Chediak-Higashi syndrome complicated by chronic active Epstein-Barr virus infection: a case report　LI Xufang^1,2, FANG Feng¹, XU Sanqing¹ (1.Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China; 2.Department of Pediatrics, Guangzhou Women and Children’s Medical Center, Guangzhou 510000, Guangdong, China)