Comparison of IgE antibody concentrations to pyromellitic dianhydride-modified laminin and human serum albumin in sera of exposed workers with respiratory complaints.

BACKGROUND: Acid anhydrides are used in a variety of industrial branches because of their highly reactive anhydride groups. Adverse effects of anhydride exposure include toxic/irritative effects as well as IgE- and IgG-mediated respiratory disorders. It was the aim of this study to examine the usefulness of conjugates of pyromellitic dianhydride (PMDA) and laminin, a respiratory tract protein, for the in vitro diagnosis of sensitization to PMDA. METHODS: Sera of PMDA-exposed workers (n = 9) and nonexposed controls (n = 8) were tested with an enzyme allergosorbent test (EAST). Human laminin and human serum albumin (HSA) were derivatized with PMDA and used as solid-phase in a commercial assay. RESULTS: Seven out of 9 exposed workers revealed elevated IgE antibody concentrations (>0.35 kU/l) against laminin-PMDA whereas 5 of 9 subjects had elevated IgE antibody concentrations to HSA-PMDA. All 9 workers had elevated IgE antibody concentrations in at least one of the two tests. Of the 4 workers who complained of shortness of breath, 3 were positive for laminin-PMDA and 2 for HSA-PMDA. All of the nonexposed subjects were negative (<0.35 kU/l) for laminin-PMDA. CONCLUSION: PMDA-modified laminin could provide an additional diagnostic tool for the detection of sensitization to PMDA.

Differentiation between cosensitization and cross-reactivity in wheat flour and grass pollen-sensitized subjects.

BACKGROUND: To diagnose baker's asthma, occupational sensitization to wheat flour should be distinguished clearly from influences of cosensitization such as it may exist in pollinosis patients. To define the route of sensitization, the cross-reactivity between wheat flour and grass pollen allergens was investigated. METHODS: Two groups of atopic individuals with or without professional contact to wheat flour were screened by skin prick test for their sensitization to wheat flour and grass pollen and, in the case of hints for cosensitization, by Enzyme Allergo Sorbent Test (EAST). Cross-reactivity between wheat flour and grass pollen allergens was investigated by IgE binding inhibition assay using sera of 20 cosensitized individuals and by immunoblots. RESULTS: The immunological cross-inhibition between wheat flour and grass pollen proves some proteins to share common allergenic determinants. Significant differences between bakers and individuals not occupationally exposed to flour could be seen in the inhibition of IgE binding to wheat flour. While the IgE binding to wheat flour allergens was only slightly inhibited by grass pollen proteins in baker's sera its inhibition was nearly complete by this extract in sera of nonexposed atopics. Immunoblots indicate that wheat proteins with a molecular weight of about 8-12 and 22 kD preferentially react with sensitized bakers' IgE and not with IgE of other individuals. IgE binding to grass pollen allergens in immunoblots and inhibition experiments showed no differences between bakers and other subjects. CONCLUSION: In the group of atopics without professional contact to flour, the positive test results from wheat flour obviously ensue from contact to cross-reacting grass pollen proteins whereas bakers are exposed and sensitized to allergens of both sources. Such cross-inhibition experiments help to identify the source of sensitization which may be difficult to obtain in case of cross-reacting allergens.

[Ammonia as inhalatory irritant]. / Ammoniak als inhalativer Reizstoff.

Bronchopulmonary damage caused by heavy exposure to ammonia may result in chronic obstructive bronchitis, bronchial hyperresponsiveness, in rare cases also in a combined ventilation pattern. Exposure to ammonia for several years, as it occurs in swine confinements in pig-fattening farms is associated with a shift-related decrease of FEV1, FEF25-75 and PEF. Several studies show that ammonia at the TLV (20 ppm) inconstantly causes severe cough. In this connection, patients frequently cannot perform maximum forced ventilation manoeuvres. This leads to reduced spirometric values which usually do not represent bronchial obstruction. This interpretation is supported by normal values obtained by body plethysmography. Nevertheless, corresponding disorders may be associated with significant health impairment. Altogether, the results point predominantly to long-term effects. Obviously, continuous inflammation of the airways favours the development of chronic bronchitis. On this basis, susceptible subjects respond with airway symptoms, especially cough, upon re-exposure.

