Chironomid midge sensitization in sewage workers: case study

Non-biting chironomid midges (Diptera: Chironomidae) may cause sensitization and allergic reactions in humans and have recently been identified as a potential health problem in Swedish municipal sewage treatment plants. To investigate, on a pilot scale, the allergenic potential of chironomids in sewage workers, all workers (n = 8) at a sewage treatment plant and local controls (n = 16) completed a symptom questionnaire, underwent measurement of the fraction of nitric oxide in exhaled air, spirometry, and provided serum samples for the determination of atopy status and the prevalence of specific immunoglobulin E (IgE) antibodies against Chironomus thummi (Chi t) using a commercial fluorescence enzyme immunoassay (FEIA). Three sewage workers (38%) but no controls (0%) were FEIA positive for C. thummi-specific IgE antibodies (P < 0.05). No other health-related findings were significantly different between the groups. The study suggested that occupational exposure to Chironomids may cause sensitization with circulating IgE-antibodies in sewage workers.

Occupational allergy to aquarium fish food: red midge larva, freshwater shrimp, and earthworm. A clinical and immunological study

BACKGROUND

Chironomids seem to be the main cause of occupational allergy to aquarium fish food.

OBJECTIVE

The aim of this study was to investigate the pattern of occupational sensitization to 3 different arthropod species used as components of aquarium fish food.

METHODS

The study sample comprised 8 workers from a fish food packing department. The control group comprised 40 atopic patients (20 of whom were allergic to mites). We performed prick tests with extracts of red midge larva (Chironomus thummi), freshwater shrimp (Gammarus species), earthworm (Tubifex species), and other arthropod species and a battery of common inhalant allergens. We measured peak expiratory flow rate (PEFR) and specific immunoglobulin (Ig) E and performed a methacholine challenge test, nasal challenge test, and immunoblotting. Cross-reactivity analyses were completed using immunoblotting and CAP inhibition.

RESULTS

Prick test results were positive to red midge larvae in 7 patients (87.5%), Gammarus in 5 (62.5%), Tubifex in 3 (37.5%), and mites in 6 (75%). In the mite-allergic controls, 30% had positive prick test results to red midge larvae. PEFR decreased > or = 20% during the packing process in all patients, and in 1 patient it indicated a dual asthmatic response. Methacholine challenge test results were positive in all participants. Nasal challenge tests were performed in 4 patients, and the results were positive. Specific IgE to red midge larvae was detected in 62.5%, Gammarus in 50%, and Tubifex in 16%. Bands of approximately 14-15 kDa and 31 kDa were observed in Gammarus and red midge larvae extracts. Cross-reactivity assays demonstrated that Gammarus totally inhibited red midge larvae, while Tubifex did so partially. Dermatophagoides pteronyssinus showed very low inhibitory capacity.

CONCLUSIONS

Aquarium fish food arthropods are potent allergens with an elevated prevalence of sensitization and variable degree of crossreactivity. This is the first report of occupational allergy to Tubifex. More data are necessary to identify and characterize the responsible allergens.

Impact of tributyltin on immune response and life history traits of Chironomus riparius: single and multigeneration effects and recovery from pollution

Chironomids play an important role in the detritus cycle and as a component in brackish- and freshwater benthic and terrestrial food webs. If TBT is present in their environment, then they may accumulate tributyltin (TBT) during their juvenile period, which negatively affects many of their life history characteristics. The aim of this experiment is to test the effects of three TBT sediment concentrations (nominal 30, 90, and 180 μg/kg) on life history traits (development time, survival, fecundity, and weight) and immune response (number of hemocytes and phenoloxidase activity) of the nonbiting midge, Chironomus riparius. These responses were recorded immediately after one generation of TBT exposure, and in the long run during five consecutive generations. We also assessed recovery from pollution after four generations of TBT exposure. In a single generation, TBT affected all measured parameters, except phenoloxidase activity, when compared to the control. Long-term-effects of TBT lead to extinction of all treatments after the fifth generation. Again, all measured variables significantly differ from the control, although TBT had varying effects on the measured variables. Most of the effects of TBT on population viability were not evident during recovery, once TBT was removed from the sediment. The effect of previous TBT contamination was observed only in delayed larval development, suggesting that TBT has only limited maternal/epigenetic effects on individual condition. However, altered schedules in the life-cycle can have unexpected ecological impacts. TBT decreases the viability of Chironomus riparius and the effect will become stronger if exposure to TBT continues for many generations. Yet, the harmful effect of TBT disappears quickly as the TBT is removed from the environment.

