Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
HIV testing is now required for non-HIV-AIDS-related immunological studies in areas of high HIV prevalence. Ethical guidelines for testing in these circumstances need clarification and sensitive protocols need to be developed.
How does air pollution affect asthma and allergic rhinitis? Particulate and gaseous pollution drive proallergic inflammation through the generation of oxidative stress, which is regulated by individual genetic susceptibility.