Lack of Cross-Reactivity of Anti-DNA Antibodies to Ribonucleoproteins in a New Commercial Blot System for Specific ANAs

Anti-DNA antibodies often exhibit cross-reactivity. It has been observed that anti-DNA antibodies cross-react with A and D snRNP proteins in an in-house developed Western blot assay but do not cross-react with native U1RNP in ELISA or immunoprecipitation experiments. We have analyzed the cross-reactivity of anti-DNA antibodies to snRNP A and D in a recently developed commercial blot assay (InnoLIA, Innogenetics). In our experience anti-DNA antibodies do not cross-react with proteins A and D in this blot system. Hence this new blot system avoids the cross-reactivity problems in the assessment of antinuclear antibody specificity for both Sm and U1snRNP.