Diagnosis of red meat allergy with antigen-specific IgE tests in serum

Abstract

Red meat allergy is a tick-associated hypersensitivity reaction to galactose-α-1,3-galactose (α-gal) and is characterized by anaphylaxis, angioedema, urticaria and/or gastrointestinal symptoms occurring 3–6 hours after ingesting red meat such as beef, pork, or lamb. Diagnosis of red meat allergy is challenging due to the unusually long delay in symptom onset and poor sensitivity of skin prick tests with commercial meat extracts. The primary diagnostic tools available for this disease are quantification of α-gal-, beef-, pork-, and/or lamb-specific IgE in serum, however the diagnostic performance of these tests has not been reported. Using patient data for n=135 patients with red meat allergy and n=37 controls, we found that measurement of α-gal-specific IgE using the bovine thyroglobulin (bTG) ImmunoCAP method had the best overall sensitivity (100%) and specificity (92.3%) for diagnosis of red meat allergy. Measuring α-gal-specific IgE using the streptavidin (SA)-CAP technique or beef- or pork-specific IgE using ImmunoCAP were also effective tests with high sensitivities (89–92%) and variable specificities (65–82%). Lamb-specific IgE and total IgE had essentially no diagnostic value for red meat allergy. Positive and negative predictive values mirrored these trends. Taken together, these findings indicate that the α-gal-specific IgE test by bTG ImmunoCAP is the most useful for establishing a diagnosis of red meat allergy, although α-gal-specific IgE by SA-CAP and beef- and pork-specific IgE by ImmunoCAP are also effective tests.