Cross-reactivity between IgE-binding proteins from Anisakis simplex and Dermatophagoides pteronyssinus

The role of helminths in the development of non-communicable diseases

Non-communicable diseases (NCDs) like cardiovascular disease, chronic respiratory diseases, cancers, diabetes, and neuropsychiatric diseases cause significant global morbidity and mortality which disproportionately affect those living in low resource regions including low- and middle-income countries (LMICs). In order to reduce NCD morbidity and mortality in LMIC it is imperative to understand risk factors associated with the development of NCDs. Certain infections are known risk factors for many NCDs. Several parasitic helminth infections, which occur most commonly in LMICs, have been identified as potential drivers of NCDs in parasite-endemic regions. Though understudied, the impact of helminth infections on the development of NCDs is likely related to helminth-specific factors, including species, developmental stage and disease burden. Mechanical and chemical damage induced by the helminth in combination with pathologic host immune responses contribute to the long-term inflammation that increases risk for NCD development. Robust studies from animal models and human clinical trials are needed to understand the immunologic mechanisms of helminth-induced NCDs. Understanding the complex connection between helminths and NCDs will aid in targeted public health programs to reduce helminth-induced NCDs and reduce the high rates of morbidity that affects millions of people living in parasite-endemic, LMICs globally.

Gene expression and allergenic potential of Pseudoterranova bulbosa L3 from different infection sites in North Atlantic cod (Gadus morhua)

The recent advances in molecular methods and data processing have facilitated research on anisakid nematodes. While most research efforts were made regarding the genus Anisakis, since this genus is held responsible for the majority of reported clinical signs, there is still a demand for data on the genus Pseudoterranova. Several case studies of severe invasive anisakidosis affecting various organs caused by species of the P. decipiens complex have been described. To better understand the way these parasites might infest their fish host, we examined whether parasite location within the fish host affects gene expression. A de novo assembly of the transcriptome of Pseudoterranova bulbosa, isolated from North Atlantic cod, was analysed for patterns of differential gene expression between samples taken from liver and viscera. We additionally searched for homologs to known nematode allergens, to give a first estimate of the potential allergenicity of P. bulbosa. There was a subtle difference in the gene expression of samples taken from liver and viscera. Seventy genes were differentially expressed, 32 genes were upregulated in parasites isolated from liver and 38 genes were upregulated in parasites from viscera. Homologs of five nematode allergens were identified among the genes expressed by P. bulbosa. Our transcriptome of P. bulbosa will be a valuable resource for further meta-analyses and resequencing projects.

Proteomic Profiling and In Silico Characterization of the Secretome of Anisakis simplex Sensu Stricto L3 Larvae

Anisakis simplex sensu stricto (s.s.) L3 larvae are one of the major etiological factors of human anisakiasis, which is one of the most important foodborne parasitic diseases. Nevertheless, to date, Anisakis secretome proteins, with important functions in nematode pathogenicity and host-parasite interactions, have not been extensively explored. Therefore, the aim of this study was to identify and characterize the excretory-secretory (ES) proteins of A. simplex L3 larvae. ES proteins of A. simplex were subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, and the identified proteins were then analyzed using bioinformatics tools. A total of 158 proteins were detected. Detailed bioinformatic characterization of ES proteins was performed, including Gene Ontology (GO) analysis, identification of enzymes, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis, protein family classification, secretory pathway prediction, and detection of essential proteins. Furthermore, of all detected ES proteins, 1 was identified as an allergen, which was Ani s 4, and 18 were potential allergens, most of which were homologs of nematode and arthropod allergens. Nine potential pathogenicity-related proteins were predicted, which were predominantly homologs of chaperones. In addition, predicted host-parasite interactions between the Anisakis ES proteins and both human and fish proteins were identified. In conclusion, this study represents the first global analysis of Anisakis ES proteins. The findings provide a better understanding of survival and invasion strategies of A. simplex L3 larvae.

