The hazard of mould hyposensitization in children with asthma

Going over Fungal Allergy: Alternaria alternata and Its Allergens

Fungal allergy is the third most frequent cause of respiratory pathologies and the most related to a poor prognosis of asthma. The genera Alternaria and Cladosporium are the most frequently associated with allergic respiratory diseases, with Alternaria being the one with the highest prevalence of sensitization. Alternaria alternata is an outdoor fungus whose spores disseminate in warm and dry air, reaching peak levels in temperate summers. Alternaria can also be found in damp and insufficiently ventilated houses, causing what is known as sick building syndrome. Thus, exposure to fungal allergens can occur outdoors and indoors. However, not only spores but also fungal fragments contain detectable amounts of allergens and may function as aeroallergenic sources. Allergenic extracts of Alternaria hyphae and spores are still in use for the diagnosis and treatment of allergic diseases but are variable and insufficiently standardised, as they are often a random mixture of allergenic ingredients and casual impurities. Thus, diagnosis of fungal allergy has been difficult, and knowledge about new fungal allergens is stuck. The number of allergens described in Fungi remains almost constant while new allergens are being found in the Plantae and Animalia kingdoms. Given Alt a 1 is not the unique Alternaria allergen eliciting allergy symptoms, component-resolved diagnosis strategies should be applied to diagnose fungal allergy. To date, twelve A. alternata allergens are accepted in the WHO/IUIS Allergen Nomenclature Subcommittee, many of them are enzymes: Alt a 4 (disulfide isomerase), Alt a 6 (enolase), Alt a 8 (mannitol de-hydrogenase), Alt a 10 (aldehyde dehydrogenase), Alt a 13 (glutathione-S-transferase) and Alt a MnSOD (Mn superoxide dismutase), and others have structural and regulatory functions such as Alt a 5 and Alt a 12, Alt a 3, Alt a 7. The function of Alt a 1 and Alt a 9 remains unknown. Other four allergens are included in other medical databases (e.g., Allergome): Alt a NTF2, Alt a TCTP, and Alt a 70 kDa. Despite Alt a 1 being the A. alternata major allergen, other allergens, such as enolase, Alt a 6 or MnSOD, Alt a 14 have been suggested to be included in the diagnosis panel of fungal allergy.

Immunotherapy of mold allergy: A review

Mold allergies are common, mainly target the respiratory tract and present as allergic rhinitis and/or bronchial asthma. Molds include a large group of different allergens that induce all types of allergic reactions. Allergen specific immunotherapies (AITs) to molds are common; however, at the present time, they are limited to Alternaria. This review presents not only the benefits but also the problems with such types of AIT based on the literature and our experience.

Mold allergens in respiratory allergy: from structure to therapy

Allergic reactions to fungi were described 300 years ago, but the importance of allergy to fungi has been underestimated for a long time. Allergens from fungi mainly cause respiratory and skin symptoms in sensitized patients. In this review, we will focus on fungi and fungal allergens involved in respiratory forms of allergy, such as allergic rhinitis and asthma. Fungi can act as indoor and outdoor respiratory allergen sources, and depending on climate conditions, the rates of sensitization in individuals attending allergy clinics range from 5% to 20%. Due to the poor quality of natural fungal allergen extracts, diagnosis of fungal allergy is hampered, and allergen-specific immunotherapy is rarely given. Several factors are responsible for the poor quality of natural fungal extracts, among which the influence of culture conditions on allergen contents. However, molecular cloning techniques have allowed us to isolate DNAs coding for fungal allergens and to produce a continuously growing panel of recombinant allergens for the diagnosis of fungal allergy. Moreover, technologies are now available for the preparation of recombinant and synthetic fungal allergen derivatives which can be used to develop safe vaccines for the treatment of fungal allergy.

Sublingual immunotherapy for Alternaria-induced allergic rhinitis: a randomized placebo-controlled trial

BACKGROUND

Respiratory allergy due to Alternaria is a relevant clinical problem, and specific immunotherapy may represent a viable treatment option. Sublingual immunotherapy (SLIT) is safe and effective, but data for Alternaria are lacking.

