Benchmark 6E
The Human Organism: Physical Health
Grades 9-12, page 146

Some allergic reactions are caused by the body's immune responses to usually harmless environmental substances. Sometimes the immune system may attack some of the body's own cells.

NSES Content Standard C 
Life Science: Structure and function in living systems
Grades 5-8, page 157
Disease is a breakdown in structures or functions of an organism. Some diseases are the result of intrinsic failures of the system. Others are the result of damage by infection by other organisms.