New classification system for systemic lupus erythematosus moves forward
The immunologic domains
Antiphospholipid antibodies: Anticardiolipin immunoglobulin G more than 40 GPL units, anti-beta2GP1 IgG more than 40 units, or lupus anticoagulant positive (13).
Complement proteins: Low C3 or low C4 (19) and low C3 and low C4 (27).
Highly specific antibodies: Anti-dsDNA antibody (38) and anti-Smith antibody (40).
,Moving forward
Screening 10 domains with their attendant components may seem a bit clunky now, Dr. Johnson noted, but the final iteration should be more streamlined. Plus, she said, the system will be presented on a computer application that makes calculation much easier. “We’re aiming for feasibility and simplicity, but, at the same time, when you have a complex disease, you don’t want oversimplification. You may lose sensitivity and specificity.”
After further streamlining, Dr. Johnson said, the next step will be validating in a large retrospective patient cohort. “Right now, we are still collecting data for the validation cohort, which will be drawn from 36 centers. We’ll analyze sensitivity and specificity, comparing this system with the other two. We hope to present all these data at the ACR meeting in the fall.”
While research classification is the system’s raison d’être, it will undoubtedly influence diagnosis and clinical assessment as well, Dr. Johnson said. “ACR and EULAR are very clear that they only support the validation of classification criteria. The diagnosis of SLE is still within the hands of the physician. But, we know that classification criteria do inform our concept of the disease, so it’s likely these will shift the way we think about diagnosing lupus as well. We do hope to identify patients with earlier disease, so they have the opportunity to be involved in research” that may modify their disease course and, ultimately, prevent permanent damage and improve quality of life.
Dr. Johnson had no disclosures related to the development of the classification criteria.
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