High prevalence of autoimmune urticaria in children with chronic urticaria

BACKGROUND: The etiology of chronic urticaria (CU) in childhood often remains unrecognized. Recently, in adults it has been shown that approximately 40% of patients with CU have autoimmune urticaria (AU); however, no data are available in children. OBJECTIVE: To determine the prevalence and possible risk factors for AU in children with CU. METHODS: Ninety-three consecutive children (52 male; median age, 7.8 years) with CU were evaluated for AU by means of autologous serum skin test (ASST) in all and serum-induced basophil histamine release (HR-urticaria test) in 52. All other known causes of CU were excluded as appropriate. RESULTS: A cause for CU was identified in 44 children (47%), whereas 49 (53%) remained idiopathic. ASST and HR-urticaria test had positive results in 22 of 49 (45%) and in 16 of 31 (52%) children with idiopathic CU compared with 1 of 44 (2%) and 5 of 21 (24%) with CU of a known cause, respectively ( P <.00001; P=.09). Sensitivity, specificity, and positive and negative predictive values of the ASST for diagnosing AU are 78%, 85%, 74%, and 88%. The prevalence of AU in childhood is 31% (15/52; 95% CI, 24%-51%). None of the variables studied were predictive for development of AU. CONCLUSION: Our results demonstrate for the first time that children have the same ability as adults to produce functionally active autoantibodies directed against IgE or IgE receptor and that AU occurs in children in as many as 30% of cases. The addition of screening for AU dramatically decreases the rate of the idiopathic form from 52% to 20%.     

Correlation between T-cell and mast cell activity in patients with chronic urticaria

BACKGROUND: The presence of autoantibodies reacting with the high affinity IgE receptor (FcepsilonRIalpha) usually indicates a more severe form of chronic urticaria (CU). Previously, we showed an increased lymphocyte reactivity in CU patients; however, the relation between enhanced cellular immunity and the presence of anti-FcepsilonRIalpha-specific autoantibodies has not been investigated. METHODS: Cellular and humoral immune reactivity of 50 CU patients and 28 healthy controls was studied.Serum sIL-2R, neopterin, and tryptase levels were measured to assess T-cell, monocyte/macrophage and mast cell activity, respectively. Helicobacter pylori (HP)-specific IgG antibody, and IgE levels were also tested. Anti-FcepsilonRIalpha-specific autoantibody was determined by Western blotting. In vivo histamine-releasing activity of patients' sera was assessed by the autologous serum skin test (AST). RESULTS: 17/50 CU patients, who both had IgG-type anti-FcepsilonRIalpha-antibodies by Western blotting and a positive AST response, were classified as autoimmune CU. All patients with CU had significantly higher serum sIL-2R and tryptase levels than healthy controls (p = 0.000257, p = 0.000166, respectively), indicating T-cell and mast cell activation. Patients with higher sIL-2R levels also had higher tryptase levels; the strongest correlation was shown in the autoimmune subgroup of patients (rho = 0.688, p = 0.002). There was a tendency towards higher tryptase levels in the autoimmune subgroup, as compared to the nonautoimmune CU patients. While the serum IgE was significantly lower in autoimmune than in nonautoimmune CU (p = 0.000836), there was no significant difference in their sIL-2R, neopterin and HP-specific IgG antibody levels. CU patients with a positive AST response (38/50) had significantly higher tryptase levels (p = 0.0107) when compared to the negative skin test group. CONCLUSIONS: The significant correlation between sIL-2R and tryptase levels in patients with CU indicates that T cell activation is proportional to mast cell degranulation in these patients. The increased level of tryptase in autoimmune CU may suggest more severe disease.     

