Hyper IgM syndrome and complement Clq deficiency in an individual with systemic lupus erythematosus-like disease.

Many immunedeficiency syndromes are associated with autoimmune disorders. We here report on a girl with a systemic lupus erythematosus-like disease who suffered from both hyperimmunoglobulin M syndrome (HIGMS) and C1q deficiency. Despite severe central nervous system-lupus like disease, probably due to C1q deficiency, kidney function was relatively spared. IgM autoantibody might play a protective role against lupus-glomerulonephritis.

A convenient and sensitive allergy test: IgE crosslinking-induced luciferase expression in cultured mast cells.

BACKGROUND: For the detection of allergen-specific IgE in sera, solid-phase IgE-binding assays like the CAP test are commonly used. Although such immunochemical methods are very sensitive, they frequently produce false positives. Degranulation of the human IgE receptor (FcεRI)-transfected rat mast cell (RBL) lines seems to be a possible indicator for human IgE, but spontaneous mediator release from these cells in the presence of human sera is not negligible. METHODS: The nuclear factor of activated T-cells (NFAT)-responsive luciferase reporter gene was stably transfected into human FcεRI-expressing RBL-SX38 cells. One established clone (RS-ATL8) was sensitized with 1 : 100 dilution of sera from patients with egg white allergy and then stimulated with purified or a crude extract of egg white allergen. RESULTS: Sensitization with 15 pg/ml IgE was sufficient to detect IgE crosslinking-induced luciferase expression (EXiLE) by anti-IgE stimulation. Allergen-specific EXiLE was elicited by as little as 1 fg/ml of egg white protein without cytotoxicity. There was a good correlation between results with EXiLE and oral food challenge tests on patients with egg allergy (P = 0.001687, Fisher's exact test). The measured values of EXiLE and the CAP test also correlated well (R = 0.9127, Spearman's test). CONCLUSION: The EXiLE test using RS-ATL8 cells is a promising in vitro IgE test to evaluate the biological activity of the binding between IgE and allergens.

State of the art and new horizons in the diagnosis and management of egg allergy.

Egg allergy is one of the most frequent food allergies in children below the age of three. Common symptoms of egg allergy involve frequently the skin as well as the gut and in more severe cases result in anaphylaxis. Non-IgE-mediated symptoms such as in eosinophilic diseases of the gut or egg-induced enterocolitis might also be observed. Sensitization to egg white proteins can be found in young children in absence of clinical symptoms. The diagnosis of egg allergy is based on the history, IgE tests as well as standardized food challenges. Ovomucoid is the major allergen of egg, and recent advances in technology have improved the diagnosis and follow-up of patients with egg allergy by using single allergens or allergens with modified allergenic properties. Today, the management of egg allergy is strict avoidance. However, oral tolerance induction protocols, in particular with egg proteins with reduced allergenic properties, are promising tools for inducing an increased level of tolerance in specific patients.

Up-regulated cytokine-inducible SH2-containing protein expression in allergen-stimulated T cells from hen's egg-allergic patients.

BACKGROUND: Although changes in the fine balance of allergen-specific T cells are crucial in the pathogenesis of allergic diseases, their roles in the allergic reaction to hen's eggs (HE) have not yet been fully analysed. OBJECTIVE: Using microarray technology, allergen-stimulated T cells from HE-allergic children were analysed to identify genes that are specifically up-regulated in these cells. METHODS: RNA from CD4(+) CD14(-) cells, fractionated from allergen-stimulated peripheral mononuclear cells, was analysed using a whole-genome microarray and real-time RT-PCR. The protein expression of selected genes was ascertained by flow cytometry. RESULTS: In microarray analyses of allergen-stimulated T cells, 43 genes were up-regulated in HE-allergic children but not in non-HE-allergic children. Among these, up-regulation of three genes, cytokine -inducible SH2-containing protein (CISH), nuclear factor of kappa light polypeptide gene enhancer in B-cell inhibitor Z (NFKBIZ) and B-cell CLL/lymphoma 2 (BCL2), was confirmed by real-time quantitative RT-PCR. CISH, but not NFKBIZ or BCL2, showed a significantly higher ratio of antigen-stimulated cell transcription over unstimulated cells in HE-allergic than in non-HE-allergic children (P<0.01). Flow-cytometric analysis revealed that the percentage of CD25(+)CISH(+) cells in CD4(+) cells from patients with HE allergy was significantly higher than that in controls (P<0.01). The expression level of CISH was significantly higher in IL-4(+) Th2 cells than in IFN-gamma(+) Th1 cells. CONCLUSION: We noted that CISH expression in allergen-stimulated CD4(+) T cells from HE-allergic patients was significantly increased in both mRNA and protein levels compared with that from non-HE-allergic children.

