CJCP     2017 19 (4):  425-429    ISSN: 1008-8830  CN: 43-1301/R Changes in serum YKL-40 level and humoral immune function and their significance in children with recurrent pneumonia MA Wei-Yin, PENG Shao, ZHANG Ting Department of Pediatrics, First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, China Received: 2016-11-06  Revised: 2017-01-19  Online: null Supporting info