Farinae Extract Research Articles

Effects of cytokine milieu secreted by BCG-treated dendritic cells on allergen-specific Th immune response.

Bacillus Calmette-Guérin (BCG) is reported to suppress Th2 response and asthmatic reaction. Dendritic cells (DCs), the major antigen-presenting cells, infections with BCG are known to result in inducing various cytokines. Thus, DCs are likely to play a role in the effects of BCG on asthma. This study aims at investigating that cytokine milieu secreted by BCG-treated DCs directly enhances allergen-specific Th1 response and/or suppresses Th2 response in allergic asthma. DCs and CD3+ T cells were generated from Dermatophagoides farinae-sensitive asthmatics. DCs were cultured with and without BCG and subjected to flow cytometric analysis. IL-12 and IL-10 were determined from the culture supernatants. Some DCs were cocultured with T cells in the presence of D. farinae extracts after adding the culture supernatants from BCG-treated DCs, and IL-5 and IFN-γ were determined. BCG-treated DCs enhanced significantly the expressions of CD80, CD86, and CD40, and the productions of IL-12 and IL-10. Addition of culture supernatants from BCG-treated DCs up-regulated production of IFN-γ by T cells stimulated by DCs and D. farinae extracts (p<0.05), but did not down-regulate production of IL-5 (p>0.05). The cytokine milieu secreted by BCG-treated DCs directly enhanced allergen-specific Th1 response, although did not suppress Th2 response.

A High-Molecular-Weight Mite Antigen (HM1) Fraction Aggravates Airway Hyperresponsiveness of Allergic Mice to House Dusts and Whole Mite Cultures

Background: The house dust mite Dermatophagoides farinae is the most common aeroallergen causing human allergic asthma. Previously, we demonstrated that a high-molecular-weight allergenic fraction (HM1), which was abundant in D. farinae extracts, induced a proliferative response of T cells from healthy donors. The induction was mediated through the activation of macrophages without MHC class II restriction. In this study, we investigate whether HM1 influences the development of airway inflammation in murine models of asthma. Methods: BALB/c mice were injected twice intraperitoneally with D. farinae fecal extract (Dff) at an interval of 5 days. They were exposed daily to aerosolized antigen (group 1: Dff, group 2: HM1, group 3: HM1-depleted Dff and group 4: PBS) for 10 days. The effect of HM1 on their airway inflammation was evaluated by measuring acetylcholine-induced airway hyperresponsiveness and inflammatory cell infiltration in lung tissue. Results: The inhalation of the whole fecal extract or the HM1 fraction induced airway hyperresponsiveness which was detectable after 24 h and was maintained for as long as 120 h. The inhalation of extract depleted of the HM1 fraction induced hyperresponsiveness measured at 24 h but this was not maintained for 120 h. Macrophage infiltration was significantly prolonged in mice inhaling the whole extract and the HM1 fraction compared to the HM1-depleted extract. Conclusion: The inhalation of the high-molecular-weight HM1 fraction of D. farinae prolonged airway hyperresponsiveness and macrophage inflammation in a mouse model of hypersensitivity. The results indicate that the HM1 fraction which can induce T cell proliferation through macrophage activation may play a role in the duration of airway responsiveness.

免疫療法による花粉症の発症予防とその機序 スギ花粉感作成立個体に対する予防的免疫療法

This study was designed to investigate whether prophylactic immunotherapy for individuals sensitized to Japanese cedar pollen could prevent an outbreak of pollen-induced allergic rhinitis. A total of 13 non-atopic volunteers and 67 patients sensitized to Dermatophagoides farinae (D. farinae) and Japanese cedar pollen were enrolled in the study. Before enrollment in the study, all of the 67 patients had perennial nasal symptoms due to D. farinae, but no seasonal aggravation of nasal symptoms. 32 patients were treated with immunotherapy using standardized D. farinae extracts alone (control group), and the remaining 35 patients were treated with immunotherapy using the same D. farinae extracts and Japanese cedar pollen extracts (immunotherapy group). The following results were derived from the study:1. Prophylactic immunotherapy significantly decreased incidences of the outbreak of seasonal allergic rhinitis due to pollen.2. IL-4 synthesis during the pollen season by peripheral blood T cells stimulated with the cedar pollen allergen were enhanced in the control group, whereas IL-4 synthesis during the season was not enhanced in the immunotherapy group. In particular, IL-4 synthesis during the season did not differ between the non-atopic volunteers and the patients who were treated with prophylactic immunotherapy for more than 3 years.In conclusion, prophylactic immunotherapy could prevent the outbreak of seasonal allergic rhinitis in those who had been sensitized to the pollen. Therefore, it is likely that prophylactic immunotherapy is a new method of decreasing the incidence of seasonal allergic rhinitis in Japan.