Allergen-specific helper T cell response in patients with cow's milk allergy: Simultaneous analysis of proliferation and cytokine production by carboxyfluorescein succinimidyl ester dilution assay.

BACKGROUND: The role of antigen-specific T cells in the allergic reaction to cow's milk or in tolerance induction is not yet fully understood. OBJECTIVE: This study was designed to analyse both cow's milk protein (CMP)-specific T cell proliferation and cytokine production simultaneously in children with cow's milk allergy (CMA) in comparison with subjects with various allergic backgrounds. METHODS: Carboxyfluorescein succinimidyl ester was used to detect cow's milk-specific T cells by flow cytometry. The intra-cytoplasmic cytokine production of these antigen-specific T cells was also analysed. RESULTS: Significant differences of both CMP-specific CD4+ cell proliferation and cytokine production between CMA and non-allergic children were observed. While the proliferative responses of children who recently outgrew CMA were not significantly different from those of patients, the patterns of cytokine production were similar to those of non-allergic children. CONCLUSION: These results suggest that the presence of CMP-specific T cell clones per se does not produce CMA, but that the T-helper type 2-skewed pattern of those T cells is associated with adverse reactions. Although it is not possible to distinguish between individual patients with and without CMA on the basis of CFSE assays, these results contribute to the understanding of the pathogenesis and tolerance induction of CMA.

Assessment of cross-reactivity between Japanese cedar (Cryptomeria japonica) pollen and tomato fruit extracts by RAST inhibition and immunoblot inhibition.

BACKGROUND: An association between pollinosis and sensitivity to fruits and vegetables has been reported. Although Japanese cedar (Cryptomeria japonica) pollinosis is one of the most widespread diseases in Japan, there have been no reports demonstrating cross-reactivity between Japanese cedar pollen and other plant food. OBJECTIVE: The aim of this study was to demonstrate cross-reactivity between Japanese cedar pollen and tomato fruit (Lycopersicon esculentum) using RAST inhibition and immunoblot inhibition. METHODS: The RAST and immunoblot inhibition were performed using sera from patients with oral allergy syndrome (OAS) after ingesting fresh tomatoes. We identified some proteins that took part in cross-reactive IgE by the determination of N-terminal amino acid sequences and a homology search through the SWISS-PROT database. RESULTS: In the RAST inhibition, the bindings of IgE from the sera from four out of five (4/5) subjects to Japanese cedar pollen discs were inhibited by more than 50% by preincubation of the serum with tomato fruit extracts. Likewise, the IgE bindings to tomato fruit discs were inhibited more than 50% by Japanese cedar pollen extracts in 3/5 sera. In immunoblot inhibition, IgE binding activities of some protein bands on both membranes were decreased by heterologous inhibitors. However, the combinations of these protein bands involved in cross-reactivity were different between patients. CONCLUSION: We have demonstrated cross-reactivity between Japanese cedar pollen and tomato fruit using RAST inhibition and immunoblot inhibition.

A 33-kDa allergen from rice (Oryza sativa L. Japonica). cDNA cloning, expression, and identification as a novel glyoxalase I.

Cereal proteins are known to cause allergic reactions such as Baker's asthma and severe atopic dermatitis to certain populations. In rice allergy, proteins with molecular masses of 14-16, 26, 33, and 56 kDa have been demonstrated to be potentially allergenic. In this study, to identify and characterize the 33-kDa allergen, designated Glb33, this protein was first purified to homogeneity, and its cDNA clone was isolated. When expressed in Escherichia coli, the recombinant Glb33 was shown to be as reactive as the native Glb33 with mouse IgG and patients' IgE antibodies to Glb33. The Glb33 cDNA coded for a protein of 291 amino acids with two 120-amino acid residue repeats, and the amino acid sequence showed similarity to glyoxalase I from various organisms, including human, plant, yeast, and bacterium. As expected, both native Glb33 purified from rice seeds and the recombinant protein had glyoxalase I activity that catalyzes condensation of methylglyoxal and glutathione into S-lactoylglutathione. However, Glb33 had a higher sequence identity to the bacterial glyoxalase I rather than to known plant and yeast enzymes. Both the Glb33 transcript and the protein were detected not only in maturing seeds of rice but also in its stem and leaf. Taken all together, the rice allergen, Glb33, was identified to be a novel type of plant glyoxalase I that is expressed in various plant tissues, including maturing seeds.

