Allergenicity of vertebrate tropomyosins: challenging an immunological dogma

With the exception of tilapia tropomyosin, other anecdotic reports of tropomyosin recognition of vertebrate origin are generally not accompanied by clinical significance and a dogmatic idea is generally accepted about the inexistence of allergenicity of vertebrate tropomyosins, based mainly on sequence similarity evaluations with human tropomyosins. Recently, a specific work-up of a tropomyosin sensitised patient with seafood allergy, demonstrated that the IgE-recognition of tropomyosin from different fish species can be clinically relevant. We hypothesise that some vertebrate tropomyosins could be relevant allergens. The hypothesis is based on the molecular evolution of the proteins and it was tested by in silico methods. Fish, which are primitive vertebrates, could have tropomyosins similar to those of invertebrates. If the hypothesis is confirmed, tropomyosin should be included in different allergy diagnosis tools to improve the medical protocols and management of patients with digestive or cutaneous symptoms after fish intake

No disponible

Allergenicity of vertebrate tropomyosins: Challenging an immunological dogma.

With the exception of tilapia tropomyosin, other anecdotic reports of tropomyosin recognition of vertebrate origin are generally not accompanied by clinical significance and a dogmatic idea is generally accepted about the inexistence of allergenicity of vertebrate tropomyosins, based mainly on sequence similarity evaluations with human tropomyosins. Recently, a specific work-up of a tropomyosin sensitised patient with seafood allergy, demonstrated that the IgE-recognition of tropomyosin from different fish species can be clinically relevant. We hypothesise that some vertebrate tropomyosins could be relevant allergens. The hypothesis is based on the molecular evolution of the proteins and it was tested by in silico methods. Fish, which are primitive vertebrates, could have tropomyosins similar to those of invertebrates. If the hypothesis is confirmed, tropomyosin should be included in different allergy diagnosis tools to improve the medical protocols and management of patients with digestive or cutaneous symptoms after fish intake.

Diamine oxidase levels in different chronic urticaria phenotypes

BACKGROUND: Diamine oxidase (DAO) is a polyamine-degrading enzyme also implicated in histamine metabolism. Chronic urticaria (CU) has a wide spectrum of clinical presentations and causes. Anisakis sensitisation associated chronic urticaria (CU+) has been characterised as a phenotype with different clinical and immunological characteristics and possibly associated with previous acute parasitism. We aimed to analyse serum DAO levels in different CU phenotypes. We further analysed the possible association of DAO with fish eating habits. METHODS: We studied 35 CU+ patients and 39 non-sensitised CU patients (CU−) as well as 19 controls. We analysed fish-eating frequency as well as fish intake associated exacerbation of CU (FIAE) or gastro-intestinal complaints (GI). DAO levels were further analysed with respect to lymphoproliferative responses, cytokine and specific IgE production. RESULTS: DAO levels were not different between CU and controls, but were significantly higher in CU+ than in CU−. CU+ patients with FIAE had lower DAO levels, but no differences were detected in patients with GI. DAO levels correlated positively with oily and canned fish consumption in CU−. In CU+, DAO levels correlated positively with specific Anisakis IgE, percentages of proliferation in Anisakis stimulated peripheral blood lymphocytes, serum IL-2 and IL-6, but correlated negatively with mitogen stimulated TGF-β in supernatants. CONCLUSIONS: DAO levels in CU depend on fish-eating habits and in CU+ on the amount of specific IgE production. In the CU+ phenotype, lower levels of DAO predispose to urticaria exacerbation after fish intake, probably due to a relative insufficient enteric availability of this enzyme

No disponible

Diamine oxidase levels in different chronic urticaria phenotypes.