Allergy to chironomid larvae (red migde larvae) in non professional handlers of fish food

Chironomids are insects which inhabit wetlands. In countries such as Sudan, The United States. Egypt and Japan they are the cause of serious environmental allergy. In Europe, and particularly in Spain, allergy to Chironomids is infrequent and has only been described in patients who handle Chironomid larvae which form part of certain fish foods.

MATERIALS AND METHODS

We report a case of hypersensitivity to the Chironomid Midge (Chironomus thummi thummi) in a 23-year-old patient who on two occasions, after being in contact with fishfood, suffered rash, rhinoconjunctivitis, dyspnea and dysphagia. A Prick test was carried out with the habitual pneumoallergens, Chironomid Midge extract (PBS: 1.3 mg/ml), Common Mosquito (Culex pipiens), Squid, Mussel, Prawn and Anisakis. Conjunctival provocation was also carried out with Chironomid Midge extract; detection of specific IgE for Chironomid Midge, Common Mosquito (Aedes comunis), Mussel, Squid, Shrimp, Anisakis, house dust and house mites by means of the CAP technique; detection of IgE by means of ELISA in response to Chironomid Midge, Aedes mosquito, Squid, Prawn, Mussel and Anisakis; ELISA-inhibition and Immunoblott-inhibition.

RESULTS

The positive results of the cutaneous tests, the detection of specific IgE and conjunctival provocation confirmed the existence of an IgE-mediated mechanism. In our patient, the in vitro techniques demonstrated cross reactivity with the Common Mosquito.

CONCLUSIONS

We report on a patient with a case history of rhinoconjunctivitis, rash, dyspnea, and dysphagia after handling fish food. The etiological agent was the Chironomid larvae. The sensitization of our patient has been demonstrated by means of in vivo and in vitro techniques.

Molecular cloning and characterization of tropomyosin, a major allergen of Chironomus kiiensis, a dominant species of nonbiting midges in Korea

Chironomids are widely and abundantly distributed in the vicinity of standing waters. Larvae of Chironomus and some other genera are known to contain hemoglobins, which have been described as a major allergen, and the adults that have no hemoglobins also have been reported to contain allergens. In this study, we tried to establish the role of chironomid allergy and characterize the allergen of Chironomus kiiensis adults. Skin tests using C. kiiensis adult extracts were performed on patients with allergic symptoms. A cDNA library of C. kiiensis adults was screened with C. kiiensis immune mouse sera to identify allergens, and results were confirmed using skin test-positive human sera. Recombinant allergen was expressed in Escherichia coli and purified by affinity chromatography using nickel-nitrilotriacetic acid agarose to investigate its allergenic properties. Out of 275 allergic patients 14.2% showed a positive reaction to C. kiiensis adult crude extracts in the skin test. The tropomyosin was cloned by immunoscreening and expressed in Escherichia coli. C. kiiensis tropomyosin has a high homology at the amino acid level with tropomyosins which were previously known to be allergens in various arthropods (Periplaneta americana, 86.3%; Panulirus stimpson, 78.9%; Dermatophagoides pteronyssinus, 76.5%). Specific immunoglobulin E antibodies reacting to recombinant tropomyosin were detected in 17 (81%) of 21 patients whose skin test results were positive. Cross-reactivity against house dust mites and other insects was noticed with mouse anti-recombinant tropomyosin immune serum. C. kiiensis adults were shown to be an important source of inhalant allergens in Korea. Molecular cloning of C. kiiensis tropomyosin was performed and IgE reactivity was demonstrated using skin test-positive human sera. Recombinant tropomyosin will be useful for further studies or clinical applications.

