Serum levels of 9[alpha],11[beta]-PGF2and cysteinyl leukotrienes are useful biomarkers of anaphylaxis

To the Editor: Anaphylaxis is a life-threatening hypersensitivity reaction.1 Mast cell (MC) activation results in the release of multiple mediators,2 but their relation to the outcome of an anaphylactic episode remains poorly defined, and systematic analyses concurrently investigating several mediators are sparse. According to the manufacturer, tryptase levels greater than 11.4 μg/L can be regarded as increased. Time seems decisive in the case of histamine because patients with food allergy (n = 11) undergoing controlled challenges show slight yet significant (P = .005) increases (maximum increase, 35%) in serum histamine levels after approximately 15 minutes, despite their mild symptoms (unpublished results).