BACKGROUND: Diamine oxidase (DAO) is a polyamine-degrading enzyme also implicated in histamine metabolism. Chronic urticaria (CU) has a wide spectrum of clinical presentations and causes. Anisakis sensitisation associated chronic urticaria (CU+) has been characterised as a phenotype with different clinical and immunological characteristics and possibly associated with previous acute parasitism. We aimed to analyse serum DAO levels in different CU phenotypes. We further analysed the possible association of DAO with fish eating habits. METHODS: We studied 35 CU+ patients and 39 non-sensitised CU patients (CU-) as well as 19 controls. We analysed fish-eating frequency as well as fish intake associated exacerbation of CU (FIAE) or gastro-intestinal complaints (GI). DAO levels were further analysed with respect to lymphoproliferative responses, cytokine and specific IgE production. RESULTS: DAO levels were not different between CU and controls, but were significantly higher in CU+ than in CU-. CU+ patients with FIAE had lower DAO levels, but no differences were detected in patients with GI. DAO levels correlated positively with oily and canned fish consumption in CU-. In CU+, DAO levels correlated positively with specific Anisakis IgE, percentages of proliferation in Anisakis stimulated peripheral blood lymphocytes, serum IL-2 and IL-6, but correlated negatively with mitogen stimulated TGF-ß in supernatants. CONCLUSIONS: DAO levels in CU depend on fish-eating habits and in CU+ on the amount of specific IgE production. In the CU+ phenotype, lower levels of DAO predispose to urticaria exacerbation after fish intake, probably due to a relative insufficient enteric availability of this enzyme.

Positive associations between infections of Toxoplasma gondii and seropositivity with Anisakis simplex in human patients suffering from chronic urticaria.

Toxoplasma gondii is a food-borne and orofecal microorganism which produces chronic infection, and attempts have been made to prove its negative association with atopy in the context of the hygiene hypothesis. Anisakis simplex is a fish parasite associated with chronic urticaria (CU) in endemic regions. We analysed the relationship between both infectious agents in CU. We included 42 patients with chronic urticaria (18 patients with CU associated with A. simplex sensitization and 24 not sensitized CU patients). Patients were assessed for atopy by a skin prick test (SPT) against common aeroallergens and for respiratory symptoms. Anisakis simplex sensitization was assessed by SPT and specific IgE by CAP fluoro-enzyme immunoassay (CAP-FEIA). Anti-T. gondii IgG levels were measured by enzyme-linked immunosorbent assay (ELISA). CU patients were analysed with respect to T. gondii seropositivity, A. simplex sensitization, atopy and immigrant status. The seroprevalence of T. gondii was 40.5% in CU patients and 42.1% in the control group. Immigrants were more frequently infected by T. gondii (41.2% versus 12%; P =0.036). Anti-T. gondii IgG antibodies were associated with past A. simplex parasitism (odds ratio 6.73; P =0.03) and independently with atopic sensitization (odds ratio 5.85; P =0.04). In CU patients, T. gondii has no protective effect on atopic sensitization or A. simplex sensitization.

Identification of tetrahydrocarbazoles as novel multifactorial drug candidates for treatment of Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative brain disorder and the most frequent cause of dementia. To date, there are only a few approved drugs for AD, which show little or no effect on disease progression. Impaired intracellular calcium homeostasis is believed to occur early in the cascade of events leading to AD. Here, we examined the possibility of normalizing the disrupted calcium homeostasis in the endoplasmic reticulum (ER) store as an innovative approach for AD drug discovery. High-throughput screening of a small-molecule compound library led to the identification of tetrahydrocarbazoles, a novel multifactorial class of compounds that can normalize the impaired ER calcium homeostasis. We found that the tetrahydrocarbazole lead structure, first, dampens the enhanced calcium release from ER in HEK293 cells expressing familial Alzheimer's disease (FAD)-linked presenilin 1 mutations. Second, the lead structure also improves mitochondrial function, measured by increased mitochondrial membrane potential. Third, the same lead structure also attenuates the production of amyloid-beta (Aß) peptides by decreasing the cleavage of amyloid precursor protein (APP) by ß-secretase, without notably affecting α- and γ-secretase cleavage activities. Considering the beneficial effects of tetrahydrocarbazoles addressing three key pathological aspects of AD, these compounds hold promise for the development of potentially effective AD drug candidates.

Specific IgG4: possible role in the pathogenesis and a new marker in the diagnosis of Anisakis-associated allergic disease.