[Nationwide investigation of insect allergy in patients with allergic rhinitis]

To clarify the role of insects as allergens in allergic rhinitis (AR), specific IgE antibodies (sIgE) to the moth, midge, and cockroach together with 10 other allergens were measured using sera from 560 AR patients, who visited 20 otolaryngological clinics nationwide from Hokkaido to Kyushu. Nasal challenge tests were also conducted with allergen disks of these 3 insects in 65 AR patients. Frequencies of sIgE positive to the moth, midge, and cockroach were 32.5%, 16.1%, and 13.4%. Frequencies of sIgE positive to these insects were not affected by patients' residential location, age, medication, or association with bronchial asthma. The prevalence of patients with positive nasal challenge increased depending on the RAST class to the insects. Among the patients whose RAST class were 3 and 4, nasal challenges with cockroach or moth extracts were positive in 55.6% or 61.5%. A strong correlation of sIgE titers was observed between the moth and midge, but the correlation between the cockroach and moth, and between the cockroach and midge were weak. No correlation of sIgE titers was found between house dust mites and these 3 insects. These results show that the moth, midge, and cockroach are inhalant allergens causing allergic rhinitis in Japan.

Chironomid potent allergens causing respiratory allergy in children

Generally speaking, chironomids contain potent inhalant allergens. The skin prick tests with chironomid crude extract (Chironomus (C.) calipterus) were positive in 20 out of 25 children with respiratory allergy. The skin prick tests with house dust mite crude extract (Dermatophagoides pteronyssinus) were positive in 3 of these 20 chironomoid positive skin tests. Chironomid-specific IgE-ELISA were demonstrated in the sera of 17 (85%) of the chironomid skin positive patients. These 17 patients gave negative skin prick test to house dust mite crude extract. It is concluded that chironomid allergens should be considered when dealing with human respiratory allergy caused by arthropods.

Identification of Chironomus kiiensis allergens, a dominant species of non-biting midges in Korea

Non-biting midges are known to contain potent inhalant allergens. IgE antibody responses to the crude extract of Chironomus kiiensis adults, a dominant chironomid species in Korea, were examined. With the IgE-ELISA or passive cutaneous anaphylaxis reactions, increased levels of chironomid-specific IgE were detected in the skin test positive human sera, or immunized BALB/c mouse sera with the crude extract adsorbed to alum. IgE-immunoblot analysis showed major IgE-reacting protein band patterns, which reacted with more than 50% of the skin test positive human sera, at 110, 80, 73, 46, 40, 37, 34, and 31 kDa. The reactive band patterns were largely similar between skin test positive humans and immune BALB/c mice. However, the bands of 55, 31, 27, 26, 24, and 23 kDa were found only in sensitized humans, but not in immunized mice.

Patterns of immunoglobulin E sensitization to chironomids in exposed and unexposed subjects

We present our study of four patients with occupational type I allergy to red midge larvae (group 1) who we compared with seven individuals also sensitized to red midge larvae but who had not apparently been exposed to them (group 2). All patients showed elevated specific IgE against Chironomus thummi, and positive skin prick tests (SPT) and provocation tests with red midge larvae. We carried out SPT with Dermatophagoides pteronyssinus, Acarus siro, shrimp, cockroach and common mosquito (Culex pipiens) and specific serum IgE was also determined. The red midge larvae wheal size was significantly larger in group 1 (x = 149.2 mm2) than in group 2 (x = 18 mm2). Significant differences between levels of IgE anti-C. thummi were also found in group 1 (x = 52.12 kU/l) and in group 2 (x = 1.5 kU/l). The patients in group 2 had high levels of specific IgE against other allergens (D. pteronyssinus, shrimp and/or common mosquito) and had positive SPTs with these allergens, while the patients in group 1 were only sensitized to chironomids. The IgE-immunoblotting profile was quite different in both groups. The patients in group 1 seemed to have IgE against Chi t 1, the main Chironomus allergen, while the patients in group 2 had IgE against several protein bands in Chironomus, mosquito, shrimp and D. pteronyssinus extracts, some of them with equivalent molecular weights. We believe that the patients in group 2 were sensitized to Chironomus as a result of cross-reactivity with other insect or crustacean species.

Mosquito bite hypersensitivity

We report a patient who experienced systemic anaphylaxis after several mosquito bites. The skin tests were positive, by prick and intradermal tests, with two species of common mosquito (Aedes communis and Culex pipiens) and also with red midge larvae (Chironomus). Specific IgE against Aedes communis was demonstrated. We carried out SDS-PAGE and immunoblotting with whole body extracts of Aedes communis and Culex pipiens and with red midge larvae. The immunoblotting results showed specific IgE against two proteins of approximately 30 kDa with the extract of Culex pipiens. We also found IgE against one protein of a slightly lower molecular weight with Aedes communis, and against several proteins (the most important with a molecular weight between 30 and 70 kDa) with the Chironomus extract. Cross-reactivity between these insect species was suspected.