OBJECTIVE

To assess the efficacy of standardized SLIT in patients sensitized to Alternaria in a randomized, prospective, double-blind, placebo-controlled trial.

METHODS

Patients with rhinitis with or without intermittent asthma and ascertained allergy to Alternaria were enrolled. After a baseline season, SLIT or matched placebo was given for 10 months. Symptoms and rescue medication intake were recorded on diary cards between June and October. Skin prick testing was performed and specific IgE, IgG4, and precipitin levels were measured at baseline and at the end of the study.

RESULTS

Twenty-seven patients (age range, 14-42 years) were randomized, and 26 completed the study. The baseline characteristics were homogeneous in the 2 groups. After treatment, patients receiving SLIT had a significant improvement in symptoms and a reduction in medication intake vs placebo and vs the run-in season, whereas no change was seen in the placebo group. Skin prick test reactivity significantly decreased only in the SLIT group. No change was seen in specific IgG4 levels in the 2 groups, whereas Alt a 1 specific IgE levels significantly increased in the active group. One patient in the active group reported oral itching and conjunctivitis at the beginning of treatment.

CONCLUSION

SLIT seems effective and safe and may represent a valuable therapeutic option in respiratory allergy due to Alternaria.

Effect of allergen-specific immunotherapy with purified Alt a1 on AMP responsiveness, exhaled nitric oxide and exhaled breath condensate pH: a randomized double blind study

Background

Little information is available on the effect of allergen-specific immunotherapy on airway responsiveness and markers in exhaled air. The aims of this study were to assess the safety of immunotherapy with purified natural Alt a1 and its effect on airway responsiveness to direct and indirect bronchoconstrictor agents and markers in exhaled air.

Methods

This was a randomized double-blind trial. Subjects with allergic rhinitis with or without mild/moderate asthma sensitized to A alternata and who also had a positive skin prick test to Alt a1 were randomized to treatment with placebo (n = 18) or purified natural Alt a1 (n = 22) subcutaneously for 12 months. Bronchial responsiveness to adenosine 5'-monophosphate (AMP) and methacholine, exhaled nitric oxide (ENO), exhaled breath condensate (EBC) pH, and serum Alt a1-specific IgG₄ antibodies were measured at baseline and after 6 and 12 months of treatment. Local and systemic adverse events were also registered.

Results

The mean (95% CI) allergen-specific IgG₄ value for the active treatment group increased from 0.07 μg/mL (0.03-0.11) at baseline to 1.21 μg/mL (0.69-1.73, P < 0.001) at 6 months and to 1.62 μg/mL (1.02-2.22, P < 0.001) at 12 months of treatment. In the placebo group, IgG₄ value increased nonsignificantly from 0.09 μg/mL (0.06-0.12) at baseline to 0.13 μg/mL (0.07-0.18) at 6 months and to 0.11 μg/mL (0.07-0.15) at 12 months of treatment. Changes in the active treatment group were significantly higher than in the placebo group both at 6 months (P < 0.001) and at 12 months of treatment (P < 0.0001). However, changes in AMP and methacholine responsiveness, ENO and EBC pH levels were not significantly different between treatment groups. The overall incidence of adverse events was comparable between the treatment groups.

Conclusion

Although allergen-specific immunotherapy with purified natural Alt a1 is well tolerated and induces an allergen-specific IgG₄ response, treatment is not associated with changes in AMP or methacholine responsiveness or with significant improvements in markers of inflammation in exhaled air. These findings suggest dissociation between the immunotherapy-induced increase in IgG₄ levels and its effect on airway responsiveness and inflammation.