IgG4 and IgE are immunoglobulin isotypes which are mediated by the same Th2-mediated mechanism. The postulated pathogenic and protective function of IgE or IgG4, respectively, in allergic disease is opposite in parasitic infection. The possible role of IgG4 against recombinant major allergens on the appearance of different forms of Anisakis simplex-associated allergic disease was studied. Gastro-allergic anisakiasis (GAA) and Anisakis-sensitization-associated chronic urticaria (CU+) were compared for specific IgE, IgG4 and the respective recognition of Ani s 1 and Ani s 7. Gastro-allergic anisakiasis showed higher IgE and IgG4 levels against crude extract and both recombinant allergens. Whereas IgE recognition of Ani s 7 did not differ and supports both clinical entities to be associated with previous acute parasitism, the IgE recognition rates of Ani s 1 and IgG4 recognition of both Ani s 1 and Ani s 7 were higher in GAA. IgG4 levels were associated with IgE, but also with age, time to last parasitic episode and frequency of fish intake. Logistic regression analysis showed that the presence of specific IgG4 against Ani s 7 was an independent marker associated with GAA. In the diagnosis of Anisakis-associated allergic disease phenotypes (GAA versus CU+), measurement of specific IgG4 against recombinant allergens could be useful. Further, evaluation of specific IgE and IgG4 facilitates more insight into the protective versus pathogenic potential of IgE and IgG4.

Ani s 1 and Ani s 7 recombinant allergens are able to differentiate distinct Anisakis simplex-associated allergic clinical disorders.

Diagnosis in gastro-allergic anisakiasis (GAA) is straightforward, when clinical history is combined with further allergological evaluation of specific IgE by means of skin prick test and serum specific IgE. In Anisakis simplex sensitisation associated chronic urticaria (CU+), clinical evaluation of possible previous parasitism is difficult, and positive serum specific IgE could be due to cross-reactivity or other unknown factors. In this study, we evaluated the association between IgE seropositivity to the recombinant allergens Ani s 1 and Ani s 7 and several A. simplex-associated allergic disorders. Twenty-eight patients with GAA and 40 patients with CU+ were studied and their IgE responses were compared with a control group composed of patients with chronic urticaria not sensitized to A. simplex (CU-) according to the skin prick test, as well as a group of 15 healthy subjects not referring urticaria or currently A. simplex associated symptoms. 82.1% of GAA patients and 42.5% of CU+ patients were positive for Ani s 1 (P < 0.001), while the Ani s 7 allergen was recognized by 92.9 and 92.5% of sera from patients with GAA and CU+, respectively. The combined positivity obtained for both allergens reached 100% in GAA, and 95% in CU+. IgE determinations to Ani s 1 and Ani s 7 allergens are useful to diagnose the Anisakis infections and to differentiate among several A. simplex-associated allergic disorders. The IgE responses to Ani s 1 are mainly associated with GAA, while this molecule cannot be considered a major allergen in CU+ patients.

Different serum cytokine levels in chronic vs. acute Anisakis simplex sensitization-associated urticaria.

The knowledge on immune mechanisms of chronic urticaria (CU) at the cytokine level is widely scarce. We compared pro- and anti-inflammatory as well as Th1- and Th2-associated serum cytokine levels in two phenotypes of CU: associated with (CU+) and without (CU⁻) sensitization against Anisakis simplex, a ubiquitous fish parasite, that has been associated with acute urticaria in gastro-allergic anisakiasis (GAA) and with CU+. Thirteen CU+ and 19 CU⁻ patients were compared with 13 GAA patients and 15 control subjects for cytokines, measured by cytometric bead array. Urticaria activity score was positively correlated with IL-6 in CU⁻. Serum levels of IL-10 were lower in CU+ and CU⁻ with respect to the control group. Median IFN-γ was lower in all urticaria groups. Patients with previous parasitism by A. simplex displayed higher TGF-ß levels than subjects without previous parasitism. The main finding was lower levels of IL-17 in CU+ with respect to GAA or controls, with a further tendency to even lower levels in CU⁻. Different urticaria phenotypes are associated with distinct serum cytokine levels.

Different clinical presentation of Anisakis simplex associated urticaria is dependent on the frequency of raw fish intake

No disponible

Towards a differential definition of atopy: Anisakis simplex and the relationship between parasites and arthropods in respiratory allergy.

