither offending foods were eliminated, nor anti-allergic drugs, systemic steroids and steroid ointment administered. This was accompanied by reduced proliferative responses of peripheral blood mononuclear cells (PBMCs) to ovalbumin (OA). Another patient showed a transient improvement of AD symptoms, from severe to mild, and thereafter returned to severe accompanied by increased proliferative responses of PBMCs to OA. Radioallergosorbent test (RAST) scores for hen's egg in all five patients did not change in each level in each patient, except the transiently decreased RAST scores for hen's egg in one patient, after the infection. Thus, in patients with AD who are sensitive to food, the improvement of AD symptoms that appeared within 4 weeks of natural measles virus infection was related to reduced proliferative responses of PBMCs to the food antigen following the infection.

Allergenicity and nutritional adequacy of soy protein formulas

Soy protein formulas are used for different conditions, including cow milk protein allergy, lactose and galactose intolerance, and severe gastroenteritis. Feeding soy protein formulas to normal term infants is associated with normal growth, normal protein nutritional status, and normal bone mineralization. Recent studies of infants fed soy protein formulas exclusively during the first months of life revealed no immunologic abnormality; however, the use of such formulas for management of cow milk protein allergy and for prevention of atopy is controversial. Although in the past decade many studies have stressed soy allergenicity, soy allergenicity has been confirmed by the challenge test in only a few studies. In this article we review the studies dealing with the allergenicity of soy protein formulas. We also present our own data on their use in the prevention and management of cow milk protein allergy.

Fatal and near-fatal anaphylactic reactions to food in children and adolescents

BACKGROUND AND METHODS

Reports of fatal or near-fatal anaphylactic reactions to foods in children and adolescents are rare. We identified six children and adolescents who died of anaphylactic reactions to foods and seven others who nearly died and required intubation. All the cases but one occurred in one of three metropolitan areas over a period of 14 months. Our investigations included a review of emergency medical care reports, medical records, and depositions by witnesses to the events, as well as interviews with parents (and some patients).

RESULTS

Of the 13 children and adolescents (age range, 2 to 17 years), 12 had asthma that was well controlled. All had known food allergies, but had unknowingly ingested the foods responsible for the reactions. The reactions were to peanuts (four patients), nuts (six patients), eggs (one patient), and milk (two patients), all of which were contained in foods such as candy, cookies, and pastry. The six patients who died had symptoms within 3 to 30 minutes of the ingestion of the allergen, but only two received epinephrine in the first hour. All the patients who survived had symptoms within 5 minutes of allergen ingestion, and all but one received epinephrine within 30 minutes. The course of anaphylaxis was rapidly progressive and uniphasic in seven patients; biphasic, with a relatively symptom-free interval in three; and protracted in three, requiring intubation for 3 to 21 days.

CONCLUSIONS

Dangerous anaphylactic reactions to food occur in children and adolescents. The failure to recognize the severity of these reactions and to administer epinephrine promptly increases the risk of a fatal outcome.

Inhibition of proliferative responses of lymphocytes to food antigens by an anti-allergic drug, N(3',4'-dimethoxycinnamoyl) anthranilic acid (Tranilast) in children with atopic dermatitis

Experimental studies have shown that N(3',4'-dimethoxycinnamoyl) anthranilic acid (Tranilast) inhibits reaginic antibody-mediated hypersensitivity reactions, and it has been demonstrated to be an effective drug for patients with bronchial asthma. On the other hand, from the nature of the cellular infiltrate seen in eczematous lesions, it appears that some form of cell-mediated immunity may be involved in addition to IgE-mediated immunity in the pathogenesis of atopic dermatitis (AD). Moreover, we have previously reported that the proliferative responses of peripheral blood mononuclear cells (PBMCs) to ovalbumin (OA) or bovine serum albumin (BSA) in children with AD who are sensitive to hen's egg or cow's milk were significantly higher than those of healthy children and hen's egg or cow's milk sensitive children with immediate symptoms. In this study, we have showed that the proliferative responses of PBMCs to OA were dose-dependently inhibited by Tranilast on patients with AD. The responding cells to OA were shown, through separation experiments, to be T cells, and the proliferative responses of T cells to OA were also dose-dependently inhibited by Tranilast. Moreover, the inhibition was thought to occur at the initial stage of the proliferative reactions. These results suggest that Tranilast can be clinically applied to patients with AD.

