Case report of venom immunotherapy for a patient with large local reactions

A Pitfall to Avoid When Using an Allergen Microarray: The Incidental Detection of IgE to Unexpected Allergens

The introduction of new laboratory techniques to detect specific IgE antibodies against single allergen molecules rather than whole extracts represents a significant advance in allergy diagnostics. The advantages of such component-resolved diagnosis can be summarized as follows: (1) the ability to identify the truly responsible allergens in polysensitized patients, whether they be genuine (causing specific sensitization to their corresponding allergen source) or primary (the original sensitizing molecule); (2) distinguishing these allergens from simply cross-reactive components; (3) improving the appropriateness of the prescribed specific immunotherapy; and (4) identifying a risk profile for food allergens. Component-resolved diagnosis is performed using either a singleplex (1 assay per sample) platform or a multiplex (multiple assays per sample) platform. Using an immuno solid-phase allergen chip microarray that falls into the latter category--it currently tests sensitivity to 112 allergens--may lead to a pitfall: detecting IgE to unexpected allergens, such as Hymenoptera venom. In fact, testing insect venom sensitivity in individuals with no history of reactions to stings is contrary to current guidelines and presents the physician with the dilemma of how to manage this information; moreover, this may become a legal issue. Based on what is currently known about venom allergy, it remains likely that a positive sensitization test result will have no clinical significance, but the possibility of reacting to a future sting cannot be completely ruled out. Because this problem has not been previously encountered using the more common allergy tests, no indications are currently available on how to effectively manage these cases.

Venom immunotherapy reduces large local reactions to insect stings

BACKGROUND

Large local reactions to insect stings cause significant morbidity and impair quality of life. Venom immunotherapy is not recommended because of a low risk for future systemic reaction and unproven efficacy in preventing large local reactions.

OBJECTIVE

To determine the feasibility of performing a controlled trial to examine the efficacy of venom immunotherapy in reducing the size and duration of large local reactions.

METHODS

Sting challenge in 41 patients with previous large local reactions and positive venom skin tests caused large local reactions 16 cm or larger in 34 patients, and 29 consented to treatment. Venom immunotherapy was initiated in 19, and 10 were untreated controls. Sting challenge was repeated after 7 to 11 weeks (control patients then began venom immunotherapy), and annually for as long as 4 years.

RESULTS

After 7 to 11 weeks of treatment, the size and duration of large local reactions decreased 42% and 53%, respectively, in treated patients and 18% in controls (P < .01 for both). The response was similar after 1 year, and improved after 2 to 4 years to 60% and 70%, respectively.

CONCLUSIONS

Venom immunotherapy significantly reduced the size and duration of the large local reactions, and the efficacy improved over a period of 2 to 4 years of treatment. Further studies are needed to establish the safety and efficacy of venom immunotherapy for large local reactions, the optimal duration of treatment, and the mechanism for the differences in degree and rate of clinical response compared with venom immunotherapy in systemic reactors.

Dialyzed venom skin tests for identifying yellow jacket-allergic patients not detected using standard venom

BACKGROUND

The chance of a nonspecific intradermal skin test response at venom concentrations greater than 1.0 microg/mL limits the diagnostic range and can interfere with the diagnosis of some affected patients.

OBJECTIVE

To compare the diagnostic ranges and clinical detection rates of skin tests using dialyzed yellow jacket venom (DYJV) and undialyzed YJV (UYJV), particularly in patients who have had negative venom skin test results.

METHODS

Both DYJV and UYJV from the same original lot were diluted from 100 microg/mL to skin test concentrations of 0.01, 0.1, 1.0, 3.0, and 10 microg/mL. Participants included 10 nonallergic controls, 20 patients with a positive history and positive skin test results using UYJV, and 24 patients with a positive history but negative skin test results using UYJV (17 of whom had a positive IgE anti-YJV serology).

RESULTS

Dialyzed venom skin test results were positive at 10 microg/mL or less in 79% of patients with a positive history but negative skin test reactions using UYJV. The dialyzed venom skin test results showed a half-log shift to the left from the undialyzed venom results in linear regression analysis, indicating a greater detection rate with skin tests using DYJV. Results of skin tests with dialyzed venom were positive in 3 of 4 patients who had negative undialyzed venom skin test results and who experienced a systemic reaction to challenge stings.

CONCLUSIONS

The DYJV improves the ability of skin tests to detect yellow jacket allergy and should be subject to further study.

Advances in hymenoptera venom immunotherapy

PURPOSE OF REVIEW

Venom immunotherapy is highly effective treatment, capable of improving health-related quality of life. This overview examines advances in various aspects of this treatment.

RECENT FINDINGS

New findings on the immunological mechanisms of the early and long-term efficacy of venom immunotherapy have been made. The decision to start and then to stop venom immunotherapy is best made on an individual case basis and should take into account medical and other factors, like the influence on patient quality of life. Venoms for use in immunotherapy should be selected according to the geographical distribution of each species and partial cross-reactivity between certain types of venom. Rapid protocols seem to be as safe as slower ones, though the major incidence of bee venom immunotherapy side-effects remains. Patients suffering from mast cell diseases seem to be at greater risk for an adverse reaction during treatment, without influencing its efficacy that much until the immunotherapy is actually ongoing. A number of new strategies for venom immunotherapy, mostly based on genetic engineering, have been described, and so far only a few have been used in humans.

