Late and immediate systemic-allergic reactions to inhalant allergen immunotherapy

Comparison of Pediatric and Adult Systemic Reactions to Subcutaneous Immunotherapy

BACKGROUND

Subcutaneous immunotherapy (SCIT) has been used to treat allergic rhinitis for over a century, and current regimens have wide variability with an array of practice styles and dosing strategies. Although there are some statements about contraindications and cautions, no specific formal age- or weight-based dosing guidelines are utilized when administering SCIT.

OBJECTIVE

The primary objective of this study was to estimate the overall incidence rate of any reaction to SCIT and to consider the severity of the reaction by grade in children and adults.

METHODS

A retrospective chart review was conducted to document the number and severity of episodes of systemic reactions (SRs) in pediatric and adult subjects. Crude incidence rates were estimated as the number of SRs relative to the total injections administered. Adjusted incidence rate ratios were generated using a generalized estimating equation approach, which accounted for multiple visits within subjects.

RESULTS

The incidence rate for any SR was 0.2%. The unadjusted incidence rate of any SR was significantly higher in children compared with adults (P < .001), although not significant when adjusted for asthma, gender, and phase of SCIT (P < .054). However, the incidence rate for grade 1 and 2 SRs in children was 1.89 times the incidence rate for adults, adjusting for these variables (P < .015).

CONCLUSIONS

These results suggest that current SCIT practices are associated with a higher rate of SRs, specifically of grade 1 and 2 SRs, in children than adults. Further studies are necessary to evaluate if changes in dosing strategies for children, such as a lower starting dose, a decrease in target maintenance dose, or a slower build-up phase, are warranted.

Managing anaphylaxis in the office setting

BACKGROUND

Although the definition of anaphylaxis for clinical use may vary by professional health care organizations and individuals, the definition consistently includes the concepts of a serious, generalized or systemic, allergic or hypersensitivity reaction that can be life-threatening or even fatal.

METHODS

In this review, we presented the important topics in the treatment of anaphylaxis in the office setting. This review will discuss triggers and risk factors, clinical diagnosis, and management of anaphylaxis in the office setting.

RESULTS

Anaphylaxis in the office setting is a medical emergency. It, therefore, is important to prepare for it, to have a posted, written anaphylaxis emergency protocol, and to rehearse the plan regularly. In this review, we presented the important steps in managing anaphylaxis in the office. Treatment of anaphylaxis should start with epinephrine administered intramuscularly at the first sign of anaphylaxis. Oxygen and intravenous fluids may be needed for moderate-to-severe anaphylaxis or anaphylaxis that is quickly developing or if the patient is unresponsive to the first injection of epinephrine. Antihistamine therapy is considered adjunctive to epinephrine, which mainly relieves itching and urticaria. Corticosteroids, with an onset of action of 4-6 hours, have no immediate effect on anaphylaxis.

CONCLUSION

To prevent near-fatal and fatal reactions from anaphylaxis, the patient, the family, and the physician must remember to follow the necessary steps when treating anaphylaxis. In anaphylaxis, there is no absolute contraindication for epinephrine.

An EAACI "European Survey on Adverse Systemic Reactions in Allergen Immunotherapy (EASSI)": the methodology

At present, there is no European report on clinically relevant systemic reactions due to the regular use of allergen immunotherapy (AIT), administered either subcutaneously or sublingually (SCIT and SLIT, respectively) outside clinical trials. Using an electronic survey and a “harmonised terminology” according to MedDRA, we aimed to prospectively collect systemic adverse reactions due to AIT from real life clinical settings.

Under the framework of the EAACI, a team of European specialists in AIT, pharmacovigilance, epidemiology and drugs regulation set up a web-based prospective pilot survey to be conducted in three European countries (France, Germany and Spain). A designated “national coordinator” was responsible for following ethics requirements relative to each country and to select at least 30 doctors per country.

Patients were recruited the same day they received their first dose of either SCIT or SLIT. Patient inclusion criteria were: adults and children, with IgE mediated pollen, house dust mite, Alternaria, and/or animal dander respiratory allergies who will initiate AIT.

A list of 31 symptoms terms were extracted from the MedDRA (Medical Dictionary for Regulatory Activities) dictionary to harmonize the reporting of all adverse systemic reactions in this survey.

The SurveyMonkey® online instrument was used by participant doctors to submit information directly to a blinded central database.

Three questionnaires were generated: i) the Doctor Questionnaire, ii) the Patient Questionnaire and iii) the Adverse Reaction Questionnaire. A handbook and a mistake report form were given to each doctor.

In this paper, we describe the methodology followed.

Safety of immunotherapy in patients with rhinitis, asthma or atopic dermatitis using an ultra-rush buildup. A retrospective study

BACKGROUND

Allergen-specific immunotherapy is a proven, highly effective treatment for IgE-mediated diseases. However, ultra-rush immunotherapy is prescribed infrequently because of the perception that accelerated immunotherapy buildup leads to a higher rate of systemic reactions.

OBJECTIVE

To evaluate the frequency of adverse reactions in patients with IgE-mediated diseases receiving house dust mite (HDM) ultra-rush immunotherapy.

METHODS

A retrospective, observational study was conducted for patients with IgE-mediated diseases receiving allergen-specific immunotherapy. Subcutaneous immunotherapy with depigmented polymerized mites extract was administered in two refracted doses of 0.2 and 0.3 ml at first injection, and in single 0.5 ml doses in subsequent monthly injections. A 30 min observation time was required after each injection. Systemic reactions were graded using the World Allergy Organisation grading system.

