Functional insights into the infective larval stage of Anisakis simplex s.s., Anisakis pegreffii and their hybrids based on gene expression patterns

BACKGROUND

Anisakis simplex sensu stricto and Anisakis pegreffii are sibling species of nematodes parasitic on marine mammals. Zoonotic human infection with third stage infective larvae causes anisakiasis, a debilitating and potentially fatal disease. These 2 species show evidence of hybridisation in geographical areas where they are sympatric. How the species and their hybrids differ is still poorly understood.

RESULTS

Third stage larvae of Anisakis simplex s.s., Anisakis pegreffii and hybrids were sampled from Merluccius merluccius (Teleosti) hosts captured in waters of the FAO 27 geographical area. Specimens of each species and hybrids were distinguished with a diagnostic genetic marker (ITS). RNA was extracted from pools of 10 individuals of each taxon. Transcriptomes were generated using Illumina RNA-Seq, and assembled de novo. A joint assembly (here called merged transcriptome) of all 3 samples was also generated. The inferred transcript sets were functionally annotated and compared globally and also on subsets of secreted proteins and putative allergen families. While intermediary metabolism appeared to be typical for nematodes in the 3 evaluated taxa, their transcriptomes present strong levels of differential expression and enrichment, mainly of transcripts related to metabolic pathways and gene ontologies associated to energy metabolism and other pathways, with significant presence of excreted/secreted proteins, most of them allergens. The allergome of the 2 species and their hybrids has also been thoroughly studied; at least 74 different allergen families were identified in the transcriptomes.

CONCLUSIONS

A. simplex s.s., A. pegreffi and their hybrids differ in gene expression patterns in the L3 stage. Strong parent-of-origin effects were observed: A. pegreffi alleles dominate in the expression patterns of hybrids albeit the latter, and A. pegreffii also display significant differences indicating that hybrids are intermediate biological entities among their parental species, and thus of outstanding interest in the study of speciation in nematodes. Analyses of differential expression based on genes coding for secreted proteins suggests that co-infections presents different repertoires of released protein to the host environment. Both species and their hybrids, share more allergen genes than previously thought and are likely to induce overlapping disease responses.

Diagnostic use of recombinant Tha p 2 in the allergy to Thaumetopoea pityocampa

Thaumetopoea pityocampa causes allergies and skin and ocular lesions. No commercial tools are currently available for the clinical diagnosis of this allergy. We aimed to develop an in vitro method for the diagnosis of this allergy to avoid patients undergoing in vivo tests with insect extracts. Recombinant Tha p 2 was produced and used in an ELISA validated with 15 allergic patients. Subsequently, 42 subjects recruited from a random sampling cross-sectional study were analysed. The ELISA sensitivity and specificity were 93.3% and 100%, respectively, for the allergic patients and 71.4% and 95.3%, respectively, for the epidemiological study. The positive ELISA results correlated with the skin prick test areas with the whole body and the setae extracts. Professional exposure and short latency of symptoms onset were risk factors for a positive result in the ELISA. In conclusion, our ELISA is very useful for T. pityocampa allergy diagnosis and for epidemiologic testing.

Anisakis/Ascaris IgE ratio improves specificity for the diagnosis of Anisakis simplex sensitization in travellers and immigrants

Anisakis simplex is a fish parasite responsible for human infection and is able to induce IgE-mediated reactions with several clinical manifestations. Laboratory diagnosis of Anisakis allergy is based on the detection of specific IgE using parasite whole antigen. Unfortunately, these diagnostic tools detect cross-reactivities with other nematodes and micro-organisms leading to low specificity of the diagnostic tests. The aim of this retrospective study was to assess the diagnostic value of specific IgE to Anisakis for diagnosis of A. simplex-sensitization in native Spanish residents (IMM, n=766) and subjects coming from tropical and sub-tropical geographic areas (TRO, n=233). Since Ascaris is the human parasite most closely related to Anisakis, specific IgE to Ascaris was also determined to assess Anisakis cross-reaction with other nematodes and the diagnostic value of Anisakis/Ascaris IgE ratio for Anisakis allergy was examined. IMM and TRO groups showed similar specific IgE to Anisakis levels, while TRO had higher levels of specific IgE to Ascaris than IMM group (p=0.001). ROC curve analysis determined that an Anisakis specific IgE threshold of 0.71 kU/L yielded 93% and 82% specificities in IMM and TRO groups, respectively. A cut-off value ≥4.4 for Anisakis/Ascaris IgE ratio increased specificity to 95% for samples having IgE to Ascaris ≥0.35. In conclusion, the ratio of specific IgE to Anisakis and Ascaris improved remarkably the specificity and this parameter easily obtained from the commercially available system could be useful in the diagnosis of hypersensitivity to A. simplex.

[Skin reactions on exposure to the pine processionary caterpillar (Thaumetopoea pityocampa)]

The pine processionary caterpillar is the larval form of the Thaumetopoea pityocampa moth. Mediterranean forests regularly suffer plagues of this insect, which has been moving north as a result of global warming. When the small urticating hairs that develop during the last 3 larval stages are shed and can become airborne. If they come in contact with skin, they can cause a variety of reactions, notably contact urticaria and papular rashes. Irritation can also occur if the hairs lodge in the mucosa of the conjunctiva or in the respiratory tract. Several cases of anaphylactic reactions have been reported in recent years. Mechanical (irritative) mechanisms may be involved in the pathogenesis of lesions, or immunoglobulin E-mediated allergic hypersensitivity reactions may be implicated when the process is rapid, recurrent, and progressively more severe.