Serum-induced basophil CD63 expression by means of a tricolour flow cytometric method for the in vitro diagnosis of chronic urticaria

BACKGROUND: Functional autoantibodies against the alpha-chain of the high-affinity IgE receptor (FcepsilonRIalpha) identify a subset of patients with chronic urticaria (CU) due to autoreactivity, as assessed by an in vivo positive response to autologous serum skin test (ASST). We performed a study to standardize the serum-induced basophil activation assay by flow cytometry (FCM) using a new tricolour method, assessing the diagnostic performance of this test in discriminating between ASST+ and ASST- CU patients. METHODS: Sera of 64 CU patients (22 ASST+ CU and 42 ASST- CU) and 10 healthy subjects were tested for their ability to induce basophil CD63 expression when incubated with whole blood of both atopic (DA) and non-atopic donors (DNA). Using a triple-labelled strategy with anti-CD123, anti-HLA-DR and anti-CD63 antibodies, CD63+ basophils were identified on a selected population of CD123+ HLA-DR- cells. In 3 ASST+ CU patients who underwent cyclosporine therapy, the assay was performed before and after treatment. RESULTS: The ASST+ CU sera resulted in a significant higher induction of basophil CD63 expression compared with ASST- CU and healthy donors sera; when whole blood from DA was used, sensitivity and specificity of the assay were 95.5% and 90.5% respectively. ASST+ CU serum activity was significantly decreased during cyclosporine A treatment, in parallel with clinical remission. CONCLUSIONS: Chronic urticaria serum-induced CD63 expression assay performed on DA whole blood by means of our tricolour FCM method could be the most useful tool for identification of a subset of patients with autoimmune CU and may become a promising tool also for monitoring treatment efficacy.     

Validation of basophil histamine release against the autologous serum skin test and outcome of serum-induced basophil histamine release studies in a large population of chronic urticaria patients

BACKGROUND: Endogenous histamine-releasing factors (HRFs) are involved in 30-60% of patients with chronic urticaria (CU). Evidence for their existence comes from in vivo studies of autoreactivity with the autologous serum skin test (ASST), in vitro immunoassays demonstrating autoantibodies against the immunoglobulin E (IgE) or the high affinity IgE receptor (FcepsilonRI) and serum-induced histamine release (HR) from basophils and mast cells. We have examined the correlation between the ASST and a new basophil histamine-releasing assay (the HR-Urtikaria test) in a group of well-characterized CU patients and subsequently determined the frequency of HR-Urticaria-positive sera from a larger population of CU patients. SUBJECTS: Group 1 consisted of 28 patients with CU (16 were ASST-positive) 20 patients with atopic dermatitis, 24 patients with allergy to birch and nine healthy controls. Group 2 consisted of 873 unselected CU patients. METHODS: White blood cells containing 1-2% basophils from a healthy nonatopic donor were incubated with patients sera in the presence of interleukin (IL)-3. Histamine was measured by the glass fibre method. RESULTS: Using the ASST as the true outcome, the HR-Urticaria test showed a sensitivity and specificity of 75% in group 1 using a cut-off value for HR of >16.5%. None of the controls was positive in the HR-Urticaria test. In group 2, we found no difference in the frequency of positives between male (34.6%, n = 254) and female adults (35.1%, n = 576) but twice as many females as males were tested. CONCLUSIONS: Our studies have shown that the HR-Urticaria test has a good sensitivity and specificity for endogenous HRFs demonstrated by the ASST in patients with CU and that about one-third of unselected patients with CU have a positive result.     

Evidence of in vivo basophil activation in chronic idiopathic urticaria

BACKGROUND: Approximately 40% of chronic idiopathic urticaria (CIU) subjects have autoantibodies to either FcepsilonRIalpha or IgE. The effect of such autoantibodies on circulating basophil activation status is unknown. OBJECTIVE: The expression of cell surface activation markers on basophils from CIU, non-allergic, and allergic subjects were compared. Further, the relationship between marker expression and serum factors reported in CIU, such as histamine-releasing activity (HRA) and immunoreactivity to FcepsilonRIalpha were examined. METHODS: Peripheral blood was obtained from CIU, allergic, and non-allergic donors and fractionated by density gradients. Enriched basophils (1-12%) were analysed by flow cytometry for expression of activation markers including CD63, CD69, and CD203c. Dilutions of serum (5-50%) were analysed for HRA on basophils from a normal donor. Serum was tested for immunoreactivity by western blotting to a standard cell lysate prepared from an RBL-SX38 cell line transfected with human FcepsilonRIalpha. RESULTS: CIU subjects (n=9) and allergic subjects (n=8) exhibited enhanced expression of CD63 and CD69, as compared with non-allergic subjects (n=7); however, no difference was seen among groups for CD203c expression. Five CIU and two non-allergic subjects had evidence of significant serum HRA (>20%), whereas two CIU, two allergic, and three non-allergic subjects had evidence of serum immunoreactivity to FcepsilonRIalpha. Serum HRA and serum immunoreactivity to FcepsilonRIalpha were not associated with enhanced surface marker expression. CONCLUSION: Basophil activation marker expression is increased in CIU subjects and is not associated with serum factors. In addition, serum HRA and FcepsilonRIalpha immunoreactivity are not unique to CIU, or related to enhanced circulating basophil marker expression.     

