Fungi which don't often cause infections in people with healthy immune systems but can under some circumstances, and can be tremendous problems in patients that have weakened immune systems.

真菌在免疫系统健康的情况下通常,不引起感染,但在某些情况下也会感染,那就成了极大的问题,在免疫系统脆弱的病人体内

耶鲁公开课 - 生物医学工程探索课程节选

U.S. universities work fine by comparison, but higher education is not immune to problems.

FORBES: Craig R. Barrett

You'd think that export-heavy aerospace, of all U.S. industries, would be immune to problems radiating from the U.S. subprime mess.

FORBES: Boeing: Getting Beyond The Turbulence

This should help researchers focus on the specific immune-system problems that underlie the disease.

ECONOMIST: Human genomics