Contact angioedema and rhinoconjunctivitis caused by Dendrobaena species and Sarcophaga carnaria used as fishing bait

The flesh fly Sarcophaga carnaria is commonly used as fishing bait. Immunoglobulin (Ig) E-mediated reactions caused by the handling of this bait have been reported. The earthworm Dendrobaena species is increasingly being used as fishing bait but there have been no reported cases of allergy to this species to date. We studied a 26-year-old amateur angler who presented rhinoconjunctivitis, urticaria, and angioedema on handling S carnaria. He started to use Dendrobaena species instead but developed the same symptoms. The aim of this study was to identify the allergens involved in the patient's clinical reactions. The study was performed using immunoglobulin (Ig) E immunoblotting and immunoblotting inhibition assays.The patient's serum detected allergens from Dendrobaena species (of an apparent molecular weight of approximately 150, 60, 37, 24, 21 and 19 kDa) and S. carnaria (approximately 70 kDa and a smear ranging from 50 to 40 kDa). The patient was diagnosed with allergy to both Dendrobaena species and 5 carnaria. This is the first case describing Dendrobaena species as an allergic agent.

Different Th1/Th2 responses to Anisakis simplex are related to distinct clinical manifestations in sensitized patients

Anisakis simplex is a fish parasite capable of inducing inflammatory and allergic reactions in humans who eat raw or undercooked fish. The aim of this study was to characterize the T helper type 1 (Th1)/Th2 immune response to parasite crude (CE) and thermostable (TsE) extracts in A. simplex-sensitized patients. Cytokines were quantified by a multiplex flow cytometric method in short-term whole blood cultures. Higher concentrations of IL-2, IL-4 and IL-5, measured with the CE and TsE, were found in patients than in controls. Patients showing urticaria-angio-oedema or anaphylaxis (UA/A) had higher total and specific IgE levels than those with gastrointestinal symptoms (GI). The UA/A group showed high levels of IL-5 and IL-4 and low expression of IFN-gamma than the GI group. The GI group had significantly higher IFN-gamma/IL4 ratio than the UA/A group. Four patients with severe GI symptoms reporting a delayed skin test reaction had very low values of specific IgE to A. simplex and higher IFN-gamma/IL4 ratios than that observed in other patients belonging to the GI group. This short-term whole blood test can be useful for immune response characterization in Anisakis infection and showed that heated parasite antigens are still capable of inducing cellular immune response in sensitized patients.

Multiple acute parasitization by Anisakis simplex

Hypersensitivity to Anisakis is an increasingly prominent medical problem throughout the world, due to a better understanding of diseases induced by parasites and to modern culinary habits of eating raw or undercooked fish. We describe the case of a patient who presented epigastric pain, wheals, erythema, and pruritus 3 hours after the ingestion of fish. More than 200 larvae were obtained by endoscopy. However, the patient only developed an immune response with specific immunoglobulin E and eosinophilia peaking at day 18 and decreasing during the 17-month follow-up. Only eosinophilia reached normal limits.

Anisakis Simplex Antigens in Fresh and Frozen-thawed Muscle of Anchovies in Vinegar

Marinated fish treatment using low pH to enlarge the storage life of fish as in anchovies in vinegar, does not kill Anisakis simplex larvae infesting fish muscle. To kill the larvae it is compulsory in many countries to freeze fish intended to be marinated raw, which prevents the consumer to be infested with the live larvae. However, it is not known if A. simplex antigens are released to the media after freezing and vinegar processing, which may cause allergic reaction to A. simplex sensitized consumers. Anchovy fillets were artificially infested with A. simplex L3, treated with a vinegar solution and chilled stored for 10 days. Infested frozen-thawed fillets were treated and stored in the same conditions. Viability of the larvae, SEM, immunoblotting and immunohistochemistry were performed on the treated fillets before and after pepsin treatment. Viability of the larvae was detected only in the chilled fillets; however, A. simplex antigens were detected in the chilled and in the frozen-thawed fillets even after pepsin treatment. This suggests that the consumption of anchovies in vinegar may be a potential hazard when ingested by sensitized consumers, even if freezing kills the larvae.

Selective allergy to lobster in a case of primary sensitization to house dust mites

Allergy to only 1 kind of seafood is uncommon. We report a case of selective allergy to lobster. We studied a 30-year-old man who suffered generalized urticaria, facial erythema, and pharyngeal pruritus after eating lobster. He had a more than 10-year history of mild persistent asthma and sensitization to house dust mites. The study was performed by skin prick test, and prick-prick test, oral food challenge, specific immunoglobulin (Ig) E determinations by CAP (Phadia, Uppsala, Sweden) and ADVIA-Centaur (ALK-Abelló, Madrid, Spain), and IgE-immunoblotting. The patient's serum recognized 2 allergens of around 198 kDa and 2 allergens of around 65 kDa from the lobster extract, allergens of around 15, 90, and 120 kDa from Dermatophagoides pteronyssinus extract, and allergens of around 15 and 65 kDa from Dermatophagoides farinae extract. Serum did not recognize purified shrimp tropomyosin. Immunoblot-inhibition assay results indicated cross-reactivity between lobster and mite allergens. This is the first report of selective allergy to lobster.

