Isolation of a heat-resistant allergen from the fish parasite Anisakis simplex

The thermal stability of allergenic peptides from the fish parasite Anisakis simplex has not been fully elucidated. This is of special relevance for physicians who should clearly indicate if sensitized patients should avoid ingestion of raw fish only or whether well-cooked fish should also be avoided, if allergenic peptides derived from the parasite remain immunologically detectable. An allergen was purified after heating a crude parasite extract for 30 min. The allergen was further purified by an ethanol fractionation procedure followed by a reversed-phase HPLC. The N-terminal amino acid sequence was obtained. This allergen was detected by 27% of sensitized subjects. The N-terminal amino acid sequence of the 9 kDa allergen showed no similarities to other known proteins. A minor low molecular weight allergen from A. simplex is highly resistant to heating and it could therefore have significant clinical relevance.     

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: sensitization and clinical allergy

PURPOSE OF REVIEW: Whereas gastric anisakiasis has been known for several decades, the implications of Anisakis simplex-related allergic disorders had not been thoroughly studied until the late 1990s. This article reviews recent knowledge of allergic disorders ascribed to A. simplex contact or parasitism. RECENT FINDINGS: Gastroallergic anisakiasis describes an acute hypersensitivity reaction emerging in the context of an acute parasitism by the nematode A. simplex. But other frequent allergic disorders like chronic urticaria are now being studied for a possible relationship with A. simplex parasitism. In recent investigations, non-IgE mediated mechanisms, such as the involvement of other immunoglobulin isotypes (IgG4), or non-immunological events are discussed. SUMMARY: The experience of the last several years shows that allergic hypersensitivity symptoms in gastroallergic anisakiasis are clinical events accompanying a wide range of immunologic reactions as a host response against a ubiquitous parasite. The discussed and reviewed studies should motivate allergists around the world to search for this entity. Further studies in the field of allergy could benefit from the experience of this peculiar food-related disorder.     

Exposure to the fish parasite Anisakis causes allergic airway hyperreactivity and dermatitis

BACKGROUND: Several case reports show allergy and anaphylactic reactions to the fish parasite Anisakis in the domestic and occupational setting. Further research is needed on the prevalence and mechanisms of disease. OBJECTIVE: To determine the prevalence of Anisakis sensitization and related symptoms among workers in 2 fish-processing factories, and to use gene-deficient mice to determine the working mechanisms of Anisakis allergy. METHODS: A modified version of the European Community Respiratory Health Survey was used to interview 578 South African fish-processing workers. Sensitization to Anisakis, seafood, and common aeroallergens was determined by skin prick test. Lung function was measured by spirometry and methacholine challenge. Serum eicosapentaenoic acid levels were used as an index of seafood consumption. Sensitized wild-type, IL-4, or IL-4 receptor alpha-deficient mice were challenged orally with Anisakis extract. Allergic reactions, lung pathology, antibodies, cytokines, mast cell proteases, and histamine were evaluated. RESULTS: The prevalence of sensitization to Anisakis was higher than the prevalence of sensitization to fish (8% vs 6%). Anisakis-specific IgE reactivity was associated with bronchial hyperreactivity and dermatitis, and significantly increased with fish consumption. In mice, Anisakis infective larvae (L3) induced a striking T(H)2/type 2 response. Food-allergic-type reactions induced by oral challenge with Anisakis extract were absent in IL-4 receptor alpha knockout mice. CONCLUSION: Anisakis sensitization in fish-processing workers is associated with allergic symptoms and correlates with high levels of fish consumption. Anisakis proteins induce allergic reactions in sensitized mice by IL-4/IL-13-mediated mechanisms. CLINICAL IMPLICATIONS: Anisakis allergy should be considered in fish-processing workers with allergic symptoms.     

Characterization of allergens secreted by Anisakis simplex parasite: clinical relevance in comparison with somatic allergens

BACKGROUND: Diagnostic methods for the study of allergic reactions to Anisakis simplex (A.s.) based on whole-body extracts of the larva are clearly insufficient. OBJECTIVES: To study the allergenicity of the proteins secreted by the parasite. Comparison with somatic antigens and determination of their clinical importance in allergic patients were also addressed. METHODS: An excretory/secretory (E/S) extract was produced by culturing third-stage A.s. larvae. It was used to perform immediate skin tests and to determine specific IgE in 10 patients diagnosed with allergy to A.s. Both tests were compared with the results obtained with the whole-body extract (somatic (S)). The molecular weight (MW) of their allergens was determined by immunoblotting, and a single-blind placebo-controlled oral challenge with E/S proteins was performed. Finally, allergens' resistance to gastric pepsin and acid pH was explored. RESULTS: A.s. larvae secreted allergens more potent than those present in the S extract. The skin prick test wheal area produced by E/S molecules and the absorbance obtained in the determination of specific IgE with these allergens (ELISA) were 5.8 times bigger than those obtained with S extract. MW allergens of 72 and 56 kDa in E/S extracts and those of 56, 48 and 43 kDa in S extract were recognized by more than 50% of the patients. Partial cross-reactivity between them was revealed by immunoblotting inhibition studies. Oral challenge with E/S extract (up to 479 microg) was negative in all the patients. Treatment of E/S proteins with gastric pepsin inhibited the binding of the E/S allergens for specific IgE. The acid pH did not affect the overall binding of IgE to E/S extract. It decreased by 15.23% and 19.96% at pH 4 and 2, but the difference was not statistically significant. CONCLUSION: A.s. secretes allergens more potent than somatic antigens and should be used in the diagnostic procedures. These allergens are inactivated by the pepsin, which supports the theory that live larva is necessary to induce an allergic reaction in most of the patients.     

