Text Box: THE ASSESSMENT OF CLONALITY IN HEMOPHAGOCYTIC SYNDROME Xiao Yan, Lin W Department Of Pediatrics, Union Hospital, Tongji Medical College Huazhong University of Science and Technology, Wuhan, China Objective: To verify the existence of clonal proliferation in hemophagocytic syndrome. Methods: Restriction Fragment length polymorphism (RFLP) of human androgen receptor gene (HUMARA) and phosphoglycerate kinase (PGK) at X chromosome. Results: 2 of 13 patients were show to be clonal at presentation. The one patient died after one month and the other who was therapy by VP-16 became remission. Conclusion: Hemophagocytic syndrome is considered a reactive and no clonal proliferation. But in clinical, some cases often show severe progress. Our results that the hemophagocytic syndrome with clonal proliferation is reconciliation with clinical phenomenon. 2377