Th2-skewed T cells correlate with B cell response to α-Gal and tick antigens in α-Gal syndrome.

Abstract

Tick bites have been shown to transmit a novel form of severe food allergy, the galactose-α-1,3-galactose (α-Gal) syndrome (AGS). Cellular responses to α-Gal in AGS patients have to date not been thoroughly scrutinized. Therefore, we investigated T and B cell proliferation, activation and cytokine profiles in response to tick protein extract (TE) and α-Gal-free TE in AGS patients and healthy controls. T and B cells from both patients and controls proliferated in response to TE, but significantly more in the patients. B cell proliferation, but not T cell proliferation, in AGS patients was reduced by removing α-Gal from the TE. In addition, TE induced a clear Th2 cytokine profile in AGS patients. Expression of CD23 by B cells correlated only to T cell proliferation. However, both B cell proliferation and CD23 expression were reduced when CD40L and IL-4 were blocked. A large proportion of the IgG1 and IgE antibodies binding TE in AGS patients were directed against the α-Gal epitope. We have for the first time investigated T and B cell responses to α-Gal carrying tick proteins in AGS patients, which will be essential for the understanding of the immune response against an allergenic carbohydrate transmitted by ticks.