Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation of the synovial joints, which leads to joint swelling, progressive joint erosion and ultimately lead to cartilage and bone destruction. The disease is often disabling and significantly affects quality of life. Rheumatoid arthritis is prevalent in all ethnic groups, affecting approximately 0.4-1.0% of the population of the western world. As is often the case with autoimmune diseases, there is a female overrepresentation. Onset is most frequent between the ages of 40 and 50, but people of any age can be affected. While rheumatoid arthritis primarily affects joints, problems involving other organs of the body are known to occur. Extra-articular manifestations are clinically evident in about 15–25% of individuals with rheumatoid arthritis.
Indications: Suspicion of rheumatoid arthritis. An early and accurate diagnosis Early and accurate diagnosis is therefore of outmost importance and presence of autoantibodies to citrullinated proteins/peptides (anti-CCP) has an important prognostic value for the disease and antibodies can be detected even before the onset of clinical symptoms. The anti-CCP2 test has a very high specificity and sensitivity and is a reliable and accurate toolset for the early diagnosis and follow-up of RA. Due to its great clinical use, anti-CCP is included in the ACR/EULAR criteria for diagnosing RA.
The diagnosis of RA is primarily based on clinical, radiological and immunological parameters. A widely used serological parameter is rheumatoid factor (RF), and IgM RF occurs in about 60-80% of the patients. Although the analysis has a good sensitivity, it has a bad specificity and occurs in healthy people and in patients with other autoimmune diseases (e.g Sjögren’s syndrome) and in chronic infections. Even though the analysis has a bad specificity, a positive RF test is considered an important prognostic factor. The presence of RF is one of the tests included in the ACR (the American College of Rheumatism) criteria for RA. Studies have shown that anti-CCP occurs in about 75% of patients with RA with a specificity of 96%. The antibodies are rare in healthy people and also rare in other inflammatory diseases. The antibodies against CCP are mainly of IgG class with a high affinity. They emerge several years before the first symptoms. The correlation between anti-CCP and early RA is good but not between anti-CCP and age or sex. Anti-CCP seems to be of prognostic value and has a good ability to distinguish between erosive and non-erosive RA.
Disease outcome may vary from mild clinical symptoms to severe systemic disease when joint destruction is accompanied with these extra-articular manifestations. Treatment: So far, no therapy has been developed that cures the disease. Current therapies may, however, slow down the extent of swelling and erosive damage. To achieve the greatest therapeutic potential and effect it is essential to initiate treatment at an early stage of the disease.