Simplex Allergy Research Articles

Anisakis simplex: Immunomodulatory effects of larval antigens on the activation of Toll like Receptors

AimsThe objective of this investigation is to evaluate the mechanisms Anisakis simplex employs to modify its host immune system, regarding the larval antigens interactions with Toll-Like-Receptors (TLRs). Methods and ResultsIn a previous study, we described that the stimulation of bone marrow derived dendritic cells (BMDCs) with A. simplex larval antigens drive an acute inflammatory response in BALB/c mice, but a more discrete and longer response in C57BL/6J. Moreover, when A. simplex larval antigens were combined with TLR agonists (TLR 1/2–9), they modified mainly TLR2, TLR4 and TLR9 agonists responses in both mice strains, and also TLR3, TLR5 and TLR7 in BALB/c. Antigen-presenting ability was analyzed by the detection of CD11c + cells expressing surface markers (CD80-86, MHC I-II), intracellular cytokines (IL-10, IL-12, TNF-α) and intracellular proteins (Myd88, NF-κβ) by Flow Cytometry. Secreted IL-10 was measured by ELISA. ConclusionOur findings confirm not only that the host genetic basis plays a role in the development of a Th2/Th1/Treg response, but also it states A. simplex larval antigens present specific mechanisms to modify the innate response of the host. As allergies share common pathways with the immune response against this particular helminth, our results provide a better understanding into the specific mechanisms of A. simplex allergy related diseases.

ST上昇型心筋梗塞を疑われたアニサキスアレルギーによるKounis症候群の1例

ST上昇型心筋梗塞を疑われたアニサキスアレルギーによるKounis症候群の1例

Idiopathic anaphylaxis.

Idiopathic anaphylaxis (IA) or spontaneous anaphylaxis is a diagnosis of exclusion when no cause can be identified. The exact incidence and prevalence of IA are not known. The clinical manifestations of IA are similar to other known causes of anaphylaxis. A typical attack is usually acute in onset and can worsen over minutes to a few hours. The pathophysiology of IA has not yet been fully elucidated, although an IgE-mediated pathway by hitherto unidentified trigger/s might be the main underlying mechanism. Elevated concentrations of urinary histamine and its metabolite, methylimidazole acetic acid, plasma histamine and serum tryptase have been reported, consistent with mast cell activation. There is some evidence that corticosteroids reduce the frequency and severity of episodes of IA, consistent with a steroid-responsive condition. Important differential diagnoses of IA include galactose alpha-1,3 galactose (a carbohydrate contained in red meat) allergy, pigeon tick bite (Argax reflexus), wheat-dependent exercise-induced anaphylaxis, Anisakis simplex allergy and mast cell disorders. Other differential diagnoses include "allergy-mimics" such as asthma masquerading as anaphylaxis, undifferentiated somatoform disorder, panic attacks, globus hystericus, vocal cord dysfunction, scombroid poisoning, vasoactive amine intolerance, carcinoid syndrome and phaeochromocytoma. Acute treatment of IA is the same as for other forms of anaphylaxis. Long-term management is individualized and dictated by frequency and severity of symptoms and involves treatment with H1 and H2 receptor blockers, leukotriene receptor antagonist and consideration for prolonged reducing courses of oral corticosteroids. Patients should possess an epinephrine autoinjector with an anaphylaxis self-management plan. There are anecdotal reports regarding the use of omalizumab. For reasons that remain unclear, the prognosis of IA is generally favourable with appropriate treatment and patient education. If remission cannot be achieved, the diagnosis should be reconsidered.

High prevalence of Anisakis simplex hypersensitivity and allergy in Sicily, Italy

BackgroundAnisakis simplex can elicit allergic reactions when ingested in raw or marinated fish. The prevalence of A simplex hypersensitivity and allergy in Sicily (Italy), an area where the consumption of raw or marinated fish is very common, has not been investigated thus far. ObjectiveTo investigate the prevalence of A simplex sensitization and its clinical relevance in a large group of unselected patients. MethodsAll consecutive patients referred to the authors' allergy clinic during a 22 month-period were included in the study, evaluated for sensitization to A simplex and other allergens depending on their clinical history, and investigated for allergic symptoms after the ingestion of raw or marinated fish. ResultsOf 3,419 patients screened, 527 (15.4%) were sensitized to A simplex and 29 of these (5.5% of sensitized patients) had a history of A simplex allergy. Approximately 30% of patients had mono-sensitization to A simplex. Co-sensitization to house dust mites or molds yielded an odds ratio of 1.98 or 3.18, respectively, for allergy to A simplex. ConclusionA high prevalence of A simplex sensitization in a large proportion of patients with mono-sensitization was found, confirming that eating habits influence sensitization to this nematode. Allergic symptoms from A simplex ingestion in raw or marinated fish were quite frequent, with symptoms ranging from oral allergy syndrome to anaphylaxis. Patients sensitized to A simplex were more prone to have allergic symptoms when they had co-sensitization to house dust mites or molds, suggesting possible cross-reactive but clinically relevant allergens between these allergenic sources.