A double-blind, placebo-controlled oral challenge study with lyophilized larvae and antigen of the fish parasite, Anisakis simplex

BACKGROUND: The third-stage larvae of Anisakis simplex may be a hidden source of allergens in fish. The objective was to determine whether the ingestion of lyophilized A. simplex larvae, or antigen, induces clinical symptoms in a group of A. simplex-sensitized patients. METHODS: Double-blind, placebo-controlled oral challenges were conducted in 11 individuals who had experienced allergic reactions after eating fish. Another patient had chronic urticaria unrelated to the ingestion of fish. All patients had positive skin tests and specific IgE determinations for A. simplex and negative skin tests to a battery of fish species. Conjunctival tests with A. simplex extracts were conducted in all patients and in five controls. The 12 patients received capsules containing either lactose or one, five, or 25 lyophilized larvae of A. simplex at 2-h intervals in a double-blind fashion. The highest single dose was 100 larvae. ECP and tryptase levels in serum were measured before and after the last oral challenge. Lyophilized antigen was also given to five patients. RESULTS: None of the 12 patients experienced a positive reaction after the ingestion of the placebo, the lyophilized larvae, or the antigen. Tryptase and ECP levels before and after challenges did not change significantly. Conjunctival provocation tests were positive in 11 out of the 12 patients and in none of the controls. CONCLUSIONS: The ingestion of 100 lyophilized A. simplex larvae, or its equivalent in antigen, does not induce clinical symptoms in individuals with a clinical history and laboratory findings of hypersensitivity to A. simplex. The data suggest that only the ingestion of live larvae may be capable of inducing allergic manifestations.     

Distribution of Anisakis simplex in fish caught in the Ligurian Sea

A total of 822 individuals of 5 fish species were sampled in the western coastal area of the Mediterranean Sea and examined for the presence of Anisakis simplex larvae in the body cavity, muscle, and viscera. A. simplex mean intensity (mI) and prevalence (Pr) values were very high in the common scad (Trachurus trachurus; Pr 80–100%, mI 19.3–36.8) and the blue scad (T. picturatus; Pr 80–100%, mI 18.2–70.7), moderate in the blue whiting (Micromesistius poutassou), and low in the red mullet (Mullus barbatus) and the striped mullet (M. surmuletus). The larval burden was strongly related to host length in the common and blue scad. Received: 23 December 1999 / Accepted: 17 January 2000     

Anaphylaxis due to hypersensitivity to Anisakis simplex

Anaphylactic reactions are among the most frequent causes for requests for emergency medical care. It is possible that no clear precipitating factor can be found delaying the onset of adequate treatment and increasing the risk of new episodes of anaphylaxis in the future. Hypersensitivity to Anisakis simplex, an intestinal parasite found in fish, is an unusual cause of anaphylaxis but it should always be borne in mind in countries where a great deal of fish is consumed, especially if it is eaten raw or undercooked. 3 cases of anaphylaxis due to hypersensitivity to A. simplex are described.     

Herpes simplex clinical and pathogenetic aspects

Immunologic Research - Primary infection with herpes simplex virus of either type 1 or type 2 occurs frequently, however, recurring disease develops in only a small fraction of the population....     

EDTA-dependent pseudothrombocytopenia: clinical aspects and laboratory tests

EDTA-dependent pseudothrombocytopenia (EDTA-PTCP) is a phenomenon caused by EDTA-dependent anti-platelet antibody. This antibody induces platelet agglutination in vitro, resulting in a decrease in platelet counts. It is necessary for clinicians to consider the possible presence of PTCP in cases of patients having low platelet counts without any hemorrhagic tendency. In this article, we describe some aspects of EDTA-PTCP including, (1) characteristics of platelet agglutination, (2)possible mechanisms for antibody production, (3) several methods to determine the true platelet number, and also (4) a few similar phenomena induced by antibodies independent of EDTA.     

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.     

Exploring tumourigenic potential of the parasite Anisakis: a pilot study

Parasitology Research - Anisakiasis is a global disease caused by consumption of raw or lightly cooked fish parasitised with Anisakis spp. third-stage larvae. Cases in the literature show...     

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.     

Fungal infections of the immunocompromised host: clinical and laboratory aspects.

Fungal infections of the immunocompromised host are being seen with greater frequency than ever before. In addition, a growing list of unusual and unexpected etiologic agents presents a unique and difficult challenge to the clinician and microbiologist. The clinical manifestations of opportunistic fungal infections are often not characteristic and, in many instances, may prevent a rapid diagnosis from being made. Clinical microbiology laboratories should consider any organism as a potential etiologic agent. This requires that all fungi recovered from immunocompromised patients be thoroughly identified and reported so that their clinical significance may be assessed. This review presents a brief discussion of the clinical and laboratory aspects of some fungal infections seen in this important group of patients.     

Coryneform bacteria in infectious diseases: clinical and laboratory aspects.

Coryneform isolates from clinical specimens frequently cannot be identified by either reference laboratories or research laboratories. Many of these organisms are skin flora that belong to a large number of taxonomic groups, only 40% of which are in the genus Corynebacterium. This review provides an update on clinical presentations, microbiological features, and pathogenic mechanisms of infections with nondiphtheria Corynebacterium species and other pleomorphic gram-positive rods. The early literature is also reviewed for a few coryneforms, especially those whose roles as pathogens are controversial. Recognition of newly emerging opportunistic coryneforms is dependent on sound identification schemes which cannot be developed until cell wall analyses and nucleic acid studies have defined the taxonomic groups and all of the reference strains within each taxon have been shown by molecular methods to be authentic members. Only then can reliable batteries of biochemical tests be selected for distinguishing each taxon.