RESULTS

575 patients were included. The age range was 1-83 years. Most patients had respiratory diseases (544) and 101 patients had atopic dermatitis. A total of 27 patients (4.6%) experienced 139 reactions (reactions/injections: 1.9%); 22 patients (3.8%) experienced 134 local reactions (local reactions/injections: 1.8%). Eight patients (1.3%) experienced eight systemic reactions (systemic reactions/injections: 0.1%). Five systemic reactions were grade 2 and three grade 1. Two systemic reactions were reported during buildup. There were no fatalities.

CONCLUSION

Taking into account the possible bias for the retrospective design of this study we observed that immunotherapy for patients with IgE-mediated diseases using a depigmented polymerized mites extract, with an ultra-rush buildup, has similar frequency of systemic reactions than that seen in slower buildup immunotherapy in other studies. Accelerated buildup could improve patients' adherence and reduce dropout rates.

The risk and management of anaphylaxis in the setting of immunotherapy

BACKGROUND

Anaphylactic events due to immunotherapy are probably not completely preventable. There is always an inherent risk surrounding the administration of an allergen to an individual who is sensitized to the substance administered.

METHODS

There are, however, effective measures to reduce the risk of these events, and to optimize the assurance of a good outcome in the face of such an event.

RESULTS

Of prime importance in preventing these episodes is the regular assessment of the patient's health status, especially in regard to asthma, and the careful attention to the prevention of dosing errors.

CONCLUSION

Of equal importance, in regard to assuring a good outcome should such an event occur, are the rapid recognition of symptoms and the immediate injection of epinephrine, the drug of choice for the treatment of any episode of anaphylaxis.

Systemic reactions associated with subcutaneous allergen immunotherapy: timing and risk assessment

BACKGROUND

Subcutaneous allergen immunotherapy (SCIT) is associated with risk of systemic reaction. Although risk factors have been identified, the incidence of immunotherapy-related systemic reactions has not changed in recent years.

OBJECTIVES

To examine patterns of systemic reaction and determine whether risk of systemic reaction from SCIT is associated with patterns of response to skin tests to inhalant allergens recorded before receiving SCIT.

METHODS

We carried out a retrospective review from January 2001 to December 2007. Patterns of systemic reaction from immunotherapy were examined. Cases were matched with controls by age (±10 years), sex, and time of injection (±1 week) to determine whether a pattern of more than 33% 3+ and 4+ skin test responses is associated with elevated risk for systemic reaction.

RESULTS

Rate of systemic reaction from SCIT was 0.28% (46/16,375) per injection visit. Twenty patients had 46 systemic reactions. All severe reactions occurred within 30 minutes. The estimated odds of systemic reaction were almost 6 times higher for patients with more than 33% 3 to 4+ positive skin tests (OR = 5.83; 95%CI: 1.23-27.59, P = .026). For each additional 4+ skin test, the estimated odds for systemic reaction increased by 17% (P = .020).

CONCLUSIONS

A small number of patients receiving SCIT account for a large proportion of systemic reactions. Skin test patterns demonstrating a greater number of larger skin tests responses to inhalant skin testing are associated with significantly elevated risk for systemic reaction in patients receiving SCIT.

Immunotherapy throughout the decades: from Noon to now

OBJECTIVE

To review major milestones in the development of subcutaneous allergen immunotherapy in 20-year segments.

DATA SOURCES

Review of the literature available in textbooks and journals.

STUDY SELECTION

Articles and books addressing major achievements in the development of subcutaneous allergy immunotherapy were selected for inclusion in this review.

RESULTS

Immunotherapy administration has improved the lives of possibly millions of patients with hay fever. Asthmatic symptoms have been relieved if not ablated in millions as well. Insect venom hypersensitivity became treatable and highly effective. In the beginning years of immunotherapy, it was clear that immunotherapy worked; in the later years, the mechanisms for this efficacy were discovered. In this case, the therapy preceded its validation. Methods, materials, and safety have vastly improved. Postulated mechanisms explain much but not everything.

CONCLUSIONS

There is still research to be accomplished, improvements to be made, and, of course, patients to be made well.

Omalizumab-associated anaphylactic reactions reported between January 2007 and June 2008

BACKGROUND

Anaphylaxis associated with omalizumab treatment is a growing concern. The broader context in which omalizumab-associated allergic reactions occur has not been well described.

OBJECTIVE

To identify and characterize recently reported anaphylactic reactions associated with omalizumab administration.

METHODS

The US Food and Drug Administration Adverse Event Reporting System reports between January 1, 2007, and June 30, 2008, were queried for new reactions primarily suspected to be due to omalizumab. Reaction characteristics were analyzed for a reaction descriptor of anaphylactic or anaphylactoid shock or reaction and for dermal, respiratory, cardiovascular, and gastrointestinal reaction descriptor terms that in combination could be interpreted as constituting anaphylaxis. Associated narratives for these reports were obtained and were examined further.

RESULTS

There were 85 cases with an anaphylaxis descriptor and 33 cases without a descriptor of anaphylaxis but with multisystem allergic reactions (mostly respiratory and skin or mucosal) that were consistent with anaphylaxis. Of these 118 cases, 32 were after the first dose and 14 were after the second dose of omalizumab. Seventy-seven of the 118 cases were categorized as requiring hospital admission or prolongation, had life-threatening reactions, underwent treatment with epinephrine or corticosteroids, or had omalizumab treatment withheld or discontinued. Nineteen of the 118 reactions were described as occurring within 1 hour of omalizumab injection.