Lettuce-induced anaphylaxis. Identification of the allergen involved

BACKGROUND

Only 2 allergenic proteins have been described in lettuce allergy: a 16-kDa protein (putative profilin) and a lipid transfer protein (LTP) named Lac s 1.

OBJECTIVE

Our aim was to identify the allergens involved in the anaphylactic reactions of 2 patients who had eaten lettuce.

METHODS

The study was performed by Ig (immunoglobulin)-E immunodetection and immunodetection-inhibition assays.

RESULTS

Both patients' sera showed specific IgE binding to a single protein from the crude lettuce extract (apparent molecular weight of 14 kDa). To characterize the allergen detected, the lettuce extract underwent proteolytic digestion and heat treatment and was highly resistant to both. The patients' sera also recognized the major peach allergen Pru p 3 by immunodetection. When the lettuce allergen was incubated with both Pru p 3 from peach peel and recombinant Pru p 3, the immunodetection-inhibition assay indicated that patients were sensitized to the lettuce LTP Lac s 1.

CONCLUSIONS

The allergen involved in the lettuce-induced anaphylaxis of our patients was the LTP Lac s 1.

Sensitization to serum albumins in children allergic to cow's milk and epithelia

Patients with persistent milk allergy and specific immunoglobulin E (IgE) to bovine serum albumin (BSA) have a greater risk of rhinoconjunctivitis and asthma because of animal dander. To prove the cross-reactivity between serum albumin (SA) of different mammals in milk, meat, and epithelia and determine if heat treatment of meats decrease the allergenicity of albumins. The study was performed using SDS-PAGE and IgE-immunoblotting using sera from eight patients sensitized to milk, BSA, and animal danders. Sera from non-allergic and only animal dander allergic subjects served as a control. With one exception, all patients' sera recognized SA in different meats (beef, lamb, deer, and pork), epithelia (dog, cat, and cow), and cow's milk. Some patients even were only sensitized to SA in meat and epithelia. Danders' allergic only recognized other proteins in epithelia but not SA. No patients reacted to SA from heated meat extracts. Serum albumin is an important allergen involved in milk, meat, and epithelia allergy. The first contact with SA was through cow's milk and patients developed sensitization to epithelia SA even without direct contact with animals. Patients with both BSA and cow's milk allergy must avoid raw meats and furry pets.

Unsuspected Lupin Allergens Hidden in Food

BACKGROUND

Lupin is a herbaceous plant from the legume family whose seed allergens usually have cross-reaction with peanut. Lupin flour is used in human nutrition because of its high nutritional and functional qualities.

AIMS

The aim of this work was to detect non-specified lupin proteins contained in several manufactured foods.

METHODS

Serum from a patient suffering anaphylactic episodes after ingestion of a certain brand of cookies and with oral allergy syndrome after eating chicken bouillon was used as a tracer. Lupin seeds and commercial food extracts were analyzed by SDS-PAGE, immunoblotting and immunoblotting inhibition. Lupin extract allergenicity after thermal processing was also analyzed.

RESULTS

A lupin allergen with a molecular weight close to 14 kDa was detected in extracts from cookies, a chicken bouillon cube and a chicken dehydrated soup.

CONCLUSIONS

The presence of unsuspected, hidden non-specified lupin sources in food labeling was demonstrated. According to the results of this study, it is important for food-allergic patients that food labels should declare all the components irrespective of their quantity.

Seropositivity to a major allergen of Anisakis simplex, Ani s 1, in dyspeptic patients with Helicobacter pylori infection: histological and laboratory findings and clinical significance

Previous studies have demonstrated a high prevalence of seropositivity to the Ani s 1 protein in dyspeptic patients with Helicobacter pylori infection, but it is not known whether this represents episodes of anisakiasis misdiagnosis or previous exposure to the parasite without clinical relevance. To investigate the clinical significance of seropositivity to the Ani s 1 protein, a cohort study was performed with 87 consecutive dyspeptic patients who were treated for H. pylori infection. Fourteen (16.5%) patients were seropositive for the Ani s 1 protein, which was associated with the consumption of uncooked fish (p 0.0002). There were no differences in histological findings between subjects seropositive or seronegative for Ani s 1, but seropositive patients had increased eosinophil and basophil leukocyte counts (p < 0.05). Anti-Ani s 1 IgE was associated with a lack of improvement in the group of patients with non-ulcer dyspepsia after successful eradication of H. pylori (p 0.016). Thus, in at least a subset of patients with H. pylori infection, seropositivity to Ani s 1 could have clinical relevance. In addition, these data highlight that only anisakiasis associated with severe allergic or gastric symptoms is currently being diagnosed.

IgE binding to pepsin-digested water soluble and insoluble wheat proteins

BACKGROUND

Positive skin prick tests to wheat are a common finding among atopic patients, but only a minor fraction of these patients show immediate clinical symptoms after wheat ingestion. The aim of this study was to evaluate the allergenicity of wheat proteins after pepsin treatments.