Protective as well as enhancing effects of parasite infections on allergic disease have been postulated. Previous studies on this relationship focused frequently on skin test reactivity against aeroallergens, being house dust mites (HDM) the main agents responsible for a positive atopy outcome. We aimed to analyse the possible relationship between human parasite infection induced Anisakis simplex urticaria and respiratory allergy. A total of 86 patients with gastro-allergic Anisakiasis and 203 patients with chronic urticaria sensitized against A. simplex were studied for sensitization against aeroallergens and evaluated for rhinoconjunctivitis or bronchial asthma (RCBA). We compared the results with a control group of 250 consecutive patients referred for evaluation of allergic RCBA and atopy prevalence data of our region. Whereas no effect of A. simplex related disease on the overall allergic respiratory disease could be detected, a highly significant higher prevalence of RCBA associated HDM sensitization, but diminished allergy against other common aeroallergens (pollen, mould or dander) was observed in these groups. The relationship between A. simplex parasitism-associated acute or chronic urticaria on one side and allergic respiratory disease on the other side depends on the definition of atopy. We propose a differential definition of atopy, with a special emphasis on arthropod related sensitization.

Allergy and parasites reevaluated: wide-scale induction of chronic urticaria by the ubiquitous fish-nematode Anisakis simplex in an endemic region.

BACKGROUND: The ubiquitous fish-nematode Anisakis simplex produces acute urticaria or angioedema in the course of gastro-allergic anisakiasis. We studied the relationship between this nematode and chronic urticaria (CU), as well as the clinical usefulness of measuring specific IgG4 in A. simplex-sensitized patients with CU. METHODS: First, the prevalence of sensitization to A. simplex was estimated in 135 consecutive CU patients and the result was compared with known data about sensitization in a healthy population. Then, clinical response to a 2-month diet without fish was analyzed in 76 CU patients. The improvement rate in patients with and without sensitization to A. simplex was compared. Finally, the improvement rate, other clinical data and specific immunoglobulins in sensitized patients with and without detectable specific IgG4 were compared. RESULTS: a) The A. simplex sensitization rate in CU patients was 52.6 % compared with a known prevalence of between 16 and 20 % in our region. b) Of 65 sensitized patients, 52 experienced clinical improvement after the diet compared with only three of 11 patients without sensitization to A. simplex (p = 0.001). c) Of 43 patients with detectable specific IgG4, 38 showed clinical improvement compared with only 14 of 22 patients without detectable IgG4 (p = 0.02). Eight of nine patients with previous fish-associated cutaneous symptoms had detectable specific IgG4 compared with 15 of 32 patients who reported no previous fish-associated symptoms or acute urticaria (p = 0.03). CONCLUSIONS: Our results indicate that A. simplex is a possibly widespread etiologic agent able to induce CU. This parasite model constitutes the first report that associates an infectious agent with CU on a large scale. The detection of IgG4 antibodies reflects a previous acute parasitic infection and a temporary diet without fish improves symptoms in most patients with detectable specific IgG4.

Allergy and parasites reevaluated: wide-scale induction of chronic urticaria by the ubiquitous fish-nematode Anisakis simplex in an endemic region

Antecedentes: El nematodo Anisakis simplex (A.s.), presente en el pescado, produce urticaria o angioedema agudos en el curso de la anisakiasis gastroalérgica (AGA). Hemos estudiado la relación entre este nematodo y la urticaria crónica (UC), así como la utilidad clínica de la medición de la IgG4 específica en pacientes sensibilizados al A.s. con urticaria crónica. Métodos: En primer lugar, evaluamos la prevalencia de la sensibilización al A.s en 135 pacientes consecutivos de UC y la comparamos con los datos conocidos sobre la sensibilización de la población sana. A continuación, analizamos la respuesta clínica de 76 pacientes de UC a una dieta de dos meses sin pescado. Comparamos el índice de mejoría en los pacientes con y sin sensibilización al A.s. Finalmente, comparamos el índice de mejoría, otros datos clínicos y las inmunoglobulinas específicas en los pacientes sensibilizados con y sin IgG4 específica detectable. Resultados: a) El índice de sensibilización al A.s. en los pacientes de UC fue del 52,6 %, frente a una prevalencia conocida del 16 al 20 % en nuestra región. b) 52 de 65 pacientes sensibilizados experimentaron una mejoría clínica tras una dieta sin pescado, frente a sólo 3 de 11 pacientes no sensibilizados al A.s. (p = 0,001). c) 38 de 43 pacientes con IgG4 específica detectable mostraron una mejoría clínica, frente a sólo 14 de 22 pacientes sin IgG4detectable (p = 0,02). 8 de 9 pacientes con síntomas previos asociados al pescado presentaron IgG4 específica detectable, frente a 15 de 32 pacientes que manifestaron no haber padecido previamente ningún síntoma ni urticaria aguda asociados al pescado (p = 0,03). Conclusiones: Nuestros resultados ponen de manifiesto que el A.s. es un posible agente etiológico muy extendido capaz de inducir la UC. Este estudio del parásito supone la primera información que asocia a gran escala una infestación con la UC. La detección de los anticuerpos IgG4 refleja un parasitismo agudo previo, y una dieta temporal sin pescado mejora los síntomas en la mayoría de los pacientes con IgG4 específica detectable

