The human immune system is one of the most effective defence mechanisms known to nature. It can ward off myriad microbial invaders: bacteria, viruses and parasites. It is sometimes overwhelmed by disease, of course, but the billions of men and women who now live on Earth are a testament – at least in part – to the effectiveness of their immune defences.
However, on occasions they go too far. Instead of killing off invading organisms, our immune systems turn on our own tissue and attack it. Conditions such as type 1 diabetes, rheumatoid arthritis, and lupus are all triggered in this way, very often with deeply unpleasant consequences.
In the case of rheumatoid arthritis, immune cells – mainly lymphocytes and macrophages – start to attack the tissue that makes up joints, and these become painful, stiff and swollen. Around one-third of those who develop rheumatoid arthritis will have stopped working within two years of its onset, so painful are its effects. And given that the disease affects more than 400,000 people in the UK, its financial impact is also high: estimates suggest it costs the economy between £3.8bn and £4.8bn a year.
Source : theguardian
No comments:
Post a Comment