Ant venom immunotherapy: a double-blind, placebo-controlled, crossover trial. A controlled trial of immunotherapy in insect hypersensitivity. Immunotherapy improves health-related quality of life of adult patients with dermal reactions following yellow jacket stings. Venom immunotherapy reduces large local reactions to insect stings. Sublingual immunotherapy for large local reactions caused by honeybee sting: a double-blind, placebo-controlled trial. The value of immunotherapy with venom in children with allergy to insect stings.
The jack jumper ant Myrmecia pilosula is responsible for about 90% of ant venom anaphylaxis in southeastern Australia. We aimed to establish whether M pilosula venom immunotherapy (VIT) prevents lifethreatening sting anaphylaxis in otherwise healthy adults.
                We did a double-blind, placebo-controlled crossover trial of M pilosula VIT. Participants were randomly allocated either immunotherapy, in accordance with the semirush hyposensitisation regimen, or placebo. The primary endpoint was systemic reaction after a deliberate sting challenge. Analysis was per protocol.
                We randomly allocated 68 healthy volunteers (aged 20-63 years) who were allergic to M pilosula venom to placebo (33) and VIT (35). Four on placebo were stopped early and 12 on VIT had their treatment allocations revealed before the sting challenge, thus 29 on placebo and 23 on VIT were included in the primary analysis. Objectively defined systemic reactions to sting challenges arose in 21 of 29 participants (72%) on placebo (8 reactions were associated with hypotension) and none of 23 on VIT (p<0.0001). Of the remaining 12 on VIT who underwent sting challenges after treatment allocations were revealed, only one reacted to sting challenge with transient urticaria that did not require treatment. After crossover of the placebo group to VIT, one of 26 had a reaction to sting challenge (transient urticaria). In all patients who had VIT, we recorded objective systemic reactions in 22 of 64 (34%) during VIT; two of which were hypotensive.
                In well motivated, highly allergic, but otherwise healthy adults, VIT is highly effective in prevention of M pilosula sting anaphylaxis. The risk of systemic reactions during VIT means that treatment should be given where there is immediate access to resuscitation facilities. Insect hypersensitivity is currently treated by immunization using whole-body extracts. We compared this regimen with immunotherapy using insect venoms or placebo in groups of 20 patients matched for history and sensitivity, as judged by venom skin test, histamine release and IgE antibody to venom. After six to 10 weeks of immunization, systemic reactions to stings occurred in seven of 12, seven of 11, and one of 18 patients treated with placebo, whole-body extract, and venom, respectively. Placebo and whole-body extract gave similar results and were significantly less effective than venom immunotherapy (P less than 0.01). The 14 patients with failure of treatment with whole-body extract and placebo were subsequently provided with venom immunotherapy; one reacted to a subsequent sting. We conclude that venom immunotherapy is clinically superior to therapy on whole-body extract or placebo. In many European centers insect venom allergic patients with a reaction confined to the skin are only offered an epinephrine auto-injector and not venom immunotherapy (VIT). Previously we showed that VIT improves health-related quality of life (HRQL) of yellow jacket allergic patients with more than dermal reactions.
                To examine whether HRQL of dermal reactors is impaired and to examine the influence of VIT on HRQL in comparison with the EpiPen.
                Patients with solely dermal reactions were asked if they were willing to be randomized either to VIT or EpiPen, after receiving patient information. Before and 1 year after enrollment, patients completed the Vespid allergy Quality of Life Questionnaire (VQLQ), Burden of Treatment and Expectation of Outcome.
                Of 55 patients eligible for the study, 29 consented to randomization: 15 to VIT, 14 to EpiPen. The remaining 26 patients preferred to choose their treatment: 11 VIT and 15 EpiPen. The VQLQ score of patients randomized to VIT improved (mean change 0.83 (SD 0.87), in contrast to patients randomized to the EpiPen whose scores deteriorated (mean change -0.42 (SD 0.64), P < 0.0001), resulting in an overall difference of 1.25 [95% confidence interval (CI): 0.63-1.87]. With a minimal important difference of 0.5 indicating a clinically significant improvement, VIT generated an number needed to treat (NNT) of 1.7. Dermal reactors did not consider VIT burdensome and rated this treatment as being superior to the EpiPen.
