Autoantibody Targets Identified in Lupus Patients

Patients with the autoimmune disease systemic lupus erythematosus (SLE) produce autoantibodies that can cause damage to multiple organ systems.

A microarray has been developed to identify cytokines, chemokines, and other circulating proteins as potential targets of the autoantibodies produced by SLE patients, and are implicated in inflammatory autoimmune disease and diseases of immune deficiency.

Scientists at Stanford University (CA, USA) and their colleagues from other institutes designed a nitrocellulose-surface microarray containing human cytokines, chemokines, and other circulating proteins and demonstrated that the array permitted specific detection of serum factor-binding probes. They used antibody binding assays and an indirect B cell-activating factor (BAFF) enzyme-linked immunoassay to detect autoantibodies.

Serum profiling from individuals with SLE revealed that among several targets, elevated immunoglobulin G (IgG) autoantibody reactivity to BAFF was associated with SLE compared with control samples. BAFF reactivity correlated with the severity of disease-associated features, including interferon (IFN)-α–driven SLE pathology. Of the other novel targets of autoantibodies they identified, the observed reactivity to the growth factors epidermal growth factor, (EGF), and somatotropin (HGH) were of particular interest.

Further screening of samples derived from individuals with SLE and other inflammatory autoimmune diseases revealed striking array reactivity to these and other growth factor targets, including various isoforms of fibroblast growth factor (FGF). The idea of an inverse relationship between inflammation- and growth factor-mediated pathways is an area of increasing interest in the field of inflammation.

The authors concluded that the implication of growth factor-targeted autoantibodies in the potential trade-off between tissue growth/repair and inflammation is one intriguing avenue to pursue. That serum factor-protein microarrays facilitated the detection of autoantibody reactivity to serum factors in human samples and that BAFF-reactive autoantibodies may be associated with an elevated inflammatory disease state within the spectrum of SLE. The study was published on November 25, 2013, in the Journal of Clinical Investigation.

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