Birch pollen-related food as a provocation factor of allergic symptoms in children with atopic eczema/dermatitis syndrome

BACKGROUND: Food allergy to cow's milk or hen's egg is a common problem in children with atopic eczema/dermatitis syndrome (AEDS) but the role of birch pollen-related food for the induction of allergic symptoms is still not clear. PATIENTS/METHODS: Twelve children (median age 5 years) with AEDS underwent an oral challenge with those birch pollen-related foods which were reported to induce no immediate symptoms, but were consumed on a regular basis. Total IgE and specific IgE to birch pollen, Bet v 1/2 and various birch pollen-related foods were determined. RESULTS: Seven of 12 children showed immediate and/or late eczematous reactions upon ingestion of birch pollen-related foodstuff. Four children showed a worsening of eczema 24 h upon oral challenge with a significant difference in SCORAD before and after challenge. There were no differences in terms of total IgE or birch pollen-specific IgE between children with a late eczematous response and non-reacting children. CONCLUSIONS: Birch pollen-related food may induce allergic symptoms in children with AEDS who exhibit a sensitization to birch pollen. Oral challenge tests should be performed in those children who suffer from severe AEDS and who are highly sensitized to birch pollen allergens even in the absence of a history suggestive of food allergy.     

IgE-binding components of cultured human keratinocytes in atopic eczema/dermatitis syndrome and their crossreactivity with Malassezia furfur

BACKGROUND: Atopic eczema/dermatitis syndrome (AEDS) patients display immunoglobulin E (IgE) reactivity to several antigens, e.g. saprophytic yeasts as Malassezia furfur. AEDS patients also show IgE autoreactivity towards cells of their own tissue including epidermis. PURPOSE OF THE STUDY: The aim of this study was to investigate the IgE autoreactivity of AEDS patients to cultured keratinocytes and to reveal potential crossreacting epitopes in cultured keratinocytes and M. furfur. MATERIAL AND METHODS: Serum samples of 27 AEDS patients were analyzed, of these 13 were M. furfur radioallergosorbent test (RAST) positive and 14 negative. Four urticaria, three psoriasis, and seven nonatopic patients were included as controls. The studies were performed by using IgE immunoblotting and immunoblotting inhibition methods. RESULTS: Ten IgE-binding protein bands were detected in cultured human keratinocytes by IgE immunoblotting using sera from adult AEDS patients. Anti-keratinocyte IgE antibodies were more associated with elevated S-IgE level than M. furfur RAST. Clear crossreactivity with M. furfur could not be shown. CONCLUSIONS: The possible pathomechanism of anti-keratinocyte IgE antibodies is not due to IgE epitope mimicry of saprophytic yeast and local tissue in AEDS skin.     

Urinary leukotriene levels are increased during exacerbation of atopic eczema/dermatitis syndrome. Relation to clinical status