CONCLUSIONS

Allergic reactions to omalizumab continue to be reported. Some patients not labeled as having anaphylaxis have multisystem allergic reactions consistent with anaphylaxis, raising questions about the adequacy of the Food and Drug Administration categorizations. The characteristics of these patient reports point toward a spectrum of systemic allergic reactions associated with omalizumab use.

Systemic tolerability of specific subcutaneous immunotherapy with index-of-reactivity-standardized allergen extracts administered using clustered regimens: a retrospective, observational, multicenter study

BACKGROUND

Subcutaneous immunotherapy is an etiological therapy for certain IgE-mediated diseases. It is usually administered in 2 phases: induction and maintenance. Administration in clustered schedules during the induction phase may be a valid alternative to reach the maintenance dose early if the treatment is well tolerated.

OBJECTIVES

To compare the tolerability of different clustered schedules in subcutaneous immunotherapy with standardized allergen extracts administered and to identify factors associated with increased risk of systemic reactions (SRs).

METHODS

Retrospective, observational, multicenter study in patients with allergic respiratory disease.

RESULTS

Data from 1,147 patients were collected. Thirty-nine patients (3.4%) experienced 42 SRs (0.6% of doses). According to the European Academy of Allergy and Clinical Immunology SR grading system, there were 7 grade 0 reactions (16.7%), 26 grade 1 reactions (61.9%), 8 grade 2 reactions (19.0%), and 1 grade 3 reaction (2.4%). There were no grade 4 SRs (anaphylactic shock). We observed a higher risk of SRs in patients who received an initial dose higher than 0.3 index of reactivity (IR); only 2 reactions occurred after administration of the initial dose of the regimen, both with 0.4 IR. The remainder appeared in subsequent injections, although never with a dose lower than 0.35 IR.

CONCLUSIONS

Clustered regimens with IR-standardized extracts are an alternative to classic immunotherapy thanks to their low incidence of SRs compared with other rapid regimens during the induction phase. The ideal clustered regimen should start at an initial dose no greater than 0.35 IR to minimize the incidence of SRs.

Complexities of diagnosis and treatment of allergic respiratory disease in the elderly

Atopic diseases such as rhinitis and asthma are relatively common in children and young adults. However, many patients aged >65 years are also affected by these disorders. Indeed, the literature suggests that between 3-12% and 4-13% of individuals in this age range have allergic rhinitis and asthma, respectively. However, these numbers are most likely underestimates because atopic diseases are frequently not considered in older patients. The diagnosis of both allergic rhinitis and asthma in older patients is more difficult than in younger patients because of a wide differential diagnosis of other diseases that can produce similar symptoms and must be excluded. Furthermore, treatment of these disorders is complicated by the potential for drug interactions, concern about the adverse effects of medications, in particular corticosteroids, and the lack of drug trials specifically targeting treatment of older patients with allergic rhinitis and asthma.

Anaphylactic reactions during immunotherapy

Subcutaneous immunotherapy (IT) with aeroallergen extracts is venerable treatment modality. The major risk associated with IT with commercial aeroallergen extracts is the uncommon occurrence of severe near-fatal or fatal anaphylaxis after injections. The objectives of this article are to review the reported incidences of severe anaphylaxis (near-fatal reactions and fatal reactions), define factors contributing to these events, and identify preventive measures that are likely to reduce or eliminate future fatal and near-fatal anaphylactic events. As with any treatment, anticipated benefits attributed to IT must be weighed against its potential risks.

Fatalities following allergen immunotherapy

Allergen immunotherapy has been in use for nearly 100 yr and has become an important method of reducing allergic symptoms in select patients with allergic rhinitis, asthma, and insect venom hypersensitivity. Unfortunately, immunotherapy has been associated with anaphylaxis and death. Although the relative risk of severe reactions to immunotherapy is low, the number of such reactions has increased since the introduction of standardized and more potent extracts. There are a number of risk factors associated with such severe anaphylactic reactions. Such risk factors include errors in dosage, failure to reduce the dosage after a longer than scheduled interval, administration of the wrong extract, inadvertent intravenous administration, failure to postpone injection because of infection or asthma exacerbation, failure to observe patients for appropriate length of time, failure to adhere to guidelines for established contraindications, concurrent use of beta-adrenergic blocking agents, uses of mixtures of allergens, immunotherapy during the active allergy season, and types of allergens. In this review, we focus on these and other risk factors in attempts to reduce the risk of anaphylaxis following allergen immunotherapy.

Safety of rush immunotherapy to multiple aeroallergens in an adult population

BACKGROUND

Rush immunotherapy has many potential benefits but a higher incidence of systemic reactions compared with traditional immunotherapy. The safety of rush immunotherapy to multiple aeroallergens has not been widely studied.

OBJECTIVE

To examine the safety of rush immunotherapy to multiple aeroallergens in a primarily adult population and to identify risk factors for systemic reactions.

METHODS

A retrospective review of 65 patients who received rush immunotherapy to multiple aeroallergens in a university-based allergy practice was conducted. All patients were premedicated with prednisone, cetirizine, ranitidine, and zafirlukast or montelukast. Percutaneous skin testing was performed, major allergen content was analyzed in every fourth patient's immunotherapy extract, and systemic reactions were graded.

