The additional values of microarray allergen assay in the management of polysensitized patients with respiratory allergy

BACKGROUND

The IgE response is directed against specific components from an allergenic source. The traditional diagnostic methods use whole extracts, containing allergenic, nonallergenic and cross-reactive molecules. This may pose diagnostic challenges in polysensitized patients. Microarray techniques detect specific IgE against multiple molecules, but their value in term of additional information and economic saving has not been yet defined.

OBJECTIVE

We assessed the additional diagnostic information provided by an allergen microarray in a large population of polysensitized subjects.

METHODS

In this multicentre study, allergists were required to carefully record diagnosis and treatment of consecutive patients referred for asthma/rhinitis, using the standard methodology (history, skin prick test, IgE assay). Then, a microarray allergen assay was carried out. Clinicians were required to review their diagnosis/treatment according to microarray results.

RESULTS

318 allergic patients (30% reporting also nonrespiratory symptoms) and 91 controls were enrolled. The clinicians reported at least one additional information from the microarray in about 60% of patients, this resulting in therapeutic adjustments. In 66% of patients IgE to pan-allergens were detectable, being this clinically relevant in 38% of patients with polysensitization to pollens.

CONCLUSION

Microarray IgE assay represents an advancement in allergy diagnosis, as a third-level approach in polysensitized subjects, when the traditional diagnosis may be problematic.

Adherence to pharmacological treatment and specific immunotherapy in allergic rhinitis

The term compliance simply indicates how much doses of the prescribed medication are taken, whereas the term adherence implies also an agreement between patient and physician about the therapeutic plan, and it is therefore preferred. Adherence is a main problem in all long-term treatments. Thus, it represents a problem also in the case of rhinitis, expecially concerning specific immunotherapy that must be assumed continuously for several years. Many factors can affect the adherence, depending on patient, on treatment itself and on the healthcare context, and all those factors usually interact. The adherence measured in controlled trials is usually good, but this does not reflect what happens in real life, where adherence should be preferably measured. There are few data on the adherence in real life for pharmacological treatments of allergic rhinitis (e.g. nasal steroids or antihistamines), whereas more data are available for specific immunotherapy. In this latter case, in real life, adherence seems to be far from optimal, for both sublingual and subcutaneous immunotherapy, although the recent studies agree on the fact that some interventions (i.e. patients' education, strict follow-up, regular contacts) could effectively improve the adherence. In this article, the literature concerning the adherence to pharmacological treatments and immunotherapy in allergic rhinitis was searched and reviewed.

IgE to staphylococcal enterotoxins are undetectable in sera from patients with nasal polyposis

Nasal polyposis is a frequent disease, sometime associated with asthma and non steroidal anti-inflammatory drugs intolerance. Staphylococcus aureus colonization can play a pathogenetic role in same cases by a severe eosinophilic inflammation, which can suggest new therapeutic approaches. Staphylococcus aureus colonization has been demonstrated by local specific enterotoxins IgE dosage in polyps homogenates. This study demonstrate lack of detection of serum enterotoxins specific IgE to staphylococcal in patients with nasal polyposis, compared with healthy subjects.

Allergen immunotherapy: 100 years, but it does not look like

Allergen immunotherapy (AIT) is the only treatment able to act on the causes and not merely on the symptoms of allergy. AIT was introduced 100 years ago but remained an empirical treatment for more than 40 years, when the first controlled trial in 1954 opened the era of scientific evidence. A major advance was the introduction of venom immunotherapy to prevent anaphylaxis from insect stings in 1978. Concerning inhalant allergens, currently AIT may be administered in two forms, subcutaneous (SCIT), and sublingual immunotherapy (SLIT). A large number of trials, globally analyzed in a number of meta-analyses, gave sound evidence to the efficacy and safety of SCIT and SLIT in allergic rhinitis and asthma. Adverse systemic reactions are still a drawback for SCIT while safety and tolerability of SLIT are very good, provided recommended doses and schedules of administration are used A significant advance for SLIT development was the registration in Europe of the standardized quality tablets. New applications, such as food allergy and atopic dermatitis, as well as new routes of administration, are currently under evaluation. After 100 years of use, AIT has a central role in the management of allergy and the ongoing improvement seems able to warrant to AIT an even brighter future.