Background: The ubiquitous fish-nematode Anisakis simplex produces acute urticaria or angioedema in the course of gastro-allergic anisakiasis. We studied the relationship between this nematode and chronic urticaria (CU), as well as the clinical usefulness of measuring specific IgG4 in A. simplex-sen-sitized patients with CU. Methods: First, the prevalence of sensitization to A. simplex was estimated in 135 consecutive CU patients and the result was compared with known data about sensitization in a healthy population. Then, clinical response to a 2-month diet without fish was analyzed in 76 CU patients. The improvement rate in patients with and without sensitization to A. simplex was compared. Finally, the improvement rate, other clinical data and specific immunoglobulins in sensitized patients with and without detectable specific IgG4 were compared. Results: a) The A. simplex sensitization rate in CU patients was 52.6% compared with a known prevalence of between 16 and 20% in our region. b) Of 65 sensitized patients, 52 experienced clinical improvement after the diet compared with only three of 11 patients without sensitization to A. simplex (p = 0.001). c) Of 43 patients with detectable specific IgG4, 38 showed clinical improvement compared with only 14 of 22 patients without detectable IgG4 (p = 0.02). Eight of nine patients with previous fish-associated cutaneous symptoms had detectable specific IgG4 compared with 15 of 32 patients who reported no previous fish-associated symptoms or acute urticaria (p = 0.03). Conclusions: Our results indicate that A. simplex is a possibly widespread etiologic agent able to induce CU. This parasite model constitutes the first report that associates an infectious agent with CU on a large scale. The detection of IgG4 antibodies reflects a previous acute parasitic infection and a temporary diet without fish improves symptoms in most patients with detectable specific IgG4

Serum CD23 is not altered in gastroallergic anisakiasis, but correlates with the production of specific IgE and the amount of polyclonal stimulation.

BACKGROUND: Previous studies have shown elevated serum levels of the cytokines IL-4 and sCD23 in atopic patients and parasitic disease. Gastroallergic anisakiasis is an acute parasitic disease, accompanied by IgE-mediated clinical symptoms and an important increase of specific and total IgE. METHODS: Sixteen patients with acute urticaria/angioedema due to parasitism by Anisakis simplex after intake of raw or undercooked fish were selected, and serum samples were taken in the emergency room within 24 h (day 0; n=16), after 1 month (n=16), and after 6 months (n=10). Serum samples were studied for specific IgE against A. simplex, total IgE, sCD23, and IL-4. RESULTS: Mean values for sCD23 did not change in the observation period. Only 4/16 serum samples showed measurable IL-4 levels. Specific IgE and total IgE levels were found to be elevated after 1 month; after 6 months, they fell to nearly basal values. There was a positive correlation between sCD23 and specific IgE at day 0 and follow-up (r=0.55-0.69, P<0.026); a positive correlation between sCD23 and total IgE (r=0.54-0.62, P<0.056). Basal sCD23 could moderately predict the percentual increment of total IgE in the first month (r=0.56, P<0.038). CONCLUSION: Thus, it seems that interindividual variability of sCD23 is an important factor, with higher values predisposing to more production of unrelated IgE, independently of the parasite's action.