Hypersensitivity to chironomid larvae

Chironomid larvae (red midge larvae) are often used by aquarists as fish food. Their hemoglobins can cause IgE-mediated allergic diseases in exposed and unexposed people. The aim of this study was to find out the prevalence of positive skin tests to chironomids in patients suffering from rhinitis and/or bronchial asthma in Ciudad Real (Spain). A total of 465 patients were submitted to skin prick tests with chironomids in addition to common inhalant allergens. The patients with positive skin prick test (wheal > or = 3 mm) to these larvae answered a questionnaire. Skin prick tests with Acarus siro, shrimp, cockroach and mosquito (Culex pipiens) were carried out. Serum levels of total IgE and anti-Chironommus thummi, anti-Dermatophagoides pteronyssinus, anti-shrimp, and anti-mosquito (Aedes communis) IgE were determined. Conjunctival or nasal provocation tests were carried out with chironomids. Of the 465 patients skin tested, 19 showed a positive skin prick test with chironomids, corresponding to 4.1% of all patients and 6% of the atopic patients. None were monosensitized. Significant correlations were found between skin prick test results with chironomids and mites (p < 0.005). Of the 19 patients, 15 had positive skin prick test with the common mosquito C. pipiens. Seven patients showed elevated anti-D. pteronyssinus IgE, six elevated anti-shrimp IgE, and 10 showed elevated anti-A. communis IgE. Provocation tests with chironomids were positive in 14 patients (four nasal and 10 conjunctival tests). Conjunctival provocation tests were carried out in 16 controls and were positive in three; all three showed positive skin prick test with chironomids. One patient had occupational allergy from the larvae (aquarist). After mosquito bites, five patients showed immediate wheal reactions and one patient suffered an anaphylactic reaction after several mosquito bites. Only two patients remembered having been in contact with chironomids as fish food. We found hypersensitivity to these larvae in patients without apparent contact to them. These patients could have become sensitized in various ways, including: 1) inhaling particles of chironomids or others that are cross-reactive with them; 2) exposure to products used as fish food containing chironomids; and, 3) through cross-reactivity with other allergens such as mites, shrimp or mosquitoes.

Cross-reactivity between IgE-binding proteins from Anisakis, German cockroach, and chironomids

Anisakis simplex larvae parasitize animals used as seafood and can produce a specific immune response in man. The ingestion of seafood contaminated with stage three of A. simplex larvae can induce a specific IgE response with clinical symptoms, usually urticaria, even if the fish is cooked before ingestion and the invasive infestation power destroyed by heating. Our preliminary studies showed a strong association of A. simplex sensitization with Ascaris lumbricoides, Daphnia, chironomid spp., Atlantic shrimp (Pandalus borealis), and German cockroach (Blattella germanica). We conducted the cross-reactivity study with cockroach, a ubiquitous insect, and Chironomidae (red mosquito larvae), a work-related allergen, without any possibility of Anisakis contamination. Serum samples were collected from 60 pediatric patients, with serum specific IgE to A. simplex. Both specific-IgE and immunoblot-inhibition studies, with a serum pool from 18 patients, were performed to determine whether the association of sensitizations to nematodes and arthropods was due to immunologic cross-reactivity. In addition, serum samples from 21 of 60 patients who showed also sensitization to German cockroach were used for individual immunoblot studies. In the serum pool, dose-dependent inhibition of B. germanica and Chironomus spp, was observed after preincubation with the A. simplex extract. Immunoblot of Anisakis, inhibited with Chironomus and German cockroach, yielded a partial blot inhibition but mainly on bands below 41 kDa. Blot inhibition of German cockroach and Chironomus with Anisakis was dose related. The band patterns in individual blots were heterogeneous, but most of them had bands of 30-43 kDa. None of these sera recognized allergens in the 14-kDa area. In our study, CAP-inhibition and immunoblot-inhibition analysis of Anisakis showed that several IgE-binding components could be shared by the three allergens.

