From the Guidelines
Rheumatoid arthritis (RA) is primarily classified into three main types: seropositive RA, seronegative RA, and juvenile idiopathic arthritis (JIA), with treatment approaches varying by type but generally including conventional DMARDs, biological DMARDs, and JAK inhibitors 1.
Types of RA
The main types of RA are:
- Seropositive RA, characterized by the presence of rheumatoid factor (RF) and/or anti-citrullinated protein antibodies (ACPA) in the blood, affecting about 70-80% of RA patients and typically associated with more severe disease progression.
- Seronegative RA, which lacks these antibodies but still presents with similar inflammatory symptoms, though often with a better prognosis.
- Juvenile idiopathic arthritis (JIA), which affects children under 16 years of age and has several subtypes including polyarticular (similar to adult RA), oligoarticular (affecting few joints), and systemic (with widespread inflammation).
Treatment Approaches
Treatment approaches for RA vary by type but generally include:
- NSAIDs for pain management
- Conventional DMARDs like methotrexate (starting at 7.5-15mg weekly) 1
- Biological DMARDs such as TNF inhibitors (e.g., adalimumab, etanercept)
- JAK inhibitors (e.g., tofacitinib, baricitinib)
Importance of Early Diagnosis and Treatment
Early diagnosis and treatment are crucial regardless of type, as they can significantly slow disease progression and prevent joint damage 1. Regular monitoring through blood tests and imaging is essential to track disease activity and adjust treatment accordingly. The European League Against Rheumatism (EULAR) recommends a treat-to-target approach, with the goal of achieving clinical remission or low disease activity 1.
From the Research
Types of Rheumatoid Arthritis (RA)
- Rheumatoid arthritis (RA) can be classified into two main types: seropositive and seronegative, depending on the presence or absence of rheumatoid factor (RF) and/or anti-citrullinated protein antibodies (ACPA) 2.
- Seropositive RA is characterized by the presence of RF and/or ACPA, while seronegative RA is defined by the absence of these autoantibodies 2.
- However, studies have shown that a substantial proportion of patients with seronegative RA may still have autoantibodies such as ACPA fine-specificities, IgA/IgG RF, and anti-carbamylated-protein (CarP) antibodies 2.
Autoantibodies in RA
- Rheumatoid factor (RF) is an autoantibody that targets the Fc region of IgG and is often used as a diagnostic marker for RA 3, 4.
- Anti-citrullinated protein antibodies (ACPAs) are a type of autoantibody that targets citrullinated proteins and are highly specific for RA 3, 4.
- Anti-carbamylated protein antibodies (anti-CarP Abs) are another type of autoantibody that has been implicated in the pathogenesis of RA 3.
- The presence of these autoantibodies can provide valuable information for diagnosis, prognosis, and treatment of RA 5, 6.
Clinical Relevance of Autoantibodies in RA
- The combination of RF and ACPA is associated with increased systemic inflammatory mediators and more rapid progression from preclinical to clinical RA 6.
- The presence of ACPA and RF in seronegative RA is associated with worse clinical outcomes 2.
- Determination of immunoglobulin A (IgA) isotypes of RF and ACPA may provide prognostic information, as their presence is associated with reduced therapeutic responses to TNF inhibitors 5.