Double-blind, placebo-controlled study of Alternaria alternata immunotherapy: clinical efficacy and safety

Allergen-specific immunotherapy (ASIT) with fungal extracts has been beset by safety and efficacy problems, which result mainly from qualitative and quantitative variations. Little has been published on the safety and efficacy of these extracts. The objective was to analyze the safety and efficacy of ASIT with an Alternaria alternata extract. A total of 28 patients were selected with rhinitis and/or bronchial asthma because of Alternaria allergy and monosensitization to molds. The patients were randomized to an active ASIT or placebo group, both groups on a conventional immunotherapy schedule (increasing weekly doses until maintenance dose and then monthly doses). Adverse reactions were classified with the European Academy of Allergology and Clinical Immunology system. Clinical efficacy was analyzed for a year with symptom/medication diary cards, peak expiratory flow (PEF) measures, clinical severity score, severity of symptoms (visual analog scale), subjective evaluation of treatment by the patient and the physician, and a quality of life questionnaire. Twenty-three patients completed the study; all reached the established maintenance dose with only two mild adverse reactions in the whole sample. Significant improvements were found after 6 months in respiratory symptoms in the active treatment group, and in all symptoms in both groups. PEF increased significantly in the active treatment group but not in the placebo group. The severity of asthma decreased in the active treatment group, and the severity of rhinitis decreased in both groups. Visual analog scale scores for severity of symptoms improved in all phases in the active treatment group, but only after 12 months in the placebo group. Physicians judged the disease course as significantly better in the active treatment group. ASIT with the A. alternata extract was safe, with clinical improvements after one year of treatment.

Immunotherapy with Alternaria alternata: present and future

The prevalence of fungal allergies is greater than previously believed; consequently, such processes have been underestimated as potential causes of respiratory tract disease. Most patients sensitized to fungi exhibit perennial symptoms, though their intensity increases in the summer and autumn months. Skin reactions to the antigens of Alternaria alternata are associated with a high risk of allergic respiratory conditions in the presence of spores of this fungus -fundamentally in children and young adults- with a special form of presentation as life-threatening asthma. Very few controlled studies have examined the efficacy and safety of fungal extract immunotherapy -the main problem being the lack of standardized extracts for the diagnosis and treatment of such patients. In the year 2005 a tolerance study was made in children in relation to a depot extract containing the predominant antigen of Alternaria, with two different regimens (short and cluster). Tolerance was found to be good, with a 0.95 % incidence of local reactions and a 0.95 % incidence of grade 2 systemic reactions. Few studies involving sublingual immunotherapy have been conducted to date.

Immunotherapy in fungal allergy

For decades airborne fungal spores have been implicated as causative factors in respiratory allergy. Exposure to high atmospheric spore counts and sensitization to specific fungal allergens have been associated with severe asthma, mainly in young adults. Although the prevalence of sensitization to commercial fungal extracts is approximately 3% in epidemiologic studies, in selected patients, particularly with asthma, the sensitization rate might increase to 30%. Of the estimated number of more than 1 million of different fungal species, approximately 80 fungi have been connected with respiratory allergy. Currently, diagnosis and specific therapy of fungal allergy is hampered by the poor quality of most of the commercially available extracts. Clinical efficacy of specific immunotherapy with fungal extracts has been shown in 79 actively treated patients in four controlled trials, with only two fungal species, namely Alternaria alternata and Cladosporium herbarum. The use of recombinant fungal allergens might create new prospects in diagnosis and specific immunotherapy for fungal allergy.

Systemic reactions and fatalities associated with allergen immunotherapy

OBJECTIVE

The primary objective of this review is to discuss systemic allergic reactions and risk factors associated with the injection of allergen vaccines.

DATA SOURCES

A review of the literature on anaphylactic reaction, adverse effects, and fatalities associated with allergen immunotherapy (IT) was conducted.

STUDY SELECTION

The expert opinion of the author was used to select relevant data.

RESULTS

Systemic allergic reactions associated with the injection of allergen vaccines usually begin within 20 minutes. However, on occasion, they begin 20 to 30 minutes or longer after an injection. Such reactions can also occur after allergen skin testing. Most reactions associated with skin testing and allergen IT are mild and readily respond to appropriate treatment. However, severe and even fatal reactions have been reported with both skin testing and IT.

