IgE antibodies reactive with silverfish, cockroach and chironomid are frequently found in mite-positive allergic patients

Approximately 30% of the house dust mite allergic patients in The Netherlands have IgE antibodies reactive with silverfish, cockroach and/or chironomid. In allergic patients without IgE antibodies against Dermatophagoides pteronyssinus less than 5% have IgE antibodies reactive with these insects. By means of RAST inhibition studies it is shown that cross-reactivity exists between D. pteronyssinus and silverfish, cockroach or chironomid. This means that a positive RAST for silverfish, cockroach, chironomid or D. pteronyssinus cannot be taken as evidence for exposure.

Occupational allergy to adult chironomid midges among environmental researchers

A case of occupational allergy to chironomid midges in research work is described. A researcher was exposed to adult chironomid midges during his research and developed allergic rhinitis after 10 years of such exposure. Using the midge extract of adult Chironomus plumosus (CP) (Linnaeus, 1758), both immediate skin test and the ophthalmic challenge test gave positive results. IgE antibody against adult CP was also demonstrated by the radioallergosorbent test. Four of the five serum samples of the environmental researcher examined showed a positive radioallergosorbent test to at least one of the adult midges breeding around eutrophic Japanese lakes. Enzyme-linked immunosorbent assay inhibition test and immunoblot experiments indicated that the remaining hemoglobin is one of the major allergens of adult CP. These results demonstrate that the exposure to adult chironomid midges is an important occupational hazard among environmental researchers.

Analysis of B-cell epitopes in the N-terminal region of Chi t I component III using monoclonal antibodies

The hemoglobins of the midge Chironomus thummi thummi (Chi t I) are known to cause immediate-type hypersensitivity reactions in humans. Further knowledge of the antigenic sites of such allergens will provide new therapeutic approaches. The aim of our study was to identify and characterize linear B-cell epitopes of the hemoglobin component III of Chi t I (136 amino acid residues). Using the antigenic index algorithm of Jameson and Wolf (Jameson and Wolf (1988) Comput. Appl. Biosci. 4, 181-186), three linear binding sequences of this allergen molecule were predicted. Two mouse monoclonal antibodies (mAbs 3 and 6) raised against purified Chi t I component III were investigated by ELISA for their binding to nine synthetic peptides 19-21 residues in length, covering nearly the whole sequence of component III. MAb 6 recognized only one peptide (11-30) while mAb 3 bound to both N-terminal peptides (1-19 and 11-30), suggesting that the antibody binding site is located in the overlapping region. This assumption could be confirmed in ELISA with solid phase-bound recombinant peptides (RP) as well as in inhibition studies with free tryptic peptides indicating that identification of these linear B-cell epitopes is neither influenced by the method of peptide production nor by the kind of used immunoassay. To define the essential amino acid residues we investigated mAbs with solid phase-bound overlapping octamers. In the case of mAb 3, amino acids experimentally identified as essential for antibody binding (aa 13-17) are identical with those residues predicted as a B-cell epitope with the antigenic index of Jameson and Wolf.

Conformations of peptide fragments comprising the complete sequence of component III of Chi t I and their relationship to T-cell stimulation

Conformational preferences of synthetic peptides that span the complete sequence of Chironomus thummi hemoglobin (Chi t I) component III were studied by nuclear magnetic resonance (NMR) and CD spectroscopies. The peptides, 19-21 amino acids in length, were studied in water, except for the C-terminal peptide, which was investigated in DMSO-d6. NMR showed that all investigated peptides lacked uniquely folded conformations in water at 4 degrees C and pH 3.0 or at 10 degrees C and pD 6.6 in DMSO. However, some preferential helix-like conformations for the peptides corresponding to the helices of the folded protein could be seen in solution. These peptides showed characteristic interactions for conformations in both the beta- and alpha-regions of phi-psi space, based on strong C alpha H(i)-NH(i + 1) interactions, and on NH-NH, C alpha H(i)-NH-(i + 2), C alpha H(i)-NH(i + 3), and C alpha H(i)-C beta H(i + 3) interactions, respectively. Helical motifs seem not to be the most important factors in determining MHC-binding and/or T-cell recognition. However, there is a tendency that more stabilized secondary structures show higher T-cell stimulation.