RESULTS

Systemic reactions were observed in 25 patients (38%). All systemic reactions occurred with the final 3 doses of the protocol. Most (72%) occurred after the final dose of the protocol. Nineteen (76%) of the reactions were mild, 5 (20%) were moderate, and 1 (4%) was severe. Systemic reactions were associated with a higher degree of skin test sensitivity and the presence of weed or dog allergen in the extract (vaccine).

CONCLUSIONS

Rush immunotherapy is associated with a relatively high incidence of systemic reactions, but most reactions are mild and easily treated. The degree of skin sensitivity to the allergens administered and the presence of dog or weed allergen in the extract may be predictors for the development of systemic reactions.

Systemic reactions to immunotherapy: influence of composition and manufacturer

BACKGROUND

Although immunotherapy clearly demonstrated the benefit of reducing allergic symptoms, it has the drawback of adverse events, mainly systemic reactions that could be very inconvenient for patients and even life-threatening.

OBJECTIVE

The aim of the present study was to assess the incidence of systemic reactions to immunotherapy in a large number of patients, and its potential relationship with the characteristics of therapy, such as allergen composition or manufacturing laboratory.

METHODS

This study analysed the administration of specific immunotherapy during a period of 5 years, involving 1212 patients affected by respiratory hypersensitivity or hymenoptera venom anaphylaxis. Commercial extracts were supplied by five different laboratories. All the patients were attended at an out-clinic immunotherapy unit by the same experienced staff. Immunotherapy was given following a conventional schedule, modified according the usual recommendations.

RESULTS

A total of 250 adverse reactions have been recorded, resulting in a frequency of 0.84% over the total number of injections. Seventy-nine of them (32%) were systemic reactions (0.27% SR/injection). The 79 systemic reactions were observed in 60 patients (5% of the patients). The frequency of systemic reactions was significantly lower (P < 0.01) on the group of mites than on the other groups. The frequency of systemic reactions varies according to the manufacturing laboratory. In the case of mite extracts, although one of the laboratories had a lower frequency of adverse systemic reactions, it did not reach the level of statistical significance. However, in relation to pollen extracts, preparations of one of the manufacturers had a significantly lower frequency of systemic reactions. Concerning the time of occurrence, 27% of systemic reactions were delayed, thus they appeared at least 30 min after the vaccine injection, most of them due to pollen extracts.

CONCLUSION

This is a preliminary study to evaluate the factors that could facilitate the appearance of systemic reactions demonstrating that not only the composition but also the manufacturer is connected to systemic reactions. Although further studies are needed to clearly establish the influence of manufacturer on frequency and time of appearance of systemic reactions, it seems necessary to reach a wide consensus on allergen extract standardization methods.

Systemic reactions to allergen immunotherapy: a review of the literature

Since its introduction the safety of specific immunotherapy (SIT) was assessed by many well-designed studies. SIT is accepted as an effective treatment of allergic diseases despite the occurrence of side-effects, among which systemic reactions (SRs) are the most dangerous. The reported frequency of SRs after SIT varies among the studies and several factors influence it. Asthma is a particular risk factor for systemic side-effects. Furthermore, SRs occur more often in patients with high allergen sensitivity as determined by skin testing or RAST. Making dosage errors is also considered to be a high risk. It is reported that reactions are more common during rush and clustered induction treatment, whereas a significantly lower incidence of SRs occurred with the use of standardized modified allergen vaccines than with aqueous extracts. On the basis of valuable guidelines, precautions to minimize the risk of SRs from SIT were recommended. Injections should be given or supervised by doctors well-trained in this form of treatment in a clinic where there is the immediate availability of a resuscitative equipment. Consideration should be given to evaluate the patient's conditions and to monitor subjects for a minimum of 30 minutes after the injections. Therefore, if appropriately done, the risk of SIT is negligible.

Safety of inhalant allergen immunotherapy with mass units-standardized extracts

BACKGROUND

Allergen-specific immunotherapy (SIT) is an effective treatment for patients with respiratory allergies. However, subcutaneous injection of allergens can provoke systemic side-effects.

OBJECTIVE

This study was carried out to determine the incidence and risk factors o fsystemic reactions caused by SIT treatment, using extracts of different inhalant allergens, adsorbed in aluminium hydroxide and biologically standardized with the major allergens quantified in mass units.

METHODS

Five hundred and fifty-five subjects with allergic rhinitis and/or asthma were evaluated on clinical history and skin prick test (SPT) reactions to common inhalant allergens. Subcutaneous SIT was administered to all patients, according to the suggested precautionary guidelines and administration schedule. Patients were treated with house dust mite, grass pollen, Parietaria judaica pollen and olive pollen extracts, each receiving one or two extracts.

RESULTS

A total of 36,359 injections were administered in the 555 patients. We observed 34 episodes of serious systemic side-effects (0.093% of all injections), in 29 patients (5.2% of all patients), and no fatalities. About 55% of patients reported mild rhinitis and asthma. The majority (59%) of the serious systemic reactions (SSR), and all the anaphylactic reactions, were immediate (i.e. occurred within 30 min after the injection). Asthmatic subjects were at higher risk of SSR than patients with rhinitis (P = 0.01). Most of the side-effects observed occurred during the dose-increase phase (P < 0.05). There was no association of SSR with age, gender, SPT reactivity or allergen type.