BACKGROUND: Leukotrienes are potent mediators of allergic inflammation and their role in the pathogenesis of allergic disorders, particularly asthma, is well established. Their importance in the pathogenesis of atopic eczema/dermatitis syndrome (AEDS) is still unclear. We aimed to compare urinary cysteinyl leukotriene (Cys-LT) levels during exacerbation and remission of AEDS in relation to clinical status, IgE levels, and eosinophil counts. METHODS: Urinary Cys-LTs were measured by direct enzyme immunoassay in 17 adult patients with AEDS and in 17 healthy controls in whom atopy had been excluded. Cys-LTs were compared during exacerbation and remission of AEDS in relation to the clinical status measured by SCORAD. Total IgE levels were measured by enzyme-linked immunoassay (ELISA). RESULTS: Mean clinical score during the exacerbation was 64.3 +/- 3.1 and during remission 22.4 +/- 4 (P < 0.01). Cys-LTs levels were significantly higher during the exacerbation of AEDS than in the control group (230.9 +/- 20.8 vs 123.2 +/- 9.9 pg/mg creatinine; P < 0.005). During the remission, the difference between AEDS patients and the control group was not significant (96.3 +/- 8.7 vs 123.2 +/- 9.9 pg/mg creatinine; P = 0.8). During AEDS exacerbation Cys-LTs levels were significantly correlated with the clinical status (rS = 0.73, P < 0.01) and with eosinophil counts (r = 0.86; P < 0.01) but not with the duration of the disease, age of patients, or IgE levels. CONCLUSIONS: Our results point to enhanced biosynthesis of Cys-LTs during the AEDS exacerbations. Inflammatory cells, e.g. eosinophils are the most probable source of Cys-LTs. A strong correlation between Cys-LT levels and clinical status may in part explain preliminary clinical observations of efficacy of leukotriene antagonists in alleviating symptoms of AEDS.     

Detection of basophil-activating IgG autoantibodies in chronic idiopathic urticaria by induction of CD 63

BACKGROUND: Approximately 40% to 50% of patients with chronic idiopathic urticaria (CIU) have functional IgG autoantibodies against FcepsilonRIalpha or IgE, which induce histamine release from basophils and cutaneous mast cells. A positive autologous serum skin test response is believed to reflect the presence of these autoantibodies. OBJECTIVE: We sought to further define the functional properties of and develop a sensitive functional assay for detection of autoantibodies in patients with CIU. METHODS: Sera from patients with CIU (n=61) and sera from healthy control subjects (n=23) were incubated with donor basophils. Activation of basophils was determined on the basis of CD 63 surface expression, as analyzed on a FACScan flow cytometer. RESULTS: A positive basophil activation test result was found in 51% of patients with CIU, and basophil-activating properties were present in the IgG fractions of sera. When both the in vitro test and the autologous serum skin test were considered, basophil/mast cell-activating autoantibodies were present in 62% of the patients. Patients with a positive basophil activation test result had a significantly higher prevalence of other autoantibodies, had more severe urticaria, and were more likely to have angioedema. CONCLUSION: The results demonstrate the presence of basophil-activating autoantibodies in about 50% of patients with CIU. The data support the autoimmune cause of the disease and provide a simple test for detection of these autoantibodies.     

Autoantibodies in chronic idiopathic urticaria and nonurticarial systemic autoimmune disorders

BackgroundChronic idiopathic urticaria (CU) has been associated with other autoimmune diseases and basophil-activating autoantibodies to FcεRI or IgE. It is unknown whether patients with systemicautoimmune diseases have a similar prevalence of these autoantibodies.ObjectiveTo compare the prevalences of basophil-activating autoantibodies (elevated CU Index) in patients with CU, rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE). Clinical characteristics and laboratory studies were examined for an association with the CU Index.MethodsAdult patients, 27 with CU, 27 with RA, and 26 with SLE, and 20 healthy controls were compared on the basis of the CU Index panel, anti-IgE, and antithyroid antibodies.ResultsThe CU Index values were significantly higher in the CU group when compared with the RA group but not when compared with the SLE group. 33% of CU, 23% of SLE, 3.7% of RA, and 15% of controls had apositive CU Index. Elevated antithyroid antibody levels did not correlate with a positive CU Index in any of the groups. An elevated CU Index in the SLE group was not associated with age, sex, ethnicity, disease severity, or history of atopy.ConclusionThe CU Index values were elevated in patients with CU and SLE. The presence of these autoantibodies did not correlate with disease activity or presence of thyroid antibodies. Functional autoantibodies may not be specific for chronic idiopathic urticaria, and their role in nonurticarial systemic autoimmune diseases requires further investigation.     