METHODS

Six patients with positive specific IgE and/or skin prick test to soluble wheat proteins and to gluten were studied. Five of them had no symptoms after wheat ingestion and showed a negative oral challenge test. All sera were analysed with extracts obtained after pepsin hydrolysis during different time periods of water-soluble and insoluble wheat proteins by IgE immunoblotting.

RESULTS

A pepsin-sensitive allergen of around 35 kDa was recognized by the five atopic negative wheat oral challenge patients in the undigested water-insoluble extract. A patient showing immediate urticaria after wheat ingestion detected a pepsin-resistant allergen with similar molecular weight. Finally, an inhalation-induced asthma patient recognized water-soluble proteins (of around 14 kDa) that could correspond to the alpha-amylase inhibitors.

CONCLUSIONS

Our immunoblotting method shows better correlation with the clinical symptoms than skin prick test and CAP results. Pepsin resistance of the acetic acid-soluble wheat proteins may be responsible for the immediate symptoms of the patient who presented immediate urticaria.

Isolation and characterization of a heat-resistant beef allergen: myoglobin

BACKGROUND

Meat allergy is rarely reported. Most of the described cases are sensitizations to bovine serum albumin.

OBJECTIVE

The aim of the study was to describe a case of allergy to a new meat allergen and, after its characterization.

METHODS

A 35-year-old nonatopic female with allergic episodes after ingestion of several types of meat was studied. Skin tests (prick and prick-to-prick); total and specific immunoglobulin E (IgE) determination; sodium dodecyl sulphate-polyacrylamide gel electrophoresis and specific IgE determination by immunoblotting under different conditions were performed. A 17-kDa allergen was semipurified by ethanol fractionation and its amino-terminal sequence was determined. The existence of specific IgE directed to this protein was studied by immunoblot in 80 atopic patients.

RESULTS

The patient showed specific IgE antibodies to a 17-kDa protein. During the isolation of this allergen it was found that a 70-90% (vol/vol) ethanol concentration was able to purify the protein. The characterization revealed that it was a heat-resistant protein without disulfide bonds. N-terminal amino acid sequence (16 residues) showed identity with myoglobin. The study of specific IgE to this allergen among atopic patients showed that it was recognized by about 1% of the subjects.

CONCLUSIONS

We describe a case of meat allergy caused by myoglobin. This is the first described case of monosensitization to this protein.

Cutaneous reactions to pine processionary caterpillar (Thaumetopoea pityocampa) in pediatric population

Cutaneous lesions caused by pine processionary caterpillar (Thaumetopoea pityocampa, TP) are frequent in pinewood areas. However, no epidemiological studies have been performed so far in the pediatric population. In this study, we evaluated the relevance of reactions to pine processionary caterpillar in the pediatric population of our environment and determined the possible role of an IgE-mediated mechanism. A questionnaire was developed and given to 1,101 children and adolescents ranging from 3 to 17 years of age from rural areas with large pine forests. A total of 653 questionnaires were answered by the children or their parents. The search for immunoglobulin E (IgE)-mediated cases was based on the presence of a suspected reaction to caterpillar and confirmed by in vivo (skin prick) and in vitro (immunoblotting) tests. Sixty of the 653 people interviewed (9.18%) identified a cutaneous reaction from exposure to the processionary caterpillar. Within this group only four cases (6.7%) were because of an IgE-mediated mechanism. The predominant clinical feature of these patients with allergy to caterpillar was contact urticaria. We present the first study of cutaneous reactions to pine processionary caterpillar in a large pediatric population. This is a frequent pathology in pinery zones and only in a minority of the cases are because of an IgE-mediated allergic mechanism. This fact contrasts with studies in adults, where this percentage is much greater.

Ultrastructural localization of Ani s 1, a major allergen from the fish parasite Anisakis simplex

No data about the nature or function of the first major Anisakis simplex allergen, named Ani s 1, is available. The aim of this study was to investigate the ultrastructural localization of this protein, to obtain further information about it. Ani s 1 was detected in secretory granules of the excretory gland and occasionally lining the main excretory canal. Our results suggest that Ani s 1 could be a secretory product and could have an enzymatic function related to mechanisms of infection.

Isolation and characterization of Tha p 1, a major allergen from the pine processionary caterpillar Thaumetopoea pityocampa

BACKGROUND

Pine processionary caterpillars induce dermatitis by a toxic-irritative mechanism. The existence of true allergic reactions to allergens from these caterpillars has been recently demonstrated by positive immediate skin prick tests and specific IgE determination by immunoblotting using crude larval extracts. The aim of this work was to purify allergens from the crude larval extract in order to characterize IgE-binding proteins from these caterpillars.

METHODS

Allergens were separated by ethanol gradient fractionation and reversed phase HPLC. The N-terminal amino acid sequence of a selected allergen was obtained after SDS-PAGE and transfer. The clinical relevance of this allergen was measured using sera from patients allergic to caterpillar.

RESULTS

An allergen with a molecular weight close to 15 kDa was purified. It was recognized by 9 out of 11 allergic patients (82%). Its N-terminal amino acid sequence had no homologies to any other protein already described in data bases. For this reason, no information about its biological function could be obtained.

CONCLUSIONS

This 15-kDa IgE-binding protein is a major caterpillar allergen and shows no homologies to other insect allergens already described.