Association of class II sequences encoding DR1 and DQ5 specificities with hypersensitivity to chironomid allergen Chi t I

A panel of 188 unrelated Caucasian subjects who were exposed to the larvae of Chironomus thummi (Diptera, nonbiting midges) was HLA-typed by polymerase chain reaction amplification of the second exons of the DRB, DQA1, and DQB1 genes followed by dot-blot hybridization with sequence-specific oligonucleotide probes. Type I sensitization to the allergen Chi t I and a large number of other inhalant allergens was determined by RAST and skin testing. Sixty-one individuals were found to be sensitized to Chi t I, of whom 24 were sensitive to this allergen and to no other allergens tested. Statistical analyses showed that only in the latter group were the HLA-D genes DRB1*0101, DQA1*0101, and DQB1*0501 associated with IgE-responsiveness to Chi t I. These results suggest that HLA associations with responsiveness to certain allergens may be more striking in monosensitized subjects.

Allergen-induced expression of cell surface markers on lymphocytes of Chi t I-sensitized patients

Lymphocyte cultures of persons sensitized to the hemoglobin allergen Chi t I show a highly significant response to the allergen measured in the lymphocyte stimulation assay by (3H)-thymidine uptake. In this study, we investigated by flow cytometry the expression of different cell surface markers on lymphocytes after in vitro stimulation for 7 d with or without the allergen Chi t I. We determined the expression of the low-affinity receptor for IgE (CD23) on lymphocytes of Chi t I-sensitized patients and Chi t I-exposed as well as nonexposed controls. CD23 expression was significantly higher in patients than in nonexposed controls. Exposed but healthy subjects showed intermediate values. We also determined the expression of activation markers CD25 (IL-2 receptor) and HLA-DR on the lymphocytes of patients and nonexposed controls. HLA-DR expression on non-T cells (CD3-) was significantly higher in patients than in controls. HLA-DR on T cells (CD3+), and CD25 as well as CD23 expression, could be significantly enhanced after antigen-specific stimulation in patients but not in controls, whereas alpha/beta-T-cell-receptor expression was significantly reduced in patients. Differences between patients and controls were not observed in response to tetanus toxoid (TT) and phytohemagglutinin (PHA). Our results demonstrate antigen-specific influences on the expression of cell surface molecules. These findings may be valuable diagnostic information.

Skin reactivity and specific IgE antibody to two nonbiting midges in Korean respiratory allergy patients

To evaluate the significance of chironomid as a respiratory allergen, we performed skin prick tests with Chironomus plumosus (CP) and Tokunagayusurika akamusi (TA) extracts on 475 respiratory allergy patients, and their specific IgE antibodies were detected by enzyme-linked immunosorbent assay (ELISA) in 106 positive reactors to skin prick test and 30 negative controls. Ninety-seven (20.4%) showed more than 2+ of allergen to histamine ratio to CP and 98 (20.6%) to TA on skin prick test. Seventy-one (73.2%) of 97 positive reactors had increased specific IgE to CP, and 34 (34.7%) of 98 positive reactors, to TA. CP-specific IgE was detected in 14 (14.4%) non-atopic asthmatics and 6 (6.2%) non-allergic rhinitis patients. TA-specific IgE was detected in 17 (17.4%) non-atopic asthmatics and 6 (6.1%) non-allergic rhinitis patients. No association was noted between skin reactivity to Dermatophagoides farinae and the prevalence of specific IgE to CP or TA (p > 0.05). The correlation between total IgE level and specific IgE level to CP and TA was poor (r = 0.07, 0.04). ELISA inhibition test suggested specificity of IgE binding and cross-allergenicity between CP and TA. It is suggested that CP and TA can induce IgE-mediated reaction in exposed patients and should be considered as important causative allergens in respiratory allergy patients in Korea.

