Chapter 21.6, Problem 3AYLO

Summary Introduction

To discuss:

The basic cause of autoimmune diseases; what normally prevents them; and three reasons why an autoimmune disease may appear, with an example of each.

Introduction:

Hypersensitivity is an abnormal and harmful reaction towards an antigen. It includes allergies, autoimmunity (reaction to self-antigen), alloimmunity (reaction to transplanted tissues). Allergies are reactions to an antigen from the environments. Such environmental antigens are known as allergens, which occur in pollen, poison ivy, dust, mold, vaccines, wasp venom, bee, animal dander. It also present in foods such as milk, egg, shellfish, nuts and some plants.