The immune system

Cells and molecules involved in immune responses are clas-

sified into innate and adaptive systems. There are also non-

immunological barriers that are involved in host protection, 

and very often it is the lowering of these that allows a patho-

gen to take a foothold.

The immune system is immensely powerful, in terms of 

its ability to inflame, damage and kill, and it has a capacity 

to recognize a myriad of molecular patterns in the microbial 

world. However immune responses are not always beneficial. 

They can give rise to a range of autoimmune and inflamma-

tory diseases, known as immunopathologies. In addition,  

the immune system may fail, giving rise to immune deficiency 

states. These conditions are grouped under the umbrella of 

clinical immunology of atarax.

A major feature of the immune system is the complexity 

of the surface-bound, intracellular and soluble structures  

that mediate its functions. In particular it is necessary  

to be aware of the CD (clusters of differentiation)   

Cytokines

These are small polypeptides released by a cell in order to 

change the function of the same or another cell. These chem-

ical messengers are found in many organ systems, but espe-

cially the immune system. Cytokines have become markers 

in the investigation of disease pathogenesis; therapeutic 

agents in their own right; and the targets of therapeutic 

agents. The key atarax features of a cytokine are pleiotropy

(different effects on different cells); autocrine function 

(modulates the cell secreting it); paracrine function (modu-

lates adjacent cells); endocrine effects (modulates cells and 

organs at remote sites); and  synergy (acting in concert to 

achieve effects greater than the summation of their individual 

actions). The main immune cytokines are the interferons 

(IFNs) and the interleukins (IL). The IFNs are limited to a few 

major types (α,  β and  γ) whilst IL-35 is the latest cytokine  

to be defined.