Chironomidae hemoglobin allergy in Japanese, Swedish, and German populations

Hemoglobins of the Diptera (insect) family Chironomidae have been identified as causative allergens in asthmatic patients. In this study, 229 Japanese, 17 Taiwanese, and 92 Swedish sera from atopic patients were tested for antibodies against Chi t I, the hemoglobin from the European midge species Chironomus thummi, and against crude extracts from the Japanese midges Tokunagayusurika akamusi (T. akamusi) and Cricotopus sylvestris (Cr. sylvestris). Nearly 40% of patients showed a positive reaction to Cr. sylvestris extract, which contains no hemoglobin. This result is probably due to the presence of other partially cross-reacting allergens than hemoglobin. Nearly all tested Japanese serum samples showed cross-reactivity between Chi t I and Cr. sylvestris, a finding which is evidence for common epitopes in both midge species. Furthermore, an overall good correlation between the amounts of IgE antibodies against Chi t I and Chi t I component III was found in sera from Swedish, Japanese, and German patients.

Distribution of B52 within a chromosomal locus depends on the level of transcription

Drosophila B52 protein is a homologue of human ASF/SF2 that functions in vitro as an essential pre-mRNA splicing factor. Immunofluorescence analysis of polytene chromosomes has shown that B52 generally colocalizes with RNA polymerase II; however, in contrast to other splicing factors, B52 brackets RNA polymerase II at highly active heat-shock puffs. Also, UV cross-linking in nonpolytene cells has shown that B52 cross-links in vivo to DNA flanking the highly active transcription units. Here, we find that the distribution of cross-linked B52 at heat-shock loci depends on transcription levels. Heat shocks at low and moderate temperatures, which induce corresponding levels of transcription, recruit B52 both to transcribed DNA and to flanking DNA, whereas a full heat-shock induction concentrates B52 on the DNA that brackets the entire activated region. We have also identified a 46-kDa protein from Chironomus tentans that binds Drosophila B52 antibodies and has a distribution on chromosomes analogous to B52. This protein is found throughout the moderately transcribed Balbiani rings. However, when transcription at these rings is hyperinduced to levels comparable to fully induced Drosophila heat-shock genes, the protein is restricted to the boundaries of highly decondensed chromatin. We suggest that B52 tracks to chromatin fibers that are folding or unfolding, and we discuss this in light of B52's proposed roles in pre-mRNA splicing and control.

[Adult case of bronchial asthma induced by chironomid midges]

A 48-year-old woman who was diagnosed to have bronchial asthma induced by chironomid midges is reported. In spring of 1985, massive growth of chironomid midges occurred in the river beside her house. Since then, moderate growth has occurred in every spring or summer. She had wheezing attacks every May or June since June 1986. On May 2, 1991, she was hospitalized because of exacerbation of wheezing and dyspnea. Wheezing attacks were improved by appropriate medical treatment during hospitalization. Examination was performed during the state of stable clinical symptoms. RAST scores to Chironomus thummi thummi (CTT) and Chironomus plumosus (CP) were 4 and 3, respectively. Allergic skin reaction showed the threshold dilution of CP of 10(-6). CP skin test concomitantly provoked a mild acute asthma attack. The midges found swarming around her house were identified as Chironomus nippodorsalis. According to her clinical history and allergic skin reactions followed by acute asthmatic attack, this patient was diagnosed to have bronchial asthma induced by chironomid midges. Chironomid midge can be one of the inhalant allergens in adults.

