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Management of Systemic Lupus Erythematosus

The 2019 European Alliance of Associations for Rheumatology/
American College of Rheumatology (EULAR/ACR) classification criteria
for SLE include a positive ANA ≥1:80 by HEp-2 IIF at least once, as an
obligatory entry criterion. 23

• Anti-double stranded deoxyribonucleic acid antibodies
Anti-dsDNA antibodies react against antigenic determining factors
present in the deoxyribonucleic acid (DNA). It is highly specific for
the diagnosis of SLE with ≥90% specificity. 23; 24, level III Anti-dsDNA
antibodies are identified in 60 - 80% of SLE patients and only <2.5% in
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healthy controls.
• Extractable nuclear antigen autoantibodies
Autoantibodies to ENA are important diagnostic markers for several
systemic autoimmune diseases including SLE. Among ENA antibodies
for SLE are anti-Smith (anti-Sm), anti-Sjögren’s-syndrome-related
antigen A (anti-SSA), anti-Sjögren’s-syndrome-related antigen B (anti-
SSB) and antibodies to ribonucleoprotein (anti-RNP).

Anti-Sm antibodies are highly specific and predictive but less sensitive
compared with ANA in the diagnosis of SLE. They are never found in
healthy individuals and rarely identified in patients with other rheumatic
disease. 21; 23
Anti-SSA and anti-SSB are also known as anti-Ro and anti-La
autoantibodies respectively. Both have the highest prevalence
in Sjögren’s syndrome where the presence of anti-Ro antibodies
constitutes a classification criterion. The prevalence of anti-Ro and
anti-La antibodies in SLE patients is around 25 - 30% and 10 - 15%
respectively. 25, level III

Anti-RNP are antibodies against small ribonucleic acid (RNA)
component of nuclear riboproteins and have structural similarities
with anti-Sm antibodies. They are present in 25 - 40% of SLE
patients. 25, level III

Anti-SSA/SSB and anti-RNP antibodies are less-specific markers
of SLE as they are found in other autoimmune rheumatic disorders as
well as SLE. 21; 23 However, these antibodies were associated with
pulmonary arterial hypertension in a case-control study on patients with
SLE: 26, level II-2
 anti-RNP (OR=12.399, 95% CI 3.581 to 42.934)
 anti-SSA (OR=4.836, 95% CI 1.675 to 13.598)
• Antiphospholipid antibodies
aPL are autoantibodies directed against phospholipid-binding proteins.
The common clinical assays for aPL include lupus anticoagulant (LA)

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