Expression and functionality of allergenic genes regulated by simulated gastric juice in Anisakis pegreffii

To better understand the molecular mechanisms underlying allergens and parasite immunity and discover the stage-enriched gene expression of fish-borne zoonotic nematodes in the stomach, we used RNA-seq to study the transcriptome profiles of Anisakis pegreffii (Nematoda: Anisakidae, AP) in simulated gastric juice. Mobile L3 larvae were incubated in simulated medium at 37 °C in 5% CO₂ (AP-GJ) and the control group larvae were collected in PBS under the same conditions (AP-PBS). We found that the sequences of A. pegreffii were highly similar to Toxocara canis sequences. Among the transcripts, there would be 138 up-regulated putative genes and 251 down-regulated putative genes in AP-GJ group. Several lipid binging-related genes were more highly expressed in AP-GJ larvae. Moreover, 17 allergen genes were up-regulated and 29 were down-regulated in AP-GJ larvae. Eleven allergen genes belonged to one or more of the following three categories: biological process, cellular component, and molecular function. According to KEGG analysis, the main pathways that were represented included protein processing in transcription, immune system, cancer, and infectious disease. In particular, the most significant changes in the expression of parasite-derived allergen products occurred in AP-GJ larvae. This study helps us to extend our understanding of the biology of the fish-borne zoonotic parasite A. pegreffii and could be helpful for more precise risk assessment and providing guidelines for allergic consumers.

Proteomic analysis of Ascocotyle longa (Trematoda: Heterophyidae) metacercariae

Ascocotyle longa is parasitic trematode with wide distribution throughout America, Europe, Africa, and Middle East. Despite the fact that this fish-borne pathogen has been considered an agent of human heterophyiasis in Brazil, the molecules involved in the host-parasite interaction remain unknown. The present study reports the proteome profile of A. longa metacercariae collected from the fish Mugil liza from Brazil. This infective stage for humans, mammals and birds was analyzed using nLC-MS/MS approach. We identified a large repertoire of proteins, which are mainly involved in energy metabolism and cell structure. Peptidases and immunogenic proteins were also identified, which might play roles in host-parasite interface. Our data provided unprecedented insights into the biology of A. longa and represent a first step to understand the natural host-parasite interaction. Moreover, as the first proteome characterized in this trematode, it will provide an important resource for future studies.

Analysis of Ani s 7 and Ani s 1 allergens as biomarkers of sensitization and allergy severity in human anisakiasis

The high frequency of infection by Anisakis simplex (A. simplex) has led to an increase in IgE sensitization, turning allergy to this parasite a relevant contemporary health problem. Improving the lack of conventional diagnosis test specificity is crucial to better understand these clinical scenarios. Specific IgE (sIgE) to A. simplex extract by ImmunoCAP (Anisakis-sIgE) was determined in sera from 403 blood donors (BD) from Cantabria (North of Spain) of which 51 subjects resulted sensitized. Among these latter, 47 were asymptomatic (sABD). The values of total IgE, prick-test, Anisakis-sIgE, and sIgE to Ani s 1 (anti-rAni s 1) and Ani s 7 (anti-rAni s 7) were compared between 46 sABD and 49 A. simplex allergic patients. The IgE seroprevalence by ImmunoCAP among BD was 12.65%. Allergic patients and sABD showed significant differences in all serum biomarkers evaluated. The area under the curve was assessed for Anisakis-sIgE (0.892), sIgE-rAni s 1 (0.672) and sIgE-rAni s 7 (0.668). After a severe reaction, significantly higher levels of Anisakis-sIgE and sIgE anti-rAni s 1 were detected. Determinations of sIgE by ImmunoCAP, Ani s 1 and Ani s 7 presented different sensitization patterns between allergic and asymptomatic individuals. The Ani s 1 allergen arises as a possible biomarker to detect patients at risk of suffering severe allergic reactions.

Role in Allergic Diseases of Immunological Cross-Reactivity between Allergens and Homologues of Parasite Proteins

Implied under the rubric of the hygiene hypothesis is that helminth infection can protect against allergic disease. It is well known that helminths induce processes associated with type 2 immune responses, but they also induce important regulatory responses that can modulate these type 2-associated responses-modulation that influences responses to bystander antigens including allergens. Indeed, most epidemiological studies demonstrate a beneficial effect of helminth infection on atopy, but there are also convincing data to demonstrate that helminth infection can precipitate or worsen allergic inflammation/disease. Reasons for these disparate findings are much debated, but there is a school of thought that suggests that helminth-triggered type 2-associated responses, including IgE to cross-reactive aeroallergens, can offset the regulatory effects imposed by the same organisms. The cross-reactivity among helminths and allergenic tropomyosins dominated the antigen/allergen cross-reactivity field, but recent data suggest that cross-reactivity is much more common than previously appreciated. It has been demonstrated that a high degree of molecular similarity exists between allergens and helminth proteins. Thus, an understanding of the mechanisms underlying the response induced by helminth infection and their impact on the induction of allergic disease in the host are critical for designing therapies using iatrogenic infections or parasite products to treat inflammatory diseases and for developing vaccines against helminth parasites.