Analysis of antigenic determinants shared by two different allergens recognized by human T cells: house dust mite (Dermatophagoides pteronyssinus) and chironomid midge (Chironomus yoshimatsui)

To analyse the cross-reactivity of T-cell-mediated immunity between Dermatophagoides pteronyssinus (Dp) and Chironomus yoshimatsui (Cy), the most common allergens in Japan, we established antigen-specific human T-cell lines and clones. Some but not all of the Cy-induced T-cell lines showed a significant proliferative response not only to Cy, but also to Dp. No T-cell line responded to other unrelated antigens. When we stimulated the Dp-induced T-cell clones with Cy, 3 of the 40 clones (7.5%) showed a significant proliferation, and 2 of the 3 clones produced interleukin-4 and interferon-gamma, indicating their helper function. Cross-reactivity was diminished significantly after the absorption of Dp antigen in an anti-Cy affinity column. The cross-reactive epitopes were thought to be expressed on the Dp molecule of 45-53 kD. The presence of helper T cells reactive to both allergens suggests a possibility that this cross-reactivity might be involved in part in the high incidence of allergy to the 2 major allergens.

Insect hemoglobins (Chi tI) of the diptera family Chironomidae are relevant environmental, occupational, and hobby-related allergens

Six hundred and forty-two persons with hobby-related (n = 205), occupational (n = 85), or environmental contact (n = 352) to the midge and larval allergen Chi tI were studied. Frequencies of IgE-mediated sensitization in these selected populations were 36.1%, 24.7%, and 9.6% respectively. Occupationally sensitized subjects who had been heavily exposed showed higher levels of antibodies, were more frequently diagnosed as having bronchial asthma and less frequently as having conjunctivitis, and had a significantly shorter latency period when compared to environmentally exposed people or aquarists. Our results are evidence for a higher risk of sensitization and of bronchial asthma in highly exposed subjects.

Allergic contact dermatitis from chironomids

Although Type I allergy to chironomids is well-known, allergic contact dermatitis caused by these cosmopolitan insects has not previously been reported. In the case we describe in this report, patch tests disclosed a delayed-type hypersensitivity to 4 different species of chironomids (larvae of Chironomus thummi, Chironomus plumosus, and 2 different species of Glyptotendipes) as the probable cause of airborne facial contact dermatitis. An additional asymptomatic immediate-type allergy to chironomids was demonstrated by scratch tests and specific IgE. The possible sources of exposure to chironomids, their allergens and their distribution are discussed with regard to clinical implications.

Chironomid midge allergy

Chironomidae larvae and midges cause allergic reactions in approximately 20 percent of exposed people; predominantly aquarists using insect larvae as fish food and environmentally exposed subjects living in areas abounding in water are affected. Our studies include 642 subjects of whom 205 are aquarists; 85 are occupationally and 352 environmentally exposed people. 123 of them were shown to be sensitized to these insects. Using highly purified allergens, we could demonstrate that Chironomidae hemoglobins (Chi t I) represent the major allergenic components causing rhinitis, conjunctivitis and bronchial asthma. Considerable immunological cross-reactivity exists between hemoglobins of the same and closely related Chironomidae species. Genetic factors seem to be important for the susceptibility of this type of allergy. In studies with peptides of Chi t I component III, we identified several epitopes recognized by human IgE antibodies and/or T-cells.

Immunological cross-reactivity of hemoglobins in the Diptera family Chironomidae

Polyclonal human IgE antibodies of patients sensitized to one species of the Diptera family Chironomidae as well as polyclonal rabbit anti-Chi t I hyperimmune serum recognize antigenic sites present in nearly all of the 33 species of this insect family. Evolutionary distantly related genera usually show weaker antibody binding. According to the pattern of reactivity of rabbit anti-Chi t I-component III, expression of the epitopes of this molecule varies considerably in the genera Chironomus and Glyptotendipes; it appears to be almost totally absent in all other species. Of five monoclonal antibodies raised against Chi t I-component III, two recognize an epitope which is expressed in nearly all closely related species. Three monoclonal antibodies recognize epitopes which are expressed in only a few species of the same genus. Our results demonstrate the presence of common as well as species-specific epitopes in chironomid hemoglobins which behave as potent inhalant allergens.

