American Board of Psychiatry and Neurology (ABPN) Practice Exam

What type of antibodies can be seen in patients with peripheral nerve myelin issues?

1. Anti-nuclear antibodies

2. Complement-fixing antibodies

3. Antineutrophil cytoplasmic antibodies

4. Anti-double-stranded DNA antibodies

The correct answer is: Complement-fixing antibodies

In patients with peripheral nerve myelin issues, complement-fixing antibodies are associated with certain types of neuropathies, especially those that are autoimmune in nature. Peripheral nerve myelin damage can be a result of conditions such as Guillain-Barré syndrome or chronic inflammatory demyelinating polyneuropathy (CIDP), wherein the immune system mistakenly attacks the myelin sheath surrounding nerves. Complement-fixing antibodies function by binding to antigens on the surface of cells, activating the complement system. This process can lead to an inflammatory response that damages the myelin. It is an important mechanism in the pathophysiology of autoimmune demyelinating conditions. On the other hand, anti-nuclear antibodies are more commonly associated with systemic lupus erythematosus and other connective tissue diseases rather than specifically targeting peripheral nerve myelin. Antineutrophil cytoplasmic antibodies primarily target neutrophils and are associated with vasculitis and not directly related to peripheral neuropathies. Anti-double-stranded DNA antibodies are also primarily linked to systemic lupus erythematosus and do not play a direct role in peripheral nerve myelin issues. Therefore, the presence of complement-fixing antibodies is the most relevant to the context of peripheral nerve myelin