Clinical Connections in the Serology of SLE

Cozzani E, Drosera M, Gasparini G, Parodi A. Serology of Lupus Erythematosus: Correlation between Immunopathological Features and Clinical Aspects. Autoimmune Dis. (2014) 2014:321359. Epub 2014 Feb 6. (Open access )

Systemic lupus erythematosus (SLE) is associated with a wide variety of autoantibodies, but not all have diagnostic or clinical value.

A detailed review in the journal Autoimmune Disease has pointed out that anti-nuclear antibodies (ANAs) are present in about 95% of SLE patients with active disease, and while they have high diagnostic ability they have low sensitivity.

Different subsets of ANAs have varying degrees of clinical utility.

For example, the review says that antibodies to double stranded-DNA (ds-DNA) and anti-Smith (anti-Sm) antibodies are most useful in diagnosing SLE. But while anti-Sm is highly specific for SLE, the antibodies don’t always point to explicit clinical manifestations. In contrast, anti-ds-DNA is highly sensitive to disease activity and is also associated with renal and central nervous involvement. That said, anti-nucleosome antibodies might be even more useful.

Other observations:

•   Anti-nucleosome antibodies are an excellent marker for SLE and are good predictors of flares in inactive disease. They may be preferable to ds-DNA antibodies as they appear first.

•   Anti-histone antibodies are a characteristic finding of drug-induced lupus.

•   Anti-SSA/Ro and anti-SSB/La antibodies are associated with neonatal lupus erythematosus.

•   Anti-Ro/SSA antibodies are associated with photosensitivity rashes, especially in subclinical SLE.

•   Anti-ribosomal P antibodies play a role in neuropsychiatric lupus, but their association with clinical manifestations is still unclear.

•   Anti-phospholipid antibodies (APLs) are linked with anti-phospholipid syndrome, cerebral vascular disease, and neuropsychiatric lupus. Only about a third of lupus patients with these antibodies exhibit clinical features of the syndrome.

•   Anti-C1q antibodies signal glomerular injury; elevated titers may also predict renal flares. They are found in a number of other rheumatic diseases besides lupus.

•   Anti-RNP (anti-ribonucleoprotein) antibodies are regarded as a marker of Sharp's syndrome, but can also be found in SLE and a number of other rheumatic disorders.

•   Anti-PCNA (anti-proliferating cell nuclear antigen) antibodies are found in 5-10% of SLE patients, especially those with arthritis and low levels of complement, but levels vanish after treatment with steroids or cytotoxic drugs.