Identification and characterization of the allergens in the tomato fruit by immunoblotting.

BACKGROUND: Although the tomato fruit (Lycopersicon esculentum) has been widely investigated for breeding purposes, there have been few studies on tomato allergenicity. We attempted to identify the tomato fruit allergens and to compare the concentrations of IgE-binding proteins among the different growth stages with sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. METHODS: An immunoblot experiment on tomato fruit extracts was performed using sera from 11 patients with oral allergy syndrome (OAS) to tomatoes. Bands reacting with IgE from more than half of the OAS patients' sera were excised and subjected to determination of N-terminal amino acid sequences using the automated Edman degradation method. Moreover, we compared the concentrations of these proteins at each growth stage of the tomato fruit with SDS-PAGE and immunoblotting. RESULTS: Four proteins binding with IgE from more than half of the OAS patients' sera were determined to be polygalacturonase 2A (PG2A), beta-fructofuranosidase, superoxide dismutase (SOD) and pectinesterase (PE). The concentrations of PG2A, beta-fructofuranosidase and PE were highest in the red ripening stage with both SDS-PAGE and immunoblotting. CONCLUSION: The concentrations of 3 of 4 tomato allergens increased during ripening.

IgE-binding activity to enzyme-digested ovomucoid distinguishes between patients with contact urticaria to egg with and without overt symptoms on ingestion.

BACKGROUND: We occasionally see egg-allergic children who develop contact urticaria to hen's egg despite the absence of the overt symptoms on ingestion. The mechanisms remain to be elucidated. METHODS: Twenty-one subjects with positive reactions to 20-min patch tests for egg-white antigens were divided into subgroups with positive (n = 10) and negative (n = 11) results to oral challenge tests by the same antigens. We measured IgE antibody for egg white and its components, and IgE-binding activities to digestive enzyme-treated ovomucoid by RAST inhibition. RESULTS: There were no significant differences in IgE antibody titers to egg white (positive vs negative: 30.3% vs 15.3%, P=0.130), ovomucoid (21.5% vs 10.2%, P= 0.078), ovotransferrin (9.9% vs 3.7%, P = 0.105), and lysozyme (3.4% vs 2.9%, P=0.944), except ovalbumin (16.8% vs 5.6%, P=0.024), between the positive and negative subjects in the provocation tests. In contrast, the concentration (1.93 microg/ml) of pepsin-treated ovomucoid needed for 50% RAST inhibition in the challenge-positive subjects was significantly (P=0.0003) lower than that (114.9 microg/ml) of negative subjects. Similar but less significant differences were obtained when ovomucoid fragments treated with chymotrypsin (0.91 microg/ml vs 6.86 microg/ml, P=0.014) and trypsin (0.75 microg/ml vs 4.67 microg/ml, P= 0.041) were used as inhibitors. CONCLUSIONS: We suggest that IgE antibodies from subjects showing contact urticaria despite the absence of reactions to the ingestion of egg white recognize the epitope(s) unstable to digestive enzymes.

Clinical significance of IgE-binding activity to enzymatic digests of ovomucoid in the diagnosis and the prediction of the outgrowing of egg white hypersensitivity.

