Are cytokine patterns in aqueous humour useful in distinguishing corneal graft rejection from opacification due to herpetic stromal keratitis?

Purpose: Intra-ocular cytokine profiles were determined to study the immuno logical mechanisms of corneal graft opacification due to rejection and/or h erpetic stromal keratitis (HSK). Methods: Sera and aqueous humour (AH) were sampled shortly after the onset of corneal graft opacification, group I (n =18). In eyes with clear grafts, samples were taken 5 months after transpla ntation, group II (n=59). Samples of non-inflamed eyes, prior to cataract s urgery, were used to determine baseline cytokine levels, group III (n=49). Total protein (TP) levels were measured with Bradford reagent and interleuk in (IL)-6, IL-10, IL-4 and interferon (IFN)-gamma with ELISAs. Results: All patients who's corneal grafts showed clinical evidence of graft opacificat ion due to rejection and/or HSK were sampled. In the AH-samples of group I, increased levels of TP were found in 60% (9/15), IL-6 in 79% (11/14), IL-1 0 in 39% (7/18) and IL-4 in none (0/12). IFN-gamma was detected in 19% (3/1 6), in the case of HSK only. In contrast, samples obtained from patients wi th clear grafts in group II showed increased levels of TP in 36% (20/55), I L-6 in 14% (8/57) and IL-10, IL-4 or lFN-gamma in none (n=58). Conclusions: During corneal graft rejection and/or HSV-infection, increased levels of T P and IL-6 in AH confirmed anterior chamber inflammation with breakdown of the blood-aqueous barrier. Based on the data presented, cytokine patterns i n the AH do not appear to distinguish corneal opacification due to graft re jection from that due to herpes keratitis.