Heating inactivates the enzymatic activity and partially inactivates the allergenic activity of Asp o 2.

BACKGROUND: Sensitization to various flours and flour additives in the baking industry has been known for some time. However, most studies refer to allergens in their native state. OBJECTIVE: The aim of our study was to find out how high temperatures during the baking process influence enzymatic and allergenic activities of the common flour additive alpha-amylase (Asp o 2), a relevant allergen for bakers derived from Aspergillus oryzae. METHODS: In order to assess the allergenicity of Asp o 2 during the baking process, four to 11 correspondingly sensitized bakers were investigated by Enzyme Allergo-Sorbent Test (EAST) with native Asp o 2 and Asp o 2 heated to 80, 90, 95, 99.8 or 200 degrees C. Furthermore, the enzymatic activity was assayed in simulated baking processes at the above mentioned temperatures. RESULTS: Elevated temperatures resulted in a gradual loss of IgE antibodies' recognition of Asp o 2 in two commercially available enzyme products. The enzymatic activity decreased more rapidly. Heating the enzyme to 200 degrees C abolished both the enzymatic and the allergenic activity of the enzyme. CONCLUSION: Based on these results, alpha-amylase in flour additives partially retains its allergenicity. This finding could be relevant for consumers.

A clinical and immunological study on 92 workers occupationally exposed to anhydrides.

This study aimed at investigating sensitizing and hazardous effects of a new acid anhydride, pyromellitic dianhydride (PMDA), in addition to those of phthalic anhydride, maleic anhydride and trimellitic anhydride, in a group of 92 exposed workers in two German chemical plants. Of the 92 workers, 56 reported work-related complaints with a predominance of phlegm and dyspnoea in those exposed to anhydride dust for less than 1 year. Haemorrhagic rhinitis occurred only after a prolonged exposure of more than 15 years. Specific IgE antibodies to anhydride-HSA conjugates could be detected in 15 exposed subjects, 12 of whom had work-related symptoms. The IgE-positive group had significantly more impaired lung function parameters than the IgE-negative group. The proportion of IgE-positive subjects was highest in the groups with dyspnoea (5/18), cough (6/24) and rhinitis (11/44) whereas only 1 of 11 workers with haemorrhagic rhinitis had such antibodies. A follow-up study of 23 affected workers was performed after 10 months to assess clinical symptoms, lung function and IgE antibody levels. This follow-up study showed the absence of obstructive ventilation patterns in three out of six subjects in addition to cessation of symptoms in most initially affected workers who were no longer exposed. On the other hand, 14 workers under continuous exposure had comparable pathological findings on re-examination. Our results confirm that anhydrides including the lesser known PMDA, behave as respiratory irritants and as immediate-type sensitizers. They predominantly induced reversible symptoms in workers whose exposure stopped after a working period of about 0.7 years. Abnormal lung function parameters normalized in nearly 50% of these subjects.

Allergic reaction after eating alpha-amylase (Asp o 2)-containing bread. A case report.

A 29-year-old female bakery shop assistant was occupationally sensitized to flour allergens and Aspergillus alpha-amylase (Asp o 2). The latter represents a strongly allergenic component of routinely used baking additives. The patient had repeatedly responded to the consumption of white bread with rhinitis, conjunctivitis, and, occasionally, wheal and flare reactions. She underwent allergologic investigations including oral challenge tests with commercially available bread loaves. Elevated specific IgE antibodies against bread extracts, Asp o 2, and flour allergens were detectable in her serum. The provocation test with bread resulted in a running nose together with a strong increase in nasal resistance. All symptoms subsided about 3 h after the challenge. None of the above symptoms could be observed when bread free of Aspergillus alpha-amylase was administered. This outcome provides evidence of a clinically relevant persistent allergenicity to Asp o 2 in bread.