Food-specific IgG4 lack diagnostic value in adult patients with chronic urticaria and other suspected allergy skin symptoms

BACKGROUND

Specific IgG4 dosing against food is proposed to the public by a lot of commercial laboratories as a reliable method to diagnose food intolerance. Actually, few data on IgG4 responses to foods in adults are available in the literature. In this study we evaluated the clinical utility of specific IgG4 dosing against food in adult patients with suspected food allergy/intolerance.

METHODS

A case series of 73 adult patients with suspected food allergy and clinical manifestations of chronic urticaria or other allergy-supposed skin symptoms were tested for specific IgG4 against foods. An open food challenge was carried out for all IgG4-positive food. All positive open tests were controlled by double-blind placebo-controlled food challenge.

RESULTS

Forty-five patients (62%) were IgG4 positive for a number of foods, mainly egg, milk, casein and wheat. None of the patients with IgG4-positive testing showed adverse reactions, neither immediate nor delayed, to the corresponding food.

CONCLUSIONS

In adult patients, testing for specific IgG4 lacks clinical utility for the diagnosis of food allergy or intolerance. Dosing of IgG4 should not be part of the diagnosis and therapy of adult patients with allergy-like skin diseases.

Respiratory allergy induced by exclusive polysensitization to serum albumins of furry animals

In this report we describe un unusual case of exclusive allergic sensitization to furry animals, as a possible study model to speculate about different modalities ofsensitization to allergens of common and less common mammalian species. A 27-year-old woman referred in our Allergological Centre for the occurrence of conjunctival and severe respiratory symptoms after contact with several animals such as cats, dogs, rabbits, horses, cows etc. Patient underwent clinical and anamnestic evaluation including a detailed information on the modality of exposure to different furry animals. Skin-prick-test (SPT) was performed with our routine panel of commercial standardized extracts (Lofarma Laboratories, Milan, Italy). Some animal allergenic extracts (rabbit, horse, rat, mouse, cavia, cow and hamster) have been tested by SPT one week after the routine SPT A blood sample was taken for measurement of total IgE and specific IgE (CAP System, Phadia, Uppsala, Sweden) as well as Immunoblotting procedures. The results of in vivo and in vitro procedures revealed allergic sensitization only to animal-derived allergens. Total IgE were 59.3 kU/L. Immunoblotting showed a specific IgE-mediated sensitization of the patient to cow's, rabbit's and horse's serum albumins (SA). In conclusion, our case report confirms the role of SA as cross-reacting agent in allergic sensitization to furry animals. This finding suggests to perform SPTs to several furry animal allergens in all individuals with high level of allergic sensitization to common pets (cats and/or dogs) in order to identify allergy to other animals and consequently to avoid future exposures at risk.

How much specific is the association between hymenoptera venom allergy and mastocytosis?

BACKGROUND

The preferential association of mastocytosis with hymenoptera sting reactions is well known, but there is no data on the prevalence of clonal mast cell disorders in subjects with severe systemic reactions due to foods or drugs.

METHODS

Patients with food- or drug-induced severe systemic reactions, including anaphylaxis, and increased serum tryptase were studied for the presence of mastocytosis, and compared with a population of patients with hymenoptera allergy. The aetiological role of foods or drugs was assessed according to current recommendations. Systemic reactions were graded in severity according to the procedure described by Mueller. Serum tryptase was considered increased if the level was >11.4 ng/ml. Subjects with increased tryptase had dermatological evaluation and Bone marrow(BM) aspirate-biopsy, which included histology/cytology, flow cytometry and detection of KIT mutations.

