What condition is characterized by the presence of anti-IgG antibodies?

Rheumatoid arthritis is characterized by the presence of anti-IgG antibodies, specifically against modified forms of IgG known as rheumatoid factors (RF). These antibodies play a crucial role in the pathogenesis of the disease by contributing to the inflammatory processes that target the synovial joints, leading to joint destruction and deformity. The production of these anti-IgG antibodies indicates an autoimmune response that affects not only the joints but can also have systemic effects.

While other conditions on the list involve autoantibodies, they produce different types of antibodies or are associated with different pathogenic mechanisms. For instance, Goodpasture's syndrome is characterized by antibodies against collagen in the basement membranes of the kidneys and lungs. Systemic lupus erythematosus (SLE) is associated with a wide array of autoantibodies, including anti-dsDNA and anti-Sm, rather than specifically anti-IgG antibodies. Pemphigus vulgaris is primarily associated with antibodies against desmogleins, leading to skin blisters. Thus, the distinct presence of anti-IgG antibodies is a hallmark of rheumatoid arthritis, linking its immune dysregulation to joint pathology specifically.