Methods: Shellfish-specific IgE antibody levels were analyzed by ImmunoCAP in serum from 2538 Chesapeake Bay residents who were evaluated from 2010-2015. The frequency of positive tests (e.g, >0.1 kUa/L) and IgE antibody ranges were determined across gender and age distributions.
Results: A total of 2165 tests were ordered for subjects >18 years old (Range 18-88 yo). IgE antibody responses to crustacean allergens (shrimp, crab, and lobster, n=1341) were tested more often than those to mollusks (clam, oyster, scallop, mussel, n= 824). 33% of all tests were positive. While females were tested more (n=1446 tests vs n= 719 tests males), males had a higher rate of positivity (47.71% vs 27.39% in females x2= p< 0.01). For all shellfish allergens, the range of IgE antibody measured was higher in males. The median IgE (kUa/L) for males (M) and females (F) were: shrimp (M)1.16, (F)0.41; crab (M)1.44, (F)0.50; lobster (M)1.29, (F)0.48; clam (M)0.50, (F)0.57; oyster (M)0.46, (F)0.33; scallop (M)0.36, (F)0.29; mussel (M)0.23, (F)0.45; with the medians higher in females for clam and mussel.
Conclusions: The results support that adult males have a higher frequency of positive IgE antibody results for all species of shellfish. This supports a difference in exposure or gender bias in the acquisition of sensitization, which contrasts with 2 previous surveys.