IgE sensitization profiles to food, inhalant and insect venom in Norwegian blood donors and their impact on blood transfusions.

Allergen-specific immunoglobulin-E (As-IgE) in blood donors (BD) can be transferred to transfusion recipients via plasma-containing blood components (PCBC) and sensitize recipient's mast cells. These cells can activate upon allergen exposure and cause allergy. This study aimed to assess sensitization profiles against an array of allergens in BD to identify donors with As-IgE and explore if this IgE can lead to allergic symptoms in recipients. Furthermore IgE sensitization was characterized in donors of PCBC that were associated with allergic transfusion reactions (ATR) in recipients. Serum samples from 300 randomly selected BD (RSBD) and 40 BD selected following 26 ATRs in patients transfused with PCBC from these donors were collected. IgE sensitization was tested by a line-blot enzyme-immunoassay and an ELISA-based IgE multiplex assay. Thirty-eight per cent of the RSBD had IgE to one or several allergens. High IgE levels with a potential to transfer to recipients of PCBC were also detected in some BD. Investigation of 2/3 of the PCBC from sensitized RSBD revealed no reports of ATR in recipients. IgE testing of donors associated with an ATR showed sensitization in 65% of the cases. We conclude that IgE testing of BD can reveal sensitization to different allergens, even though persons with severe allergies are not accepted as BD. The sensitization frequency appears higher in BD of PCBC that led to an ATR compared to the RSBD. No reports on ATR were found for PCBC from sensitized RSBD. More studies are needed to address the role of IgE-sensitization of BD in ATR.