Immediate hypersensitivity to Malassezia furfur and Candida albicans mannans in vivo and in vitro

BACKGROUND: Elevated and correlative Malassezia furfur (M. furfur) and Candida albicans (C. albicans) mannan-specific IgE have been demonstrated in atopic eczema dermatitis syndrome (AEDS) of the head, neck and shoulder (HNS) region of the skin. The significance of these antibodies in vivo has not been demonstrated. METHODS: Sixty-five AEDS patients with HNS distribution were included. Serum total IgE (S-IgE) and yeast antigen-specific (Cetavlon-purified mannan and whole extract antigens of M. furfur and C. albicans) IgE were measured and skin prick tests (SPT) were performed with the yeast antigens. RESULTS: Mannan-specific IgE and SPT were positive in 51 and 48% of patients with M. furfur and in 42 and 22% with C. albicans, respectively. Whole extract-specific IgE and SPT were positive in 85 and 95% of patients with M. furfur and in 91 and 57% with C. albicans, respectively. The highest correlation between specific IgE and SPT was seen with M. furfur mannan (r = 0.60; P < 0.0001). Both M. furfur mannan-specific IgE (r = 0.76; P < 0.0001) and SPT (r = 0.44; P = 0.0005) correlated with S-IgE. CONCLUSIONS: Mannan-induced immediate hypersensitivity in vivo was demonstrated in SPT. The significant correlation between M. furfur mannan-specific IgE and SPT suggests that mannan is an important allergen in yeast hypersensitive AEDS in vivo.     

Chronic urticaria and Helicobacter pylori.

BACKGROUND: Although the clinical manifestations of chronic urticaria (CU) are similar in most patients, a variety of factors should be taken into consideration. In general, the cause of CU cannot be determined in most patients, and it is considered idiopathic. In the past several years, relationships between some patients with CU and hepatitis C or autoimmune thyroid diseases have been established. Similarly, other factors may also be considered as possible causes to explain certain patients with CU. Previously, some patients with CU have had their disease attributed to Helicobacter pylori (HP), but the relationship was only clinical. OBJECTIVE: None of the patients previously described included an immunological study. Thus, we studied a patient with CU, who showed marked clinical improvement after eradication of HP, to demonstrate an IgE relationship with this skin disease. METHODS: First, blood analytical parameters, roentgenograms, fecal examination for parasites, and skin tests were performed to try to establish an etiology. In addition, endoscopy with gastric biopsy confirmed HP colonization, and eradication treatment was prescribed. To investigate an immunological relationship, other tests performed included the following: HP-specific IgG, histamine release induced by HP, HP-specific IgE, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis with immunoblotting. RESULTS: The blood analytical parameters, roentgenograms, fecal examination for parasites, and skin tests were all negative. In contrast, the tests for HP-specific IgG, histamine release induced by HP, and HP-specific IgE were all positive. In addition, the sulfate-polyacrylamide gel electrophoresis with immunoblotting showed specific IgE binding to an extract of HP. CONCLUSIONS: Our results may indicate an immunological IgE relationship between HP colonization and CU in this particular patient.     

Interrelationships of quantitative asthma-related phenotypes in the Epidemiological Study on the Genetics and Environment of Asthma, Bronchial Hyperresponsiveness, and Atopy

BACKGROUND: Delineating asthma subphenotypes is of interest to understand the cause of the disease. Few studies have addressed the interrelationships of quantitative asthma-related traits. OBJECTIVE: We sought to study the interrelationships of allergy markers and FEV(1) in relation to asthma and sex in children and adults. METHODS: Total IgE levels, skin prick test (SPT) positivity, eosinophil counts, and FEV(1) were assessed in 299 asthmatic cases (children and adults) recruited in chest clinics and 309 nonasthmatic population-based control subjects in the French Epidemiological Study on the Genetics and Environment of Asthma, Bronchial Hyperresponsiveness, and Atopy. RESULTS: Allergy parameters were significantly higher in asthmatic cases than in control subjects for children and adults and for both sexes. Sex and age modified the pattern of concordance of high IgE levels, SPT positivity, and eosinophilia among asthmatic cases, with the greatest overlap in male children (64%) and the lowest in male adults (18%). Patterns of change over the lifespan of IgE levels, eosinophil counts, and FEV(1)/height(2) varied, with the acceleration of FEV(1) decrease being particularly evident in asthmatic adults. In adult cases and control subjects, SPT positivity (particularly to indoor allergens) was significantly related to IgE levels but not to eosinophil counts. The association of eosinophil counts with IgE levels was evident only in children. Environmental factors (smoking, pets, and country living) did not alter the patterns observed. CONCLUSIONS: Each allergy-related phenotype showed a distinct relation with asthma, with the role for eosinophils being different than that for IgE levels and SPT responses. CLINICAL IMPLICATIONS: Taking age and sex into account is essential for understanding the interrelationships of the various allergy-related phenotypes to asthma status.     

