Antinuclear antibodies: Marker of diagnosis and evolution in autoimmune diseases

Abstract

Antinuclear antibodies (ANAs) are autoantibodies that attack self-proteins within cell nucleus structures; their presence in serum may indicate an autoimmune disease. Also, positive ANA test results have been obtained in chronic infectious diseases, cancers, medication-related adverse events, and even healthy individuals. As a result, a correct interpretation of the presence of ANAs is needed. Identification of ANAs subtypes is an important part of clinical immunology. The presence of ANAs in patient blood specimens is detected using a cell-line substrate from human laryngeal carcinoma (HEp-2 cells). On this substrate, ANAs will bind specific antigens, which will lead to a suggestive fluorescent emission. The fluorescence patterns visualized under the fluorescence microscope can be correlated with certain subtypes of ANA and certain autoimmune diseases. Depending on the subtype of ANA present in the serum and the targeted antigen, several staining patterns are reported, namely, nuclear patterns, nucleolar patterns, cell cycle patterns, or cytoplasmatic patterns. Identification of a certain pattern can lead to diagnosis of a certain autoimmune disease.