                VIT results in a clinically significant improvement of HRQL in most patients with reactions limited to the skin following yellow jacket stings. Prescription of an EpiPen in patients not choosing this treatment is associated with deterioration in HRQL and should therefore be avoided as definitive treatment in these patients. 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.
                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.
                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.
                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.
                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. Sublingual immunotherapy (SLIT) proved effective and safe in respiratory allergy, and thus its use in hymenoptera allergy can be hypothesized.
                We sought to assess, in a proof-of-concept study, whether SLIT might potentially be beneficial in hymenoptera allergy. The sting challenge in large local reactions (LLRs) was used to test this hypothesis.
                We performed a randomized, double-blind, placebo-controlled study involving patients with LLRs who were monosensitized to honeybee. After the baseline sting challenge, they were randomized to either SLIT or placebo for 6 months. The treatment (Anallergo, Florence, Italy) involved a 6-week build-up period, followed by maintenance with 525 microg of venom monthly. The sting challenge was repeated after 6 months.
                Thirty patients (18 male patients; mean age, 44.5 years) were enrolled, and 26 completed the study, with 1 dropout in the active group and 3 dropouts in the placebo group. In the active group the median of the peak maximal diameter of the LLRs decreased from 20.5 to 8.5 cm (P = .014), whereas no change was seen in the placebo group (23.0 vs 20.5 cm, P = not significant). The diameter was reduced more than 50% in 57% of patients. One case of generalized urticaria occurred in a placebo-treated patient at sting challenge. No adverse event caused by SLIT was reported.
                Honeybee SLIT significantly reduced the extent of LLRs, and its safety profile was good. Although LLRs are not an indication for immunotherapy, this proof-of-concept study suggests that SLIT in hymenoptera allergy deserves further investigation. Trials involving systemic reactions and dose-ranging studies are needed. The treatment of patients allergic to insect stings with insect-venom injections has been shown to be 97 percent effective in reducing the risk of sting-induced anaphylaxis. However, the frequency of systemic reactions to subsequent stings in unimmunized adults with previous reactions is approximately 60 percent. To determine which factors, in addition to a history of reaction and evidence of venom-specific IgE antibody, predispose patients to future insect-sting reactions, we studied a venom-sensitive group of children who were deemed to be at relatively low risk for severe reactions; 28 percent of them received venom therapy.
                We studied 242 children, 2 through 16 years of age, each of whom had had a systemic allergic reaction, affecting only the skin, to an insect sting. Each child had a positive skin-test reaction to one or more of five hymenopteran venoms. Sixty-eight children received immunotherapy with insect venom and 174 did not; about half were randomly assigned to treatment groups, and the rest were assigned on the basis of the patient's (or the parents') choice. The results of accidental stings during four years of observation were evaluated.
                In the treated group, 84 stings in 36 patients resulted in one systemic reaction (1.2 percent of stings). In contrast, 196 stings in 86 untreated children resulted in 18 systemic reactions (9.2 percent of stings, P less than 0.001). Sixteen of these 18 reactions were judged to be milder than the patient's reaction to the first sting, 2 were similar in severity, and none were more severe.
                These data confirm that immunotherapy with insect venom prevents recurrences of systemic reactions after subsequent insect stings. Because of the surprisingly low rate of reactions among untreated children, we could not identify any characteristics that were predictive of repeat reactions. Since only 9.2 percent of stings in the untreated children led to a systemic reaction and since there was no progression to a more severe reaction, we conclude that venom immunotherapy is unnecessary for most children who are allergic to insect stings.