Pine processionary caterpillar allergenicity increases during larval development

BACKGROUND

In European countries, pine processionary caterpillar (Thaumetopoea pityocampa) is one of the species of Lepidoptera able to affect humans. Its allergenicity has been demonstrated in previous studies. However, in all of them larval extract in the fifth stage of development has been used as antigen. Therefore, allergenicity of other larval stages was unknown. The objective of our study was to detect allergenic changes of pine processionary caterpillar during larval development.

METHODS

Pine processionary caterpillar extracts in all larval stages were analyzed by SDS-PAGE. Immunoblotting was performed using patient sera with suggestive history of allergy and a positive prick test.

Pine processionary caterpillar as a new cause of immunologic contact urticaria

Nowadays, caterpillars are included among the agents that elicit contact urticaria by a non-immunologic mechanism. Our objective was to find the rôle that an IgE-mediated mechanism could have among patients with suspected contact urticaria from pine processionary caterpillars. 16 patients with suspected contact urticaria from this caterpillar were studied by prick testing and specific IgE detection by immunoblotting. 87% of the patients had a positive prick test and immunoblotting for caterpillar extract. In these allergic patients, the symptoms associated with urticaria were: angioedema (79%), conjunctivitis (36%) and severe anaphylaxis (14%). The most frequent localizations of the wheals were the neck (100%) and forearms (93%). Angioedema was more frequent on the eyelids (79%). The IgE-immunoblot detected in the caterpillar extract several reactive bands, with apparent MWs from to 45 to 4kDa. A total of 5 major allergens were identified, but a band around 14kDa proved to be the dominant allergen. Sensitization to Thaumetopoea pityocampa was found to be the most important mechanism of airborne contact urticaria from this caterpillar. Low-MW proteins are the main IgE binding components of crude caterpillar extract.

Isolation and characterization of a major allergen from the fish parasite Anisakis simplex

BACKGROUND

Ingestion of raw or undercooked fish can lead to infection of human subjects by the fish parasite Anisakis simplex, a disease known as anisakiasis or anisakidosis. Patients sensitized to this fish parasite show high levels of total and specific IgE. Cross-reactions seem to explain the fact that specific IgE antibodies are also found in a high number of normal subjects, as reported in other parasitoses.

OBJECTIVE

We sought to purify and characterize a major IgE-binding protein from the parasite.

METHODS

A protein was purified from the crude parasite extract by means of ethanol precipitation and reversed-phase HPLC. Its clinical relevance was tested on 20 parasite-positive sera by using IgE and IgG4 immunoblotting. A monospecific human serum was used to study its localization in the parasite body.

RESULTS

A 24-kd protein was purified, to which only 45% of the sera had specific IgG4, but 85% of sera had specific IgE. The protein was present only in the excretory gland, as shown by immunohistochemistry. N-terminal amino acid sequence (17 residues) showed no homology to previously described proteins.

CONCLUSION

A simplex contains a potent allergen in the excretory gland. This major parasite allergen, named Ani s 1, could have important clinical relevance, as shown by the high number of positive sera in the specific IgE immunoblotting.

Identification of allergens involved in occupational asthma due to carmine dye

BACKGROUND

Carmine has been implicated as an etiologic agent of occupational asthma, but the allergens involved have not been yet identified.

OBJECTIVE

To identify the allergens involved in occupational asthma due to carmine dye.

METHODS

An in vitro study based in SDS-PAGE and IgE immunoblotting with carmine and cochineal extracts was performed. Sera from three carmine dye workers diagnosed with occupational asthma induced by carmine dye and from seven nonatopic subjects were used.

RESULTS

Three proteins of around 30, 28, and 17 kD in raw cochineal extract and another protein of 50 kD in the boiled one were demonstrated by SDS-PAGE. Two proteins of around 50 and 28 kD were observed in the carmine extract by the same technique. Specific IgE binding bands at 17 kD in cochineal raw extract, at 50 kD in the boiled one, and at 28 kD in carmine extract were demonstrated by IgE immunoblotting.

CONCLUSIONS

We have identified three allergens of around 17, 28, and 50 kD implicated in occupational asthma of three carmine workers.

Allergy to Anacardiaceae: description of cashew and pistachio nut allergens

Some members of the Anacardiaceae family, such as cashew nut, pistachio nut and mango, have been reported to cause immediate allergic reactions. We report three cases of anaphylaxis to cashew nuts. With the aim of describing the allergens existing in cashew and pistachio nuts, patients were prick tested with cashew and pistachio extracts. Specific IgE against both nuts was studied by CAP and SDS-PAGE/immunoblotting. It was found that skin tests and specific IgE to cashew and pistachio nuts were positive in the three patients. Both nuts showed several protein bands in SDS-PAGE. The strongest IgE-binding bands had similar molecular weights (15, 30 and 60 kDa) in cashew and pistachio nuts. These main bands were found to be sensitive to reducing agents. It was concluded that these three patients suffered immediate reactions to cashew nut due to an IgE-mediated mechanism.

Anisakis simplex: a cause of intestinal pseudo-obstruction

OBJECTIVE

the ingestion of Anisakis simplex larvae may lead to the appearance of gastrointestinal symptoms. However, the number of reported cases of parasitization by Anisakis in Spain is lower than would be expected in a country with the second-highest fish consumption per inhabitant in the world, particularly since fish is often eaten raw or only slightly cooked. We suggest that the incidence of anisakiasis in Spain would be higher if complementary studies were used in all patients suspected of having anisakiasis.