BACKGROUND: We frequently encounter subjects without overt symptoms despite high IgE antibodies to egg white and its components. The measurements of these antibodies are not necessarily efficient for the diagnosis or the prediction of the outcome of egg allergy in children. METHODS: Specific IgE antibodies to egg white and its components, including ovomucoid, ovalbumin, ovotransferrin and lysozyme, were measured by direct RAST assays. IgE-binding activity to ovomucoid degraded by pepsin, trypsin and chymotrypsin was examined by RAST inhibition. Thirty subjects were divided into two groups with positive (n=18; mean age +/- SD = 42 +/-25 months) and negative (n=12; mean age +/- SD = 48 +/-31 months) oral challenge tests with egg white antigens. The individuals with positive results to the first challenge tests were given the second provocation tests at mean intervals of 32 months. IgE-binding activity of the sera collected on the first challenge to these ovomucoid fragments was compared between subjects with positive and negative reactions to the follow-up challenge tests. RESULTS: There were no significant differences in IgE antibody titers to egg white and its components between the positive and negative groups at the first and the second challenge tests. IgE-binding activity to ovomucoid digests after treatments with pepsin (p = 0.000008) and trypsin (p=0.037), except chymotrypsin (p=0.062), were significantly higher in subjects with positive challenge tests than in those with negative results. The difference was most remarkable in the IgE-binding to pepsin digests; the average concentrations (mean - SD and mean + SD) needed for 50% RAST inhibition in the positive group and in the negative group were 2.6 microg/ml (0.3 and 25) and 94.2 microg/ml (24.7 and 358.7), respectively. A significant difference was still observed in the inhibition tests using filtrates of pepsin digests with a membrane with MW 10,000 (p=0.014) and 3,000 (p=0.042) of cutoff. The concentration (mean= 0.8, mean - SD=0.2, mean + SD=3.4; microg/ml) of pepsin-treated ovomucoid required for 50% RAST inhibition in the subjects with positive second challenge results was significantly (p=0.033) lower than that (mean=6.8, mean-SD=0.6, mean + SD=73.9) of the negative group. CONCLUSION: IgE-binding activity to pepsin-digested ovomucoid was of diagnostic value to distinguish the challenge-positive subjects from the negative subjects. Subjects with high IgE-binding activity to pepsin-treated ovomucoid are unlikely to outgrow egg white allergy.

[Respiratory symptoms by oral challenge tests with egg white antigens in egg-allergic children].

One hundred and ninety one subjects showing histories of immediate hypersensitive response to egg white ingestion and/or positive IgE antibody titers specific for egg white were enrolled in double-blind placebo-controlled oral challenge with freeze and dried, heated or heated and ovomucoid-depleted egg white antigens. Seventy seven were male and 114 female, and their ages ranged from 11 month to 10 years 5 month; 118 of them had atopic dermatitis, seven had asthma and 33 had both atopic dermatitis and bronchial asthma and 33 had urticaria. One hundred four children developed 147 positive symptoms including 131 immediate reactions and 16 non-immediate reactions by oral challenge tests. Respiratory symptoms were observed in 25 cases (17%) including cough alone in 12 cases (8.2%), and both wheezing and cough in 13 cases (8.8%). These were all observed as immediate reactions and accompanied with dermal symptoms. Frequency of respiratory symptoms correlated with specific IgE antibody titers for egg white. Heated and ovomucoid-depleted egg white was more hypoallergenic that heated or freeze and dried egg white with respect to respiratory symptoms as well as other symptoms. We concluded that respiratory symptoms were provoked through oral challenges with egg white in a part of egg-allergic children.

[Assessment of allergenic activity of heated and ovomucoid-depleted egg white].

We investigated allergenic activity of heated and ovomucoid (OM)-depleted egg white by RAST inhibition tests, skin tests and and oral challenge tests. Freeze-dried egg white, OM and ovalbumin (OA) were coupled with CNBr-activated paper discs. Freeze-dried, heated, and heated and OM-depleted egg white antigens were used as inhibitors in RAST inhibition tests. Freeze-dried egg white significantly inhibited the IgE-binding to freeze-dried egg-white-, OM- and OA-discs. Heated egg white showed a significant inhibition against only OM-disc, but heated and OM-depleted egg white didn't effectively suppress IgE-binding to all discs. Fifty-six patients were subjected for skin tests and 27 patients for oral challenge tests with freeze-dried egg white, heated egg white and heated and OM-depleted egg white. Eighteen of 25 subjects with positive prick tests results to freeze-dried egg white showed negative results to heated egg white. Four of 7 cases with positive prick test results to heated egg white gave negative results to heated and OM-depleted egg white. 20-minutes patch tests showed almost similar results to prick tests. Four of 8 subjects showing positive oral challenge tests with freeze-dried egg white were negative to heated egg white. All of 4 with positive oral challenge tests by heated egg white were negative results to heated and OM-depleted egg white. These evidence indicated that heated and OM-depleted egg white was more hypoallergenic than heated egg white.

Allergenic activity of heated and ovomucoid-depleted egg white.

