Abstract:
The actuality and significance of the topic. Some researchers consider that
rheumatoid arthritis (RA) is not a single disease, but rather a collection of diseases. It
could also be a disease with many different causes. However, RA is ultimately defined
based on two main subtypes in adults: seropositive and seronegative. In seropositive
RA, serological tests demonstrate high levels of antibodies called anti-cyclic
citrullinated peptides (anti-CCP) and rheumatoid factor (RF). These are specific
markers for RA and can appear long before overt symptoms of the disease. About 60%
to 80% of people diagnosed with RA have anti-CCP and RF. By definition, people with
seronegative RA do not have these antibodies and complexes in their serum, although
this is controversial.[...]