通年性アレルギー性鼻炎に対する免疫療法 Ｔ細胞の抗原反応性からみた作用機序

This study was designed to investigate the working mechanism of Immunotherapy at the level of T cell reactivity to the allergen and to determine possible predictable factors of successful Immunotherapy for allergic rhinitis. Peripheral blood mononuclear cells were obtained from 60 patients with perennial allergic rhinitis due to Dermatophagoides farinae, and were cultured with Der f 1 for 96 hours to determine the cytokine synthesis. Forty-six patients were treated for 2 years with Immunotherapy using standardized D. farinae extracts, and the remainder were treated with antiallergic medications. Clinical improvement was obtained in more than 90% of the patients treated with Immunotherapy. IL-5 synthesis was significantly reduced in the patients treated with Immunotherapy. However, such reduction was not observed in the patients treated with antiallergic medications. The suppression of the allergen-induced IL-5 synthesis was most likely to be involved in the working mechanism of Immunotherapy. However, this study has failed to determine predictable factors of successful Immunotherapy for allergic rhinitis.

Monoclonal antibodies to recombinant Der f 2 and development of a two-site ELISA sensitive to major Der f 2 isoallergen in Korea

Der f 2 is a major sensitizing allergen in patients allergic to house dust mites worldwide. Isoforms of Der f 2 have been reported and are known to have different antigenicities. The aim of this study was to facilitate antigenic analysis and to develop an improved method for the detection of Der f 2 isoallergen, which is prevalent in Korea. A two-site ELISA was developed with monoclonal antibodies (mAbs) which were produced against recombinant Der f 2 (rDer f 2) and applied to assess Der f 2 in bedding samples. A major isoform of Der f 2, found in Korea, was found to have amino acid variations especially at position 100 from lysine to glutamic acid, which is known to reduce significantly the binding affinity of mAbs when used to assess group 2 allergens. The detection limit of the developed two-site ELISA was determined to be about 8 ng/ml with rDer f 2 and 1 microg/ml with Derntatophagoides farinae crude extract. The average amount of Der f 2 in dust obtained from bedding samples from 89 homes in Seoul was estimated to be 25.61+/-10.70 microg/g dust. Assays using mAbs for rDer f 2 could be useful for the assessment of environmental allergen exposure and mAbs could be used to further characterize the isoallergens of Der f 2.

Peripheral blood mononuclear cell responses to Dermatophagoides farinae in canine atopic dermatitis

Atopic dermatitis is a chronic inflammatory and pruritic skin disease commonly seen in dogs and humans that is characterised by the presence of allergen-specific IgE. Data from skin tests and serological analysis suggest that the house dust mite Dermatophagoides farinae is the most important allergen in dogs with atopic dermatitis. The aim of this study was to determine if D. farinae specific peripheral blood mononuclear cell (PBMC) responses could be detected in dogs with atopic dermatitis. PBMCs were isolated by the density centrifugation from dogs with atopic dermatitis that were skin test positive for D. farinae, dogs with atopic dermatitis that were skin test negative for D. farinae, and healthy dogs. Cells were cultured with increasing concentrations of the D. farinae extract, no antigen, vaccine antigens or concanavalin A (ConA). There was significantly greater responsiveness of PBMCs from the D. farinae positive dogs than from either the D. farinae negative or healthy dogs (ANOVA, P<0.05). In contrast, no significant differences were observed in the control responses between the three groups. This is the first study to demonstrate that D. farinae specific circulating memory cells are involved in the pathogenesis of canine house dust mite hypersensitivity.