BACKGROUND: No egg white products have been clearly proven to be hypoallergenic. The role of egg white proteins in allergic reactions to eggs is still debatable. OBJECTIVE: This study was designed to determine the importance of ovomucoid, an egg white protein, in the development of allergies to egg white. METHODS: We performed a double-blind, placebo-controlled food challenge in subjects with high levels of IgE antibodies for egg white to compare the allergenicities of heated and ovomucoid-depleted egg white, freeze-dried egg white, and heated egg white. Levels of IgE antibodies for egg white, ovomucoid, ovalbumin, ovotransferrin, and lysozyme were measured in serum by RAST. RESULTS: Twenty-one of 38 subjects with positive challenge responses to freeze-dried egg white had negative challenge responses to heated egg white, whereas 16 of 17 subjects (94.1%) with positive responses to heated egg white did not respond to the heated and ovomucoid-depleted egg white challenge. The subjects with positive challenge responses to freeze-dried egg white tended to have higher IgE antibody values to ovomucoid than those with negative responses. IgE antibody levels to ovomucoid were significantly higher in subjects with positive responses to a challenge with heated egg white than in those with no response. There were no significant differences in the levels of IgE antibodies to the other proteins, except ovomucoid, in the negative-response and positive-response groups in challenge tests with freeze-dried and heated egg white. CONCLUSION: The heated and ovomucoid-depleted egg white preparation was less allergenic than heated or freeze-dried preparations. Ovomucoid has a more important role in the pathogenesis of allergic reactions to egg white than other proteins in egg white.

A case retaining contact urticaria against egg white after gaining tolerance to ingestion.

A girl, 5.7 years old, gained tolerance to egg white ingestion in spite of high immunoglobulin E (IgE) antibody titers to egg white but retained contact urticaria against egg white. She developed atopic dermatitis on her face at 2 months of age and showed high IgE antibody titers to egg white and cow's milk. Accidental ingestion of egg products initiated immediate symptoms such as wheezing, urticaria, erythema and edema of the eyelids and conjunctiva three times. These symptoms were confirmed by challenge tests using boiled egg white at 3.9 years of age. She also reacted positively to a 20 min patch test on her volar arm with raw egg white. However, there were no reactions to the oral challenge test by boiled egg and freeze-dried egg white at 5.1 and 5.7 years of age, respectively. This non-responsiveness was confirmed by a double-blind, placebo-controlled food challenge using freeze-dried egg white. Nevertheless, she showed positive reactions to a 20 min patch test with freeze-dried egg white. Her IgE antibody titers to the egg white components including ovomucoid, ovalbumin, ovotransferrin and lysozyme as well as egg white were high from 2.9 to 5.7 years old. Her IgE antibody titers for the ovomucoid fragments digested by pepsin, chymotrypsin and trypsin were not lower than those of positive control subjects. The binding activity of IgE antibody to ovomucoid, however, decreased from 2.9 to 5.6 years as shown by radioallergosorbent test (RAST) inhibition assays. The IgE antibody showed weaker binding activity to pepsin- and chymotrypsin-digested ovomucoid that were filtered through cut-off 10,000 filter at the age of 2.1 and 5.7 years. We speculated that the maturation of secretion of digestive enzymes was involved in the mechanisms of the acquisition of tolerance to egg white ingestion in spite of the persistence of contact urticaria.

Primary structure and allergenic activity of trypsin inhibitors from the seeds of buckwheat (Fagopyrum esculentum Moench).

The complete amino acid sequences of two trypsin inhibitors BWI-2a and BWI-2b from the seeds of buckwheat (Fagopyrum esculentum Moench) were determined. BWI-2b consists of 51 amino acid residues containing two disulfide bonds. BWI-2a shares all amino acids with BWI-2b except for the C-terminal tripeptide: BWI-2a lacks Glu-Gly-Asn and ends with the Asp residue, making a total of 48 residues in the chain. The two disulfide bonds connect Cys11 to Cys32 and Cys15 to Cys28. BWI-2b shows no relatedness to the other buckwheat trypsin inhibitor reported [Belozersky et al. (1995) FEBS Lett. 371, 264-266]. Sequence comparison of BWI-2b with those of the other proteins included in PIR showed that BWI-2b is significantly homologous to the N-terminal region of storage proteins classified in the vicilin family. Furthermore, the allergenic activity of BWI-2b and the other buckwheat trypsin inhibitor BWI-1 was examined using the radioallergosorbent test. The result indicated that both inhibitors BWI-2b and BWI-1 have IgE binding activity, albeit to a low extent, suggesting that they might be minor allergenic proteins in buckwheat seeds.

Immediate hypersensitive reactions to buckwheat ingestion and cross allergenicity between buckwheat and rice antigens in subjects with high levels of IgE antibodies to buckwheat.

