D1.265 - Component-Resolved Diagnosis and Clinical Profiles of Anisakis Allergy in Japan

Anisakis simplex, a parasitic nematode found in marine fish, is a well-known cause of allergic reactions, including anaphylaxis, which can range from mild to life-threatening. Understanding the immune response to A. simplex antigens and identifying key factors influencing IgE sensitivity are critical for advancing diagnostic and therapeutic approaches. This study focused on evaluating IgE responses in patients with a history of anisakiasis or severe anaphylaxis to identify specific antigenic markers and their association with allergic severity. The study involved 40 patients (24 males, 16 females; mean age: 45.3 years) observed over a 12-month period.

Patients were recruited based on their history of anisakiasis or documented anaphylactic reactions following seafood consumption. Longitudinal measurements of IgE levels were performed at baseline and subsequent follow-up visits to evaluate temporal trends and associations with clinical outcomes. Live third-stage larvae of A. simplex were collected from marine fish and processed to isolate somatic (S) and excretory-secretory (ES) antigen fractions. The S fraction was prepared by homogenizing larvae in phosphate-buffered saline (pH 7.0), followed by heat treatment and filtration. The ES fraction was derived by incubating live larvae in acidic saline (pH 2.0) at 37°C for 6 hours. ELISA assays were performed using these antigen fractions to measure specific IgE binding in patient sera.

The analysis revealed no significant differences in IgE levels based on sex or prior gastric anisakiasis (P > 0.05). However, patients with a history of severe anaphylaxis exhibited significantly elevated IgE levels (P = 0.047) compared to those without such a history. Temporal trends in IgE levels showed a marginal association with severe anaphylactic episodes (P = 0.071). Among the antigen fractions tested, Ani 4 showed a statistically significant association with IgE binding (P = 0.023), indicating its potential role as a marker of allergic sensitivity. In contrast, other antigens, such as Ani 12, were not significant (P = 0.178). The time to onset of anaphylactic symptoms varied among patients and was generally not significant (P = 0.454), except in specific instances (P = 0.0129). Further analysis revealed a trend of reduction in NS to HS and NES to HES transitions, highlighting potential immune modulation.

This study provides new insights into the immunological response to A. simplex antigens in patients with anisakiasis or severe anaphylaxis. The findings emphasize the importance of specific antigens, particularly Ani 4, in driving IgE-mediated allergic responses. Elevated IgE levels in patients with severe anaphylaxis suggest their potential utility as biomarkers for disease severity. These results underscore the need for further research into the immunopathology of anisakiasis and the development of improved diagnostic and therapeutic strategies. A better understanding of antigen-specific IgE responses could enhance patient management and reduce the burden of anisakiasis-related allergic diseases.