What is the primary characteristic of Rheumatoid Arthritis (RA)?

The primary characteristic of Rheumatoid Arthritis (RA) is its autoimmune nature. RA is fundamentally an autoimmune disorder, meaning that the body's immune system mistakenly attacks its own healthy joint tissues, particularly the synovium, which is the lining of the joints. This immune response leads to inflammation, which is a hallmark of the disease and contributes to the symptoms associated with RA, such as pain and swelling.

This autoimmune aspect often differentiates RA from other types of arthritis, which may present in different patterns or with different underlying causes. The autoimmune attack leads to chronic inflammation, which can ultimately result in joint damage and can also affect other body systems, making it a systemic condition.

Understanding the autoimmune nature of RA is essential for recognizing its treatment and management approaches. Treatments often focus on modifying the immune response and managing inflammation to prevent damage to the joints and improve quality of life.

The other choices represent different aspects that may occur in various forms or stages of arthritis, but they do not encapsulate the defining feature of RA as effectively as its autoimmune characteristic. For instance, while unilateral joint pain and asymmetrical joint swelling can occur in other types of arthritis, RA often presents symmetrically and can affect multiple joints simultaneously. Cartilage degradation is a consequence of the disease but