rheumatoid factor

[Guest guest]

I was reading this book, and thought maybe this would answer some of the

questions about rheumatoid factor.

From: Arthritis and Rheumatism The Facts by , MD FRCP, Oxford

University Press, c.1980 (This is a great book BTW, even if a bit old, has a

lot of basic info on different forms of arthritis, and some rather scary but

interesting photos).

" Blood may be examined for the presence of " rheumatoid factor " . This is a

large molecular weight protein, mostly in the so-called IgM fraction, which acts

as an antibody to, and reacts with, another fraction of protein called IgG.

Proteins of this type, which are closely concerned with the body's immunological

reactions, are called " immunoglobulins " . The discovery of rheumatoid factor

nearly 40 years ago was of great theoretical interest with regard to our concept

of immunological processes in rheumatoid arthritis. It also came to be of vital

importance in classifying the types of arthritis in which rheumatoid factor is

absent-- " seronegative " arthritis as opposed to " seropositive " rheumatoid

disease. Unfortunately, in the individual patient, the test may not be all that

helpful, being positive in only about 70 per cent of patients with rheumatoid

arthritis , and tending to be negative in early or mild cases--that is, just the

sort of patient where diagnostic help is required. Further, the test is by no

means specific--that is to say it can be positive in other diseases, and indeed

is so in a small proportion of the normal healthy population. With these

qualifications, examination of the blood for rheumatoid factor can sometimes be

a useful diagnostic test, and a high concentration to some extent indicates a

rather poor outlook (prognosis); but careful interpretation of the results is

essential. The patient with little the matter with him, but who has been told

this test has been positive, takes a lot of reassuring. "

Further on in the chapter is a summary of the processes that occur in the

immune system in RA, the cells involved, immune complexes, etc. Is anyone

interested in this? Give me a shout if you are and I'll type it up in the next

day or so. Liz G