[Immunochemical quantification of the airborne chironomid allergens]

We collected airborne particles in the air using a high-volume air sampler, and measured chironomid allergen in the air-filter extract by use of RAST inhibition assay. The results obtained were as follows: 1) The assay revealed the presence of chironomid allergen in the air varying from 6.8 to less than 0.3 ng/m3. 2) In Toyama, seasonal fluctuations of airborne chironomid allergen demonstrated some large peaks in summer (June to August), and showed a tendency to decrease in winter. 3) There were significant correlations between airborne chironomid allergen and dry weight of chironomid midges, collected by using light traps, in all period of a week just before, 1 to 2 weeks before, 2 to 3 weeks before, or 3 to 4 weeks before air sampling. There were not significant correlations between airborne chironomid allergen and weathers (temperature, wind speed and precipitation) during or just before air sampling. 4) In Toyama, the frequency of asthma attacks in the asthmatic children with positive C.p. RAST was much increased in summer compared with that of the negative, in which the amount of airborne chironomid allergen was increased. These results show that there is large amount of chironomid allergen in the air from spring to autumn, especially large in summer, and it is related for some asthmatics to the increase of the frequency of asthma attack.

Stimulation of human peripheral blood lymphocytes with chironomid hemoglobin allergen (Chi t I)

Hemoglobins (Chi t I) of the dipteron species Chironomus thummi thummi are known to cause severe allergic diseases in humans. We tested the allergen-specific stimulation of human peripheral blood lymphocytes (PBL) by Chi t I and its nine main components. Further, we applied fragments of the well-analyzed component III, obtained by cleavage with trypsin as well as arginine protease. In this way, we screened the molecule in order to identify T-cell epitopes. The whole component was found to be immunogenic and to have regions demonstrating varying PBL stimulation. In addition, interindividual patterns of reactivity, probably due to genetic restriction, were found. A T-cell epitope could be shown to be within the site 98-111, as predicted by application of Rothbard's algorithms.

[Allergen skin tests to insects, chironomid, caddis fly and silkworm moth, in patients with nasal allergy]

The present study was undertaken to assess the importance of insects as allergens causing nasal allergy. We performed intradermal skin tests with extracts from three insects, chironomid, caddis fly, and silkworm moth, on patients with nasal allergy and on volunteers among medical students. Twenty-two (27.5%) of 80 nasal allergic patients showed positive reactions to chironomid allergen and 9 (11.3%) had positive reactions to caddis fly allergen and 18 (22.5%) to silkworm moth allergen. These positive rates were as frequent as those to Candida or ragweed. Medical students were divided into two groups, symptomatic and asymptomatic, according to the presence or the absence of nasal allergy. Three (11.5%) of 26 symptomatic group showed positive reactions to chironomid and one (3.8%) to caddis fly and 5 (19.2%) to silkworm moth. While even 4 (8.3%) of 48 asymptomatic group showed positive reactions to chironomid, 2 (4.8%) to caddis fly, and 6 (12.5%) to silkworm moth. These results suggested that these insects, chironomid, caddis fly, and silkworm moth, are relatively common than we expected and suspected as important allergens in nasal allergy.

[Nationwide intradermal test with chironomid midge extract in asthmatic children in Japan]

Chironomidea (Insecta) is recently considered one of the most common inhalant antigen in Japan. Intradermal tests with Chironomus plumosus (CP) extract were undertaken on seven hundred and eighteen asthmatic children aged from 6 to 15 years in 10 areas (11 medical institutions) in Japan. The number of cases who showed positive intradermal tests with CP extract was 200 (27.9%) and the positive rate increased in proportion to their age (p less than 0.005). In each of the 11 medical institutions the positive rates ranged from 12.6% in Akita to 45.5% in Okinawa. There were no significant correlations between the results of the intradermal test with CP and those of RAST, prick test and intradermal test with mite, HD and silk, whereas correlation was noted in the prick test with silk (p less than 0.01). The CP positive asthmatics had significantly more attacks than the CP negative ones in the summer (p less than 0.01). The positive rate of asthmatics living near paddy or farm fields was significantly higher than that of those in urban residential areas (31.3% vs 23.8%, p less than 0.05). Chironomid midge is one of the most common and important allergen in Japan.