Flow-cytometric analysis of T-cell receptor expression in peripheral blood lymphocytes

BACKGROUND

Lymphocytes of subjects sensitized to the insect-derived allergen Chi t 1-9 are, in response to the allergen, characterized by an elevated proliferation and increased expression of activation markers such as HLA-DR and CD25 in vitro. A restriction for HLA-DR B1 in monosensitized patients was found.

OBJECTIVE

The aim of this study was to investigate whether the response to the allergen Chi t 1-9 involves the preferential cell surface expression of a specific alpha/beta T-cell receptor type.

METHODS

The T-cell receptor repertoire was measured with 7 monoclonal antibodies to epitopes on the variable region of the alpha- and beta-chain by flow cytometry. Cell lines of 9 patients were established with Chi t 1-9, 6 with tetanus toxoid and 6 with phytohaemagglutinin in the presence of interleukin 2. In addition, non-stimulated lymphocytes as well as lymphocytes of 5 non-sensitized controls exposed to Chi t 1-9 were examined.

RESULTS

Each of the 9 sensitized and 5 control subjects studied showed an individual pattern of lymphocyte expression for each T-cell receptor specificity. However, after stimulation specific to Chi t 1-9 for 2 weeks, a significant increase in V beta 8-expressing cells was measurable only in patients sensitized to Chi t 1-9. The cells of the 5 control subjects showed no significant changes due to the allergen stimulation.

CONCLUSION

These data suggest that the expression of certain T-cell receptor types plays an important role in the development of Chi t 1-9 allergy.

Studies of bronchial asthma induced by chironomid midges (Diptera) around a hypereutrophic lake in Japan

There have been few reports on hypersensitivity to chironomid midges in bronchial asthmatic patients around the area of hypereutrophic natural lakes, which have been notorious as an environmental hazard due to the massive occurrence of adult chironomids during several periods of the year. Our study investigated IgE antibodies to chironomid midges in bronchial asthmatic patients around the Lake Suwa area in comparison with those of the Matsumoto area (control area). A total of 123 adult patients with bronchial asthma were investigated by measurement of IgE antibodies with extracts of three chironomid midges (Chironomus yoshimatsui, C. plumosus, and Tokunagayusurika akamusi), mite, and silkworm. In addition, in the allergy testing, 12 common inhalant antigens were used. Of 123 adult patients with bronchial asthma, 65 (52.8%) produced positive allergy tests. Thirty-three (50.8%) were positive to mite, 28 (43.1%) to silkworm, 11 (16.9%) to C. yoshimatsui, eight (12.3%) to C. plumosus, and three (4.6%) to T. akamusi. We compared our results with the previous reports. The number of positive tests to silkworm in the Lake Suwa area was higher than in other areas. However, C. plumosus and T. akamusi showed a lower number of positive reactions. We considered the lower positive number of C. plumosus and T. akamusi tests in the Lake Suwa area to be related to the advanced age of patients in this area. The chironomids are an important cause of asthma, together with mite and silkworm, in the Lake Suwa area, but affect old asthmatic patients less than asthmatic children.

IgE antibodies against midge and moth found in Japanese asthmatic subjects and comparison of allergenicity between these insects

The specific IgE antibodies to moth (Bombyx mori) and midge (Chironomus yoshimatsui) were measured by the Pharmacia CAP system in 51 house-dust-mite-sensitive asthma patients. None of these patients had definite histories of exposure to these insects or apparent evidence of insect-induced asthma symptoms. The RAST-inhibition assay was performed to investigate cross-allergenicity between these two insects. Furthermore, IgE immunoblotting was done to study the IgE-binding components in moth and midge extracts. Thirty (59%) of these patients showed positive IgE antibodies to moth, while 25 (49%) showed positive IgE antibodies to midge. Those frequencies of positivity were similar to that for Japanese cedar pollen, which is well known to cause allergy. A significant correlation (r = 0.863) was observed between IgE antibody titers of these two insects. The results from the RAST-inhibition assay indicated cross-allergenicity between these insects and also the existence of species-specific allergens. Fifteen IgE-binding components in moth extract were observed. The most frequent IgE-binding protein was the 79-kDa (84.2%), followed by the 72-kDa (78.9%), the 82-kDa (57.9%), and the 76-kDa (57.9%) proteins. Those were considered to be major allergens in moth. Twenty-four IgE-binding components in midge extract were observed. However, no IgE-binding protein to which over 50% of patient sera reacted was observed. These results suggest that these two insects may be considered to bear important allergens and that there is cross-allergenicity between these insects as well as species-specific allergens.