METHODS

we studied 6 patients with a diagnosis of intestinal obstruction who frequently ate fish. Skin prick tests with seafood, inhalant allergen and Anisakis extracts were done. Total and specific IgE against Anisakis larvae were tested with a CAP system radioimmunoassay and immunoblot assays. Oral challenge tests with frozen larvae were also used.

RESULTS

a positive skin prick result and high levels of total and specific IgE were found in all patients. The results of immunoblot assays for IgE did not show a consistent pattern, but a group of several low (14-18 kDa) and intermediate molecular weight antigens (30-50 kDa) were found in all patients. All patients tolerated the oral challenge test well.

CONCLUSIONS

in our patients with intestinal pseudo-obstruction and a history of frequent fish eating, the clinical and laboratory findings were suggestive of parasitization by Anisakis simplex larvae as the cause of the obstruction. Such complementary studies should be used whenever there is a suspicion of anisakiasis. The results of the oral provocation test show that the intake of dead larvae does not induce clinical parasitization.

A 17-kDa allergen detected in pine nuts

BACKGROUND

Few cases of allergy to pine nuts have been described. We report a case of anaphylactic reaction to pine nuts. The patient needed to be treated in the emergency room due to a systemic reaction immediately after eating pine nuts.

METHODS

The patient was studied by prick tests and prick by prick tests. Specific IgE was measured by CAP and by SDS-PAGE/immunoblotting by a diffusion method.

RESULTS

The patient showed positive prick by prick tests to pine nuts (12 mm of maximum wheal diameter). Specific IgE was positive (0.79 kU/l). The patient's serum recognized several proteins by immunoblot. However, a 17-kDa allergen band was detected with high intensity. This protein was found to be sensitive to reducing agents, losing its IgE-binding properties after reduction.

CONCLUSIONS

The patient presented an IgE-mediated reaction and detected a 17-kDa protein from pine nuts not previously described.

Allergy to the pine processionary caterpillar (Thaumetopoea pityocampa)

BACKGROUND

The contact with the pine processionary caterpillar (Thaumetopoea pityocampa) induces dermatitis and ocular lesions by a mechanic and toxic mechanism. However, IgE-mediated hypersensitivity to this caterpillar has been demonstrated in two recent studies.

OBJECTIVE

To find if an IgE-mediated mechanism was operative among patients with suspected previous reactions to processionary caterpillars, particularly exposed workers.

METHODS

Fifty-five patients were studied by skin prick test (SPT), and specific IgE detection by immunoblotting.

RESULTS

A total of 58.18% patients had a positive SPT for caterpillar extract. Positive SPT patients had more generalized cutaneous reactions (47%) and oedema (50%) as well as a shorter latency period (mean, 36 min) and duration of cutaneous lesions (mean, 26 h) than the patients with negative SPT. A total of 60% of the positive SPT patients had occupational exposure to the processionary caterpillar. The occupationally exposed workers showed significant symptoms from October to December. The anaphylactic reactions only appeared in allergic patients with occupational exposure and were also more frequent from October to December. These patients with anaphylactic reactions had a major size of SPT and the exercise was found in them to be a variable that increased the symptoms. The IgE immunoblot detected in the caterpillar extract several reactive bands with apparent molecular weights from to 35-4 kDa in 72% of the cases with positive SPT.

CONCLUSIONS

Allergic reactions to T. pityocampa urticating hairs have different clinical characteristics than those induced by a toxic-irritative mechanism and are more frequent than suspected. Allergic reactions to this caterpillar among occasional visitors to pine-wood areas, and particularly in pine-forest workers, should be taken into consideration by allergists.

Lack of crossreaction with Bet v 1 in patients sensitized to Dau c 1, a carrot allergen

BACKGROUND

Pollen-related food allergies to fresh fruit and vegetables are a well-known clinical phenomenon. Allergens related to Bet v 1 are responsible for these cross-reactions.

OBJECTIVE

To characterize the allergen recognized by four carrot-allergic patients.

METHODS

Sera from four patients showing strong immediate systemic reactions after contact or ingestion of raw carrot were studied by immunoblotting. The 18-kD allergen, named Dau c 1, was isolated by ethanol precipitation and specific extraction after SDS-PAGE and its N-terminal amino acid sequence was determined.

RESULTS

All the patients had significant levels of specific IgE to carrot, but no specific IgE to birch pollen was detected in any of them. IgE immunodetection with the sera only recognized a single band of around 18 kD in raw carrot and in celery (with weaker reaction). No reactive band was found with birch pollen. These results were confirmed using a polyclonal anti-carrot antiserum. The carrot IgE-binding protein had a pl of 4.2 and its N-terminal sequence was homologous to that of Bet v 1 and to allergens previously described in celery and other foods. The four patients studied were not sensitized to birch pollen and three of them tolerated fruit ingestion.

CONCLUSION

The whole study indicated that a sensitization to Dau c 1 induces IgE antibodies that do not cross-react with birch pollen allergens.