Characterization and cloning of a major high molecular weight house dust mite allergen (Der f 15) for dogs

Although house dust mites (HDM(s)) are important elicitors of canine allergy, the low molecular weight molecules defined as major allergens for humans do not appear to be major allergens for dogs. Western blotting of Dermatophagoides farinae ( D. farinae) extracts with sera from sensitized dogs showed that the majority of animals had IgE antibodies specific for two proteins of apparent molecular weights of 98 and 109 kDa (98/109 kDa). The N-terminal sequences of these two proteins were identical, suggesting they were very closely related, and sequencing of internal peptides showed the protein(s) to have homology with insect chitinases. A purified preparation of 98/109 kDa proteins elicited positive intradermal skin tests (IDST(s)) in a group of well-characterized atopic dogs sensitized to D. farinae, but not in normal dogs. A rabbit polyclonal antiserum raised against the purified proteins was used to immunoscreen a D. farinae cDNA library. The mature coding region of the isolated chitinase cDNA predicts a protein of 63.2 kDa; sequence analysis and glycan detection blotting suggest that the molecule is extensively O-glycosylated. Monoclonal antibodies made against the purified native protein were used to localize the chitinase in sections of whole D. farinae mites. The protein displayed an intracellular distribution in the proventriculus and intestine of the mite, suggesting that it has a digestive, rather than a moulting-related, function. The high prevalence of IgE antibodies to this antigen in canine atopic dermatitis makes it a major HDM allergen for dogs, and the protein has been formally designated Der f 15.

Serum Specific IgE Reactivity to Recombinant Der f 11 in Asthmatic Children

This study was designed to examine the prevalence of positive serum IgE reactivity to the recombinant group11 Dermatophagoides farinae allergen (rDer f 11) in asthmatic children in Taiwan. Using immunoblot analysis in a preliminary study of 18 asthmatic children, 13 (72.2%) reacted positively to rDer f 11 and 16 (88.9%) showed positive reactivity to D. farinae extracts. The allergenicity of rDer f 11 was further evaluated with in vivo skin tests and in vitro IgE immunodot assays in 24 mite skin-test-positive asthmatic children. Whereas 17 (70.8%) had positive skin tests to rDer f 11, 18 (75.0%) had positive serum IgE reactivity to rDer f 11. A good coincidence (87.5%) between the immunodot assay and the skin test was confirmed in these asthmatic children. Moreover, the prevalence of serum IgE reactivity to rDer f 11 was further investigated in a large panel of 49 mite skin-test-positive asthmatic children. Again, 38 (77.6%) had positive serum IgE reactivity to rDer f 11 in immunodot assays. Taken together, the positive IgE reactivity to rDer f 11 in immunodot analysis ranged from 75 to 77.6% in two groups of 73 mite skin-test-positive asthmatic children. High incidence of serum IgE antibodies specific for rDer f 11 in the present study suggests that Der f 11 is a novel major allergen of house dust mites.

Monoclonal antibodies to recombinant Der p 2, a major house dust mite allergen: specificity, epitope analysis and development of two-site capture ELISA.

House dust mite allergens have been well established as sensitizing agents that are important in the induction of allergic diseases. In order to analyze epitopes of the allergen and to develop a quantitative method of the allergen exposure, monoclonal antibodies against a recombinant Der p 2 (rDer p 2), one of the major allergens of Dermatophagoides pteronyssinus, were produced. Four monoclonal antibodies produced were species-specific and did not cross-react to the D. farinae crude extract. Two of the monoclonal antibodies were found to be IgG1 and the others were IgM. For the analysis of epitopes, a Der p 2 cDNA encoding 126 amino acids (aa) was dissected into three fragments with several overlapping peptides. A (aa residues 1-49), B (44-93), and C fragment (84-126). Three monoclonal antibodies showed reactivities to the recombinant B fragment and to the full-length rDer p 2, but one monoclonal antibody reacted only with the full-length rDer p 2. Two-site capture ELISA was developed using two different monoclonal antibodies for quantitating Der p 2 in house dust. The sensitivity limit was 4 ng/ml with rDer p 2 and 8 micrograms/ml with the D. pteronyssinus crude extract. The result suggested that the assay using monoclonal antibodies against rDer p 2 could be useful for the environmental studies and for the standardization of mite allergen extracts.

