Abstract
Hepatitis A virus (HAV) usually results in asymptomatic infection or mild disease, but in a small subset of patients it can lead to severe disease and even liver failure. In this issue of the JCI, Kim et al. identify a polymorphism associated with this increased disease risk in the gene that encodes the HAV receptor--TIM1. Importantly, this TIM1 gene polymorphism protects from the development of atopic diseases in HAV-seropositive individuals.