CONCLUSIONS

Risk factors for skin testing and allergen IT include: 1) patients, particularly asthmatic patients, suffering with seasonal exacerbation of their symptoms; 2) patients who demonstrate exquisite sensitivity to particular allergen(s); 3) patients on beta-blockers; 4) patients with asthma, especially if their asthma is unstable; 5) patients in whom rush IT is used; and 6) patients in whom high doses of potent standardized allergen vaccines are used. It is essential that strict attention be paid to the risk factors for systemic reactions, and that techniques and management be initiated both before and after skin testing or IT to minimize these risks. Done properly, the risk of skin testing and IT is minimal.

Immunotherapy for childhood asthma: is there a rationale for its use?

OBJECTIVE

This paper reviews the literature regarding immunotherapy in the management of childhood asthma. Immunotherapy is a well established treatment of venom allergy and allergic rhinitis, however its use in asthma remains controversial.

DATA SOURCES

We reviewed the pediatric literature from 1966 to 1994 and evaluated the existing studies for clinical efficacy of immunotherapy in childhood asthma.

STUDY SELECTION

Only 12 purely pediatric studies existed over the time period that we reviewed. The studies used a variety of different antigens including house dust, house dust mite, grass, mold, cat, dog, and combinations of antigens.

RESULTS

In reviewing the studies, we assessed study duration, number of subjects, whether it was blinded, placebo controlled or open labeled, the measures of clinical efficacy and the assessments of specific and nonspecific bronchial reactivity. The studies were very heterogeneous, and therefore direct comparison and extrapolation of conclusions was difficult. The majority of the studies demonstrated either an improvement in asthmatic symptoms or a decrease in bronchial reactivity to the specific antigen employed, or both. The minority of studies demonstrated no clinical efficacy. The most consistent evidence of benefit was suggested in those trials employing house dust mite therapy, while immunotherapy for grass and cats demonstrated some benefit but the number of studies employing these treatments was very small. There are no trials that provide convincing evidence that immunotherapy with dog and mold antigens is effective for childhood reactive airway disease.

CONCLUSION

Asthma is a multifactorial disease with many triggers. In establishing a role for immunotherapy one must consider all the different aspects such as allergic triggers, environmental stresses, and viral infections. The literature is unclear as to when immunotherapy should be initiated for childhood asthma. While there are suggestions that immunotherapy should be considered for the child with mild or moderate asthma and dust mite sensitivity when pharmacotherapy is not efficacious, the immunomodulatory properties of immunotherapy may actually be more tailored for early intervention in asthma rather than for use once symptoms have occurred. More research is required in order to clarify whether immunotherapy should be recommended more often for the treatment of childhood asthma.

Safety considerations in assessing the role of immunotherapy in allergic disorders

Specific immunotherapy (SIT) is accepted as an effective treatment of allergic diseases when high quality extracts are used. However, this form of treatment can cause untoward reactions among which systemic reactions are the most severe. Although life-threatening reactions are rare and deaths exceptionally reported, SIT should be prescribed by allergists to patients with well defined characteristics, and administered with care by (or under the close supervision of) physicians trained to deal rapidly with the reactions. Reactions with standardised extracts occur mostly during the dose increase phase but they can be prevented using adapted schedules and premedication. During maintenance injections or when vial batches are changed, standardised extracts of known shelf-life usually result in a low rate of systemic reactions. Patients with asthma are more prone to develop systemic reactions, and allergens should not be administered to patients with a forced expiratory volume in 1 second (FEV1) under 70% of predicted or in those who have unstable or symptomatic asthma. Systemic reactions may be observed with all allergens and allergenic preparations although it appears that high molecular weight extracts may be safer.

Recurrent pericarditis: a rare complication of allergen immunotherapy

We report on a 29-year-old woman suffering from hay fever due to grass and olive tree pollens. She developed recurrent pericarditis during her first course of immunotherapy with an alum-adsorbed pollen extract. A causal relationship was established between the allergen injections and the acute pericarditis episodes on two consecutive occasions, which presented with blood eosinophilia. Blood cultures and serological tests for microorganisms were negative. There were no signs of autoimmune disease or systemic vasculitis. To the best of our knowledge, allergen immunotherapy-induced pericarditis has not been previously reported.