Induction of histamine release in parasitized individuals by somatic and cuticular antigens from Onchocerca volvulus

The host immune response in onchocerciasis is believed to contribute to the clinical manifestations of infection. Mazzotti and chronic inflammatory reactions might be mediated by mechanisms involving specific IgE and reactivity of mast cells and basophils to the parasite antigens. In this report, we show that Onchocerca volvulus antigens are capable of inducing histamine release. Three types of extracts were prepared from the parasite: soluble total, surface, and cuticular collagen. Soluble extracts released histamine in all individuals with onchocerciasis at significantly higher levels (P < 0.05) than those found in endemic controls, but similar levels to those found in patients with mansonellosis. However, cuticular collagen induced significantly (P < 0.01) higher histamine release in patients with onchocerciasis than in those with mansonellosis. No reactivity against human type IV collagen was observed. Implications derived from the presence of sensitized basophils in the pathogenesis of onchocerciasis are discussed.

Anaphylactic reaction to young garlic

BACKGROUND

Garlic is well known to cause contact dermatitis and asthma. However, it is a very rare cause of food allergy. We present the case of a 23-year-old woman with previous history of allergy to pollen and dried fruit, and food-dependent, exercise-induced anaphylaxis for which no specific food could be identified as responsible, who experienced an anaphylactic reaction after eating young garlic.

METHODS

Skin prick tests and specific IgE immunoassay with several pollens and foods were performed, as well as the prick-prick test with young garlic and SDS-PAGE followed by immunoblotting IgE to young garlic and other Liliaceae species, mustard, sesame, parsley, celery, hazelnut, almond, and pollen of birch and mugwort.

RESULTS

Skin prick tests and specific IgE were mainly positive for grass, plane tree, and mugwort pollen; peanut; hazelnut; walnut; almond; and mustard. Prick-prick tests with young garlic and garlic were positive. Total IgE was 113 U/ml. SDS-PAGE immunoblotting showed IgE-binding bands at 12 kDa to young garlic, garlic, onion, and leek extracts. Similar bands could also be detected with mugwort pollen and hazelnut extract.

CONCLUSIONS

We describe IgE-mediated reaction to young garlic in a patient sensitized to pollen and dried fruit.

Cereal alpha-amylase inhibitors cause occupational sensitization in the wood industry

BACKGROUND

Cereal flours are used in the wood industry to improve the quality of the glues necessary to produce veneer panels. However, up to now, no cases of sensitization to cereal flour in this kind of industry have been reported. Cereal alpha-amylase inhibitors have been previously described as important occupational allergens responsible for baker's asthma.

OBJECTIVE

To determine whether cereal allergens were responsible for occupational sensitization in three wood industry workers.

METHODS

The diagnosis was made by clinical questionnaire, physical examination, skin-prick tests to cereals, CAP and immunoblotting.

RESULTS

The three patients had positive skin prick tests and CAP to cereal flours. An IgE-immunoblotting revealed that only low molecular weight proteins (under 20 kDa) were detected by the three sera. These main IgE-binding proteins were members of the alpha-amylase inhibitor family which have been described as one of the group of main allergenic proteins in rye, barley and wheat. The three patients changed their workplace and remain asymptomatic in spite of the fact that they are still in contact with different woods and exposed to high concentrations of wood dust and other chemicals such as formaldehyde.

CONCLUSION

Proteins from cereal flours are important occupational allergens in some wood industries.

Occupational asthma and food allergy due to carmine

Carmine (E120), a natural red dye extracted from the dried females of the insect Dactylopius coccus var. Costa (cochineal), has been reported to cause hypersensitivity reactions. We report a case of occupational asthma and food allergy due to carmine in a worker not engaged in dye manufacturing. A 35-year-old nonatopic man, who had worked for 4 years in a spice warehouse, reported asthma and rhinoconjunctivitis for 5 months, related to carmine handling in his work. Two weeks before the visit, he reported one similar episode after the ingestion of a red-colored sweet containing carmine. Peak flow showed drops higher than 25% related to carmine exposure. Prick tests with the cochineal insect and carmine were positive, but negative to common aeroallergens, several mites, foods, and spices. The methacholine test was positive. Specific bronchial challenge test with a cochineal extract was positive with a dual pattern (20% and 24% fall in FEV1). Double-blind oral challenge with E120 was positive. The patient's sera contained specific IgE for various high-molecular-weight proteins from the cochineal extract, as shown by immunoblotting. Carmine proteins can induce IgE-mediated food allergy and occupational asthma in workers using products where its presence could be easily overlooked, as well as in dye manufacture workers.

[Eosinophilic gastroenteritis caused by bee pollen sensitization]

A 34-year-old Spanish woman with a lifelong history of seasonal rhinoconjunctivitis and honey intolerance (pyrosis and abdominal pain) developed, 3 weeks after starting ingestion of bee pollen, astenia, anorexia, abdominal pain, diarrhoea, peripheral blood hypereosinophilia and elevated serum total IgE levels. A duodenal biopsy showed eosinophilic infiltration of the mucosal layer. Other causes of hypereosinophilia were not found. Repeated parasitological stool studies, as well as a duodenal aspirate showed negative results. Symptoms, hypereosinophilia and elevated IgE levels resolved after bee pollen ingestion was stopped. This is a typical case of eosinophilic gastroenteritis by ingestion of bee pollen in a woman with intolerance to honey bee, because the patient fulfilled the usual diagnostic criteria: gastrointestinal symptoms were present, eosinophilic infiltration of the digestive tract was demonstrated by biopsy, no eosinophilic infiltration of other organs was found and the presence of parasites was excluded. Honey intolerance and/or bee pollen administration should be considered as a cause of eosinophilic gastroenteritis.

