Development of an ELISA for the efficient detection of autoantibodies against nuclear valosin-containing protein-like protein (NVL) 2 using its manipulated cDNA: Anti-NVL2 antibodies in various diseases beyond systemic sclerosis

Summary: Purpose: Anti-nuclear valosin-containing protein-like protein (NVL) antibodies have been detected only in systemic sclerosis (SSc) patients, and diverse comorbidities have been reported in anti-NVL antibody-positive SSc patients. To clarify the clinical features of anti-NVL antibody-positive patients, we developed an ELISA for measuring antibodies against NVL2, a major target of autoantibodies against NVL. Methods:<b> </b>Sera from 1,676 patients with various conditions were included. 167 anti-nucleolar antibody (ANoA)-positive sera, 120 ANoA-negative sera, and 17 healthy control sera were examined by an ELISA that uses the recombinant protein of NVL2 derived from its gene-manipulated cDNA clone (modified NVL2; mNVL2). Results:<b> </b>Eighteen ANoA-positive sera subjected to indirect immunofluorescence analysis were positive for anti-mNVL2 ELISA. Although one ANoA-negative serum was judged false positive in our anti-mNVL2 ELISA, the above 18 anti-mNVL2 ELISA-positive sera were confirmed to be positive for anti-NVL2 antibodies by immunoprecipitation-Western blotting. Six SSc patients had anti-NVL2 antibodies, whereas five with idiopathic interstitial pneumonia and seven with other diseases had anti-NVL2 antibodies. Anti-mNVL2 ELISA titers were significantly higher in the anti-NVL2 antibody-positive SSc patients than in the anti-NVL2 antibody-positive non-SSc patients (<i>P</i><0.042). Conclusions: This is the first report on non-SSc patients positive for anti-NVL2 antibodies. We found more anti-NVL2 antibody-positive cases than any previous study, to the best of our knowledge. Our ELISA, which showed an association between titers of these antibodies and SSc diagnosis, promises to expand knowledge about anti-NVL2 antibodies. Yuta Yamashita¹, Yasuhiko Yamano², Yoshinao Muro¹, Haruka Koizumi¹, Mariko Ogawa-Momohara¹, Satoshi Kamiya¹, Norika Akashi¹, Takuya Takeichi¹, Yasuhiro Kondoh², Masashi Akiyama¹ 1. Nagoya Daigaku Daigakuin Igakukei Kenkyuka Igakubu, Nagoya, Aichi Prefecture, Japan. 2. Koritsu Tosei Byoin Kokyuki Allergy Shikkan Naika, Seto, Aichi Prefecture, Japan. Clinical Research: Epidemiology and Observational Research