The Anisakis Transcriptome Provides a Resource for Fundamental and Applied Studies on Allergy-Causing Parasites

Background

Food-borne nematodes of the genus Anisakis are responsible for a wide range of illnesses (= anisakiasis), from self-limiting gastrointestinal forms to severe systemic allergic reactions, which are often misdiagnosed and under-reported. In order to enhance and refine current diagnostic tools for anisakiasis, knowledge of the whole spectrum of parasite molecules transcribed and expressed by this parasite, including those acting as potential allergens, is necessary.

Methodology/Principal Findings

In this study, we employ high-throughput (Illumina) sequencing and bioinformatics to characterise the transcriptomes of two Anisakis species, A. simplex and A. pegreffii, and utilize this resource to compile lists of potential allergens from these parasites. A total of ~65,000,000 reads were generated from cDNA libraries for each species, and assembled into ~34,000 transcripts (= Unigenes); ~18,000 peptides were predicted from each cDNA library and classified based on homology searches, protein motifs and gene ontology and biological pathway mapping. Using comparative analyses with sequence data available in public databases, 36 (A. simplex) and 29 (A. pegreffii) putative allergens were identified, including sequences encoding ‘novel’ Anisakis allergenic proteins (i.e. cyclophilins and ABA-1 domain containing proteins).

Conclusions/Significance

This study represents a first step towards providing the research community with a curated dataset to use as a molecular resource for future investigations of the biology of Anisakis, including molecules putatively acting as allergens, using functional genomics, proteomics and immunological tools. Ultimately, an improved knowledge of the biological functions of these molecules in the parasite, as well as of their immunogenic properties, will assist the development of comprehensive, reliable and robust diagnostic tools.

Nematodes within the genus Anisakis (i.e. A. simplex and A. pegreffii, also known as herring worms) are the causative agents of the fish-borne gastrointestinal illness known as ‘anisakiasis’, with infections resulting in symptoms ranging from mild gastric forms to severe allergic reactions leading to urticaria, gastrointestinal and/or respiratory signs and/or anaphylaxis (‘allergic anisakiasis’). Despite significant advances in knowledge of the pathobiology of allergic anisakiasis, thus far, the exact number and nature of parasite molecules acting as potential allergens are currently unknown; filling this gap is necessary to the development of robust and reliable diagnostics for allergic anisakiasis which, in turn, underpins the implementation of effective therapeutic strategies. Here, we use RNA-Seq and bioinformatics to sequence and annotate the transcriptomes of A. simplex and A. pegreffii, and, as an example application of these resources, mine this data to identify and characterise putative novel parasite allergens based on comparisons with known allergen sequence data from other parasites and other organisms.

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

BACKGROUND

Anisakis 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.

OBJECTIVE

To investigate the prevalence of A simplex sensitization and its clinical relevance in a large group of unselected patients.

METHODS

All 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.

RESULTS

Of 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.

CONCLUSION

A 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.

Comparisons of Allergenic and Metazoan Parasite Proteins: Allergy the Price of Immunity

Allergic reactions can be considered as maladaptive IgE immune responses towards environmental antigens. Intriguingly, these mechanisms are observed to be very similar to those implicated in the acquisition of an important degree of immunity against metazoan parasites (helminths and arthropods) in mammalian hosts. Based on the hypothesis that IgE-mediated immune responses evolved in mammals to provide extra protection against metazoan parasites rather than to cause allergy, we predict that the environmental allergens will share key properties with the metazoan parasite antigens that are specifically targeted by IgE in infected human populations. We seek to test this prediction by examining if significant similarity exists between molecular features of allergens and helminth proteins that induce an IgE response in the human host. By employing various computational approaches, 2712 unique protein molecules that are known IgE antigens were searched against a dataset of proteins from helminths and parasitic arthropods, resulting in a comprehensive list of 2445 parasite proteins that show significant similarity through sequence and structure with allergenic proteins. Nearly half of these parasite proteins from 31 species fall within the 10 most abundant allergenic protein domain families (EF-hand, Tropomyosin, CAP, Profilin, Lipocalin, Trypsin-like serine protease, Cupin, BetV1, Expansin and Prolamin). We identified epitopic-like regions in 206 parasite proteins and present the first example of a plant protein (BetV1) that is the commonest allergen in pollen in a worm, and confirming it as the target of IgE in schistosomiasis infected humans. The identification of significant similarity, inclusive of the epitopic regions, between allergens and helminth proteins against which IgE is an observed marker of protective immunity explains the ‘off-target’ effects of the IgE-mediated immune system in allergy. All these findings can impact the discovery and design of molecules used in immunotherapy of allergic conditions.

