Soluble fas ligand and soluble fas in hemophagocytic lymphohistiocytosis

Parpose: To further understand the hypercytokinemic state in hemophagocytic lymphohistiocytosis (HLH), serum levels of soluble Fas ligand (sFasL) and soluble Fas (sFas) were measured in HLH-patients, and compared with the levels of tumour necrosis factor (TNF)- α, Interferon (IFN)- γ, and soluble imerleukin-2 receptor (sIL-2R), along with clinical and laboratory findings. Patients and Methods: Serum was obtained from 11 patients who fulfilled the diagnostic criteria of HLH (Henter 1991, Imashuku 1997) Concentrations of sFasL and sFas were measured by ELISA kits (sFasL; MBL, Nagoya, sFas; Oriental Koubo, Osaka). Results: Serum sFasL levels were higher in HLH-patients (mean 4703, max 16772 pg/ml) than in patients with Epstein-Barr virus infection (mean 1194 pg/ml) or in healthy controls (<100 pg/ml). On the other hand, serum sFas levels did not increase in HLH-patients. The sFasL levels positively correlated with ALT levels (rS=0.709, p<0.05), but not with the levels of TNF- α, IFN- γ, SIL-2R, AST, LDH, ferritin, CRP, total cholesterol, and triglyceride The CD4/CD8 ratio and numbers of CD3⁺HLA-DR⁺ cells did not also correlate with serum sFasL levels Conclusions: Serum increase of sFasL was reported in T-LGL leukemia, NK cell lymphoma and rheumatic diseases Our results suggest that the circulating levels of sFasL well reflect the liver damage in HLH irrespective of Th1 type hypercytokinemia, although it is not known whether sFasL induces or inhibits the Fas-mediated tissue injury in lymohohistiocytic activation.