From the Guidelines
The diagnosis of Systemic Lupus Erythematosus (SLE) should be based on the 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria, which require a positive ANA result as an entry criterion, with a titer ≥1:80 by the indirect immunofluorescence test on HEp-2 cells (IFI) 1. The EULAR/ACR 2019 classification criteria have introduced significant changes in the diagnosis of SLE, including the use of ANA as a required entry criterion. This change has improved the performance of the criteria as a classification system, but it requires caution when used in diagnosis due to the relatively low specificity of ANA detection for SLE, which is 74.7% (IC 95%: 66.7% - 81.3%) 1. Some key points to consider when using the EULAR/ACR 2019 classification criteria include:
- The use of ANA detection as an entry criterion, which ensures the selection of a heterogeneous group of patients that will be subclassified in the next step by means of a screening algorithm using more specific criteria 1
- The importance of considering the entire clinical picture, rather than isolated findings, to differentiate SLE from other autoimmune conditions with overlapping features
- The assignment of specific points to each manifestation, which helps to confirm SLE diagnosis with a score of 10 or more points
- The inclusion of clinical domains, such as constitutional symptoms, hematologic abnormalities, neuropsychiatric manifestations, mucocutaneous features, serositis, and renal involvement, as well as immunological criteria, such as anti-dsDNA antibodies, anti-Sm antibodies, antiphospholipid antibodies, complement proteins, and direct Coombs test 1.
From the Research
Criteria for Systemic Lupus Erythematosus (SLE)
The criteria for SLE have undergone several changes since the initial proposal by the American College of Rheumatology in 1971 2. The current criteria include:
- Clinical manifestations such as skin lesions, arthritis, renal disorder, neurologic disorder, hematologic changes, and others
- Serum anti-nuclear antibody, anti-ds-DNA antibody, and anti-Sm antibody as important biomarkers of SLE patients
- The Systemic Lupus Collaborating Clinics proposed the SLICC criteria for SLE in 2012, which takes into account new knowledge of autoantibodies and the importance of low complement 2
Diagnostic Approach
The diagnostic approach for SLE involves:
- Antinuclear antibody (ANA) testing, which is positive in nearly every case of SLE, but must be interpreted in the appropriate clinical context 3
- ANA staining patterns and more specific autoantibody testing may be helpful in diagnosis of suspected SLE or ANA-associated disease 3
- Key features that warrant ANA testing include unexplained multisystem inflammatory disease, symmetric joint pain with inflammatory features, photosensitive rash, and cytopenias 3
Biomarkers and Disease Activity
Biomarkers such as anti-DNA antibodies can fluctuate widely and reflect disease activity, whereas anti-RBP antibodies tend to be stable 4. Repeat testing of anti-DNA antibodies is common, and screening strategies now involve ANA and anti-DNA antibody testing to identify patients with 'active, autoantibody-positive SLE' 4.
Clinical Management
The management of SLE is directed at complete remission or low disease activity, minimizing the use of glucocorticoids, preventing flare-ups, and improving quality of life 5. Hydroxychloroquine is recommended for all patients with SLE to prevent flare-ups, organ damage, and thrombosis and increase long-term survival 5. Pregnant patients with SLE require preconception counseling and a multidisciplinary approach to manage the increased risk of spontaneous abortions, stillbirths, preeclampsia, and fetal growth restriction 5.