Soluble Fas ligand expression in the ocular fluids of uveitis patients

Purpose. The expression of Fas ligand (FasL) in ocular tissues is thought t o play a critical role in maintaining immune privilege in the eye. In this study, to clarify the involvement of the Fas-FasL system in inflammatory pr ocesses of the eye, we examined soluble Fast (sFasL) in ocular inflammation . Methods. Using ELISA systems recently developed, sFasL concentrations in aq ueous humor (AH) and/or vitreous fluid (VF) were measured. AH was obtained from 17 eyes of 17 uveitis patients and from 12 eyes of 12 non-uveitis (cat aract) patients. VF was obtained from 22 eyes of 22 uveitis patients and 7 eyes of 7 non-uveitis (macular hole) patients. Serum levels of sFasL were a lso determined. Results. sFasL in AH and VF was below the detection limit of the ELISA syst ems in all non-uveitis eyes. On the other hand, sFasL was detected in AH fr om uveitis patients where it measured 367.0 +/- 154.7 pg/ml (mean +/- SEM). sFasL was also detected in VF from uveitis patients where it measured 1132 .2 +/- 281.7 pg/ml. None of the sera from patients with or without uveitis contained a detectable level of sFas L. Conclusions. sFasL levels in AH and VF are elevated in the eye during ocula r inflammation. Fas-FasL mediated apoptosis may play an important role in t he regulation of inflammation during uveitis.