Parker JC et al. – In a large population of SSc patients anti-RNA polymerase III antibody (ARA) ELISA was demonstrated to have a high analytical sensitivity and specificity with minimal overlap between ARA and other SSc-specific autoantibodies. Additionally, it is demonstrated that the presence of ARA correlates with identifiable patterns by indirect immunofluorescence (IIF) on HEp-2 cell substrate. Methods
A study to evaluate the analytical performance of an ELISA for the detection of ARA and to assess IIF as a method for identifying this Ab
Presence of ARA in sera from 1018 SSc pts was tested by ELISA
The sera divided into sub-populations: presence of specific autoantibodies; ANA pattern or the absence of both
Pts with ARA (n=209) had been identified by characteristic ANA pattern by IIF on HEp-2 cell substrate
The remaining 809 SSc pts acted as a control group
Results
150/157 pts were positive by ELISA providing a sensitivity of 96%
In the group where ARA had only been assessed by IIF, 100% were ELISA positive
The ANA patterns were a fine-speckled nucleoplasmic stain with additional occasional bright dots, with or w/o concurrent punctate nucleolar staining
In the SSc control group, the ELISA attained a specificity of 98%, ARA being detected in 17/809 pts
See all