Risk Factors for Adverse Systemic Reactions Occurring during Immunotherapy with Standardized Dermatophagoides farinae Extracts

The most serious problem in practical immunotherapy is the risk of occasional, potentially life-threatening adverse systemic reactions. Elucidation of the incidence of, and possible risk factors for, systemic reactions would have a profound effect on the decision about how to manage allergic rhinitis. The aim of this retrospective study was to document the incidence and risk factors of adverse systemic reactions during immunotherapy using standardized Dermatophagoides farinae ( D. farinae ) extracts for perennial allergic rhinitis. This study included 386 patients (22,722 injections) with perennial allergic rhinitis who had received immunotherapy with standardized D. farinae extracts in our clinics for the past 5 years. The incidence of systemic reactions was 6.22% per patient and 0.12% per injection. The time of onset of systemic reactions ranged from 3 to 30 min (mean 11.3 min) after injections. Our study has demonstrated that asthma, atopic dermatitis and a high level of IgE in serum, but not a high level of specific IgE in serum, are important high risk factors that may induce severe adverse systemic reactions in patients who receive immunotherapy for perennial allergic rhinitis. The incidence of systemic reactions in those who had a high level of IgE (higher than 1000 U/ml) and asthma and/or atopic dermatitis was 66.67% (12/18) per patient. Conversely, the incidence of systemic reactions in those who had none of the risk factors was 1.64% per patient. Thus, the rate of systemic reactions is thought to be reduced by 75% if patients with high risk factors are strictly excluded from immunotherapy for allergic rhinitis.

A Comparative Study of the Clinical Efficacy of Immunotherapy and Conventional Pharmacological Treatment for Patients with Perennial Allergic Rhinitis

This study was designed to compare the clinical outcome of prolonged immunotherapy for perennial allergic rhinitis with that of pharmacological treatment. Patients with perennial allergic rhinitis due to Dermatophagoides farinae ( D. farinae ) were divided into two groups; a pharmacotherapy group and an immunotherapy group. The pharmacotherapy group was treated with conventional pharmacological treatment using antihistamine tablets and topical steroid sprays and the immunotherapy group was treated with D. farinae extracts for 5 successive years. None of symptom scores at enrolment differed significantly between the groups. At 6 months and 1 year after the start of treatment the rate of decrease in each score was significantly greater in the pharmacotherapy group than in the immunotherapy group. The rate of decrease in sneezing scores, but not in the other scores, at 2 years after the start of treatment was also greater in the pharmacotherapy group than in the immunotherapy group. However, at 3 years the rate of decrease in any of the scores did not differ significantly between groups. The differences between the groups became clear-cut again after 5 years of treatment, when the rate of decrease in all of the scores was significantly greater in the immunotherapy group than in the pharmacotherapy group. Therefore, short-term treatment with pharmacological agents is probably superior to immunotherapy but, in the long-term, immunotherapy is apparently superior to pharmacological treatment with respect to clinical efficacy. In addition, prolonged immunotherapy provided long-term clinical efficacy and might provide a long-standing cure even after discontinuation of the therapy. In a questionnaire interview, approximately half of patients were very satisfied with prolonged immunotherapy, and three-quarters were fairly satisfied or more. Additionally, the magnitude of improvement in nasal stuffiness contributed significantly and exclusively to the patient evaluation of immunotherapy. We propose that prolonged immunotherapy is never inferior to anti-allergenic pharmacological treatment and that it is possible to achieve long-term clinical efficacy or long-standing cure even after the discontinuation of immunotherapy, and that patients with perennial allergic rhinitis will be very satisfied with this prolonged therapeutic technique if nasal stuffiness is considerably alleviated.

A novel anti-allergic drug, betotastine besilate, suppresses interleukin-5 production by human peripheral blood mononuclear cells.

