Diagnosis:
Autoimmune ANA testing
• One algorithm for ANA testing uses IFE slides in both the screening and titration steps. Those samples that screen positive are subject to titration to end point, with both the titer and pattern being reported. Titers alone can be used to monitor therapy for patients. Alternatively, enzyme-linked immunosorbent assay (ELISA) based testing for the specific autoantigens of interest can also be performed, and quantitative values can be used to monitor patients. A nucleolar ANA staining pattern is shown in the Figure.
• There are four basic staining patterns: (1) homogeneous (diffuse), (2) peripheral, (3) speckled, and (4) nucleolar. Each is characteristic of a different set of autoantigens that can produce ANAs.
• It is important to note that the presence of any one pattern does not correlate 100% with any one connective tissue disease. However, reasonable generalizations can be made to classify groups of antigens based on the observed patterns.
• The nucleolar pattern corresponds to proteins of the nucleolus including RNA polymerase.
• Patients with Sjögren syndrome or scleroderma usually exhibit a nucleolar pattern with ANA testing.