Anisakis simplex Hypersensitivity Is Associated with Chronic Urticaria in Endemic Areas

Background: Chronic urticaria (CU) may affect up to 1% of the general population. Anisakis simplex hypersensitivity is frequent in areas where raw fish is consumed and A. simplex allergy represents a relevant cause of acute urticaria. We assessed the possible association between CU and A. simplex sensitization in an area where marinated fish is very frequently eaten. Methods: A thorough history of CU was sought in 919 adults seen at the Allergy Center, Bari. CU patients and 187 controls underwent skin-prick testing with a commercial extract of A. simplex, and reactors were recommended a 6-month raw-fish-free diet regimen. Responders were followed after a further 3 months. Results: Of 919 subjects, 213 (23%) met the criteria for CU and 106/213 (49.7%) were sensitized to A. simplex with a significant difference between patients aged >65 or <65 years (56 vs. 41%, respectively; p < 0.05). All patients hypersensitive to A. simplex were regular consumers of marinated fish. In a control population without CU, the prevalence of A. simplex sensitization was 16% (p < 0.001). The 6-month diet regimen led to the disappearance of urticaria in 82/106 cases (77%) versus 1/42 (2%) subjects who did not change their dietary habits (p < 0.001). All nonresponders were sensitized to house-dust mites. Of 75 responders who were followed-up after 3 months, CU relapsed in 88% of those who had reintroduced raw fish versus 14% of those who were still on the diet (p < 0.001). Conclusion: In areas where raw or marinated fish is frequently eaten, A. simplex hypersensitivity is a frequent cause of CU.

IgE Sensitization to the Fish Parasite Anisakis simplex in a Norwegian Population: A Pilot Study

The reports on fish parasite Anisakis simplex allergy have increased in countries with high fish consumption in the last decade. In Norway, a high consumption country, the prevalence of immunoglobulin E (IgE) sensitization to A. simplex was still unknown. Thus, our objective was to investigate the sensitization prevalence in this country. At the Haukeland University Hospital, Bergen, Norway, two main groups of surplus serum samples were collected: one from newly recruited blood donors (BDO) and the other from the Allergy laboratory (ALL) after analysing IgE and IgE antibodies. The latter was divided into three series: one containing unsorted sera and two sorted by either Phadiatop(®) ≥0.35 kU(A)/l or total IgE ≥1000 kU/l. The sera were analysed for total IgE and IgE antibodies against A. simplex, shrimp, house dust mite (HDM), cod and cross-reactive carbohydrates (CCDs). The prevalence of IgE sensitization to A. simplex was 2.0%, 2.2% and 6.6% in BDO, the unsorted and Phadiatop(®) positive serum groups, respectively. A considerable degree of cross-sensitization to shrimp and HDM is further suggested. Unspecific binding because of high total IgE or by binding to CCDs seemed to play a minor role. The prevalence of IgE sensitization to A. simplex appears to be lower in a Norwegian population than in other high fish-consuming countries, but might still be overestimated owing to cross-sensitization.

Anisakis simplex Recombinant Allergens Increase Diagnosis Specificity Preserving High Sensitivity

