Anti-dsDNA Antibody Isotypes in Systemic Lupus Erythematosus: IgA in Addition to IgG Anti-dsDNA Help to Identify Glomerulonephritis and Active Disease

作者：Villalta Danilo; Bizzaro Nicola; Bassi Nicola; Zen Margherita; Gatto Mariele; Ghirardello Anna; Iaccarino Luca; Punzi Leonardo; Doria Andrea^*

来源：PLos One, 2013, 8(8): e71458.

DOI：10.1371/journal.pone.0071458

Objectives: To evaluate the role of serum IgG, IgM and IgA anti-dsDNA antibody isotypes in the diagnosis of systemic lupus erythematosus (SLE), and their association with clinical features and disease activity, in a large cohort of SLE patients. %26lt;br%26gt;Methods: Sera of 200 SLE patients (mean age 34+/-10.3 years; 26 male and 174 female; median duration of disease 115 months, range 7-378), and of 206 controls, including 19 Sjogren%26apos;s syndrome, 27 rheumatoid arthritis, 26 psoriatic arthritis, 15 idiopathic inflammatory myopathies (IIM), 13 systemic sclerosis, 49 infectious diseases and 57 healthy subjects, were tested for anti-dsDNA IgG, IgM and IgA isotypes. %26lt;br%26gt;Results: Selecting a cutoff corresponding to 95% specificity, the sensitivity of IgG, IgM and IgA anti-dsDNA antibodies in SLE was 55%, 30% and 49%, respectively; 12.5%, 1% and 7.5% of SLE patients had positive IgG, IgM or IgA isotype alone, respectively. SLE patients with glomerulonephritis showed higher levels of IgA anti-dsDNA (p = 0.0002), anti-dsDNA IgG/IgM (p = 0.001) and IgA/IgM (p %26lt; 0.0001) ratios than patients without renal disease. No significant associations have been found between anti-dsDNA isotypes and other clinical features. IgA anti-dsDNA (p = 0.01) (but not IgG or IgM) and IgG/IgM ratio (p = 0.005) were significantly higher in patients with more active disease (ECLAM score %26gt;4). %26lt;br%26gt;Conclusions: The detection of IgA anti-dsDNA autoantibodies seems to improve our ability to diagnose SLE and to define lupus nephritis phenotype and active disease. By contrast, IgM anti-dsDNA antibodies might be protective for renal involvement. These data support the hypothesis that anti-dsDNA antibody class clustering may help to refine SLE diagnosis and prognosis.

• 出版日期2013-8-12