Rheumatoid arthritis - Causes. Rheumatoid arthritis is an autoimmune condition, which means it's caused by the immune system attacking healthy body tissue. However, it's not yet known what triggers this. Your immune system normally makes antibodies that attack bacteria and viruses, helping to fight infection.
Trying to find out what channel Discovery is on DirecTV? Well you are in luck! It can be found on channel #278 on the DirecTV Channel Guide. Discovery is also available in HD (High Definition). The great thing is that this particular channel is available in all of the Direct TV packages like Entertainment, Choice, Choice Extra, Choice Ultimate and Premier
About Discovery Channel Discovery Channel is dedicated to creating the highest quality non-fiction content that informs and entertains its consumers about the world in all its wonder, diversity and amazement.