Allergens causing bird fancier's asthma.

The study investigates to what extent bird feathers contain relevant allergens/antigens involved in bird fancier's asthma. The study group consisted of two budgerigar fanciers, two parrot fanciers and one canary fancier. All subjects complained of asthmatic symptoms, caused by contact with their birds, and they showed a significant bronchial hyperreactivity to acetylcholine. Positive IgE antibody reactions to bird sera as well as to extracts of feathers were observed in RAST. Well-defined major allergenic bands could be detected and identified in the IgE immunoblots with feather extracts as well as with serum proteins of budgerigar, parrot, pigeon, canary, and hen (mol. mass 20-30 kDa and 67 kDa). The most pronounced bands appeared with the extracts of species to which an exposure had taken place. Weaker IgG-binding patterns were also observed. Our results show that inhalable feather dust contains several allergenic components which cross-react with serum allergens/antigens of the same as well as of other bird species. This emphasizes the significance of bird feathers for immediate-type allergic reactions.

Acute autoimmune response in a case of pyromellitic acid dianhydride-induced hemorrhagic alveolitis.

A 17-year-old man was occupationally exposed to pyromellitic acid dianhydride dust during the production of epoxy resin in a chemical factory. He was clinically diagnosed as having acute hemorrhagic alveolitis associated with anemia. The serologic analysis revealed a high concentration of IgG antibodies against pyromellitic acid dianhydride-treated human serum albumin (PMDA-HSA). Immunoblotting with PMDA-treated human serum as antigen and the patient's serum as the first antibody showed that additional PMDA-modified serum proteins other than HSA were recognized by the patient's IgG antibodies in the higher mol. mass range (> 67 kDa). No specific IgG could be detected against other anhydride conjugates (maleic acid, MA; phthalic acid, PA) with the exception of a reaction with the trimellitic acid anhydride-conjugated HSA (TMA-HSA). No specific IgE antibodies could be detected against any of the above mentioned antigens, but immunoblotting of the patient's serum indicated IgG4-type autoantibodies against in vitro PMDA-treated Ig molecules of normal serum proteins.

[Are amylases in bakery products and flour potential food allergens?]. / Sind Amylasen von Backmitteln und Backmehl relevante Nahrungsmittelallergene?

The enzyme alpha-amylase from the mould Aspergillus oryzae (Asp o II) routinely used for the production of bread, cakes and pastries has in recent years been identified as an inhalative allergen for occupational diseases (bakers' asthma). It is doubtful whether this amylase in the final product, i.e. after the baking procedure, can still be regarded as an allergen. To clarify this question, detailed case histories on 138 subjects were recorded (98 allergics, 20 patients suffering form chronic intestinal diseases, 20 healthy controls). The clinical examinations included prick skin test and IgE antibody determination using one of the customary enzyme preparations. EAST showed a few of these 138 bread consumers to be weakly sensitized to the enzyme. One of the subjects displayed a significant reaction to alpha-amylase heated to 200 degrees C. As expected, eleven bakers sensitized to alpha-amylase by inhaling it in the workplace (positive prick test, positive case history) predominantly exhibited specific IgE antibodies to the native enzyme. Apart from one weakly positive finding, heated alpha-amylase yielded negative results in this collective. Baking conditions vary widely, especially with regard to single components, temperature and duration. Thus, further investigations as to residual allergenicity or the feasible occurrence of new antigenic determinants during the production of bread, cake and pastries are required. 27% of bakers examined and 9% of atopics showed antibodies to a flour inherent enzyme, a beta-amylase. On the whole, the selected conditions hinted at a weakly sensitizing potential inherent in baking flour and in added amylase.