Anisakiasis gastro-alérgica: hipersensibilidad inmediata debida a parasitación por anisakis simplex / Gastroallergic anisakiasis: immediate hypersensitivity due to Anisakis simplex infestation

En España, hasta 1995 los casos de anisakiasis eran anecdóticos. Sin embargo, en 1995, los alergologos españoles, de la mano del grupo del Dr. Fernández de Corres, llegan al Anisakis simplex (AS) por casos de reacciones alérgicas tras consumo de pescado "presumiblemente" bien cocinado y con pruebas cutáneas e IgE específica a AS positivas. La base de la alergia al AS parecía estar en la termoestabilidad de antígenos del AS. Tras observar algunos casos de anafilaxia con parasitación por AS, se inició un estudio prospectivo en 1997 en el Hospital Universitario "La Paz" de Madrid. Se introdujeron pacientes que acudían a urgencias con síntomas alérgicos o gastrointestinales tras ingestión de productos de mar, aceptando pacientes que hubieran tomado el alimento hasta 48 horas antes. Si el cuadro digestivo persistía se realizaba endoscopia. En 18 meses se evaluaron 120 pacientes que consultaron por síntomas alérgicos y de los cuales en 96 se implicó verdaderamente al AS. En esos 18 meses, y sobre la base de los síntomas de alergia, se detectaron 24 pacientes a los que se extrajo uno o más parásitos de su estómago (más parásitos hallados en sólo 18 meses que desde 1991 en España). El boquerón en vinagre y en algunos casos la merluza fresca, presumiblemente bien cocinada, fueron la fuente de la mayoría de las parasitaciones. Los autores denominaron a esta entidad anisakiasis gastro-alérgica diferenciándola de la anisakiasis gástrica, dado que los síntomas de hipersensibilidad tras el contacto con el parásito eran más intensos y severos que los gástricos. Parecía que en su mayoría era el parásito vivo la fuente antigénica y más aún, que necesitaba fijarse a la submucosa para producir la reacción de hipersensibilidad. El paso siguiente en estos pacientes con anisakiasis gastro-alérgica fue la provocación con parásitos congelados no infectivos. Se confirmó su tolerancia en varios pacientes y a partir de entonces al resto se les permitió comer pescado congelado sin suceder ningún problema. En ese punto, la alergia a proteínas termoestables del AS parecía menos frecuente de lo presupuesto y se intuía que la repuesta IgE mediada en la mayoría de los pacientes sensibilizados correspondía a contactos (parasitaciones en forma luminal o asintomáticas) con el parásito vivo. El antecedente dietético, la clínica, la respuesta a los test cutáneos y la medición seriada de IgE específica a AS son importantes claves para el diagnóstico. Puede que existan casos de verdadera alergia a AS, pero en vistas de este estudio prospectivo deben ser infrecuentes (AU)

Gastroallergic anisakiasis: findings in 22 patients.

BACKGROUND AND AIMS: Ingestion of Anisakidae larvae in raw seafood may cause anisakiasis. However, despite the high level of consumption of seafood in Spain, only a few cases of anisakiasis have been reported until now. Anisakis simplex can cause allergic reactions in sensitized patients as a result of its parasitism in the gastrointestinal tract. The purpose of this study was to analyse the clinical findings in 22 patients with gastroallergic anisakiasis. METHODS: Patients with allergic and/or gastric symptoms after seafood ingestion were evaluated in the emergency room of the La Paz General University Hospital. Skin testing for Anisakis simplex and tests on the implicated seafood were performed and amounts of serum-specific immunoglobulin E were assessed. A gastroscopy was performed in those patients with severe allergic or/and persistent gastric symptoms after ingestion of raw or undercooked seafood. RESULTS: Twenty-two patients were diagnosed with gastroallergic anisakiasis in 1 year. Most patients presented to the emergency room of our hospital with allergic symptoms. Gastric symptoms were usually moderate. Gastroscopy revealed local mucosal oedema and gastric erosion at the point of fixation. Two or more worms were detected in three patients. The mean time of latency of allergic symptoms was 5 h, while the mean time for gastric symptoms was 3 h. CONCLUSION: Anisakis simplex parasitism was the causative agent of allergic and gastric symptoms. Gastroallergic anisakiasis appears to be a relatively common disease, that may have been underdiagnosed.