CONCLUSION

SIT performed in patients with respiratory allergies by specialized staff with the allergen extracts studied, standardized in mass units, provoked a low rate of SSR. The significant risk factors for systemic reactions were asthma and the build-up period.

[Immunotherapy with an oral Alternaria extract in childhood asthma. Clinical safety and efficacy and effects on in vivo and in vitro parameters]

Studies of immunotherapy with oral Alternaria extracts are scarce. We decided to perform a clinical trial of the clinical safety and efficacy of this extract as well as of its effects on in vivo and in vitro parameters in 39 patients with Alternaria allergy, aged between 7 and 17 years, who are also sensitized extract was used. Allergic activity was determined through RAST inhibition and skin prick test. Quantification of the principal allerten (Alt a 1) was performed through the 2-site binding assay, with a mean content of 34.2 ng Alt a 1/micro g protein. The parameters analyzed were the symptom-medication score, skin prick using the end-point technique, specific bronchial challenge test, peak flow, total and specific IgE and IgG4. Nineteen patiens received active treatment with oral immunotherapy and another 19 received symptomatic treatment. The initial phase of immunotherapy lasted 3 months until the maximum dose was reached. This was maintained for 12 months; the mean accumulated dos was 280,000 PNU. Significant differences were found in reduction in the symptom-medication score in the treated group after 12 months of immunotherapy. No differences were found in the control group. Immunotherapy was well tolerated with 0.42 adverse reactions per 100 doses administered. All adverse reactions were mild-to-moderate. In the treated group, papule size was significantly reduced. Values for the specific bronchial challenge test, expressed through PD20, were significantly higher in the immunotherapy group. Peak flow showed no changes in either group. Values of IgG4 were significantly higher in the immunotherapy group. Total and specific IgE levels showed no significant changes in either group. In conclusion, oral immunotherapy with Alternaria extract is clinically effective in pediatric patients. In general, the therapy was well tolerated. It modified specific cutaneous and bronchial reactivity in our sample and increased levels of specific IgG4, wich are implicated in humoral response.

Immunotherapy with a calcium phosphate-adsorbed five-grass-pollen extract in seasonal rhinoconjunctivitis: a double-blind, placebo-controlled study

BACKGROUND

Calcium phosphate-adsorbed allergen extracts are used for subcutaneous immunotherapy to avoid the use of aluminium adjuvants.

OBJECTIVES

A double-blind, placebo-controlled study was performed in order to confirm the safety and assess the efficacy of a standardized five-grass-pollen extract adsorbed onto calcium phosphate for specific immunotherapy (IT).

METHODS

Twenty-nine patients with seasonal rhinoconjunctivitis were randomized to receive either the active preparation (16 patients) or placebo (13 patients), in a 1-year study. During the increasing dose phase, an extract ranging from 0.1 IR per ml to 50 IR per ml was administered at a rate of one subcutaneous injection per week until a maintenance dose was reached. The patients were assessed by symptom diary and rescue medications during seasonal exposure and specific nasal and skin reactivity before and after IT. Immunological parameters (specific IgE and IgG4 antibodies) were assessed before, during and after IT.

RESULTS

The overall symptoms score (mean AUC) was not significantly different between the IT group and the placebo group during grass-pollen exposure (49.6 vs. 56, respectively). The total medication score (mean AUC) was significantly lower in the IT group than in the placebo group (11 vs. 41, P < 0.01, Mann-Whitney U-test). The cumulative symptom/medication score was significantly lower in the IT group than in the placebo group (64.5 vs. 102.3, P < 0.05, U-test). A significant increase in nasal reactivity threshold was observed after IT in the IT group (21. 4 IR/mL before IT vs. 63.4 IR/mL after IT, P < 0.01, Wilcoxon), whereas no significant changes were observed in the placebo group (31.0 IR/mL before IT vs. 37.7 IR/mL after IT). IT induced a significant reduction in grass pollen cutaneous reactivity in the actively treated group (P < 0.001). A significant increase in serum-specific IgG4 antibody response was observed in the IT group (3.1% before IT vs. 10.1% after IT, P < 0.001). Nine patients in the IT group developed moderate immediate systemic reactions vs. two patients in the placebo group.

CONCLUSION

Specific immunotherapy with calcium phosphate-adsorbed standardized grass pollen extract was safe and effective for the treatment of patients with seasonal allergic rhinoconjunctivitis.

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.

Minimising the risks of allergen-specific injection immunotherapy

The clinical advantages of allergen-specific immunotherapy are counterbalanced by the risk of inducing systemic adverse effects. Although the frequency of life-threatening systemic reactions is low, the treatment carries a risk of inducing anaphylactic reactions. A fundamental point in risk assessment is to use a clinically meaningful and internationally accepted grading system for reactions. Of importance in minimising the risk of systemic adverse effects is the identification of at-risk patients and factors, the institution of procedures for monitoring patients before injections, and the adjustment of dosages in accordance with defined rules. Asthma, especially uncontrolled asthma, is a significant risk factor for the induction of systemic reactions. Likewise, dose escalation during allergen exposure, i.e. during pollen seasons, increases the risk of adverse effects. It is recommended that standardised extracts with a documented potency and consistency between production batches are used in order to prevent overdose when changing to a new vial. The intensity of the induction regimen is a balance between the risk of inducing systemic reactions and the time required to administer the regimen. Single injections once a week are generally well tolerated, in contrast to rush immunotherapy which may carry an increased frequency of adverse effects. A clustered induction regimen (2 to 4 injections per visit) represents a compromise of a patient-friendly fast regimen without an unacceptably high frequency of systemic reactions. A major issue in improving the safety of allergen injections is minimising the human factor, e.g. mistakes of patient identification, allergen extracts and dosages. Meticulous care in monitoring every patient before the injection, which requires education and training of the staff in the dosage decision process, is the cornerstone in reducing adverse effects. Involving the patient actively in the safety monitoring process might be helpful and improves patient compliance by allowing the patient to be an active partner in the treatment. Finally, if anaphylactic reactions are induced, a successful outcome is related to the staff being able to identify the early signs and to institute immediate rescue treatment. A quality assurance programme is the optimal way to minimise the risk of immunotherapy-associated systemic reactions.

