OBJECTIVES: To assess anti-cytosolic 5'-nucleotidase 1A (cN-1A/NTC51A) autoantibodies in children with juvenile dermatomyositis (JDM) and healthy controls, using three different methods of antibody detection, as well as verification of the results in an independent cohort.
METHODS: Anti-cN-1A reactivity was assessed in 34 Dutch JDM patients and 20 healthy juvenile controls by a commercially available full-length cN-1A ELISA, a synthetic peptide ELISA and by immunoblotting using a lysate from cN-1A expressing HEK-293 cells. Sera from JDM patients with active disease and in remission were analysed. An independent British cohort of 110 JDM patients and 43 healthy juvenile controls was assessed by an in-house full-length cN-1A ELISA.
RESULTS: Anti-cN-1A reactivity was not present in JDM patients' sera or in healthy controls when tested with the commercially available full-length cN-1A ELISA or by immunoblotting, both in active disease and in remission. Also, in the British JDM cohort anti-cN-1A reactivity was not detected. Three Dutch JDM patients tested weakly positive for one of the three synthetic cN-1A peptides measured by ELISA.
CONCLUSION: JDM patients and young healthy individuals do not show anti-cN-1A reactivity as assessed by different antibody detection techniques.