The effect of a novel anti-allergic drug, betotastine besilate (betotastine) on interleukin (IL)-5 production by human peripheral blood mononuclear cells (PBMC) was investigated. PBMC of Dermatophagoides farinae extract (Df)-sensitive donors produced IL-5 and showed a proliferative response upon stimulation with relevant antigen (10 microg/ml). Df-induced IL-5 production by PBMC was significantly inhibited by betotastine at 10 and 100 microM. Betotastine also suppressed proliferation of PBMC with less potency. The effect of betotastine on IL-5 production was enhanced and significant even at 0.1 microM when the drug was added 120 min before antigen stimulation. Ketotifen and cetirizine also inhibited IL-5 production, but the effects of these drugs were significant only at 100 microM. These findings indicate that the suppression of IL-5 production may be involved in the anti-allergic effect of betotastine.

Skin test and crossreactivity studies with Euroglyphus maynei and Dermatophagoides pteronyssinus

The prevalence of sensitization to Euroglyphus maynei (E. maynei) in the United States has not been reported previously. To determine: (1) the prevalence of skin-test reactivity in allergic subjects to E. maynei compared to D. pteronyssinus, D. farinae, and B. tropicalis and (2) the allergenic crossreactivity between D. pteronyssinus and E. maynei. Skin testing with extracts of B. tropicalis and E. maynei (1:50 w/v) and standardized D. pteronyssinus and D. farinae extracts (1:50 w/v; 10,000 AU/mL) provided data on 250 subjects (87 males and 163 females) aged 9-77 years (mean age, 39.8 years) with possible allergic respiratory diseases. RAST inhibition assays were used to study crossreactivity between D. pteronyssinus and E. maynei. One hundred (40%) of 250 subjects had insignificant or no allergic diseases. Of the 150 allergic subjects (53 males, 97 females), 101 (67.3%) had a positive test (a percutaneous test with a weal diameter > or = 3 mm larger than the saline control) to at least one mite species; 60.7%, 60.0%, 28.7%, and 52.0% reacted to D. farinae, D. pteronyssinus, B. tropicalis, and E. maynei, respectively; 40 (26.7%) reacted to the four mite species. Positive tests to D. farinae, D. pteronyssinus, B. tropicalis, or E. maynei alone occurred in six (4.0%), four (2.7%), two (1.3%), and 0%, respectively. D. pteronyssinus and E. maynei showed moderately high crossreactivity in RAST inhibition assays. There is a high rate of skin-test reactivity to E. maynei in Florida. Moderately high crossreactivity exists between E. maynei and D. pteronyssinus.

Characterization of the allergen Der f 7 from house dust mite extracts by species‐specific and crossreactive monoclonal antibodies

The group 7 mite allergens react with IgE in 50% of sera from allergic patients. To determine the molecular and antigenic characteristics and heterogeneity of Der f 7 in mite extracts. Monoclonal antibodies (MoAbs) produced from mice immunized with recombinant Der f 7 were examined for crossreactivity to Der p 7 and then used for immunoblotting of 1 and 2-D gel electrophoresis. Deglycosylation was studied with N-glycosidase-F and N-terminal sequencing by Edman degradation. The epitopes of the monoclonal antibodies were compared by cross-inhibitory immunoassays. Immunoblotting of D. farinae extracts with all the anti Der f 7 MoAbs showed major reactivities at 31, 30 and 25 kDa. The strongest immunostaining was at 25 kDa which contrasted with Der p 7 where the 31 and 30 kDa bands were strongest. The relative strength of staining however varied between extracts. The 31 and 30 kDa components were glycosylation products of the 25 kDa form which had the N-terminal sequence predicted from cDNA analysis. Two MoAbs stained an 18 kDa band consistent with a degradation product. The 2-D gels showed that different components with pIs from 5.6-6.4. Both species-specific and Der p 7 crossreactive MoAbs were produced and a two-site ELISA assay for detecting group 7 allergen was developed with MoAbs recognizing different epitopes. Der f 7 has been defined by its natural N-terminal sequence and MoAbs. It apparently exists as different glycosylation and degradation products in mite extracts, the relative abundance of which differs with different preparations. A two-site ELISA to measure the allergen was developed.

Dermatophagoides farinae-1-derived peptides and HLA molecules recognized by T cells from atopic individuals.

