Karnataka PGET Medicine MCQ Answer 02

The correct answer is C

Abnormal Immunoglobulin G (IgG) antibodies are produced by the lymphocytes in the synovial membranes. They act as antigens. Other IgG and IgM antibodies react with these abnormal antigens to produce immune complexes. The reactive IgM is called the Rheumatoid Factor (RF).

Approximately 80% of the people with rheumatoid arthritis have positive titers. The other 20% are considered seronegative which means the have no identifiable RF present. So, a negative RF does not rule out the existence of RA. The factor may also be found in the presence of other autoimmune diseases and even in a small percentage of healthy people.

A normal or negative titer is less than 1:20. Levels between 1:20 and 1:80 may indicate something is going on, but not necessarily rheumatoid arthritis.Titers over 1:80 are usually, but not always indicative of rheumatoid arthritis.

Other Conditions Can Test Positive For Rheumatoid Factor

Other autoimmune diseases can also be positive for rheumatoid factor including:

• Sjogren's syndrome
• Systemic lupus erythematosus
• Scleroderma
• Polymyositis
• Dermatomyositis
• Mixed Connective Tissue Disease

Other infections or conditions which can be associated with positive rheumatoid factor include:

• Bacterial endocarditis
• Osteomyelitis
• Tuberculosis
• Syphilis
• Hepatitis
• Mononucleosis
• Diffuse interstitial pulmonary fibrosis
• Liver cirrhosis
• Sarcoidosis

Category: Karnataka PGET 2007 MCQs