Which antibodies are represented by the nucleolar pattern in the immunofluorescence test for antinuclear antibodies?

The nucleolar pattern observed in the immunofluorescence test for antinuclear antibodies specifically indicates the presence of anti-RNA antibodies. This pattern is associated with certain autoimmune diseases such as systemic sclerosis (scleroderma) and overlapping syndromes, where the nucleolus—an intracellular structure involved in ribosome production—appears prominently marked.

Anti-RNA antibodies target the RNA components found in the nucleolus, leading to the distinctive staining pattern seen under the microscope. This pattern serves as a valuable diagnostic tool, enabling clinicians to identify specific types of autoimmune responses and differentiate between various connective tissue diseases.

The other types of antibodies associated with different staining patterns do not correspond to the nucleolar pattern. For instance, antihistone antibodies are typically associated with a diffuse or homogeneous pattern, anti-dsDNA antibodies display a distinct speckled pattern, and anti-ENA antibodies (including anti-Sm and anti-RNP) are also marked by different specificities and patterns. Thus, understanding the corresponding patterns helps in diagnosing and managing autoimmune conditions effectively.