Respiratory and other hazards of isocyanates.

Isocyanates are increasingly being used for manufacturing polyurethane foam, elastomers, adhesives, paints, coatings, insecticides, and many other products. At present, they are regarded as one of the main causes of occupational asthma. The large number of workers who are exposed to these chemicals have a concentration-dependent risk of developing chronic airway disorders, especially bronchial asthma. Different pathophysiologic mechanisms are involved. Immunoglobulin E (IgE)-mediated sensitization and irritative effects have been clearly demonstrated in both exposed subjects and animals. Presumably, neural inflammation due to neuropeptide release of capsaicin-sensitive afferent nerves is crucial. We collected data on 1780 isocyanate workers who had been examined by our groups. Of them 1095 (including subjects from outpatient departments) had work-related symptoms, predominantly of the respiratory tract. Specific IgE antibodies were found in 14% of the 1095 subjects. The methacholine challenge test was shown to be an inadequate predictor of the results of inhalative isocyanate provocation tests in workers and in asthmatic controls. Isocyanate (toluene diisocyanate TDI) air concentrations of 10 ppb (0.07 mg/m3) and 20 ppb (0.14 mg/m3), respectively, did not cause significant bronchial obstruction in the majority of previously unexposed asthmatics with bronchial hyperreactivity. IgG-mediated allergic alveolitis, a rare disease among isocyanate workers, was found in approximately 1% of the symptomatic subjects. Experimental studies exhibit dose-dependent toxic effects and give evidence for tachykinin-mediated bronchial hyperreactivity after exposure to isocyanates. The clinical role of genotoxic effects of isocyanates and their by-products demonstrated here in vitro and in vivo has yet to be clarified.

Increased incidence of DNA double-strand breaks and anti-ds DNA antibodies in blood of workers occupationally exposed to asbestos.

Asbestos, proven to be carcinogenic in humans and animals, is reported to have no genotoxic effect. Asbestos workers have an increased risk of lung cancer, mesothelioma, and other tumours. Earlier findings showed that crocidolite can induce DNA strand breaks in cultured rat embryo cells as assessed by nick translation. We investigated DNA double-strand breaks in white blood cells (WBC) of ten workers occupationally exposed to asbestos. According to our results, obtained with neutral filter elution, individuals who had been exposed to asbestos fibres showed two to four times more DNA double-strand breaks (dsb) in white blood cells than ten non-exposed persons. The induced DNA fragments are of about 250 kb (compared to chromosomal DNA of Saccharomyces cerevisiae standard marker). Using additionally the chromosomal DNA protective method of agarose-plugs, DNA fragments in the range of 200 to 1000 kb have been found in the white blood cells of the same ten workers occupationally exposed to asbestos. In the white blood cells of non-exposed subjects no DNA fragments could be detected with this method. Compared to 51 non-exposed persons, elevated anti-ds DNA antibody concentrations were found in ten workers occupationally exposed to asbestos. The fact that workers occupationally exposed to asbestos have distinctly more double-strand breaks and anti-ds DNA antibodies could mean that an increased incidence of DNA-fragments may be an important indicator in the chronic effect of asbestos-associated carcinogenesis. Apparently, the chronic effects of asbestos observed here do not seem to be identical with that of previously reported acute in vitro effects.

The rubber elongation factor of rubber trees (Hevea brasiliensis) is the major allergen in latex.

BACKGROUND: Allergy to latex-containing articles is becoming more and more important because it can result in unexpected life-threatening anaphylactic reactions in sensitized individuals. METHODS: A protein of 58 kd with an isoelectric point of 8.45 was purified from raw latex and from latex gloves and identified as the major allergen, completely blocking specific IgE antibodies in the serum of latex-sensitized subjects. The allergen is a noncovalent homotetramer molecule, in which the 14.6 kd monomer was identified, by amino acid composition and sequence homologies of tryptic peptides, to be the rubber elongation factor found in natural latex of the Malaysian rubber tree. RESULTS: Competitive immunoinhibition tests showed that the starch powder covering the finished gloves is the airborne carrier of the allergen, resulting in bronchial asthma on inhalation. The purified allergen can induce allergic reactions in the nanogram range. CONCLUSION: The identification of the allergen (Hev b I) may help to eliminate it during the production of latex-based articles in the future.