Allergy is an increasingly widespread clinical problem that leads to various conditions such as allergic asthma and susceptibility to anaphylactic shock. These conditions arise from exposure to a range of environmental and food proteins (‘allergens’) that are recognised by a form of immune system antibody called IgE. This part of the immune system is thought to have evolved to provide mammals with additional rapid response mechanisms to combat metazoan parasites. Here, we address the pertinent question, ‘what makes an Allergen an Allergen’ as, although they constitute a very small percentage of known proteins, they appear to be diverse and unrelated. Using computational studies, we have established molecular similarity between parasite proteins and allergens that affect the nature of immune response and are able to predict the regions of parasite proteins that potentially share similarity with the IgE-binding region(s) of the allergens. Our experimental studies support the computational predictions, and we can present the first confirmed example of a plant pollen-like protein in a worm that is targeted by IgE. The results of this study will enable us to predict likely allergens in food and environmental organisms and to help design protein molecules to treat allergy in the future.

Fish allergy: in review

Globally, the rising consumption of fish and its derivatives, due to its nutritional value and divergence of international cuisines, has led to an increase in reports of adverse reactions to fish. Reactions to fish are not only mediated by the immune system causing allergies, but are often caused by various toxins and parasites including ciguatera and Anisakis. Allergic reactions to fish can be serious and life threatening and children usually do not outgrow this type of food allergy. The route of exposure is not only restricted to ingestion but include manual handling and inhalation of cooking vapors in the domestic and occupational environment. Prevalence rates of self-reported fish allergy range from 0.2 to 2.29 % in the general population, but can reach up to 8 % among fish processing workers. Fish allergy seems to vary with geographical eating habits, type of fish processing, and fish species exposure. The major fish allergen characterized is parvalbumin in addition to several less well-known allergens. This contemporary review discusses interesting and new findings in the area of fish allergy including demographics, novel allergens identified, immunological mechanisms of sensitization, and innovative approaches in diagnosing and managing this life-long disease.

Pregnancy and helminth infections

It has been proposed that helminth infection may be particularly detrimental during pregnancy, through adverse effects on maternal anaemia and on birth outcomes, and that anthelminthic treatment during pregnancy will therefore be particularly beneficial. However, the few treatment trials that have been conducted have given, but little support to this notion and further trials in settings of nutritional stress are needed. It has also been proposed that prenatal exposure to helminth infection has an important effect on the development of the foetal immune response. There is evidence that this may impact, long-term, upon responses to helminth and nonhelminth antigens, and to allergens. Exposure to helminths in utero may also have nonspecific effects that may modify the offspring's susceptibility to diseases mediated by inflammation, including metabolic disorders. The mechanisms of such effects are not known, but they deserve to be explored as current epidemiological findings suggest the possibility of primary prevention for inflammatory conditions such as allergy, through intervention during pregnancy.

Foodborne anisakiasis and allergy

Human anisakiasis, a disease caused by Anisakis spp. (Nematoda), is often associated with clinical signs that are similar to those associated with bacterial or viral gastroenteritis. With the globalisation of the seafood industry, the risk of humans acquiring anisakiasis in developed countries appears to be underestimated. The importance of this disease is not only in its initial manifestation, which can often become chronic if the immune response does not eliminate the worm, but, importantly, in its subsequent sensitisation of the human patient. This sensitisation to Anisakis-derived allergens can put the patient at risk of an allergic exacerbation upon secondary exposure. This article reviews some aspects of this food-borne disease and explains its link to chronic, allergic conditions in humans.

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.

Anisakis hypersensitivity in Italy: prevalence and clinical features: a multicenter study

BACKGROUND

Anisakis simplex (As), a parasite in fish, is able to sensitize humans via the alimentary tract. The prevalence of hypersensitivity and allergy to As outside the Iberian peninsula has not been investigated so far. We investigated Anisakis hypersensitivity in different areas of Italy.

