Sensitization following Hymenoptera whole body extract therapy

Basophil activation test using recombinant allergens: highly specific diagnostic method complementing routine tests in wasp venom allergy

Background

Skin testing can expose allergic subjects to potential systemic reactions, sensitization against unrelated proteins, and increased risk of future sting reactions. Therefore the continuous improvement of in vitro diagnostic methods is desirable. Recombinant allergens have been shown to improve the sensitivity of specific IgE (sIgE) detection in vitro whilst no data is available regarding their application and reliability in basophil activation test (BAT). Here we aimed to compare the specificity and sensitivity of recombinant allergens Ves v 1, Ves v 2, Ves v 3 and Ves v 5 in both specific IgE (sIgE) detection in vitro and basophil activation test.

Methods

sIgE detection by ELISA or ImmunoCAP and BAT towards the panel of recombinant allergens Ves v 1, Ves v 2, Ves v 3 and Ves v 5 were performed in 43 wasp venom allergic patients with a history of anaphylactic reaction and sIgE seropositivity, as well as 17 controls defined as subjects with a history of repetitive wasp stings but absence of any allergic symptom.

Results

The BAT performed with the recombinant allergens Ves v 1, Ves v 2, Ves v 3 and Ves v 5 markedly improved the specificity of diagnosis in wasp venom allergic subjects when compared to the respective sIgE detection in serum.

Conclusions

BAT performed with the recombinant allergens Ves v 5, Ves v 3 and Ves v 1 provides an emerging highly specific in vitro method for the detection of wasp venom allergy, compared to the sIgE detection. Recombinant allergens applied to BAT represent a step forward in developing reliable in vitro tests for specific diagnosis of allergy.

Determination of IgE antibodies to Polistes dominulus, Vespula germanica and Vespa crabro in sera of patients allergic to vespids

The study was undertaken to investigate the presence of IgE antibodies to Polistes dominulus (PD), Vespula germanica (VG) and Vespa crabro (VC) in a large group of sera belonging to patients sensitized to Vespids in Spain. RAST values showed that although the majority of patients had IgE antibodies to PD, VG and VC, there was a marked predominance of PD. These results were related to the distribution of the insect in the areas where the sera were obtained. Due to geographical and insect distribution differences, the whole area was divided into three zones: Central, East and South. Comparison of the positive RAST values obtained indicated that, although the positivity to PD predominated over VG and this over VC, there were significant differences in percentage positivities to each vespid in the different regions studied. The results of the RAST absorption studies indicated that in most instances patients were originally sensitized to one vespid and were RAST positive to the other venoms due to cross-reactivity. Only in a minority of cases were coexisting antibodies to two insects present. These results show that PD and VG are the important vespids followed to a lesser extent by VC. This study provides relevant information concerning insect distribution sensitivity in a European country.

Immunotherapy to deciduous tree pollens: specific IgE and IgG antibody patterns

Thirty-nine children with birch pollinosis were given immunotherapy (IT) for 3 years with a purified, characterized and biologically standardized pollen preparation made from either birch or a mixture of birch, alder and hazel. Levels of IgE antibodies against birch, alder and oak increased early during IT (P less than 0.01) and then decreased below the initial level (P less than 0.01). Birch-specific IgG antibodies also increased (P less than 0.01) but not as rapidly as birch-specific IgE antibodies and the levels remained increased throughout IT. There were only weak correlations between immunochemical findings before IT or during early IT on one hand and the improvement during IT on the other hand. The ratio birch-specific IgG:IgE after 1.5 and 2.5 years of IT correlated with symptom scores the following season (P less than 0.01). In 60% of the children below 13 years of age, new IgE specificities developed during IT as demonstrated with crossed radioimmunoelectrophoresis. No such new IgE specificities were found in older children. These 'new sensitivities' did not appear to have any clinical implication.

An epidemiologic study of insect allergy in children. I. Characteristics of the disease

Of 235 children with a history of allergic reactions to insect stings studied, 59 had severe life-threatening systemic reactions, 123 had mild, non-life-threatening systemic reactions, and 53 had large local reactions. The overall male-female ratio was 2:1. Venom skin tests were positive in approximately 89% of each group. Prior whole body extract therapy increased the likelihood of venom skin test reactivity to multiple insect venoms from 51 to 78%. Venom skin test results did not correlate with the severity of previous allergic reactions. One hundred and nine children with NLTR and positive venom skin tests were entered into one of two groups--venom immunotherapy or observation only. During the first six months the treatment group had the expected fourfold rise in venom-specific IgE antibody titers, whereas the observation group had a decline of the mean IgE titer. Patients in the observation group who were accidentally stung had a transient rise in IgE antibody titers. The small number of accidental stings which occurred in both groups resulted in reactions milder than the original reactions. Although based on preliminary data, venom immunotherapy may not be necessary for some children with previously mild systemic symptoms.

Sensitization to nonvenom contaminants in a venom preparation

An individual is described who appeared to be sensitive to nonvenom contaminants in a venom preparation. His IgE antibodies, measured by the immediate direct skin test and the radioallergosorbent test (RAST), reacted with a yellow jacket venom preparation obtained by "washing" of venom sacs. With yellow jacket venom obtained by electriral stimulation, there was a skin test reaction of equivocal significance and no serum antibodies were detected by the RAST. Moderate reactions were also found with yellow jacket body extracts. In contrast, sera obtained from patients with yellow jacket sting anaphylaxis showed strong reactions with the electrically stimulated venom preparation and only a few reacted with the body extract. In additional studies, the patient's serum reacted with yellow jacket extracts devoid of venom and a variety of hornet and wasp extracts. Analyses of the two yellow jacket venoms by gel diffusion using rabbit antisera showed the presence of body proteins in the venom obtained by venom sac "washing." Subsequent history revealed the presence of insect nests in the roof of the patient's bedroom, perhaps the source of inhalant exposure and sensitivity. This case history demonstrates the need for venom extracts that do not contain potentially sensitizing extraneous material.

Enzyme-linked immunosorbent assay of allergen-specific IgG antibodies in bee sting allergic patients hyposensitized with pure bee venom

An ELISA is presented for detection of IgG antibodies to bee venom. By this method, sera of 11 bee sting allergic patients, who were treated with rapid hyposensitization with pure bee venom, were tested. The highest antibody titers were observed after 30 days of treatment, a maximum rise of 7.4 +/- 1.5 log 2-titer steps. Pure bee venom is shown to be more potent immunologically than whole body bee extract. Prediction of the clinical success, measured by tolerance to a bee sting challenge, is not yet possible using venom specific IgG determinations.

A controlled trial of immunotherapy in insect hypersensitivity

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.