Background: So far, the frequency of Anisakis simplex-specific IgE antibodies has been determined by skin prick tests (SPTs) and the ImmunoCAP system. These commercial methods have good sensitivity, but their specificity is poor because they use complete parasite extracts. Our aim was to determine the frequency of sensitization to A. simplex using recombinant Ani s 1, Ani s 3, Ani s 5, Ani s 9 and Ani s 10 and to evaluate these allergens for diagnosis, comparing their performance with the commercial methods. Patients and Methods: We conducted a descriptive, cross-sectional validation study performed in an allergy outpatient hospital clinic. Patients without fish-related allergy (tolerant patients, n = 99), and A. simplex-allergic patients (n = 35) were studied by SPTs, ImmunoCAP assays and detection of specific IgE to A. simplex recombinant allergens by dot blotting. Results: SPTs and ImmunoCAP assays were positive in 18 and 17% of tolerant patients, respectively. All A. simplex-allergic patients had positive SPTs and ImmunoCAP assays. Specific IgE against at least one of the A. simplex recombinant allergens tested was detected in 15% of sera from tolerant patients and in 100% of sera from A. simplex-allergic patients. Detection of at least one A. simplex recombinant allergen by dot blotting and ImmunoCAP assay using complete extract showed a diagnostic sensitivity of 100% with both methods. However, the specificity of dot blotting with A. simplex recombinant allergens was higher compared with ImmunoCAP (84.85 vs. 82.83%). Conclusions: There are 15% of tolerant patients with specific IgE against important A. simplex allergens. The recombinant allergens studied here increase the specificity of A. simplex diagnosis while keeping the highest sensitivity. A. simplex recombinant allergens should be included with A. simplex allergy diagnostic tests to improve their specificity.

IgE sensitisation to the fish parasite Anisakis simplex in a Norwegian population . A pilot study

The reports on fish parasite Anisakis simplex allergy have increased in countries with high fish consumption in the last decade. In Norway, a high consumption country, the prevalence of immunoglobulin E (IgE) sensitization to A. simplex was still unknown. Thus, our objective was to investigate the sensitization prevalence in this country. At the Haukeland University Hospital, Bergen, Norway, two main groups of surplus serum samples were collected: one from newly recruited blood donors (BDO) and the other from the Allergy laboratory (ALL) after analysing IgE and IgE antibodies. The latter was divided into three series: one containing unsorted sera and two sorted by either Phadiatop®≥0.35 kUA/l or total IgE ≥1000 kU/l. The sera were analysed for total IgE and IgE antibodies against A. simplex, shrimp, house dust mite (HDM), cod and cross-reactive carbohydrates (CCDs). The prevalence of IgE sensitization to A. simplex was 2.0%, 2.2% and 6.6% in BDO, the unsorted and Phadiatop® positive serum groups, respectively. A considerable degree of cross-sensitization to shrimp and HDM is further suggested. Unspecific binding because of high total IgE or by binding to CCDs seemed to play a minor role. The prevalence of IgE sensitization to A. simplex appears to be lower in a Norwegian population than in other high fish-consuming countries, but might still be overestimated owing to cross-sensitization.

Ani s 10, a new Anisakis simplex allergen: Cloning and heterologous expression

Anisakiasis is a human disease caused by accidental ingestion of larval nematodes belonging to the Anisakidae family. Anisakiasis is often associated with a strong allergic response. Diagnosis of A. simplex allergy is currently carried out by test based on the IgE reactivity to a complete extract of L3 Anisakis larvae although the specificity of these diagnostic tests is poor. Improving the specificity of the diagnostic test is possible using purified recombinant allergens. A new Anisakis allergen, named Ani s 10, was detected by immunoscreening an expression cDNA library constructed from L3 Anisakis simplex larvae. The new allergen was overproduced in Escherichia coli; it is a protein of 212 amino acids and it was localized as a 22 kDa protein band in an ethanol fractionated extract from the parasite. Ani s 10 has no homology with any other described protein, and its sequence is composed by seven almost identical repetitions of 29 amino acids each. A total of 30 of 77 Anisakis allergic patients (39%) were positive both to rAni s 10 and natural Ani s 10 by immunoblotting. The new allergen could be useful in a component-resolved diagnosis system for Anisakis allergy.

Anisakis simplex: from obscure infectious worm to inducer of immune hypersensitivity.

Infection of humans with the nematode worm parasite Anisakis simplex was first described in the 1960s in association with the consumption of raw or undercooked fish. During the 1990s it was realized that even the ingestion of dead worms in food fish can cause severe hypersensitivity reactions, that these may be more prevalent than infection itself, and that this outcome could be associated with food preparations previously considered safe. Not only may allergic symptoms arise from infection by the parasites ("gastroallergic anisakiasis"), but true anaphylactic reactions can also occur following exposure to allergens from dead worms by food-borne, airborne, or skin contact routes. This review discusses A. simplex pathogenesis in humans, covering immune hypersensitivity reactions both in the context of a living infection and in terms of exposure to its allergens by other routes. Over the last 20 years, several studies have concentrated on A. simplex antigen characterization and innate as well as adaptive immune response to this parasite. Molecular characterization of Anisakis allergens and isolation of their encoding cDNAs is now an active field of research that should provide improved diagnostic tools in addition to tools with which to enhance our understanding of pathogenesis and controversial aspects of A. simplex allergy. We also discuss the potential relevance of parasite products such as allergens, proteinases, and proteinase inhibitors and the activation of basophils, eosinophils, and mast cells in the induction of A. simplex-related immune hypersensitivity states induced by exposure to the parasite, dead or alive.

