TY - JOUR T1 - Validation of a new serum granulocyte–macrophage colony-stimulating factor autoantibody testing kit JF - ERJ Open Research JO - erjor DO - 10.1183/23120541.00259-2019 VL - 6 IS - 1 SP - 00259-2019 AU - Koh Nakata AU - Tatsuki Sugi AU - Keiko Kuroda AU - Kazutaka Yoshizawa AU - Toshinori Takada AU - Ryushi Tazawa AU - Takahiro Ueda AU - Ami Aoki AU - Mitsuhiro Abe AU - Koichiro Tatsumi AU - Ryosuke Eda AU - Shotaro Kondoh AU - Konosuke Morimoto AU - Takeshi Tanaka AU - Etsuro Yamaguchi AU - Ayumu Takahashi AU - Miku Oda AU - Haruyuki Ishii AU - Shinyu Izumi AU - Haruhito Sugiyama AU - Atsushi Nakagawa AU - Keisuke Tomii AU - Masaru Suzuki AU - Satoshi Konno AU - Shinya Ohkouchi AU - Taizou Hirano AU - Tomohiro Handa AU - Toyohiro Hirai AU - Yoshikazu Inoue AU - Toru Arai AU - Katsuaki Asakawa AU - Takuro Sakagami AU - Takahiro Tanaka AU - Ayako Mikami AU - Nobutaka Kitamura Y1 - 2020/01/01 UR - http://openres.ersjournals.com/content/6/1/00259-2019.abstract N2 - Very recently, a modest but significant efficacy of granulocyte–macrophage colony-stimulating factor (GM-CSF) inhalation therapy for the treatment of mild to moderate autoimmune pulmonary alveolar proteinosis (aPAP) has been reported.As the ability to measure the level of GM-CSF autoantibody (GMAb) in the serum is required to decide the indication for this therapy, we developed a high-performance GMAb testing kit for clinical use.As the kit succeeded in reducing nonspecific IgG binding to the ELISA plate, the predictive performance shown in the training study to discriminate aPAP patients from healthy subjects was perfect, providing a cut-off value of 1.65 U·mL−1 in 78 patients with aPAP and 90 healthy subjects in an operator-blinded manner using logistic regression analysis. As in the validation study, serum samples from another 213 patients with aPAP were also blinded and evaluated in an operator-blinded manner against external 207 samples from patients with other types of PAP and patients exhibiting various ground-glass opacities on chest high-resolution computed tomography that require discrimination from PAP.The logistic regression analysis of these validation data sets revealed values of 97.6% and 100% for specificity and sensitivity, respectively. Thus, this new GMAb testing kit is reliable for the diagnosis of aPAP and differential diagnosis of other lung diseases.Using a newly developed ELISA kit, the cut-off value for serological diagnosis of autoimmune pulmonary alveolar proteinosis can be reset to 1.65 U/mL, which is externally validated against patients with conditions other than autoimmune PAP http://bit.ly/2LgFmKk ER -