SUMMARY

Although there has been progress in the past few years, much remains to be accomplished.

Osteopontin: a potential biomarker for successful bee venom immunotherapy and a potential molecule for inhibiting IgE-mediated allergic responses

Venom immunotherapy (VIT) is proven to be curative for insect allergy, but the mechanisms and the biomarkers associated with clinical efficacy remain elusive. We report herein the discovery of a leading candidate biomarker, osteopontin (OPN), for VIT. From cDNA microarray and clustering analyses, an increased expression of OPN was found in patients who completed 5-6 years of VIT and discontinued therapy for 3-6 years as compared with the untreated group. A significantly higher level of serum OPN was found in the completed treatment group as compared with the untreated group. Following VIT, kinetically increased levels of OPN associated with reduced venom specific IgE levels were noted in subjects with large local allergic reactions to venom. These findings together with the fact that OPN is involved in Th1-associated immune response strongly suggest a role of OPN as a functional biomarker for VIT.

Insect sting reactions to bees, wasps, and ants

Abstract Arthropod bites and stings are capable of inflicting injury, inciting allergic reactions, and transmitting systemic disease. Members of the Hymenoptera order are of particular importance because they are nearly ubiquitous in nature, and their stings may cause life-threatening allergic reactions. Stings from bees, wasps, and ants produce a variety of clinical and histological manifestations. Anaphylaxis following an insect sting is the most serious complication. For individuals with a specific allergy to Hymenoptera venom, immunotherapy may be a relatively safe and effective treatment option.

Diagnostic methods for insect sting allergy

PURPOSE OF REVIEW

This review overviews advances from mid-2002 to the present in the validation and performance methods used in the diagnosis of Hymenoptera venom-induced immediate-type hypersensitivity.

RECENT FINDINGS

The general diagnostic algorithm for insect sting allergy is initially discussed with an examination of the AAAAI's 2003 revised practice parameter guidelines. Changes as a result of a greater recognition of skin test negative systemic reactors include repeat analysis of all testing and acceptance of serology as a complementary diagnostic test to the skin test. Original data examining concordance of venom-specific IgE results produced by the second-generation Pharmacia CAP System with the Johns Hopkins University radioallergosorbent test are presented. Diagnostic performance of honeybee venom-specific IgE assays used in clinical laboratories in North America is discussed using data from the Diagnostic Allergy Proficiency Survey conducted by the College of American Pathologists. Validity of venom-specific IgE antibody in postmortem blood specimens is demonstrated. The utility of alternative in-vivo (provocation) and in-vitro (basophil-based) diagnostic testing methods is critiqued.

SUMMARY

This overview supports the following conclusions. Improved practice parameter guidelines include serology and skin test as complementary in supporting a positive clinical history during the diagnostic process. Data are provided which support the analytical performance of commercially available venom-specific IgE antibody serology-based assays. Intentional sting challenge in-vivo provocation, in-vitro basophil flow cytometry (CD63, CD203c) based assays, and in-vitro basophil histamine and sulfidoleukotriene release assays have their utility in the study of difficult diagnostic cases, but their use will remain as supplementary, secondary diagnostic tests.

Allergic Reactions to Insect Stings and Bites

Insect stings are an important cause of anaphylaxis. Anaphylaxis can also occur from insect bites but is less common. Insect venoms contain several well-characterized allergens that can trigger anaphylactic reactions. Effective methods to diagnose insect sting allergy and assess risk of future sting reactions have been developed. Management strategies using insect avoidance measures, self-injectable epinephrine, and allergen immunotherapy are very effective in reducing insect-allergic patients' risk of reaction from future stings. Diagnostic and management strategies for patients allergic to insect bites are less developed.

Diagnosis of Hymenoptera venom sensitivity

PURPOSE OF REVIEW

The objective of this review is to highlight recent advances in the preparation, documentation and performance of reagents and methods used in the diagnosis of Hymenoptera-venom-induced immediate-type hypersensitivity.

RECENT FINDINGS

The following potent allergens have been reported: (1) a low-molecular-weight honey-bee allergen (Api m 6) has been described; (2) venom allergens in the North American species of bumble-bee (Bombus pennsylvanicus) have been more fully characterized, with the focus on phospholipase A2; (3) the vespid venom Ves v 5 allergen has been structurally mapped to identify immunoglobulin-E-binding epitopes; (4) the possible role of carbohydrate antigen epitopes as a cause of cross-reactivity among honey-bee and vespid venom proteins has been reported; and (5) the venom of Pachycondyla chinensis, an ant found commonly in the Far East, has been described. The most significant reports during this period have focused on the less-than-ideal performance of the intradermal venom skin-test reagents. The issue of the patient that is positive for venom allergy history but negative for an intradermal venom skin test is raised, and it is suggested that there is a need for caution and the use of serology as a supplementary diagnostic test.

SUMMARY

The important issue this year is the reminder that intradermal skin tests may be negative in venom-allergic patients, possibly because of changes in the potency of the extracts. The clinical history should drive the diagnosis of insect-sting allergy. When negative confirmatory venom skin-test or serology results are considered to be inconsistent with a positive history, they should be repeated.