METHODS

Consecutive subjects seen at 34 Italian allergy centers from October to December 2010 were investigated both by specific interview and by skin prick test (SPT) with As extract.

RESULTS

A total of 10 570 subjects were screened, of which 474 (4.5%) scored positive on Anisakis SPT and 66 of these (14% of those sensitized; 0.6% of the studied population) had a history of As allergy. Marinated anchovies were the most frequent cause of allergic reactions. Thirty-four (52%) patients were mono-sensitized to Anisakis. Sensitization rate showed marked geographic differences (range: 0.4-12.7%), being highest along the Adriatic and Tyrrhenian coasts, where homemade marinated anchovies are an age-old tradition. In inland centers in northern Italy, the prevalence was directly related to the number of inhabitants. The analysis of the impact of immigration on the prevalence of Anisakis hypersensitivity showed that about 60% of sensitized subjects in Milano and Torino came from southern Italy or from non-European countries.

CONCLUSIONS

Anisakis hypersensitivity and allergy are mainly a matter of dietary habits. Areas where marinated anchovies are popular can be considered as 'endemic' for this type of food allergy, whereas immigration and, possibly, new or imported trendy food styles, such as eating raw fish carpaccios or sushi, are a major causative factor in big cities of inland zones.

Chronic urticaria is associated with a differential helminth-arthropod-related atopy phenotype

The relationship between atopic sensitization and chronic urticaria is still controversial. In this study, we aimed to compare the prevalence of aeroallergen sensitization in chronic urticaria patients with (CU/As+) and without (CU/As-) sensitization against Anisakis simplex. Forty-nine CU/As+ and 80 CU/As- patients were studied and skin prick tests (SPT) were performed against aeroallergens. We assessed sensitization in a subgroup of patients with allergic rhinoconjunctivitis and/or bronchial asthma (RCBA) and compared the prevalence with a control group of 522 non-urticaria patients with RCBA. Forty-five percent of CU/As- and 60.4% of CU/As+ patients displayed positive SPT to at least one aeroallergen. CU/As+ patients had a higher prevalence of sensitization against pollen, mould or dander (PMD) (52.2% vs 29.1%, P < 0.01), whereas the prevalence of house dust mite (HDM) sensitization was not statistically different (26.3% in CU/As- and 36.7% in CU/As+). However, in chronic urticaria patients with RCBA, 53.8% of CU/As- and 57.9% of CU/As+ patients differed in the prevalence of HDM sensitization compared to the control group (33.5%, P = 0.03), whereas no difference could be stated for PMD sensitization. Compared to RCBA patients, both CU/As+ and CU/As- patients have a higher clinically relevant sensitization rate against HDM, thus displaying a differential atopy phenotype.

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.

Helminths and allergy: the example of tropomyosin

Parasitic worms contain potent allergens, but epidemiological and experimental studies suggest that infections with certain helminths are negatively associated with the prevalence of allergic diseases. This seeming contradiction can be addressed by using filarial tropomyosin as an example. This protein shares structural features and crossreacting B-cell epitopes with other highly allergenic invertebrate tropomyosins. Nevertheless, it usually does not provoke allergic disease in infected individuals. In addition, it is one of the most prominent candidates for an anti-nematode vaccine. Recent data suggest mechanisms that might prevent hosts from developing allergic reactions against allergens of their parasites, such as filarial tropomyosin.

Anisakis simplex: the high prevalence in Madrid (Spain) and its relation with fish consumption

Anisakiosis is a nematodosis with high prevalence in Spain. In this work we (a) investigated whether a recently introduced ELISA of Anisakis simplex-specific IgE in serum suffers from cross-reactivity with other common allergens; (b) used this assay to obtain an estimate of the prevalence of A. simplex-specific IgE in the population of Madrid; and (c) related positivity to fish consumption habits. No evidence of cross-reactivity between the ELISA and other allergens was found. The prevalence of positivity was 12.4% (11.7% among healthy subjects and 16% among patients with non-digestive non-allergic pathologies). All interviewed subjects reported consumption of uncooked fish (known to be the most likely source of infection); in addition, positivity was more prevalent among subjects who habitually consumed fresh and possibly undercooked fish than among those who generally consumed frozen fish or boiled or baked fish. These results are discussed in relation to the much lower prevalence observed in Galicia (N.W. Spain).