Der f 1, the group I allergen in Dermatophagoides farinae extracts, is a major source of inhalation allergens in Japan. Using the mixture of a panel of overlapping synthetic peptides that spread over the entire Der f 1 molecule, we found that polyclonal Der f 1-specific short-term T cell lines prepared from peripheral blood of 6 individuals allergic to Der f who carry most of the common HLA haplotypes seen in the Japanese population can respond to 16 different peptides. Eight of 16 peptides stimulated T cells of more than 2 donors, regardless of the HLA types. Proliferative responses of four T cell lines were markedly inhibited by mAb HU4 (anti-HLA-DRB1+B5), one was inhibited partially by HU11 (anti-HLA-DQ4+5+6), and one was inhibited fully by a combination of HU4, L243 (anti-HLA-DRB1+B4) and PLM16 (anti-HLA-DRB3) but only partially by each of these mAbs. One of these T cell lines, DT, of which the proliferative response was partially inhibited by HU11, was cloned. Indeed, the T cell clones were restricted by DQ6 molecules on an HLA-DRB1*1501-DRB5*0101-DQA1*0102-DQB1*0602 haplotype. These results indicate that patients' T cells recognize Der f 1 in association mainly with HLA-DRA/DRB1, but that DQAI/DQB1, DRA/DRB3 and possibly DRA/DRB4 gene products also function as antigen-presenting molecules. Thus, although some peptides have a more potent T cell-stimulatory activity than others, the T cell receptor ligands formed with the Der f 1 molecule are highly heterogeneous.

Serum levels of soluble interleukin-2 receptor in patients with perennial allergic rhinitis before and after immunotherapy.

Interleukin-2 receptor (IL-2R) exists in soluble form in sera, and the rate of release of the soluble form of IL-2R (soluble IL-2R) reflects T cell activation in vivo. Since T lymphocytes play a central role in respiratory allergic disorders, the measurement of serum levels of soluble IL-2R may be useful in analyzing the disease state of allergic disorders. To investigate the serum concentrations of soluble IL-2R in 48 patients with perennial allergic rhinitis and 14 nonatopic healthy controls, with special reference to the possible changes following long-term immunotherapy. This retrospective study included 48 patients who had had variable periods of long-term immunotherapy with Dermatophagoides farinae extracts. The duration of immunotherapy ranged from 5 to 15 years. Serum samples were collected twice from each patient, before the initiation of immunotherapy and at the time of clinical assessment of immunotherapy. All the serum samples were simultaneously used for determination of soluble IL-2R concentrations, by the use of an enzyme-linked immunosorbent assay. To serve as controls, 14 nonallergic subjects of the same age range and sex were chosen. Patients with allergic rhinitis before immunotherapy had significantly higher serum levels of soluble IL-2R than nonatopic subjects. Elevated serum levels of soluble IL-2R decreased significantly following immunotherapy and the serum levels of soluble IL-2R in patients with allergic rhinitis after immunotherapy were not statistically different from those of nonatopic subjects. In addition, the percent decrease in serum soluble IL-2R correlated significantly with the duration of immunotherapy. Hyperactivity of helper T cells of atopic patients is altered after long-term immunotherapy, and such immunoregulatory changes could be theoretically involved in the mechanisms of immunotherapy.

Estimation of Der p and Der f I quantities in the reference preparations of Dermatophagoides mite extracts

A monoclonal antibody-based enzyme-linked immunosorbent assay (MoAb-ELISA) was developed to measure the major Dermatophagoides mite allergens, Der p I and Der f I. The assay was highly species-specific and sensitive. Using this assay system, the absolute mass unit of Der p I and Der f I in the reference preparations of the extracts was estimated. The primary standards used were the purified Der p I and Der f I preparations. The reference preparations of the D. pteronyssinus and D. farinae extracts (92-Dp and 92-Df), which had been prepared from the same amount of mite bodies of both species, were found to contain the same levels of the Der I allergens, 10.1 micrograms/ml of Der p I and 10.0 micrograms/ml of Der f I, respectively. A histamine release assay with leucocytes from mite-allergic donors showed that the total allergenic potency of 92-Dp and 92-Df was comparable. This results indicates that the estimated Der I levels in these extracts seem to be valid, at least, in the balance between the two species, although further comparisons of the absolute quantities by several different laboratories are needed. The Der I levels in the WHO/IUIS international reference preparation of D. pteronyssinus and the CBER standard mite extracts, E4-Dp and E5-Df, were also estimated using this assay system. They were found to contain 4.4 micrograms/vial and 13.3 micrograms/ml of Der p I and 9.5 micrograms/ml of Der f I, respectively.