RESULTS

A total of 137 subjects (57 male, mean age 42 years) were studied. Of them, 86 proved positive for drugs and 51 for foods. Overall, out of 137 patients, only nine (6.6%) had a basal tryptase >11.4 ng/ml, and only two (1.5%) were diagnosed with mastocytosis. This was clearly different from patients with hymenoptera allergy, where 13.9% had elevated tryptase and 11.1% had a clonal mast cell disorder.

CONCLUSION

The association of clonal mast cell disorders with hymenoptera allergy seems to be more specific than that with food- or drug-induced systemic reactions.

Administration regimens for sublingual immunotherapy to pollen allergens: what do we know?

The modalities of administration of sublingual immunotherapy (SLIT), including dosing, build-up phase, duration of the treatment, and frequency of the maintenance dose are largely variable. In the case of pollen (SLIT), the complexity increases, since preseasonal, coseasonal and pre-coseasonal regimens can be used. The administration regimens are of relevance from a practical point of view, but can also have economic implications. We review herein the available literature (randomized double blind controlled studies) on pollen SLIT, in order to derive experimentally-supported suggestions about the regimens of administration that should be preferred.

A prospective Italian survey on the safety of subcutaneous immunotherapy for respiratory allergy

BACKGROUND

Subcutaneous immunotherapy is effective for the treatment of respiratory allergy, and it is largely used in Italy, but no systematic safety assessment has been carried out so far.

OBJECTIVE

To assess prospectively the safety of injection immunotherapy in a multicentre, real-life survey.

METHODS

Eleven Italian allergy departments recorded the clinical characteristics of systemic reactions (SRs) due to immunotherapy. Vaccines were prescribed according to guidelines; only standardized depot extracts were used. SRs were graded according to the EAACI recommendations, and were classified as immediate or delayed.

RESULTS

One thousand seven hundred and thirty-eight patients (847 males, age range 5-71) received immunotherapy from eight different manufacturers, for a total of 2038 courses (300 patients received two extracts). A total of 60 785 injections were given over a mean immunotherapy duration of 3 years. Overall, 95 reactions were observed in 57 patients (3.28%), corresponding to 4.7% of the courses and 1.56/1000 injections. Twenty-five patients experienced more than one adverse event. There were 34 grade 2, 60 grade 3 and one grade 4 reactions and no fatality. SRs occurred more frequently in patients with asthma than in patients with rhinitis alone (4.1% vs. 1.1%), and were equally distributed between the build-up and the maintenance phase. Ragweed and grass extracts caused significantly more side effects than other allergens.

CONCLUSION

In this large prospective study, the rate of SRs was low, thus confirming that injection immunotherapy has an acceptable risk/benefit ratio when prescribed and carried out according to recommendations.

Severe respiratory syndrome induced by allergic mono-sensitization to European hamster (Cricetus cricetus) in a older woman

Although the increase in the rate of hamster ownership, no report of allergic sensitization to common hamster (Cricetus cricetus)-derived allergens as a consequence of domestic exposure has been published in Italy. A 64-year-old woman was referred to our Allergy Centre for the recent onset of conjunctival and severe respiratory symptoms (rhinitis, cough, wheezing and dyspnea). About three months ago she had purchased a common hamster as home pet. Another hamster had lived at patient's home for about four months nine years ago. The results of SPT revealed allergic sensitization to Cricetus cricetus dander only (wheal 6x7 mm, positive control 7x7 mm). Total IgE were 59.3 kU/L. Specific IgE only to Cricetus cricetus epithelia (2.10 kUA/L), were also detected. Spirometry revealed a moderate degree of bronchial obstruction. Some important considerations can be drawn from our report: a) few months of hamster ownership are probably sufficient to induce an allergic sensitization and clinical symptoms, b) older age of sensitization in comparison to other studies, c) rapid remission of clinical symptoms after the removal of hamster d) skin prick tests and/or evaluation of specific IgE for hamster allergens should be performed in all potentially susceptible individuals.

Effectiveness of vacuum-cleaning in removing Fel d 1 allergen from cotton fabrics exposed to cats

BACKGROUND

The major cat allergen, Fel d 1, is ubiquitous, and clothes of cat owners are important vehicles for its distribution and dispersal in cat-free environments.