Health risk in hospitals through airborne allergens for patients presensitised to latex.

Two nurses had to stop practicing because of severe work-related allergic respiratory or systemic symptoms. Both developed similar symptoms within a short time when they attended hospitals as outpatients or visitors or consulted a doctor or dentist, even when they had no direct contact with latex articles. The airborne latex allergen concentration in one room that induced symptoms was 128 ng per m3. In skinprick tests both women showed positive reactions to the phosphated cornstarch powder used to prevent latex gloves sticking together, but only when the powder had been in contact with latex. This powder seems a likely vehicle for the airborne latex allergen.

[Stepwise diagnosis of respiratory latex allergy]. / Stufendiagnostik der respiratorischen Latexallergie.

Latex proteins bound to the powder of latex gloves are potent aeroallergens which can cause severe immediate-type allergic reactions of the upper and lower respiratory tract. To evaluate the clinical relevance of positive skin prick tests or IgE antibodies to latex we developed a sequence of provocation tests for the diagnosis of latex induced rhinitis or asthma. 14 patients are presented, 11 working in the medical field. All had positive skin prick test to latex milk and specific IgE-antibodies to a latex glove extract, six were atopic. 14 reported symptoms of the upper respiratory tract, 11 dyspnea related to latex contact. Nasal provocation with a suspension of powder from latex gloves or a glove extract could prove latex rhinitis in all cases by rhinomanometry. Bronchial obstruction was seen in four cases with one severe asthma attack in this test. The workplace-related provocation test with latex gloves was less sensitive for latex-asthma (3/9 positive) than the direct bronchial provocation test with a latex glove extract (6/7 positive), the three latex allergic patients without a history of dyspnea remaining negative in both. Provocation tests are highly sensitive for latex allergy of the respiratory tract and therefore of special importance in the diagnostic procedure.

Occupational-type exposure tests and bronchoalveolar lavage analyses in two patients with byssinosis and two asymptomatic cotton workers.

Two workers suffering from stage III byssinosis and claiming for compensation were examined. Bronchial obstruction was present in one case. MEF25-75 values were significantly reduced and bronchial hyperreactivity was present in both subjects. Occupational-type exposure tests with cotton dust resulted in significant decreases in arterial oxygen pressure for more than 2 h and were associated with an obstructive ventilation pattern in one of the patients. Prolonged hypoxemia which is not paralleled by lung function changes is probably typical for byssinosis patients since we have never seen this in inhalative challenge tests with various environmental antigens and other occupational substances including flour dust. No specific IgE or IgG antibodies could be detected. In the two patients a hitherto unknown significant increase in CD23+ lymphocytes and granulocytosis were detected by bronchoalveolar lavage (BAL). Corresponding investigations in two cotton workers without any evidence of byssinosis revealed neither lung function changes after the exposure test nor striking BAL findings. Our results demonstrate the diagnostic value of specific challenge tests and BAL investigations in patients suffering from byssinosis, which is often difficult to diagnose.

Increased incidence of anti-dsDNA autoantibody concentration in sera of workers occupationally exposed to diisocyanates.

Sera of 87 industrial workers with a history of occupational exposition to various diisocyanates, toluene diisocyanate, hexamethylene diisocyanate and methylene-diphenyl diisocyanate were analyzed for antibodies to isocyanate-conjugated human serum albumin and for anti-dsDNA autoantibodies. Ten workers (approx. 11%) were shown to have elevated anti-dsDNA autoantibody concentrations and 13 revealed antibodies to isocyanate-modified human serum albumin. The overlap of both tests being positive was calculated at about 40%. It would seem, therefore, that routine estimation of anti-dsDNA autoantibodies could provide additional useful information for the clinical diagnosis of occupational health impairment due to isocyanate exposure.