Ani s 1, the major allergen of Anisakis simplex: Purification by affinity chromatography and functional expression in Escherichia coli

Third stage larvae of the nematode Anisakis simplex often infect marine fish and invertebrates. When the larvae are ingested orally via seafood, they can cause IgE-mediated allergic reactions as well as anisakiasis. Of the known A. simplex allergens, Ani s 1 (Kunitz/bovine pancreatic trypsin inhibitor family protein) has been demonstrated to be a major allergen, being expected to be a useful tool for diagnosis of A. simplex allergy. For a diagnostic purpose, sufficient amounts of either natural Ani s 1 (nAni s 1) or recombinant Ani s 1 (rAni s 1) with an IgE-binding capacity should be stably supplied whenever needed. In this study, therefore, we first developed a simple and rapid purification method for Ani s 1 that is based on affinity chromatography using anti-Ani s 1 antibodies as ligands. The method was shown to produce nAni s 1 with a higher yield than the previously reported methods. Then, an attempt was made to express rAni s 1 in Escherichia coli as a His-tagged protein. rAni s 1 obtained as an inclusion body was solubilized in a solvent containing denaturing and reducing reagents and purified by nickel-chelate chromatography. Refolding of rAni s 1 was accomplished by dialysis in the presence of arginine, followed by that in the absence of arginine. Fluorescence ELISA and inhibition ELISA data revealed that rAni s 1 is IgE reactive enough to be used as a diagnostic tool.

Anisakis simplex allergy and nephrotic syndrome

Background Anisakis simplex is a helmintic parasite of fish and shellfish that can induce in humans, after consumption, an immunoallergic response with multiorganic affectation, especially cutaneous (urticaria and angioedema), gastrointestinal and anaphylactic symptoms. Nephrotic syndrome can be produced by helmintic infection, especially schistosomiasis. Objective To report the unusual case of nephrotic syndrome associated to an allergic response to A. simplex. Methods A 60-year-old woman suffered from nephrotic syndrome three weeks after a generalized urticaria, angioedema and nauseas episode, following a raw anchovy's ingestion. Etiological study of nephrotic syndrome and urticaria/angioedema, cutaneous test, serum total and specific IgE determination, IgE-immunoblotting, and HLA typing were performed for diagnostic evaluation. Results Prick-test with A. simplex extract was positive. It was observed a significance increase of total IgE to the three weeks of anchovy's ingestion and then it diminished progressively. Specific IgE to A. simplex was > 100 UI/ml. Immunoblotting to A. simplex, revealed the existence of IgE-binding proteins with molecular mass ranging from 20 kDa to 99 kDa. Class I HLA expressed by the patient was type HLA-B12. Other secondary causes of nephrotic syndrome were carefully ruled out. Conclusions These data suggest, for the first time, the association between allergy to A. simplex and nephrotic syndrome.

Detection of Anisakis simplex‐induced basophil activation by flow cytometry

Laboratory diagnosis of anisakidosis is based on specific serum IgE detection. Recently, detection of allergen-induced basophil activation by flow cytometry has been proposed as a valuable tool for allergy diagnosis. To evaluate if detection of Anisakis-induced basophil activation by flow cytometry is a useful tool in the diagnosis of Anisakis allergy. Patients with Anisakis allergy (A.s.+, n = 37), patients reporting chronic urticaria or abdominal pain unrelated to fish ingestion (A.s.-, n = 51), and healthy controls (n = 12) were studied. Specific IgE to Anisakis simplex (A. simplex) was quantified with CAP-FEIA method, and basophil activation test was performed with three different concentrations of an Anisakis crude extract. Basophil gating was performed with CD123 and HLA-DR, and cellular activation was measured with CD63. A.s.+ patients showed significantly higher age and total IgE levels than did the A.s.- patients. Specific IgE to A. simplex correlated with the activated basophil percentages obtained with 15 microg/mL (r = 0.80; P < 0.001), 1.5 microg/mL (r = 0.84; P < 0.001), and 0.15 microg/mL (r = 0.82; P < 0.001) of A. simplex crude extract. Nine individuals (3 in the A.s.+ group and 6 in the A.s.- group) were nonresponders to basophil stimulation with anti-IgE. Five A.s.- patients showed positive IgE values to A. simplex while the basophil activation test was negative. According to the receiver operating characteristics curves performed between A.s.+ vs. A.s.- and A.s.+ vs. healthy controls, the cutoff for a positive basophil activation test was >or=21% (specificity = 96%, sensitivity = 100%), and 16% (sensitivity and specificity of 100%) respectively. When nonresponders were included in the A.s.+ vs. A.s.- analysis, sensitivity decreased to 95%. Multivariate logistic analysis showed that the specific basophil activation was a factor independently associated with clinical symptoms of A. simplex allergy. Detection of A. simplex-induced basophil activation by flow cytometry is a useful laboratory technique for the diagnosis of anisakidosis, supplementing specific IgE determinations.

