2.1 Patients and cohorts
A total of 469 consecutive patients with newly diagnosed LCH (age <18 years) were admitted to our center from January 1, 2017, to December 31, 2021. Three hundred seventy patients with successfully determined sCD25 at the time of diagnosis were eligible to be analyzed in the study. Ninety-nine patients not assessable for sCD25 levels were excluded from this study. Then, 359 patients who received first-line therapy were further analyzed with prognostic significance, leaving out 11 patients who directly received BRAF inhibitor dabrafenib treatment. We divided the 359 patients into two groups based on the year of enrollment: the test cohort comprised 146 patients enrolled in BCH-LCH 2014 clinical trial (www. chictr. org. cn, identifier: ChiCTR2000030457) between 2017-2018, while the validation cohort included 213 patients entered CCHG-LCH-2019 (www. chictr. org. cn, ChiCTR1900025783) between 2019-2021. A flow diagram for patient inclusion and the study cohorts was displayed in Supplementary Fig.S1.
The diagnosis of LCH was confirmed with histological examination and CD1a and CD207 immunostaining. The following characteristics were collected from our electronic medical record system and LCH disease database for each patient: demographic information, clinical and biological characteristics, examinations, treatment details, and follow-up data.
This study was approved by the Beijing Children’s Hospital Ethics Committee and was conducted in accordance with Declaration of Helsinki. Informed consents were obtained from guardians of the patients.