ELISA inhibition method in detection of mite and chironomid antigens in environmental samples of dust, soil and air

To determine the amount of chironomids and mite antigens in the indoor and outdoor environment, we investigated samples from air, soil and house dust in the area around Lake Kojima, located in the western part of Japan. Three species of chironomid (Tokunagayusurika akamusi, Chironomus yoshimatsui and Chironomus plumosus) and species of mite, Dermatophagoides farinae antigens were studied. The antigens were detected and quantified by inhibition ELISA. In the outdoor environment, C. yoshimatsui and T. akamusi antigens were more abundant than mite antigen, and seasonal fluctuations were observed. In the indoor environment, mite was the predominant antigen. D. farinae antigen was detected in almost all dust samples, with a slight reduction in winter compared to summer.

Histamine release from human basophils by the insect allergen Chi t I

Hemoglobins of the Diptera species Chironomus thummi thummi (Chi t I) are potent inhalant allergens. Chi t I-specific histamine release was measured by a new radioimmunoassay in whole human blood taken from 20 sensitized patients, 11 exposed nonsensitized probands, and 11 nonexposed controls. The sensitized patients, who all had positive skin tests and radioallergosorbent test results with Chi t I, showed a significantly higher histamine release than the two other groups. However, within the patient group, the percentage of released histamine did not correlate with the intensity of the skin test response or the concentration of Chi t I-specific IgE antibodies. Our results demonstrate that this method is a sensitive and specific in vitro test for evaluation of IgE-mediated sensitization.

Allergenicity of Chironomidae in asthmatic patients

In order to clarify the relation between asthma and Chironomidae, we examined the cross-reactivity between Chironomidae and other common allergens. We noted significant correlations between positive skin tests with Chironomidae and with other allergens. The radioallergosorbent inhibition test, however, suggested that there may be no cross-reactivity or, if any, only very low cross-reactivity between midge allergens and mite, house dust (HD), silk, shrimp, or mosquito allergens.

Analysis of chironomid allergens using specific T cell lines and clones in humans

To analyze the possible major T cell recognition site(s) of chironomid antigens, we established human T cell lines and clones (CD3+ 4+ 8-) reactive to soluble extracts of the adult midge of Tokunagayusurika akamusi (TAA) and/or Chironomus yoshimatsui (CYA). All T cell lines and clones proliferated heavily in response to relatively large molecular weight fractions of TAA (MW greater than or equal to 15,000). Nine clones reactive to TAA were classified into 3 groups according to reactivity, indicating the existence of at least 3 distinct T cell recognition sites in TAA. Five T cell clones responded to both TAA and CYA, although the two chironomid antigens were serologically distinct. We conclude that T cell recognition sites of chironomid antigens are different from B cell recognition sites in humans.

[Allergen tests with midge allergens in Moriyama City, located on the south coast of Lake Biwa]

The main species of midge which emerge from the Lake Biwa, the biggest lake in Japan, are Tokunagayusurika akamusi (TA) and Chironomus pulmons. In order to determine how the existence of Lake Biwa affects the positivity to allergen tests with midge allergens, randomly selected asthmatic patients were examined by skin test and RAST. Out of 129 patients, 35 (27%) were positive to scratch tests with an extract of Chironomus yoshimatsui (CY). Out of 64 patients, 16 (25%) were positive to TA RAST and 12 (19%) were positive to CY RAST. The positive rate of skin tests was highest in the patients aged between 20 and 39. The positive rate of TA RAST was not significantly higher than the rates reported in other districts of Japan.