Our immune system has evolved to protect us from pathogens while minimizing damage to our tissues. From ancient times, it was appreciated that recovery from a disease frequently resulted in protection against that condition, but they did not understand why it was so.
The immune system consists of an intimately linked network of cells, proteins, and lymphoid organs that are arranged in such a way as to ensure maximum protection against infection. We divide the immune defence into innate immune response and acquired immune response. The innate response provides immediate protection against an invading pathogen, but the acquired response, also known as the adaptive immune system, takes some time to develop but it confers specific and long-lasting protection.
With advanced knowledge now we understand that the immune system not only protects us from infection but its response in doing so can also lead to damaging our tissues,....