OBJECTIVE

We assessed the efficiency of a standard vacuum-cleaning in removing the cat allergen from cotton fabrics, experimentally contaminated by a prolonged contact with cats.

METHODS

Fifteen rectangles (80 x 100 cm) of a widely used cotton material were kept in baskets of male cats for 1 week. Afterwards, the squares were cut in half. One half was immediately sampled for cat allergen, and the other half was vacuum-cleaned for 15 minutes by a commercially available device before sampling. Five identical cotton rectangles not exposed to cats served as controls. Samples were collected with a high-volume vacuum air-sampler. Particulate material was harvested onto filters with 25-mm diameter and 2 microm pore size, extracted in phosphate buffer with BSA and then assayed for the Fel d 1 allergen with an ELISA method. The results were expressed as micrograms of allergen per filter.

RESULTS

After vacuum-cleaning the amounts of Fel d 1 extracted from cat-exposed fabrics were not significantly reduced ( t = 3.118; P > 0.005), with respect to the non vacuum-cleaned tissues. No Fel d 1 was found in control fabrics.

CONCLUSIONS

Our study suggest that vacuum-cleaning by using a commercially available device is not able to remove significant amounts of cat allergen from cotton fabrics exposed to cats.

Evaluation of the IgE cross-reactions among vespid venoms. A possible approach for the choice of immunotherapy

BACKGROUND

Hymenoptera venom allergy can be effectively cured with specific immunotherapy, thus the correct identification of the allergen is essential. In the case of multiple skin and serum positivities it is important to know if a cross-reaction among venoms is present. We studied by CAP-inhibition assays the degree of cross-reactivity between Vespula vulgaris and Polistes dominulus.

METHODS

Serum samples were obtained from consecutive patients with a clinical history of grade III-IV reactions to hymenoptera sting and with nondiscriminative skin/CAP positivity to both Vespula and Polistes. Inhibition assays were carried out with a CAP method, incubating the sera separately with both venoms and subsequently measuring the specific immunoglobulin E (IgE) to venoms themselves.

RESULTS

Forty-five patients (33 male, mean age 40 years, age range 12-74, total serum IgE 242 +/- 168 kU/l) were included. Their specific IgE to Vespula and Polistes were 12.03 +/- 5.70 kU/l and 10.7 +/- 2.0 kU/l (P = NS), respectively. At the CAP-inhibition assays, in 25 patients a >75% heterologous inhibition by P. dominulus venom against V. vulgaris-specific IgE was found. In six subjects V. vulgaris venom effectively inhibited the P. dominulus-specific IgE. In the remaining 14 cases the CAP-inhibition test provided intermediate and not discriminative results.

CONCLUSION

In 31/45 patients, the double sensitizations to venoms were probably the result of cross-reactions and the CAP-inhibition allowed identifying the true double sensitizations. This approach may be helpful for the correct prescription of immunotherapy in the case of V. vulgaris and P. dominulus double positivity.

Practice parameters for sublingual immunotherapy

The efficacy and safety of sublingual immunotherapy (SLIT) are currently supported by clinical trials, meta-analysis and post-marketing surveys. Practice parameters for clinical use of SLIT are proposed here by a panel of Italian specialists, with reference to evidence based criteria. Indications to SLIT include allergic rhinoconjunctivitis, asthma, and isolated conjunctivitis (strength of recommendation: grade A). As to severity of the disease, SLIT is indicated in moderate/severe intermittent rhinitis, persistent rhinitis and mild to moderate asthma (grade D). SLIT may be safely prescribed also in children aged three to five years (grade B), and its use in subjects aged more than 60 years is not prevented when the indications and contraindication are ascertained (grade D). The choice of the allergen to be employed for SLIT should be made in accordance with the combination of clinical history and results of skin prick tests (grade D). Polysensitisation, i.e. the occurrence of multiple positive response does not exclude SLIT, which may be done with the clinically most important allergens (grade D). As to practical administration, co-seasonal, pre co-seasonal, and continuous schedules are available, being the latter recommended for perennial allergens or for pollens with particularly prolonged pollination, such as Parietaria (grade D). For pollens with relatively short pollination, such as grasses and trees (cypress, birch, alder, hazelnut, olive) the pre co-seasonal and perennial schedules are preferred (grade C). The build-up phases suggested by manufacturers can be safely used (grade A), but they can be modified according to the patient's tolerance (grade C). A duration of SLIT of 3-5 years is recommended to ensure a long-lasting clinical effect after the treatment has been terminated (grade C).