Safety of allergen-specific immunotherapy. Relation between dosage regimen, allergen extract, disease and systemic side-effects during induction treatment

BACKGROUND

Allergen-specific immunotherapy is a well-documented treatment for allergic rhinitis, asthma, and allergy to Hymenoptera venoms. The drawbacks of injection immunotherapy are related to the risk of inducing systemic side-effects (especially during the induction phase), the time used to reach the maintenance dose, and the percentage of patients completing the induction phase).

OBJECTIVE

To investigate the practicability and safety of three different patient-friendly induction regimens of clustered immunotherapy (several injections administered during each visit).

METHODS

Since 1990, three different clustered induction regimens (regimen 1 = exclusively aqueous extracts; regimen 2 = a combination of aqueous and alum depot extracts; and regimen 3 = induction using exclusively alum depot extracts) have been investigated in 657 patients (10 369 injections).

RESULTS

A total of 454 systemic (immediate and late) reactions were observed in 257 patients corresponding to 4.4% of the injections and 39.1% of the patients. Most of the systemic reactions were of little or no clinical importance (93% grade 1 and grade 2) and < 1% anaphylactic reactions. The 8-week induction regimen using exclusively alum depot extracts showed a statistical significant lower frequency and severity of systemic side-effects. Immunotherapy with cat and mite allergen extracts showed the highest frequency of severe side-effects, which may be related to these extracts being used predominantly in asthmatic patients. The lowest frequency of systemic side-effects was observed in patients allergic to Hymenoptera venoms and these patients furthermore showed the highest number of patients (97%) completing the induction phase.

CONCLUSION

An 8-week clustered induction regimen using alum depot extract seems an acceptable compromise in relation to a reduction in the time used to reach maintenance dose and the risk of inducing clinically relevant systemic side-effects, and consequently imply a reduction in the costs of the treatment.

The safety and efficacy of ALLERVAX CAT in cat allergic patients

Conventional immunotherapy for cat allergy is effective in reducing cat allergy symptoms in many patients, but this type of immunotherapy can cause severe reactions, including anaphylaxis, and often requires years of injections for successful desensitization. To improve the efficacy of immunotherapy for cat allergic patients, synthetic cat allergen peptides (ALLERVAX CAT) were generated, based on analysis of the immunodominant T cell epitopes of cat allergen. These peptides lack the tertiary structure of native Fel d1 and possess a significantly reduced capacity to bind to Fel d1-specific IgE. Using these peptides, we performed a multicenter, randomized, double-blind, placebo-controlled study of 133 cat allergic patients chronically exposed to cats or who had failed previous conventional cat immunotherapy. We evaluated the safety of ALLERVAX CAT treatment and determined whether ALLERVAX CAT treatment improved tolerance to cat allergen, as measured by symptom analysis and pulmonary function testing. Three of the ALLERVAX CAT-treated patients required systemic epinephrine for adverse reactions, but the frequency of all adverse reactions in both groups was not statistically different from that of the placebo group. The majority of adverse events were "late" events, most commonly associated with respiratory symptoms, and these events declined with successive injections. ALLERVAX CAT given at a dose of 750 microg/dose improved pulmonary function in patients with reduced baseline FEV1, and global evaluation of the subjects' ability to tolerate cats improved significantly in the actively treated groups relative to placebo. Thus, although therapy with ALLERVAX CAT is associated with some adverse events in patients with severe cat sensitivity, such therapy is an effective approach for the management of cat allergy, since it improves tolerance to cats and improves pulmonary function in cat allergic patients with reduced FEV1.

Safety of home-based and office allergy immunotherapy: A multicenter prospective study

During a 1-year period, 27 otolaryngic allergy practices recorded all systemic reactions to immunotherapy resulting from 635,600 patient visits and 1,144,000 injections. Sixty percent of injections were given at home. Major systemic reactions were observed after 0. 005% of injections. There were no hospitalizations or deaths. Eighty-seven percent of major reactions began within 20 minutes of injection. Frequently observed risk factors for major reactions were buildup phase of immunotherapy, active asthma, and first injection from a treatment vial. Home and office injections had similar rates of total systemic reactions, but home-based immunotherapy had far fewer major reactions. Home-based immunotherapy was found to be safe. The methods and precautions used to treat patients with this degree of safety are specified and discussed.

