[Identification of antinuclear, nucleolar and SS-A antibodies, using an immunoassay system]

In this paper we report a solid phase ELISA for screening of antinuclear, nucleolar, and SS-A antibodies. The test system was evaluated with 158 sera that were positive by immunofluorescence (IF), some of which were immunologically characterized as containing antibodies to Sm, RNP, SS-A, SS-B, nucleolar, and DNA, and 247 IF negative that were used as a control group. Ninety eight per cent of serum samples with an antibody of known specificity and/or positive IF, were positive by the ELISA system including antinucleolar samples. Reproducibility of the assay was demonstrated by using five sequentially prepared antigenic extracts. The lineal regression from the last experiment was between 0.75 and 0.91. With this system, positive and negative ANA can be identified as the screening procedure without the need of additional studies. To our knowledge this is the first ELISA system report for the screening of antinucleolar antibodies.