HLA DR 4 (Erosive Rheumatoid Arthitis)
|Disease:||• Rheumatoid Arthritis • Pharmacogenetics/Ocular Immunogenetics|
|Methodology:||Sequence specific primers|
|Reference Range:||Reported positive with subtype or negative.|
|CPT Code:||83891; 83898(x31); 83894; 83912.|
|Schedule / Turnaround Time:||Assay performed daily. Report availability is within 48 hours from the time of specimen receipt.|
Specimen must be kept in ambient temperature and should not be refrigerated or frozen. Collect 5 ml of blood in a lavender top Hemogard (EDTA) tube.
Sample is stable at ambient temperature and should be analyzed within 76 hours.
Rheumatoid Arthritis is a heterogeneous clinical syndrome. While some patients may experience a rather benign course, others experience a rapidly progressive synovitis, leading to irreversible joint damage. The presence of the HLA DR4 genetic marker serves as a risk indicator for severe forms of the disease. Because the DR4 marker is more prevalent than the disease itself, it is not a highly specific diagnostic tool. However, taking into consideration HLA DR4 subtypes, the limitation may be resolved. For example, DR4 subtypes *04:01 and *04:04 are associated with the disease whereas the *04:02 and *04:03 members of the DR4 family are not. A strong association between the DRS heterozygotes *04:01/*04:04 and juvenile rheumatoid arthritis suggests that this genetic combination predisposes an early onset of disease. Although DR4 does not predict disease, it is a useful indicator of disease progression and prognosis when other clinical factors are taken into account. For example, the presence of the DR4 marker in a patient with pre-erosive arthritis indicates the likelihood of rapid progression to erosive disease.