Double-blind, placebo-controlled rush immunotherapy with a standardized Alternaria extract

Specific immunotherapy is ineffective with unstandardized mold extracts. A double-blind, placebo-controlled study was performed in 24 patients (5 to 56 years of age) only allergic to Alternaria. The extract was standardized by isoelectric focusing, crossed immunoelectrophoresis, crossed radioimmunoelectrophoresis, RAST inhibition, and skin tests and contained allergen Alternaria major allergen a I and antigen B. Thirteen patients received the active treatment, and 11 received the placebo. Immunotherapy was started by a 2-day rush protocol; maintenance injections were administered for 1 year. The patient's self-evaluation of the treatment was significantly (p less than 0.001) lower in the placebo-treated group. Global symptom-medication scores, including asthma and rhinoconjunctivitis, were significantly (p less than 0.005) lower in the actively treated group. Nasal challenges with Alternaria extract were performed before immunotherapy and after 1 year of treatment. There was no difference in the placebo-treated group and a significantly (p less than 0.01) increased mean provocative dose in the actively treated group. Skin tests were significantly reduced in the actively treated group. Specific IgG increased significantly in the actively treated group and were stable in the placebo-treated group. There was a significant correlation between nasal challenges and nasal symptom-medication scores (p less than 0.03) or the patient's self-evaluation of efficacy (p less than 0.05). This study demonstrated that patients only sensitized to Alternaria benefit from specific immunotherapy with a standardized Alternaria extract.

A prospective study on the safety of immunotherapy in children with severe asthma

One hundred and six of 503 (21%) consecutive children with asthma, who from 1979 to 1983 commenced hyposensitization therapy, were prospectively studied on the safety of immunotherapy. More than 80% of the patients completed therapy without side effects. Thirteen patients were withdrawn from hyposensitization due to moderate and predictable, but intolerable, side effects such as asthma/rhinitis, urticaria and subcutaneous nodules and hypersensitivity to aluminium. However, more alarming was the outcome in six children, who after an uneventful course of immunotherapy and after several months on maintenance therapy, suddenly, 5 to 20 min (mean 10 min) following an earlier tolerable allergen injection, developed severe, anaphylactic reactions, in three of them nearly fatal. Mould extracts were responsible for the most frequent and serious side effects (Alternaria iridis/alternata, 3 patients, Cladosporium herbarum, 8 patients). Furthermore, serious, but not immediately life-threatening, anaphylactic reactions occurred in two children treated with Phleum pratense. On the other hand, hyposensitization with Dermatophagoides pteronyssinus was very well tolerated.

Diagnosis and immunotherapy of mould allergy. V. Clinical efficacy and side effects of immunotherapy with Cladosporium herbarum

A placebo-controlled, double-blind study of immunotherapy with the mould species Cladosporium was performed in 22 adult asthmatics. The diagnosis of Cladosporium allergy was based on a combination of bronchial provocation test and daily symptom score in the Cladosporium season. An aqueous preparation of a potent, biologically standardized and purified extract was used in a clustered dose-increase regimen. The clinical efficacy was evaluated by a combination of symptoms (asthma score + peak flow) and consumption of antiasthmatic medication. The mean changes in symptoms and medication consumption over a 10-week registration period (peak Cladosporium season) in 1982 after 5-7 months of immunotherapy were compared with the corresponding 1981 pretreatment 10-week period. A significant (P = 0.03) difference in terms of "improved", "unchanged" and "deteriorated" patients in favour of Cladosporium treatment was found. Approximately 80% in the Cladosporium group showed improved/unchanged symptoms contrary to 30% of the placebo treated. Side effects were observed frequently but only in the Cladosporium-treated. About 70% experienced a large local reaction and 100% had episodes of asthma during dose-increase phase. Only a few severe systemic reactions occurred. Based on the clinical efficacy of the treatment we consider immunotherapy with Cladosporium feasible for highly specialized clinics.