Influence of Age on IgE Responsiveness to &lt;i&gt;Dermatophagoides farina&lt;/i&gt;&lt;i&gt;e&lt;/i&gt;, An Immunoblot Study

IgE responsiveness to Dermatophagoides farinae body extract was compared by immunoblotting among four groups of mite-sensitive asthmatic children: group I aged 0-3, group II aged 4-7, group III aged 8-11 and group IV aged 12-15. In the group I subjects, the 15-kD component was bound by 88% of sera and strongly by 56% of sera. The 25-kD component was bound by 40% of sera, but most of the binding reactions were faint. IgE binding to other components was generally low. In the group II subjects, 15- and 25-kD components were bound by 96% and 56% of sera, 30-kD and 110-kD components by 76% and 60% of sera, respectively. In addition, 18-, 40-, 59- and 80-kD components were bound by more than 30% of sera. In group III and IV subjects, the frequencies of IgE binding to these components were not significantly changed as compared with those of group II subjects. The rabbit antisera against Der f I and Der f II specifically reacted with 25- and 15-kD components, respectively. These results suggest that the 15-kD Der f II allergen is the most important antigenic constituent associated with the early IgE response to house dust-mites in mite-reactive asthmatic children.

Anaphylaxis after ingestion of beignets contaminated with Dermatophagoides farinae

A 48-year-old man was evaluated for anaphylaxis associated with ingestion of beignets prepared from a commercial mix. Microscopic examination of the patient's beignet mix revealed live Dermatophagoides farinae. Another unopened box from the same source was not infested. Skin test results to aeroallergens and foods, including all beignet mix ingredients, were positive only to D. farinae and D. pteronyssinus extracts. Skin prick test results to an infested mix extract (1: 5 wtlvol) were also positive, but no reaction was observed with noninfested mix extract. ELISA inhibition studies demonstrated significant inhibition of the patient's serum binding to D. farinae strips by infected mix extract. Parallel inhibition curves were produced by the infested mix extract and a commercial D. farinae extract. Noninfested mix extract showed no inhibition. PAST analysis with beignet mix discs showed significant binding of the patient's serum IgE to infested mix discs but not to noninfested mix discs. RAST inhibition studies revealed more than 86% inhibition of binding of the patient's IgE to infested mix discs by infested mix extract and D. farinae extract. No inhibition was observed with noninfested mix or 5% fetal calf serum-phosphate-buffered saline. We conclude that the allergen to which the patient reacted was most likely D. farinae and that ingestion of D. farinae may cause anaphylaxis in sensitive persons.

Changes in the cellular profile of induced sputum after allergen-induced asthmatic responses.

Allergen inhalation causes airway inflammation and an increase in histamine airway responsiveness. We have used cell counts in sputum induced by hypertonic saline aerosol to assess airway inflammation before and 32 h after asthmatic responses to allergen. Twelve asthmatic subjects (mean age, 27.4 yr; range, 20-38 yr) had an inhalation test with D. farinae, ragweed pollen, or cat extract. All of them developed an early response with a fall in FEV1, of 24.8% (SD, 6.3%); nine of 12 had a definite late response (fall in FEV1 greater than or equal to 15%), and 10 of 12 had an increase in airway responsiveness to histamine at 32 h (PC20 reduced by greater than twofold). Sputum was induced by hypertonic saline after the histamine test, before and 32 h after the allergen challenge, at the same time of day. The quality of the sample was scored according to visual inspection and inverted microscopy and by salivary contamination. Plugs arising from the lower respiratory tract were selected for further evaluation. Differential cell counts of eosinophils (Eo) and metachromatic cells (MCC) (mast cell and basophils) were obtained from direct smears, blind to the clinical procedures. The mean fall in FEV1 after hypertonic saline was 6.4% (range, zero to 28%). The sputum samples were adequate in 79.5% of attempts. Eo and MCC increased significantly from 3.8 (4.4) to 18.2 (22.8)% (p = 0.01) and from 0.05 (0.17) to 0.25 (0.76)% (p = 0.04), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)