BACKGROUND: Immediate hypersensitive reactions induced by buckwheat ingestion are considered to be IgE-mediated. Some subjects, however, develop no immediate adverse reactions after buckwheat ingestion despite high levels of buckwheat-specific antigens IgE. The mechanism is unknown. OBJECTIVE: To investigate the mechanisms. METHODS: RAST for buckwheat and rice and RAST inhibition between these antigens were performed using sera from 23 buckwheat-sensitive subjects and 30 buckwheat-tolerant subjects who had IgE antibodies for both buckwheat and rice. RESULTS: RAST values for buckwheat and rice were significantly correlated with each other (P < .01) in the buckwheat-tolerant group, but not in the buckwheat-sensitive group. This suggests the IgE antibodies from the subjects without any overt symptoms after buckwheat ingestion recognize the cross-reactive epitope between buckwheat and rice, whereas the IgE antibodies from those with immediate reactions to buckwheat ingestion do not. RAST inhibition assays were performed to evaluate this. RAST inhibition of heterogeneous combination of inhibitor and disc antigen such as rice and buckwheat was significantly smaller than that of homologous combination of rice and rice or buckwheat and buckwheat in the group with immediate symptoms after buckwheat ingestion. There was no significant difference in RAST inhibition between homologous and heterogeneous combinations in the group without the symptoms. CONCLUSIONS: There was cross-reactivity with IgE antibodies between buckwheat and rice and IgE antibodies from the buckwheat-tolerant subjects with high levels of IgE antibodies from the buckwheat might recognize the epitopes on buckwheat antigens which cross-react with rice antigens, whereas IgE antibodies from the buckwheat-sensitive subjects might bind to buckwheat-specific epitopes.

[Immediate hypersensitive reactions to the ingestion of egg white and IgE binding to the egg white components].

IgE is considered to be involved in immediate hypersensitive reactions (IHR) following egg ingestion. IgE antibody levels to egg-white (EW) antigens in the IHR-positive group (n = 19, mean age +/- SD = 5.2 +/- 4.5 yr) were higher than those in the IHR-negative group (n = 13, mean of age +/- SD = 3.6 +/- 2.2 yr). However, even in the IHR-negative group, some patients showed high IgE to EW. RAST inhibition tests with heat-treated (100 degrees C, 5, 10, and 30 min) egg-white antigens were performed on 13 serum samples from subjects with IHR and 9 serum samples from subjects without IHR. Heat treatment decreased the IgE-binding activity of egg white and it was speculated that IgE from IHR-negative subjects bound to relatively heat-unstable sites of egg-white antigens. Furthermore, we selected IHR-negative subjects (n = 8, mean of age +/- SD = 3.0 +/- 1.7 yr) with higher IgE antibody levels than the lowest limit of IgE to EW of the IHR-positive group and compared IgE to ovomucoid (OM), ovalbumin (OA), conalbumin (CA), and lysozyme (Ly) between these IHR-negative and positive groups. IgE-binding activities to egg-white components, including OA, CA, and Ly but not OM, were significantly decreased with heat treatment. The IHR-negative group showed significantly lower IgE to OM (untreated, 5, 10, 30 min treatment) and 5 min treated OA alone than the IHR-positive group, while no difference was found in IgE to other components between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Specific IgE antibodies and serum eosinophil cationic protein in children with atopic dermatitis alone.

Both eosinophils and specific immunoglobulin E (IgE) to foods and mites have been considered involved in the pathogenesis of atopic dermatitis (AD). The relationship between eosinophils and specific IgE, however, remains to be elucidated. Blood eosinophil counts, serum eosinophil cationic protein (ECP) and IgE to egg white, cow's milk, soybean, rice and Dermatophagoides pteronyssinus (Dp) were measured in subjects with AD alone or bronchial asthma (BA) alone. Subjects with positive IgE titers (Pharmacia radioallergosorbent test (RAST) units > 0.7) of one or more items were defined as RAST-positive. Immunoglobulin E titers to egg white, cow's milk and soybean of subjects with AD were high in early childhood and declined with aging, whereas the titers of subjects with BA were negative or low. Immunoglobulin E titers to Dp were elevated after 1 year of age in both disease groups. Eosinophil cationic protein (ECP) levels and blood eosinophil counts in the AD and BA groups were significantly higher than those of non-atopic controls. No difference in ECP levels or blood eosinophil counts were observed between RAST-positive and negative groups. It is concluded that IgE to foods such as egg white, cow's milk and soybean might have a role in the pathogenesis of AD of young children, while IgE to mites might be involved in older children. Eosinophils may also participate in AD. However, different mechanisms may be responsible for the rise in specific IgE and high ECP levels and blood eosinophil counts.