Fas mRNA expression in blood is reduced during episodes of human corneal graft rejection

Background. Our purpose is to examine levels of Fas mRNA expression in bloo d during human corneal transplant rejection. Methods. Fas mRNA expression was detected by reverse transcription-PCR in b lood from normal controls, corneal recipients at the time of transplantatio n and during episodes of rejection. Results. Samples taken at the time of a corneal rejection episode showed Fa s mRNA levels were significantly lower in these patients than either normal controls (P=0.017) or corneal transplant recipients not undergoing graft r ejection (P=0.00052). Serial samples from five patients who suffered an epi sode of rejection showed that the level of Fas mRNA is reduced during the r ejection episode and subsequently recovers. Conclusions, These results indicate low levels of Fas mRNA in blood may hav e a role in corneal transplant rejection.