Immune System and Respone...General overview

Immune Response happens when white blood cells present foreign materials to the B or T cells. 

B cells= antibody-mediated immunity (IgE)

T cells = direct cellular processes to protect the body, but does not produce antibodies.

T cells carry T cell receptors that recognize specific antigens; and there are 3 main types of T cells:
Th1=regulation of defenses against bacteria, virusus, fungi, parasites.
Th2=promotes antibody production
Th3=responsible for immune regulation of T1/T2, which gives us oral tolerance. 

T cells can cause immune dysfunction in two ways.  One is there the Th2 is dysregulated and this results in overprodcution of antibodies which cause typical allergy and allergy associated diseases (IgE, eczema, allergy induced asthma...).    The second is when the Th1 is overactive and this leads to auto-immune diseases- the body attacking itself instead of bacterian, viruses, fungi and parasites (rheumoatoid arthritis, multiple sclerosis, Crohns, psorasis...)

FPIES is thought to be a Th1 response, not over active but over RE-active.  The Th1 isn't activated to attack unless it recognizes foreign antigens (food triggers).   There are some FPIES that remain complex, and the question remains is if this over-reactive response doesn't just become over active in general turning the FPIES into an auto-immune and chronic condition that is more difficult to control. 

Gut flora helps to regulate immune system responses (continued in another post: )