Category | Biomarker | Associations | Comments |
---|---|---|---|
Susceptibility | IRF-5 | Â | Â |
 | STAT-4 HLA-DRB1 | Specific haplotypes confer increased susceptibility to SLE. Genome-wide association studies have identified many loci, mostly related to immune | Genetic epistasis between different loci has been described |
 | PTPN22 | regulatory genes |  |
 | Fcγ receptors |  |  |
 | Complement proteins | Deficiency in early components of the classical complement pathway is a strong risk factor for SLE | Partial C4 deficiency due to gene copy number variations increases the risk of SLE |
Disease activity | IFNα | High levels of IFNα or IFN inducible genes | Despite the association with activity, the |
 |  | (IFN signature) and chemokines correlated with disease activity | IFN signature was not predictive of flare in longitudinal studies |
 | B-cell subsets | CD27high plasma cells correlated with disease activity |  |
 | Serum cytokines, receptors and adhesion molecules | Multiple cytokines (for example, IL-6, IL-10, IL-16, IL-18), soluble receptors (sIL-2 R) and adhesion molecules (for example, sICAM and sVCAM) have been suggested to correlate with disease activity | Data are limited and almost all proposed candidates are still far from being established as a reliable marker in SLE |
Disease severity | IFNα | High IFN signature group has more severe disease manifestations | Holds the potential to identify high-risk patients |
Disease subtype | IFNα | High versus low IFN groups have distinct clinical features, autoantibody associations and genetic profiles | IFN signature and BLyS levels may potentially define subgroups of patients |
 | BLyS | High BLyS levels are associated with specific autoantibodies |  |
Flares | BLyS | Higher and rising BLyS levels were predictive of increase in disease activity at subsequent visit | The association has not been consistent across the studies |
Organ specific | Anti-C1-q antibodies | Correlate with the presence and severity of lupus nephritis | Potential robust marker for lupus nephritis |
 | Anti-NR2 antibodies | Associated with neuropsychiatric manifestations in a murine model | Human results have been largely negative |