Interleukin-2 production of lymphocytes in food sensitive atopic dermatitis

The proliferative responses of peripheral blood mononuclear cells (PBMC) to food antigens in 22 patients with food sensitive atopic dermatitis were significantly higher than the responses of healthy children and food sensitive children with immediate symptoms. Moreover, the activity of interleukin-2 (IL-2) in supernatants of food antigen stimulated PBMC cultures from patients with atopic dermatitis was significantly higher than that in healthy children and food sensitive children with immediate symptoms. The activity of IL-2 in culture supernatants of separated cell populations stimulated with food antigens from patients with atopic dermatitis and healthy children was investigated. The activity of IL-2 in supernatants of food antigen stimulated T cell cultures could be detected in patients with atopic dermatitis but not in healthy children. These results suggest that the increased IL-2 production after food antigen stimulation is due to increased T cell activity in food sensitive atopic dermatitis.

Allergy consultation in the management of atopic dermatitis

Allergists and dermatologists both care for patients with atopic dermatitis, and their roles may be complementary. Questions regarding food allergy, aeroallergens, and the interpretation of skin and RAST testing are answered by an allergist.

[Digestive manifestations of food hypersensitivity in adults]

Food allergy, synonymous with food hypersensitivity (FHS), is defined as an immunologically-mediated adverse reaction to food. Initiation of FHS could result from a break in the immune mucosal barrier with abrogation of oral tolerance. Food hypersensitivity is mostly due to immediate-type reaction involving IgE-dependent mastocytes activation. Changes in intestinal function and structure have been mainly studies in an animal model of rat sensitized to egg albumin. Intraluminal antigen challenge resulted in abnormalities of gut absorption, secretion and motility in sensitized rats. In man, experimental data are scarce. Gastrointestinal manifestations of immediate FHS are varying and unspecific. A role for FHS in irritable bowel syndrome is debated. Participation of delayed-type FHS to digestive diseases is still questionable, but eosinophilic gastroenteritis might be an example. In clinical practice, diagnosis of FHS demands rigorous criteria. Double blind placebo-controlled food challenge has eventually proved to be the "gold standard" test for FHS diagnosis.

Interleukin 2 therapy in severe atopic dermatitis

Interleukin 2 (IL-2) at a dose of 10,000 to 20,000 U/kg/q 8 hr was given for 9-12 days to six patients with cases of severe atopic dermatitis (AD) which were refractory to conventional therapy. After IL-2 therapy, the clinical symptoms and signs of eczema including pruritus, scratching, papulovesicles, and lichenification were much improved, but all of them recurred 2-6 weeks after stopping treatment. Adverse reactions were similar to those reported previously, but all of them subsided after discontinuation of therapy. Laboratory findings showed decreased T-cell subsets, especially CD4+ cells, and increased IL-2R+ (CD25) cells, but there was no significant change in serum IL-2, serum IgE, or in vitro IgE production. Immunopathological studies of the skin biopsies showed decreased mononuclear-cell infiltration, depletion of CD4+ cells, and enhanced expression of CD25 and HLA-DR antigens. As lymphokine-activated killer (LAK)-cell activity against cultured fibroblasts was similar in patients with AD and in normals and CD1+ Langerhans cells were not decreased after IL-2 therapy, we speculate that the depletion of helper/inducer CD4+ cells and hence abrogation of the exaggerated antigen processing and cellular activation in diseased skin are the explanation for the transient efficacy of IL-2 in the treatment of atopic dermatitis.

Elemental diet for refractory atopic eczema

A total of 37 children with refractory wide-spread atopic eczema were treated with an antigen avoidance regimen comprising hospitalisation, exclusive feeding with an elemental formula for a median duration of 30 days, and measures to reduce exposure to pet and dust mite antigens at home. After the initial period of food exclusion, food challenges were performed at intervals of seven days, and the patients followed up for at least 12 months. Ten of the children (27%) either failed to respond to the regimen or relapsed within 12 months. Improvement in the eczema was seen in 27/37 (73%) patients, by discharge from hospital their disease severity score had fallen to a median of 27% of the pretreatment figure, and only 3/27 required topical corticosteroids. There were no clinical or laboratory findings which could be used to predict the outcome. Drawbacks to the regimen were prolonged hospitalisation (median 70 days), a fall in body weight and serum albumin concentration, and a risk of anaphylactic shock (4/37 cases). A strict antigen avoidance regimen may be associated with improvement of atopic eczema where conventional treatments have failed.