Antinuclear antibodies
(Redirected from Ddx:Antinuclear Antibody)
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]
Overview
Anti-nuclear antibodies are antibodies directed against the cell nucleus. They are raised in several conditions, usually in an auto-immune condition where the immune system makes antibodies to fight its own body. Normally a test (see External Links) is administered in people with many arthritic type symptoms or skin rashes to exclude systemic lupus erythematosus(SLE). The rashes could be over both cheeks and shaped like a butterfly, or a wolf. They are known to affect almost any part of the body including kidneys and brain.
Interpreting Test Results
- A high ANA titer may indicate systemic lupus erythematosus (SLE). SLE can be present with titers from 1 to 40 and higher. Almost all people with SLE have a high ANA titer. However, most people with a high ANA titer do not have SLE. Only about one-third of people who are referred to a rheumatologist for high ANA titers are diagnosed with SLE. Other conditions may cause a high ANA titer. About 30% to 40% of people with rheumatoid arthritis have a high ANA titer. [1]
- Many conditions may result in a high ANA titer. These conditions include autoimmune diseases, such as scleroderma, Sjögren's syndrome, juvenile rheumatoid arthritis, and myositis. Other conditions with a high ANA titer include Raynaud's syndrome, viral infections, and liver disease. Although an ANA titer may help support a diagnosis for these conditions, it is not used by itself to confirm a diagnosis. A thorough medical history, physical examination, and other tests are needed to confirm a suspected autoimmune disease.
- Some apparently healthy individuals have high levels of antinuclear antibodies. For instance, some people with a family history of autoimmune disease may have a high ANA titer. The higher the titer, however, the more likely it is that the person has an autoimmune disease.
- Positive ANA is also commonly seen in Sjogren's Syndrome, the second most common auto-immune disease (more common than Lupus)
| DISEASE | ANA FREQUENCY (%) |
| Systemic Lupus Erythematosus (SLE) | 90-100 |
| Discoid Lupus Erythematosus | 21-50 |
| Drug-Induced Lupus | 95 |
| Mixed Connective Tissue Disease (MTCD) | 100 |
| Scleroderma | 31-90 |
| CREST syndrome | 95 |
| Rheumatoid Arthritis | 10-60 |
| Felty's Syndrome | 60-10 |
| Dermatomyositis | 40 |
| Autoimmune Chronic Hepatitis | 45-100 |
| Myasthenia Gravis | 35-50 |
| Immune Thrombocytopenia | 50-70 |
| Autoimmune Thyroiditis | 40-50 |
| Leukemias | 70 |
| Infectious Mononucleosis | 30-70 |
Differential Diagnosis
- Advanced age
- Chronic active hepatitis
- Cirrhosis
- Drugs
- HIV infection
- Mixed Connective Tissue Disease
- Multiple Sclerosis
- Necrotizing vasculitis
- Periarteritis nodosa
- Pregnant women
- Pulmonary Fibrosis
- Raynaud's Disease
- Rheumatoid Arthritis
- Silicone gel implants
- Sjogren's Syndrome
- Subacute bacterial endocarditis
- Systemic Lupus Erythematosus
- Tuberculosis
- Diabetes Mellitus (Type I)
References
- ↑ Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:26 ISBN 1591032016
External links
- Neuroimmunology, The Medical School, Birmingham University - Abid R Karim, Birmingham UK