Cloning and expression of a murine Fab fragment recognizing a defined linear epitope of Chironomus thummi thummi major allergen Chi t 1-9

We have cloned and expressed in bacteria the genes coding for the Fab fragment of the monoclonal antibody (MoAb) M3. M3 is a murine IgG1 antibody reactive with the major allergen Chi t 1-9 of Chironomus thummi thummi. The major allergen Chi t 1-9 is known to be an aggressive inhalant allergen and causes type-I allergy. The immunoglobulin (Ig) fragment genes were cloned as a synthetic dicistronic operon. In this operon each gene is preceded by a bacterial signal sequence to direct the recombinant protein to the periplasmic space of the bacteria. The cloned genes were expressed in Escherichia coli using the strong T7-RNA-polymerase-based system. Sequence analysis revealed that the light and heavy chains of MoAb M3 belong to the V kappa II and V kappa IIC group of the Ig family, respectively. Genes of the V kappa II and V kappa IIC group are known to be used in response to haptens. The apparent affinity constants of the parent antibody M3 and the recombinant Fab fragment are nearly equivalent.

Purification and characterization of an allergenic monomeric hemoglobin from a chironomid distributed worldwide, Polypedium nubifer

The Pol n component MV, a potent experimental allergen for mice, was purified to homogeneity from extracts of a chironomid distributed worldwide, Polypedium nubifer (PN). The Pol n I component MV was shown to have cross-reactivity to hemoglobins (Hb) derived from all species of chironomids tested. Determination of the amino acid sequence of the first 37 N-terminal residues revealed that it had 30-59% homology to Hb of an European chironomid, Chironomus thummi thummi, which had been known as an important allergen for humans. By Western blot analysis, we showed that sera from asthmatic patients, which had positively reacted to the extract of the adult PN midge, bound to the purified Pol n I component MV. Furthermore, using rabbit polyclonal antibodies raised against synthetic polypeptides corresponding to the N-terminal residues, it was demonstrated that the N-terminal amino acid sequence between position 15 and 35 contained antigenic epitope(s) for human IgE. The results indicate that the Pol n I component MV is an allergen for human beings as well as for mice, and useful as a diagnostic tool for chironomid allergy.

[Identification and characterization of allergens of Chironomus flaviplumus adults (Chironomidae, Diptera) in mice]

Non-biting midges (Chironomidae, Diptera) are one of the largest insect families, which are distributed worldwidely and are found in nearly all types of inland waters. They are known to be aggressive inhalant allergens which cause allergenic diseases. In this study, the crude antigens of Chironomus flaviplumus adults which are most widely distributed in Korea were extracted, and their allergens were analyzed with the sera from experimentally sensitized mice. The mice were immunized with 1 microg or 10 microg of the crude antigens, respectively, and the specific serum IgE levels were measured by both ELISA and passive cutaneous anaphylaxis (PCA) techniques. The highest levels of both total IgE and chironomid-specific IgE were found in the mouse sera obtained after 9 weeks of the first injection with 1 mu g crude antigen. The crude antigen was separated into 16-18 protein bands on gel by SDS-PAGE. The crude extract was assessed by SDS-PAGE/immunoblot analysis. One IgE-binding band (65 kDa) was detected by developing with colorimetric substrate, and 4 IgE-binding bands (65, 52, 35 IgE-binding and 25 kDa) by developing with CSPD chemiluminescent substrate. The SDS-PAGE gel of the crude extract of chironomid adults was equally cut into 30 pieces and each of them was eluted to isolate proteins by molecular weight, and the allergenicity of each eluate was assessed by applying P-K test on rats. Proteins of 65, 35 and 15 kDa showed the highest P-K titer (x 512) which was 16 times higher than that of the crude extract (x 32). The P-K titer of 52 kDa protein was also 4 times higher (x 128) than that of the crude extract, whereas the 25 kDa protein poorly responded, which seemed not antigenic. In conclusion, the present result in mice demonstrated that adults of Chironomus flaviplumus, a predominent species in Korea, cause allergenic diseases and the main allergens are 65, 52, 35 and 15 kDa proteins, of which 65 kDa protein seems to be a main allergen.

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.