Natural anti-FcepsilonRIalpha autoantibodies isolated from healthy donors and chronic idiopathic urticaria patients reveal a restricted repertoire and autoreactivity on human basophils

The role of autoantibodies against the alpha-subunit of the human high-affinity IgE receptor (FcepsilonRIalpha) in the pathogenesis of chronic idiopathic urticaria (CIU) is controversial. We have shown that these antibodies are widespread, apparently non-pathogenic and belong to the natural antibody repertoire. To clarify this controversy, we constructed antibody libraries from both healthy donors and CIU patients with active disease. Here we describe the first three high affinity IgM anti-FcepsilonRIalphaautoantibodies isolated from normal and urticaria libraries. Sequence analysis revealed germline VH in both cases paired with a slightly mutated VL, thus supporting their classification as natural antibodies. Strikingly, one major IgM clone was present in both CIU patients and normal donors. The anti-FcepsilonRIalpha autoantibodies recognize FcepsilonRIalpha on cells, but are non-anaphylactogenic on blood basophils, except when IgE is removed from the receptor. Based on their functional activities we propose a concept of "conditional autoimmunity" where natural anti-FcepsilonRIalphaautoantibodies can become pathogenic dependent on the state of occupancy of the FcepsilonRIalpha by its natural ligand IgE.     

Lack of association between atopic eczema/dermatitis syndrome and polymorphisms in the promoter region of RANTES and regulatory region of MCP-1

BACKGROUND: Chemokines play an important role in the pathophysiology of atopic eczema/dermatitis syndrome (AEDS) and allergy. Recently polymorphisms in the promoter region of RANTES (regulated on activation normal T cell expressed and secreted) and in the gene regulatory region of MCP-1 (monocyte chemoattractant protein-1) have been found, which increase the expression of these chemokines. The - 403A allele of the RANTES promoter region was found associated with AEDS in German children. We investigated whether the presence of these polymorphisms was associated with AEDS or allergy in Hungarian children. METHODS: One hundred and twenty-eight children with AEDS, 102 allergic children without AEDS and 303 children of comparable ages without allergic disorders were screened for genotype with a PCR-based assay. RESULTS: There were no significant differences in the frequency of these polymorphisms, or in the distribution of genotypes between the groups. The total IgE concentration, the white blood cell count and the blood eosinophil cell count did not differ between the genotypes. CONCLUSION: In this cohort of Hungarian children there was no association between - 28G, and - 403A alleles in the RANTES promoter, - 2518G polymorphism in the distal regulatory region of the MCP-1 and AEDS, or allergy.     

Anisakis simplex-sensitized patients: should fish be excluded from their diet?

BACKGROUND: Anisakis simplex (A.s.) allergy is an emerging disease. The third-stage larvae of this nematode are a source of hidden allergens in fish. There are no clear guidelines concerning dietary restrictions for patients with serum-specific IgE to this parasite. OBJECTIVE: To follow up the clinical data and immunological parameters of patients sensitized to A.s. during 6 to 23 months. METHODS: The clinical symptoms and serologic status of 17 patients with specific IgE and positive skin prick test results to A.s. were studied prospectively. Six of these had anaphylaxis (ANA) attributed to A.s. and 11 patients experienced concomitant chronic urticaria (CU). All patients were advised not to eat fish for 6 months. RESULTS: Four patients from the ANA group excluded fish, and ANA did not recur. Two other patients with ANA refused to exclude fish; one remained free of symptoms and the other experienced several urticarial episodes. During this 6-month period total IgE levels decreased in all six ANA patients; specific IgE for A.s. decreased in four patients and increased in two. Two patients from the CU group did not exclude fish, and symptoms persisted in these two patients. Clinical improvement was observed in 78% of the patients with CU who excluded fish. Total and specific IgE levels decreased in all the patients with CU. CONCLUSIONS: Because ANA symptoms are very severe, patients should always be advised to exclude fish until specific food allergens are identified. However, in patients with CU and specific IgE to A.s., only the clinical response to fish ingestion will determine the need for strict fish avoidance.     