Sensitization to the fish parasite Anisakis simplex: clinical and laboratory aspects

Hypersensitivity to Anisakis simplex is a worldwide medical problem. The parasite larvae die after freezing or cooking, but the tolerance of sensitized subjects to eating frozen fish remains a matter of controversy with contradictory findings. The aim of this study was to test if intolerance to properly cooked/frozen fish was due to the recognition of a particular allergen. Sixty-four patients with Anisakis simplex sensitization were studied by an IgE multiblot using simultaneously five different antigenic extracts. The antigens tested were a crude extract, excretory/secretory allergens, a heated extract, and two gradient ethanol precipitates of the crude extract. Intolerance was reported by 20% of the patients and was not related to the detection of any special allergen, nor to total or specific IgE levels. Intolerant patients only reported a higher frequency of digestive symptoms than the patients who tolerated fish ingestion. The most sensitive immunoblot antigen source was the 50-66% ethanol fraction of a crude extract (10x concentrated) that was found to be positive in 100% of the samples. Interestingly, 95% sensitivity in the IgE-immunoblot assay could be achieved using only two allergens, Ani s 1 and Ani s 4. Allergens from the dead larvae remain a problem for 20% of the sensitized subjects. The use of a fractionated and concentrated crude extract improved the sensitivity of the immunoblot assay.

Sensitization to Ascaris lumbricoides and severity of childhood asthma in Costa Rica

BACKGROUND

Little is known about sensitization (defined as a positive IgE) to helminths and disease severity in patients with asthma.

OBJECTIVES

To examine the relationship between sensitization (defined as a positive IgE) to Ascaris lumbricoides and measures of asthma morbidity and severity in a Costa Rican population with low prevalence of parasitic infection but high prevalence of parasitic exposure.

METHODS

Cross-sectional study of 439 children (ages 6 to 14 years) with asthma. Linear regression and logistic regression were used for the multivariate statistical analysis.

RESULTS

After adjustment for parental education and other covariates, sensitization to Ascaris lumbricoides was associated with having at least 1 positive skin test to allergens (odds ratio, 5.15; 95% CI, 2.36-11.21; P < .001), increased total serum IgE and eosinophils in peripheral blood, reductions in FEV(1) and FEV(1)/forced vital capacity, increased airway responsiveness and bronchodilator responsiveness, and hospitalizations for asthma in the previous year (odds ratio, 3.08; 95% CI, 1.23-7.68; P = .02).

CONCLUSION

Sensitization to Ascaris lumbricoides is associated with increased severity and morbidity of asthma among children in Costa Rica. This association is likely mediated by an increased degree of atopy among children with asthma who are sensitized to Ascaris.

CLINICAL IMPLICATIONS

In areas with a low prevalence of helminthiasis such as Costa Rica, Ascaris sensitization may be an important marker of severe atopy and disease morbidity in children with asthma.

Expression and secretion of RANTES (CCL5) in granulomatous calcified tissue before and after lipopolysaccharide treatment in vivo

RANTES (regulated on activation, normal T cell-expressed and secreted) is a CC chemokine appearing to be involved in the recruitment of leukocytes at inflammation sites. RANTES is produced by CD8(+) T cells, epithelial cells, fibroblasts, and platelets. It acts in vitro in leukocyte activation and human immunodeficiency virus suppression, but its role in vivo is still uncertain. In our study, we established the involvement of RANTES in an in vivo model of chronic inflammation induced by potassium permanganate, leading to calcified granulomas. In our rat model, RANTES expression (mRNA and protein) was significantly upregulated in granulomatous tissue; RANTES expression was further increased upon i.p. injection of lipopolysaccharide (LPS), while it was kept at basal levels by dexamethasone (Dex) given 18 hours before sacrifice. LPS and Dex increased and decreased, respectively, the recruitment of mononuclear cells in granulomatous tissue compared with control granulomas from phosphate-buffered saline (PBS)-treated animals. In granuloma tissue, levels of RANTES were higher in LPS-treated rats and lower in the Dex group compared to controls. RANTES was also found in the conditioned medium of granuloma tissue from treated (LPS or Dex) and untreated (PBS) rats. When LPS was added in vitro for 18 hours, RANTES was further increased, except in the Dex group (P > 0.05). On serum analysis, RANTES levels were higher in the LPS group and lower in the Dex group compared to controls. This study shows for the first time that RANTES is produced in vivo in chronic, experimental inflammatory states, an effect increased by LPS and inhibited by Dex.