%0 Journal Article %T Avidity Studies in Anisakis simplex-Associated Allergic Diseases %A Carmen Cu¨¦llar %A Ana Valls %A Consolaci¨®n de Frutos %A Marta Rodero %A Alvaro Daschner %J Journal of Allergy %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/106781 %X Gastroallergic anisakiasis (GAA) and Anisakis-sensitization-associated chronic urticaria (CU+) differ with respect to specific IgE levels. We hypothesised different immunoglobulin avidities in both entities as well as their dependence on TI and fish consumption. 16 patients with GAA and 17 patients with CU+ were included, and immunoglobulin levels were analysed by CAP (Phadia). IgE and IgG avidity indexes (AvIgE and AvIgG, resp.) were also determined. IgG avidity was higher in GAA than in CU+ ( ), whereas there was a tendency to lower IgE avidity in GAA ( ). When analysing all patients, AvIgG was positively correlated with specific IgE, IgG, and IgG4 as well as total IgE (Rho between 0.66 and 0.71; ), but AvIgE was negatively correlated with specific IgE (Rho £¿0.57; ), specific IgG4 (Rho £¿0.38; ), and total IgE (Rho 0.66; ). In GAA, weekly fish consumption was positively associated with AvIgE (Rho 0.51; ). A multivariate regression showed that time interval was the main explaining factor for AvIgE in GAA. We could show a differential behaviour of immunoglobulin isotype avidities in both entities and their dependence on fish-eating habits as well as on the time elapsed to the last parasitic episode. 1. Introduction Anisakis simplex is a fish parasite of worldwide distribution, whose third stage larva can be present in a huge number of marine teleost fishes. Humans can therefore be accidental hosts by consuming crude or undercooked fish [1]. Whereas IgE production is an evolutionary-maintained immunologic feature in mammals and thus can also be verified in all cases of human parasitic forms by this nematode, the allergenic potential has been an emerging health concern in the last years, giving rise to a large number of studies searching for proteins able to stimulate a specific IgE response [2, 3]. Gastroallergic anisakiasis has been described as a differential entity, where an acute parasitism by A. simplex produces also a clinically relevant IgE-mediated hypersensitivity reaction with appearance of acute urticaria, angioedema, or anaphylaxis [4]. It is well known that, in GAA, specific as well as total IgE and other specific immunoglobulin isotype levels depend upon the time interval elapsed (TI) between the acute parasitic episode and the obtaining of the serum sample [5]. The parasite is not adapted to the human environment and neither survives nor moults to its final stage. Even if the parasitic episode is always short-lived for mainly some hours, but maximally for a few days, as has been documented by gastroscopic findings in GAA, the immune %U http://www.hindawi.com/journals/ja/2013/106781/