Relationship between the atopy patch test and clinical expression of the disease in children with atopic eczema/dermatitis syndrome and respiratory symptoms

BACKGROUND: The atopy patch test (APT) may be the only positive skin test result in patients with either atopic eczema/ dermatitis syndrome (AEDS) or respiratory abnormalities with or without AEDS. OBJECTIVE: To investigate the possible significance of APT to dust mite by comparing the positive result to this test with that of the skin prick test (SPT) in patients with different characteristics. METHODS: A total of 297 individuals (178 boys and 119 girls) aged 5 to 221 months (mean [SD] age, 64.5 [42.1] months; median age, 58 months) were included in this study. Participants were divided into 4 groups: current AEDS, current AEDS and respiratory symptoms, past AEDS and respiratory symptoms, and respiratory symptoms with neither current nor past AEDS (control group). All the patients underwent SPT and APT using house dust mite extract. RESULTS: In the study groups, the rate of positivity was significantly higher for APT, whereas in the control group, there were significantly more positive results to SPT (P < .001 for both). Multivariate analysis showed that there was a high probability of a positive APT result in patients with AEDS (odds ratio [OR], 17.4), with AEDS and respiratory disease (OR, 21.9), and with past AEDS and respiratory disease (OR, 22.8). CONCLUSIONS: These patients with AEDS showed 2 different patterns of allergic response to allergens, one IgE mediated (as evaluated by positive SPT results) and the other cell mediated (as evaluated by positive APT results). The former seems to follow the so-called atopic march model, and the latter persists even after the disappearance of AEDS and is likely to be implicated in the pathogenesis of respiratory allergy.     

The relationship between serum IgE and surface levels of FcepsilonR on human leukocytes in various diseases: correlation of expression with FcepsilonRI on basophils but not on monocytes or eosinophils

BACKGROUND: Expression of receptors for IgE (FcepsilonR) have been mainly studied on mast cells and blood basophils in the context of allergic disease. Some reports have noted limited expression of FcepsilonR on other leukocytes, including blood monocytes and eosinophils in certain patients. An association between human blood basophil expression of FcepsilonRIalpha and serum IgE has been noted among allergic subjects. OBJECTIVE: Recent evidence supports regulation of FcepsilonRIalpha by free IgE on both mast cells and basophils. We hypothesized that this relationship would exist across an extremely wide range of IgE levels for human basophils, irrespective of underlying disease. We further examined whether a similar relationship existed between serum IgE and FcepsilonRIalpha or FcepsilonRII (CD23) expression on monocytes and eosinophils in these same subjects. METHODS: Blood was obtained from nonallergic subjects (n = 3) and subjects with allergic asthma (n = 5), atopic dermatitis (n = 3), hypereosinophilic syndromes (n = 7), hyper-IgE syndrome (n = 6), helminth infestation (n = 6), or IgE myeloma (n = 1). Levels of serum IgE were determined by using RIA and ranged from 3 to 4.7 mg/mL. Levels of cell surface FcepsilonRIalpha, FcepsilonRII, and IgE were measured by using immunofluorescence and flow cytometry. RESULTS: Basophil surface IgE density and FcepsilonRIalpha expression correlated with serum IgE levels (r = 0. 67 and r = 0.46, respectively; P <.01; n = 31) regardless of the disease state. In contrast, monocyte FcepsilonRIalpha expression did not correlate with serum IgE (r = 0.09, P >.5, n = 29), and low-level eosinophil FcepsilonRIalpha expression was only detected in a single asthmatic subject. CD23 expression was not detected on basophils or eosinophils, except for the eosinophils from the donor with IgE myeloma. CD23 was present on monocytes from some donors but did not correlate with serum IgE levels. CONCLUSIONS: In a variety of disease states, FcepsilonRIalpha expression by basophils, but not monocytes or eosinophils, correlated with serum IgE levels across a 6-log range of IgE. These data support the concept of in vivo regulation of FcepsilonRIalpha on basophils by serum IgE and further demonstrate that this is independent of allergic disease per se.     

