Patients with alpha-gal syndrome from tick bites may also be sensitized to wasp venom
New research identified cross-reactivity between tick proteins and wasp venom, with more than half of a cohort of tick-bitten patients with alpha-gal syndrome also sensitized to wasp venom, according to study results.
“The observed relation between tick bites and [alpha-gal syndrome (AGS)] has raised the question whether other biting or stinging arthropods may be associated with AGS as well,” the researchers wrote in the study, published in Clinical and Translational Allergy.
The study comprised 136 Swedish patients with AGS. Among those, 73 (53.7%) had IgE reactivity against wasp venom with a median IgE level of 0.54 kUA/L (range, 0.1-38).
Researchers noted that this 54% rate of sensitization to wasp venom is higher than that which occurs among the general population. The rate in Europe ranges from 9% to 30% depending on climate, and generally ranges from 9% to 15% in colder areas such as Sweden.
Sixty of the 73 wasp-positive patients with AGS had IgE reactivity to ticks. Of those “double-positive” patients, 41 had higher tick-specific than wasp-specific IgE levels, whereas 19 had higher IgE levels to wasp than to tick.
Also, median tick-specific IgE levels appeared significantly higher among wasp-sensitized vs. non-sensitized patients with AGS (0.93 kUA/L vs. 0.28 kUA/L (P < .006). Further analysis showed a correlation between wasp-specific and tick-specific IgE levels (P < .0005).
However, researchers did not identify alpha-gal-bearing proteins in wasp venom, “which makes it unlikely that wasp stings are directly involved in [alpha-gal] sensitization,” the researchers wrote.
“However, this finding can be related to the amount of time people spend outdoors,” they added. “Patients who spend much time in nature have a higher risk of having higher levels of [alpha-gal] due to multiple tick bites, as well as of wasp sensitization.”
The researchers also confirmed co-sensitization with the presence of Ves v 5-specific IgE in the serum pool of patients with AGS. The cross-reactivity the researchers detected between wasp and tick proteins also was not dependent on cross-reactive carbohydrate domains, they wrote.
In conclusion, the researchers noted their finding of a cross-reactivity between wasp venom and tick bites. This may explain why more than half of Swedish patients with AGS who have a history of tick bites are also sensitized against wasp venom, they wrote.