[4] He proceeded with his postgraduate clinical training in Cardiff, Oxford and Edinburgh,[4] including a career-influencing period with John Crofton, the initiator of successful combination chemotherapy for tuberculosis.
In those periods he developed a robust bronchoscopic lavage method to secure precise microbial diagnostics and improved survivals for pneumonia in immuno-suppressed subjects.
He showed that common up-regulating genetic variants of Th2 immune signalling related to allergic disorder and high IgE levels (sharing, with Dr Taro Shirakawa, the 2001 Daiwa-Adrian Prize in Medicine) but also to low burdens of parasitic work infestation - proposing an evolutionary mechanism in which prevalent parasitic worm infection has provided long term evolutionary selection for up-regulating genetic variants of Th-2 immunity.
He contributed epidemiologic data that relate diminished bacterial exposures in early childhood (less tuberculosis; more oral antibiotic receipts) to increased allergic disorder.
His current work builds on the latter and focuses on how bacterial exposures shape human immunity relevant to asthma, and how unravelling these microbial mechanisms may provide disease preventing agents.