Monomeric immunoglobulin E stabilizes FcεRIα from the human basophil cell line KU812 by protecting it from natural turnover

BACKGROUND: The high affinity IgE receptor (FcepsilonRI) on mast cells and basophils is up-regulated by its own ligand IgE; however, the mechanism is unknown. OBJECTIVE: To study the IgE-mediated effect on FcepsilonRI on basophils by using the human basophilic cell line KU812. METHODS: Expression of cell surface FcepsilonRI was assessed by flow cytometry. Western blot technique was used to illustrate tyrosine-phosphorylation and the Ca2+ level in KU812 was measured by fluorescence of Fura-2. Soluble specimens of the alpha-chain from FcepsilonRI (FcepsilonRIalpha) were obtained by lysing 107 KU812 pr. mL. FcepsilonRIalpha was detected by a sandwich immunoradiometric assay employing the IgE-binding capacity of FcepsilonRIalpha in conjunction with a monoclonal antibody. Polyclonal rabbit anti-FcepsilonRIalpha was used for detection of FcepsilonRIalpha by Western blotting. RESULTS: We found that monomeric IgE did not induce tyrosine-phosphorylation in KU812, which was the case when stimulating with IgE cross-linked by anti-IgE binding. Further, only cross-linking of IgE, but not monomeric IgE, increased the Ca2+ level. Using the immunoradiometric assay, we found a temperature dependent reduction in the amount of FcepsilonRIalpha. Samples incubated at 37 degrees C for 5 h displayed a 16-fold decrease in the FcepsilonRIalpha level compared with samples incubated at 4 degrees C. In the presence of IgE the reduction at 37 degrees C was only threefold. CONCLUSION: These results indicate that IgE does not induce intracellular signals in KU812, i.e., tyrosine-phosphorylation or Ca2+ release. Instead it appears that FcepsilonRIalpha is an unstable protein that IgE stabilizes and thereby protects from a temperature dependent turnover.     

Low numbers of interleukin-12-producing cord blood mononuclear cells and immunoglobulin E sensitization in early childhood

BACKGROUND: Successful pregnancies are associated with skewing towards a Th2 cytokine profile. Cytokine responses to allergens can be detected in cord blood mononuclear cells (CBMC), suggesting allergen priming already in utero. OBJECTIVE: To investigate the cytokine profile in CBMC after in vitro stimulation with allergens and to relate the responses to the outcome in terms of allergic disease at 2 years of age. METHODS: CBMC were isolated from 82 children. The responses to ovalbumin (OVA), birch, cat and phytohaemagglutinin (PHA) were investigated by the ELISpot technique. The numbers of IFN-gamma-, IL-4- and IL-12-producing CBMC were counted for each stimulation. The children were followed prospectively; skin prick test (SPT) and RAST towards food and inhalant allergens were assessed at 24 months of age. RESULTS: Sixteen (19.5%) children were classified as IgE sensitized (positive SPT; > or =3 mm and/or RAST; > or =0.35 kUA/L). The numbers of IL-12-producing CBMC after stimulation with birch, OVA and cat were lower among IgE-sensitized children, statistically significant for cat. IFN-gamma-producing cells, did not differ in numbers between the sensitized and non-sensitized children. Children who had atopic eczema/dermatitis syndrome (AEDS) during the observation (n=53) had significantly lower numbers of IFN-gamma-producing CBMC after stimulation with OVA and cat than their non-AEDS counterparts. CONCLUSIONS: Although the numbers of infants in our study are limited our data suggest that a low number of IL-12-producing CBMC is associated with IgE sensitization during early childhood and that a reduced number of IFN-gamma-producing CBMC promotes the development of AEDS during the first 2 years of life.