Anisakis simplexallergy: a murine model of anaphylaxis induced by parasitic proteins displays a mixed Th1/Th2 pattern

The study of the singular hypersensitivity reactions to Anisakis simplex (A.s) proteins, may help us to undestand many of the unknown immune interactions between helmiths infections and allergy. We have developed a murine model of allergy to A. simplex, that mimics human A. simplex allergy to study the specific aspects of anaphylaxis induced by parasites. Male C3H/HeJ mice were intraperitoneally sensitized to A. simplex. Mice were then intravenous or orally challenged with A. simplex. Antigen-specific immunoglobulins, polyclonal IgE, anaphylactic symptoms, plasma histamine levels and cytokine profiles were determined. Comparative IgE immunoblot analyses were also performed. Specific IgE, IgG(1) and IgG(2a) were detected in sensitized mice since week 3. Polyclonal IgE raised and peaked with different kinetics. Intravenous A. simplex challenge produced anaphylaxis in mice, accompanied by plasma histamine release. Oral A. simplex challenge in similarly sensitized mice did not caused symptoms nor histamine release. Numerous A. simplex allergens were recognized by sensitized mouse sera, some of them similar to human serum. The A. simplex stimulated splenocytes released IL-10, IFN-gamma, IL-4, IL-13 and IL-5. We describe a new animal model of anaphylaxis. It exhibits characteristics of type I hypersensitivity reactions to Anisakis simplex similar to those observed in allergic humans. Different responses to i.v. or oral A. simplex challenges emerged, which did not reflect a window tolerization period. The cytokine profile developed (mixed Th(1)/Th(2) pattern) differed from the observed in classical models of anaphylaxis or allergy to food antigens. This model may permit to investigate the peculiar allergic reactions to parasitic proteins.

Specific IgE determination to Ani s 1, a major allergen from Anisakis simplex, is a useful tool for diagnosis

The most serious limitation of the serodiagnosis of parasitoses is the occurrence of cross-reactions. The possible use of Anisakis simplex major allergen Ani s 1 for diagnosis. Forty-nine non-fish-allergic patients with Anisakis simplex hypersensitivity, 21 patients without allergic episodes suffering intestinal anisakiasis with obstruction of the intestinal lumen, and 10 unrelated sera as a control were included in this study to determine specific immunoglobulin (Ig)E and IgG to Anisakis simplex major allergen Ani s 1 by immunoblotting. Eighty-six percent of patients with Anisakis simplex hypersensitivity showed specific IgE directed to Ani s 1. Identical result was obtained for IgG detection in this group. Among patients with intestinal anisakiasis, 86% showed specific IgE, but only 29% had specific IgG (P < 0.001, two-tailed Fisher exact test). One of the 10 control subjects was positive both for IgE and IgG (P < 0.001). Determination of specific IgE directed to Anisakis simplex major allergen Ani s 1 is a useful tool for the diagnosis of hypersensitivity and intestinal anisakiasis. Further, measurement of specific IgG directed to Anisakis simplex major allergen Ani s 1 is only valid for Anisakis simplex allergy.

Anisakis simplex-sensitized patients: should fish be excluded from their diet?

