Diagnosis of Vespa affinis venom allergy: use of immunochemical methods and a passive basophil activation test

Impact of environmental factors on Apis dorsata (Giant Asian Honeybee) venom in Bandarawela, Sri Lanka

Apis dorsata stings are amongst the most frequent insect-stings in Sri Lanka. A. dorsata venom consists of a mixture of components including PLA2, melittin, hyaluronidase and apamin. However, there are no studies done in Sri Lanka to evaluate the environmental influence in venom production. We, herein, tried to correlate the variations in those four venom components of A. dorsata with environmental factors (temperature, rainfall, wind speed and relative humidity). The venom components were analyzed using high-performance liquid chromatography (HPLC) and variations in environmental factors were gathered from the Department of Meteorology, Sri Lanka. Of the four components, PLA2 (r = 0.718; p = 0.009 and r = 0.636; p = 0.026) and melittin r = 0.734; p = 0.007 and r = 0.582; p = 0.047) showed significant correlations with temperature and wind speed, respectively. Whilst relative humidity showed significant negative correlations with PLA2 (r = - 0.634; p = 0.027) and melittin (r = -0.643; p = 0.024). There was no significant correlation of climatic parameters with hyaluronidase or apamin. The results indicated a variation in the composition of venom components with the month in which the venom was collected due to climatic influence and it should be considered when therapeutic grade venom preparations are produced.

Identification of allergens in coconut milk and oil with patients sensitized to coconut milk in Sri Lanka

BACKGROUND

Despite the low prevalence of IgE sensitivity to fresh or boiled coconut milk and coconut oil, those may contain allergens of which the clinical significance remains undetermined. This study aimed to identify and compare allergens in fresh coconut milk (FCM), boiled coconut milk (BCM), unrefined wet-processed coconut oil (WPCO), and dry-processed coconut oil (DPCO) using sera from patients with allergy to coconut milk.

METHODS

The study included 18 patients with immediate hypersensitivity to coconut milk, including five who developed anaphylaxis. Sensitization was assessed by skin prick test and ImmunoCAPs using commercially available coconut extracts. Immunoblotting was performed to identify and compare allergen profiles.

RESULTS

Total sIgE levels and overall IgE reactivity of patients with anaphylaxis were higher compared to patients with allergy. Twelve allergens ranging from 5 to 128 kDa including six novel allergens with 5, 12, 47, 87, 110, and 128 kDa were visualized in immunoblots with FCM. Similarly, nine allergens of 5, 12, 17, 32, 35, 47, 87, 110, and 128 kDa were detected in BCM. One allergen (110 kDa) was discerned in all four extracts. Higher IgE prevalence was detected with three allergens of 55, 87, and 110 kDa.

CONCLUSIONS

Allergens of BCM and unrefined coconut oil (WPCO and DPCO) were determined for the first time. Novel allergens of 87 and 110 kDa and the 55 kDa allergen have the highest potential to be used in Component Resolved Diagnostics. Further, these findings demonstrate that, patients who have an allergy to coconut milk could also react to boiled coconut milk and unrefined coconut oil.

Diagnosis of Apis dorsata venom allergy: use of recombinant allergens of Apis mellifera and a passive basophil activation test

Background

Allergy to Apis dorsata (Giant Asian Honeybee) venom is the commonest insect allergy in Sri Lanka and South East Asia. However, laboratory diagnosis is difficult as the pure venom and diagnostic reagents are not commercially available.

Objective

This study assessed the use of four recombinant allergens of A. mellifera venom and the passive basophil activation test in the diagnosis of A. dorsata venom anaphylaxis.

Methods

Serum IgE levels to four recombinant allergens of A. mellifera, rApi m 1, 2, 5 and 10 were assessed and compared with serum IgE to the crude venom of A. mellifera or V. vulgaris by Phadia ImmunoCAP, in patients who developed anaphylaxis to A. dorsata stings. Basophil activation in response to venom of A. dorsata or V. affinis was assessed using a passive basophil activation test. Association of the severity of the reaction with basophil activation was compared.

Results

rApi m 1 and 10 combinedly had significant correlation (r = 0.722; p < 0.001) with the crude venom of A. mellifera (Western honeybee) and a higher positivity rate of 90% (27/30). Whereas, IgE reactivity to rApi m 2 or 5 had significant correlation (p = 0.02 and p = 0.005 respectively) with V. vulgaris crude venom. All 30 (100%) were positive to A. dorsata venom in passive BAT; 70% (21/30) had over 80% activation, 96.7% (29/30) had over 60% activation and 100% had over 50% activation. Percentage activation of basophils in patients who had mild or moderate reactions (n = 20) was significantly low (p = 0.02) from that of patients who had severe reactions (n = 10).

Conclusions

rApi m 1 and 10 when combined was sensitive for the diagnosis of A. dorsata allergy. This combination had the lowest cross-reactivity rate with Vespula vulgaris. The passive BAT is highly sensitive in A. dorsata allergy. The basophil reactivity was significantly higher in severe anaphylaxis compared to mild/moderate anaphylaxis. This finding should be further explored in further studies.

Defensive behavior of the invasive alien hornet, Vespa velutina, against color, hair and auditory stimuli of potential aggressors

Background

During recent years, invasion of the yellow-legged hornet (Vespa velutina) has occurred in Europe, Korea and Japan, and stinging accidents often occur as some V. velutina nests are in places where humans can reach them. Misleading information regarding precautionary measures for mitigating wasp attacks has only exacerbated the situation. In this study, we sought to identify appropriate countermeasures by analyzing wasp defensive behavior, with a focus on color, hair and auditory stimuli.

Methods

Defensive behavior was analyzed using video recordings by creating an experimental frame to attach experimental bundles to nine V. velutina nests in Daegu and Gyeongbuk, South Korea. For the color experiment, eight-color and single-color tests were conducted with bundles of eight colors (black, brown, yellow, green, orange, gray, red and white), and the difference in defensive behavior was tested between black hair/hairless and green hair/black hairless configurations.

Results

When presented simultaneously with bundles of eight different colors, V. velutina showed the greatest and the longest defensive behavior against the black bundle, followed by brown. A similar response was observed in single-color tests. Furthermore, there was no significant difference in the defensive behavior against black hair and black hairless, but the duration of defensive behavior was longer for black hair. A comparison between green hair and black hairless stimuli indicated that wasps are more sensitive to color than to hair texture. Vespa velutina showed no discernible responses when exposed to selected auditory stimuli (human conversation and loud music). Dark colors and dark hair are characteristic features of potential predators, to which wasps are evolutionarily predisposed, and are accordingly likely to provoke strong defensive responses. The results of this study provide scientifically credible information that can be used to base appropriate precautionary measures against wasp attacks.