In chronic idiopathic urticaria autoantibodies against Fc epsilonRII/CD23 induce histamine release via eosinophil activation

BACKGROUND

Chronic idiopathic urticaria is a common skin disorder characterized by recurrent, transitory, itchy weals for more than 6 weeks. An autoimmune origin has been suggested based on the findings of auto-antibodies (Abs) directed against either the alpha subunit of the high-affinity IgE receptor or the IgE molecule in nearly half of the patients.

OBJECTIVE

To identify other autoantigen targets in patients with chronic idiopathic urticaria.

METHODS

We used pooled IgG derived from 133 patients with chronic idiopathic urticaria to screen a random peptide library to identify disease-relevant autoantigen peptides. Among the identified peptides, one was recognized by the vast majority of patients' sera. Abs against this peptide were affinity purified from the patients' sera and assayed for their ability to induce histamine release from basophils.

RESULTS

We identified a peptide that showed similarity with the low-affinity IgE receptor (Fc epsilonRII/CD23) expressed on lymphomonocytes and eosinophils. Anti-peptide IgG Abs purified from the patients' sera bound cell surface CD23 and were able to induce histamine release from basophils. This effect appeared to be mediated by the release of major basic protein from eosinophils upon engagement of CD23. The same effects were obtained with the sera from mice immunized with the CD23 peptide.

CONCLUSION

Our results indicate that patients with chronic idiopathic urticaria have Abs against CD23 and that eosinophils, which infiltrate the skin of these patients, play a crucial role in maintaining the disease through the release of major basic protein upon engagement of the low-affinity IgE receptor by such auto-Abs.

Analysis of the positivity rate in IgE positive patients to inhalant allergens in Verona Hospital Laboratory during 2002-2003

BACKGROUND

At present test tube allergy diagnosis is becoming increasingly more comparable to skin prick tests and is therefore increasingly more reliable, not only from an analytical point of view but also from a clinical one. The cost of test tube allergens has decreased over the years and the specific IgE dosage can quickly give a good diagnostic indication.

OBJECTIVE

To study the percentage of positive subjects for each individual allergen in cases of suspected allergy, the laboratory can easily identify, also by age bracket, the positivity for those well known allergens that are more commonly responsible for allergic pathologies by using the skin prick test. Our laboratory has studied the test tube diagnostic activity of 2002 and 2003. The inhaled allergens used to identify the positivity percentage were selected from those in our Allergy Unit and which literature identifies as those more commonly positive at skin prick tests.

METHODS

The positivity rate of specific IgEs (UniCAP100- Phamarcia) were analyses for two age brackets before and after the age of 12. The younger than 12 group was then subdivided further into pre-school age (3-5 years) and school age (6-12).

RESULTS

It can be stated that in the grass group, the seasonal allergens, the most commonly positive were cereals and pellitory, the latter increasing in adult age (above 12 years). In the tree group of seasonal allergens, positivity was found to increase in adult age for olive and cypress trees. The more commonly positive perennial allergens in the adult age (above 12) are dermathophagoides and cat. Below 12, there is a strong positivity to alternaria.

CONCLUSIONS

Such test tube studies on IgE positivity are not only useful for better defining diagnostic patterns to give an initial idea of suspected allergy, but also to highlight any changes in the IgE antibody count within different age brackets, with the possibility of documenting the progress of the pathology which is characteristic of the allergy in question.