Chapter 21.6, Problem 2AYLO

Summary Introduction

To discuss:

Hypersensitivity; names and characteristics of its four types, and examples of disorders of each type.

Introduction:

Hypersensitivity is an abnormal and harmful reaction toward an antigen. It includes alloimmunity (reaction to transplanted tissues from another person), autoimmunity (reaction to one’s own tissues), and allergies. Allergies are reaction to an antigen that is from the environments. Such environmental antigens are known as allergens, which occur in pollen, dust, mold, vaccines, wasp venom, bee, animal dander, poison ivy, and foods such as milk, nuts, egg, shellfish, and some plants.