Effects of immunotherapy on symptoms, PEFR, spirometry, and airway responsiveness in patients with allergic asthma to house-dust mites (D. pteronyssinus) on inhaled steroid therapy

The present study was designed to investigate the effects of immunotherapy (IT) with an extract of Dermatophagoides pteronyssinus (Alergo-Merck Depot) during a 27-month period in patients with allergic asthma to house-dust mites. We included 11 patients (mean age 18 years) treated with a combination of IT and inhaled beclomethasone dipropionate (BDP) in comparison to another 11 (mean age 22 years) treated with BDP alone. We evaluated symptom scores, salbutamol use, peak expiratory flow rates (PEFR), spirometry, and bronchial hyperresponsiveness (BHR) during 18 months of therapy with BDP and in the 9 months after BDP interruption. The two kinds of treatment were efficient and comparable in relation to symptom score, salbutamol use, morning PEFR, FVC, and FEV1, but patients treated with IT and BDP had a faster improvement of BHR and PEFR variability. The interruption of BDP after 18 months of therapy was linked to an impairment of all end points, which were more pronounced in patients previously treated only with BDP. These findings suggest that in selected asthmatic patients allergic to house-dust mites, the association of IT and BDP is more effective than therapy with this inhaled steroid alone due to a faster and more striking improvement during the first months of treatment and to a lower rate of relapse after the interruption of therapy with BDP.

Systemic reactions to specific immunotherapy in children with respiratory allergy: a prospective study

The aim of this multi-centre prospective study was to evaluate the prevalence of systemic reactions to specific immunotherapy in children with allergic asthma and or rhinitis. One thousand and fifty-six children (653 boys and 403 girls), median age 8.5 years, were enrolled in this three-year prospective study. All the children were treated with injections of the following allergenic extracts: 689 of house dust mite, 291 of grass, 109 of Parietaria, 13 of Alternaria, 6 of Artemisia and 11 of Olea. Among 1056 treated children, 41 (3.7%) had systemic reactions: 40 children (3.7%) experienced mild symptoms such as asthma and/or urticaria, and only one shock (0.08%). A total of 47,247 injections were administered, and the rate of systemic reactions, according to the number of total injections was only 0.08%. According to the allergenic extract, systemic reactions occurred in 29/689 children (4.2%) treated with house dust mites extract (0.09% of the injections), in 9/291 children (3.1%) treated with grass extract (0.07% of the injections) and in 3/109 children (2.8%) treated with Parietaria extract (0.06% of the injections). The prevalence of systemic reactions was significantly higher (p < 0.0001) in the children treated with house dust mite extract in comparison with those treated with pollen extracts. All the systemic reactions appeared within 30 minutes following the administration of the extract and occurred in 37/41 cases (90.2%) with the same dose, previously tolerated. Most reactions were mild, and were readily controlled by immediate emergency treatment. There was no need for hospitalization.(ABSTRACT TRUNCATED AT 250 WORDS)

Systemic reactions to immunotherapy: the American Academy of Otolaryngic Allergy morbidity and mortality survey

Anaphylaxis may be defined as a systemic, immunoglobulin E-mediated (Gell-Coombs type I) hypersensitivity reaction triggered by exposure to an antigen in a previously sensitized patient. Anaphylaxis may occur in a variety of circumstances; however, when it occurs as the result of immunotherapy, it is of great concern to the practicing allergist. When describing or reporting anaphylaxis relating to immunotherapy, most allergists speak in terms of the types of reactions, local vs. systemic. Germane to this discussion is the use of the term systemic reaction, which can mean anything from mild allergy symptoms resulting from an allergy injection to bradycardia and hypotension (shock). In this article we report serious or significant systemic reactions, which are characterized by any of the following symptoms: urticaria, sneezing or nasal obstruction, throat tightness or congestion, wheezing, and shock (bradycardia or hypotension). There were no fatalities reported from the survey group. The overall reaction rate was 0.3%.

Biphasic systemic anaphylaxis: an inpatient and outpatient study

We attempted to ascertain the incidence of systemic biphasic anaphylactic reactions in both outpatients and inpatients. Madigan Army Medical Center is a large teaching facility. The Allergy Clinic staff sees approximately 20,000 patients per year, and an average of 27,000 allergy immunotherapy injections are administered each year. During the years 1988 to 1991 we collected data from a total of 35 patients who had experienced, during the 30-minute waiting period in the clinic, symptoms and signs consistent with anaphylaxis. A total of 44 anaphylactic reactions were noted, with only two (5%) involving a biphasic systemic pattern. All patients were observed and treated within the clinic until symptoms and signs had resolved. None of the patients were treated with or were presently using glucocorticosteroids during the time of their reactions. Of the reactions noted, 25 (57%) involved only cutaneous manifestations of anaphylaxis, three (7%) involved the laryngeal/upper airway area, eight (18%) involved bronchospasm alone, three (7%) involved the rhinoconjunctivae, and five (11%) involved more than one site or type. None of the patients experienced any symptoms or signs of cardiovascular compromise or collapse after allergy extract injections. During the years 1986 to 1992 a total of 59 patients were admitted to the medical ward or intensive care unit with the diagnosis of systemic anaphylaxis. Of 59 patients, four (7%) experienced a recurrent (biphasic) anaphylactic reaction without reexposure to the initial inciting agent. The remaining 55 patients (93%) did not experience any further systemic anaphylaxis after initial hospital admission and treatment. Two of the patients with biphasic anaphylaxis were first seen with hypotension and generalized urticaria.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

A prospective safety-monitoring study of immunotherapy with biologically standardized extracts

We evaluated the safety of immunotherapy in 419 patients who attended our allergy department for treatment. They were suffering from rhinitis and asthma caused by sensitization to grass pollen or Dermatophagoides pteronyssinus. Immunotherapy was given by biologically standardized aluminum hydroxide adsorbed extracts according to a conventional schedule. Local reactions were recorded in 10.5% of the patients and systemic reactions in 4.8%. Only 0.37% of the doses administered were associated with systemic side-effects. We found that 84% of the patients who showed systemic reactions were asthmatic subjects (P < 0.01), and most of them were sensitized to D. pteronyssinus (71%). Side-effects occurred more frequently during the dose-increase period (P < 0.05). After 9482 doses had been administered, no anaphylactic shock or life-threatening reactions were registered. We believe the risk associated with immunotherapy to be drastically reduced when treatment is carefully monitored by skilled personnel. In such conditions, as shown by our study, immunotherapy is safe.

