The clinical aspects of autoantibodies

Abstract

Since clinical presentation in patients with systemic sclerosis (SSc) is highly heterogeneous, disease subgrouping and prediction of future organ involvement and prognosis are extremely important in the clinical setting. Another distinctive feature of SSc is the presence of circulating autoantibodies reactive with various cellular components. Autoimmune targets include a variety of nuclear antigens that are present in cells with nuclei. In this case, they are termed antinuclear antibodies (ANAs). It has been shown that distinct ANA specificities are detected in SSc patients and are associated with unique disease manifestations. Therefore, SSc-related ANAs are attractive biomarkers in routine rheumatology practice, owing to their high specificity, mutual exclusivity, persistence for the duration of illness, and, most importantly, strong associations with characteristic constellations of clinical features. In addition, a new group of autoantibodies reactive with functional proteins, such as cell surface receptors and extracellular matrix (ECM) proteins, have been identified in SSc patients. They seem to directly activate pathways that may contribute to the pathophysiology of SSc. This chapter covers the spectrum of autoantibody specificities reported in SSc patients, their detection methods, and their clinical utility.