DNA double-strand breaks and apoptosis after in vitro exposure to toluene diisocyanate.

The immediate effect of toluene diisocyanate (TDI) on genomic DNA of sheep and rabbit white blood cells has been investigated. Following the treatment of sheep blood by TDI, the isolated DNA was analysed by anion exchange chromatography (FPLC) and melting behaviour before and after denaturation. The results of FPLC indicated that TDI induces DNA double-strand breaks in sheep white blood cells. Following denaturation of TDI-treated DNA, the results demonstrated that at least one DNA fragment, representing about 10-20% of total DNA, is cross-linked by TDI or TDI metabolite. About 39% more of double-stranded structures are reconstituted in DNA extracted from sheep white blood cells 3 hr after incubation with TDI. In addition, chromosomal DNA from rabbit blood was investigated with the 'agarose-plugs' method by pulsed-field gel electrophoresis 2 hr after incubation with TDI, and the agarose gels were quantitatively evaluated with a laser densitometer. Further studies with prednisone were conducted to correlate these results with the phenomenon of apoptosis. The in vitro results show that TDI can induce degradation of mitochondrial DNA and large DNA fragments, which result from apoptosis, to small DNA fragments.

Detection of protein changes in serum of workers following inhalation exposure to toluene diisocyanate vapors.

Serum samples of 10 workers undergoing occupational type inhalative challenge tests by toluene diisocyanate (TDI) were investigated by anion-exchange fast-protein-liquid-chromatography (FPLC) and polyacrylamide-gel electrophoresis (PAGE-SDS). Their serum chromatography profiles were compared to those of 20 unexposed individuals. The peak height of the first prealbumin peak in sera of workers after inhalative challenge tests was significantly different (p > 0, 01 Chi-square test) compared to that obtained before exposure and to that of unexposed subjects. In addition, qualitative changes of these peaks were also noted in sera of workers exposed to TDI. In the cases of exposed individuals, that peak was more diffuse with some shoulders and less symmetric in appearance. Similarly, PAGE-SDS of the serum proteins, followed by silver nitrate staining, revealed a different banding pattern after in vivo TDI exposure. One of the serum components at approximately 15 kDa showed an increase of staining intensity after exposure (n = 10), compared to unexposed subjects or to patients before exposure. This serum fraction has not yet been identified. The results here demonstrate that it is possible to detect changes of serum proteins in TDI-exposed individuals within a relatively short analysis time. This could be useful for biological monitoring of exposure, since no method for such is yet available.

[Latex proteins as the trigger of respiratory and systemic allergies]. / Latexproteine als Auslöser respiratorischer und systemischer Allergien.

56 patients (52 members of the hospital's staff, four with other employment) who had hypersensitivity reactions to latex articles and developed an immediate-type response to latex extract with the skin-prick test were studied. Specific IgE antibodies were present in the enzyme-allergo-sorbent test of 50 of the subjects. Latex-containing surgical and household gloves were the main cause of allergies. Patients with isolated contact urticaria (n = 8) had a tendency towards lower antibody concentrations than those with additional respiratory and/or systemic symptoms (n = 48). Occupation-related provocation tests triggered rhinitis in 19, conjunctivitis in ten, and bronchial obstruction in six. The main allergen was found to be a protein with a relative molecular mass of 58,000, originating from the latex milk and passing from the latex glove into the glove powder. In the course of usual activities considerable allergen inhalation can occur. Even small amounts (e.g. 400 ng/ml) can precipitate significant allergic reactions. The results show that the main latex allergen, a glycine-rich protein molecule, can cause cutaneous, inhalant and systemic hypersensitivity reactions.