Anisakis simplex (A.s.) allergy is an emerging disease. The third-stage larvae of this nematode are a source of hidden allergens in fish. There are no clear guidelines concerning dietary restrictions for patients with serum-specific IgE to this parasite. To follow up the clinical data and immunological parameters of patients sensitized to A.s. during 6 to 23 months. The clinical symptoms and serologic status of 17 patients with specific IgE and positive skin prick test results to A.s. were studied prospectively. Six of these had anaphylaxis (ANA) attributed to A.s. and 11 patients experienced concomitant chronic urticaria (CU). All patients were advised not to eat fish for 6 months. Four patients from the ANA group excluded fish, and ANA did not recur. Two other patients with ANA refused to exclude fish; one remained free of symptoms and the other experienced several urticarial episodes. During this 6-month period total IgE levels decreased in all six ANA patients; specific IgE for A.s. decreased in four patients and increased in two. Two patients from the CU group did not exclude fish, and symptoms persisted in these two patients. Clinical improvement was observed in 78% of the patients with CU who excluded fish. Total and specific IgE levels decreased in all the patients with CU. Because ANA symptoms are very severe, patients should always be advised to exclude fish until specific food allergens are identified. However, in patients with CU and specific IgE to A.s., only the clinical response to fish ingestion will determine the need for strict fish avoidance.

O-glycans as a source of cross-reactivity in determinations of human serum antibodies to Anisakis simplex antigens.

Anisakis simplex is a seafood-borne parasite that may both infect humans and cause allergy. Serodiagnosis of anisakiasis and allergy caused by this nematode is difficult since most Anisakis antigens show cross-reactivity problems. To analyse the possible role of sugar epitopes contained in Anisakis simplex antigens as causes of false-positive results in serodiagnostic assays. The antigens UA2R and UA3R recognized by two anti-Anisakis monoclonal antibodies were used in this study. Capture ELISA techniques were used to compare the reactivities with native or O-deglycosylated antigens of sera from Anisakis-free children (most of them infected by several other parasites) and from Anisakis allergy patients. O-deglycosylation was done by mild alkali treatment with NaOH. SDS-PAGE and immunoblotting were used to characterize the effects of NaOH or N-glycanase F treatment on UA3R. Native UA2R was recognized by IgG1 and IgM antibodies in the sera of both Anisakis-free subjects and allergy patients. Native UA3R was recognized by most sera from allergy patients (92% considering immunoglobulin (Ig) G1, 100% considering IgE), but also by a significant proportion of sera from Anisakis-free subjects (36% considering IgG1, 14% considering IgE). O-deglycosylation of UA3R greatly improved specificity: none of the sera from Anisakis-free patients showed either IgG1 or IgE reactivity with O-deglycosylated UA3R, while the proportion of sera from allergy patients showing IgE reactivity with this antigen was practically unaffected. O-deglycosylation of UA2R did not improve the specificity of assays using this antigen. Our results also show that the protein core of glycoproteins may be altered by even very mild alkali treatment, depending on the nature of the protein. Native glycoproteins of A. simplex should not be used for diagnostic purposes. O-deglycosylated UA3R seems to be an excellent candidate for use as target antigen in the serodiagnosis of anisakiasis and A. simplex allergy.

Allergic reactions to anisakis simplex parasitizing seafood.

The ingestion of Anisakidae ssp larvae parasitized fish can cause anisakiasis. Allergic reactions after ingestion of safely cooked but parasitized fish have been reported. Twenty-three patients who suffered allergic reactions after seafood ingestion, with negative skin tests were studied. Anisakis simplex sensitization was assessed by skin prick test and/or specific serum Immunoglobulin E (IgE). Total serum IgE and specific IgE against the implicated seafood and Ascaris lumbricoides were also determined. Manifestations of Anisakis simplex allergy were urticaria/angioedema (18/23) patients and anaphylaxis (5/23). Gastric symptoms were also observed (3/23). Sea fish and shellfish were implicated. Raw and cooked seafood ingestion caused reactions. Total serum IgE ranged from 13 to 7200 KU/L. Specific IgE to Anisakis simplex was positive (> 0.35 KU/L) in all patients, and skin tests were positive in 20. Serum-specific IgE and skin tests to the involved seafoods were negative in every patient. Serum-specific IgE to Ascaris lumbricoides was negative in 13 patients. No association between total IgE and the eosinophil count (r < 0.1) was observed, but there was some association between total IgE and specific IgE to Anisakis simplex (r = 0.58). Anisakis simplex sensitization is the cause of allergic reactions after seafood ingestion. It is important to pay attention to this new "food allergy" to diagnose correctly the etiology of adverse food reactions.

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 (nonallergic), 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. (J Allergy Clin Immunol 1997;99:497-501.)