Periodate treatment of Anisakis simplex allergens

Anaphylactic reactions after parasitized fish consumption are mediated by an IgE response. However, positive skin tests and specific IgE can also be found in many asymptomatic subjects who recognize a single medium-mol.-wt. antigen by IgE immunoblot. The study aimed to find out whether this unspecificity was due to the carbohydrate moieties of parasite antigens. Sixty-two patients with suspected parasite allergy, 51 blood donors, 18 bakers, and 38 atopic patients were studied by blotting. Parasite proteins were treated with periodate. Several selected sera were inhibited with a crude wheat extract and fungal amylase. Twelve patients (19%), eight donors (16%), six bakers (33%), and one atopic patient (3%) recognized a single medium-mol.-wt. band in blotting and should be considered false-positive. This band was periodate-sensitive, but specific IgE to this allergen could not be inhibited by a wheat extract nor by fungal amylase and was clinically irrelevant. Diagnosis of Anisakis simplex hypersensitivity by skin tests and/ or specific IgE values should always be confirmed by specific IgE immunoblotting in order to detect the presence of clinically unrelated antibodies directed to periodate-sensitive allergens. These allergens are probably not a carbohydrate moiety of a parasite glycoprotein.

Anisakis simplex, a relevant etiologic factor in acute urticaria

Anisakis simplex, a parasite of fish and cephalopods, can induce IgE-mediated reactions. This study aimed to determine the etiologic role of A. simplex in patients affected by urticaria/angioedema (AE) or anaphylaxis. We studied 100 adult subjects suffering acute episodes of urticaria/AE, by anamnesis, prick tests with A. simplex and fish-mix extracts, and total and specific IgE to both A. simplex and cod. The following criteria of A. simplex allergy were considered: 1) urticaria/AE within 6 h after fish ingestion; 2) specific IgE to A. simplex; 3) positive prick test to A. simplex extract; 4) exclusion of other suspected causes. Double-blind, placebo-controlled food challenge was not carried out because ethical considerations forbid challenge with a parasite. Specific IgE to A. simplex (> 0.7 kU/l) was found in 22 subjects, but only eight were diagnosed as having A. simplex allergy. Other allergens were involved in 37 patients, and 55 cases were considered idiopathic. Specific IgE to fish (> 0.7 kU/l) was found in two patients, but only one was diagnosed as having fish allergy. We concluded that A. simplex is an important etiologic factor in acute urticaria. We suggest that it should be considered in cases of urticaria/AE or anaphylaxis, especially after fish ingestion.

The use of IgE immunoblotting as a diagnostic tool in Anisakis simplex allergy

BACKGROUND

The fish parasite Anisakis simplex is the etiologic agent of anisakiasis and induces IgE-mediated reactions. Skin prick tests (SPTs) and the measurement of specific IgE to A. simplex were, in our experience, not valid tools with which to discriminate between allergic and nonallergic patients because many control subjects also had positive results.

OBJECTIVE

The study was carried out to assess the usefulness of IgE immunoblotting in the diagnosis of allergy to A. simplex.

METHODS

We have studied 61 patients with acute symptoms of urticaria, angioedema, or anaphylaxis and positive specific IgE to A. simplex. According to the anamnesis, time interval between ingestion of fish and clinical onset of symptoms, and exclusion of other causes of allergy, three different groups of patients were established: group A (allergic), group NA (non-allergic), and group D (doubtful). Fifty-one healthy donors were included as control subjects (group C). IgE immunoblotting with A. simplex whole-body extract was performed in all patients and control subjects.

RESULTS

Four patterns of immunoblotting were observed: type 1, with a group of several bands of medium molecular weight and others of low molecular weight; type 2, two or more bands of medium molecular weight; type 3, only one band of medium molecular weight; type 4, without any band. There was a significant predominance of blotting type 1 in group A and type 4 in group C.

CONCLUSION

These data suggest that IgE immunoblotting is the most useful approach to A. simplex allergy diagnosis.

Hypersensitivity to carrot associated with specific IgE to grass and tree pollens

This study deals with a 34-year-old female cook with no previous history of atopy, who was studied because of allergic rhinoconjunctivitis and contact urticaria in both hands associated with severe itching when she handled raw carrot. The patient had had anaphylactic episodes after accidental ingestion of raw carrots, but she tolerated cooked carrots. Skin prick tests with carrot, celery, and olive, and birch, grass, and mugwort pollens were positive. Total IgE was 411 UI/ml. Specific IgE to olive, grass, and weed pollens were 10.92, 6.17, and 2.4 AU/ml, respectively. The histamine release test was positive for carrot, celery, celeriac, and olive pollen up to a dilution of 1/10(6). Immunoblot of raw carrot showed a single IgE-binding 18-kDa band. IgE reactivity for raw carrot immunoblot was completely inhibited by carrot and by celery, but not by olive or grass pollens. Specific IgE to olive pollen was not inhibited by carrot. The existence of monosensitization to an 18-kDa protein in carrot and specific IgE to olive pollen has not been reported in the celery-carrot-mugwort-spice syndrome.