Anaphylaxis in immunotherapy

Although anaphylactic reactions resulting from immunotherapy rarely occur, when they do occur they can be life-threatening. The literature reveals more than 30 deaths attributed to immunotherapy but numerous reports of anaphylaxis. We reviewed a 5-year experience of immunotherapy in a University practice and their experience with systemic reactions is presented. More than 125,000 injections were given in this time period. Of the 550 patients receiving immunotherapy, 14% experienced anaphylactic reactions, the majority of which were mild.

Regulation of the human immune response to ragweed pollen by immunotherapy. A controlled trial comparing the effect of immunosuppressive peptic fragments of short ragweed with standard treatment

A new allergenic preparation consisting of peptic fragments of short ragweed has been tested for its clinical effectiveness. Such enzymatically derived fragments have been shown in prior murine studies to retain the T epitopes of the original allergen but to have a severe reduction in the number of B epitopes. Three groups of ragweed hayfever patients were placed on pre-seasonal immunotherapy. One group received a conventional ragweed preparation that had been enriched for antigen E (Amb a I), designated as Pool 2. The second group was given fragments of Pool 2 (fSRW) prepared by peptic digestion and the third group was injected with histamine as a placebo. Groups treated with the fSRW and Pool 2 had significantly reduced symptom-medication scores compared with the placebo-treatment group. However, fSRW-treated patients fared significantly better than Pool 2 patients (P less than 0.02). fSRW injections caused a significant rise in preseasonal specific IgG, antibodies as well as suppression of the seasonal anamnestic specific IgE increase. Similar, but not quite as marked changes occurred with Pool 2 treatment. fSRW was well tolerated and non-toxic. Thus, allergen modification by enzymatic degradation, as demonstrated here, appears to be a promising new approach for allergen immunotherapy.

Immunotherapy with a standardized Dermatophagoides pteronyssinus extract. IV. Systemic reactions according to the immunotherapy schedule

Specific immunotherapy with standardized extracts can induce systemic reactions (SRs), possibly increased by a rush immunotherapy (RIT) protocol. A prospective study in 1152 mite-allergic patients (3 to 63 years of age) examined the incidence of SRs during an RIT or a step protocol. All patients received the same standardized extract of Dermatophagoides pteronyssinus with the same maintenance dose. In the first group, 290 patients had an RIT protocol without any preventive measure. In a second group, the prevention of SRs during RIT was attempted by pretreating 160 patients with methylprednisolone (0.5 mg/kg/day), ketotifen (2 mg/day), and theophylline (10 mg/kg/day). In a third group (479 patients), the same pretreatment was associated with preventive measures and with FEV1 results and the occurrence of large local reactions. A fourth group consisted of 223 patients who received a step protocol with the same pretreatment and preventive measures. The incidence of SRs per patient was 36.2% with RIT alone, 16.2% when the pretreatment was added, and 7.2% when pretreatment and preventive measures were used. Patients receiving the step protocol had 5.4% SRs. Adrenaline had to be used from 10.0%, 4.6%, 0.2%, and 0.2%, respectively. No reaction started 45 minutes or later after the last injection. Children younger than 5 years of age had a significantly greater number of SR.

Hyposensitization in asthmatics with mPEG-modified and unmodified house dust mite extract. IV. Occurrence and prediction of side effects

A double-blind study on hyposensitization (HS) with two extracts prepared from the house dust mite Dermatophagoides pteronyssinus (Dp) was performed on a group of asthmatics with bronchial sensitivity to Dp. In 18 patients, aluminium-hydroxide was added to the Dp-extract to give a depot effect (Dp-group). Nineteen patients were treated with a similar extract in which allergenicity had been reduced by coupling to monomethoxypolyethylene glycol (mPEG-Dp-group). This extract had previously been shown to have less effect on clinical symptoms and skin sensitivity compared to the Dp-extract. In the Dp- and mPEG-Dp-groups, 778 and 675 injections were administered. Fifteen and 12 patients in the Dp- and mPEG-Dp-groups had systemic reactions (P greater than 0.05). The frequency of injections giving systemic reactions was reduced in the mPEG-Dp-group: 5.1% compared to 9.0% in the Dp-group (P less than 0.01). In the mPEG-Dp-group, reactions were mild to moderate, mainly late-occurring asthma and urticaria, whereas two episodes of anaphylaxis and four of severe asthma occurred in the Dp-group. The reduction in side effects seems promising, but a further dose increase in the mPEG-Dp-group would be necessary to compare the side effects of doses with equal therapeutic effectiveness. High frequency of late local reactions made dose increase impossible with the present slightly modified extract. The systemic side effects occurred more frequently in patients highly skin test-sensitive to Dp prior to treatment. All patients skin test-positive to less than or equal to 100 BU had systemic reactions. Systemic side effects could not be predicted from the size of previous local reactions.