Posner-Schlossman-Syndrome (PSS) is clinically characterized by acute, 
recurrent, mild, unilateral uveitis anterior accompanied by elevated intraocular 
pressure (IOP). Fuchs´ Uveitis (FU) is a chronic, low-grade-inflammatory 
disorder, involving anterior uvea and vitreous. The clinical findings show 
remarkable similarities as well as differences. In our study, we determine the 
composition of immune mediators in aqueous humor of patients with PSS and FU and 
evaluate if immune mediators play a crucial role in specific viral intraocular 
inflammation and IOP rises. Aqueous humor samples from 81 uveitis patients (= 
eyes) presenting with either PSS or FU were collected at one time point. Local 
intraocular antibody synthesis to rubella virus was confirmed in 65 patients, 
whereas 16 were tested positively for human cytomegalovirus. Thirteen patients 
with PSS and 10 patients with FU were treated with glaucoma medications. 
Additionally, 11 cataract patients acted as control group. Immune mediator 
concentrations were measured by Bio-Plex Pro assay. We observed in both PSS 
(IFN-γ: 174.9 pg/mL; TNF-α: 25.1 pg/mL) and FU (IFN-γ: 25.4 pg/mL; TNF-α: 27.2 
pg/mL) groups a significantly increased level of T-helper 1 immune mediators 
compared to controls (IFN-γ, TNF-α: 0 pg/mL) [median]. Notably, PSS patients 
(IL-1RA: 73.4 pg/mL; IL-8: 199.4 pg/mL; IL-10: 33.4 pg/mL; IP-10: 126350 pg/mL) 
showed a stronger and more active ocular inflammatory response, than FU patients 
(IL-1RA: 4.3 pg/mL; IL-8: 72.4 pg/mL; IL-10: 1.6 pg/mL; IP-10: 57400 pg/mL). 
Furthermore, a negative correlation between mediators and IOP was seen in the 
PSS group, potentially caused by acetazolamide-treatment. Our findings show that 
immune mediators play a crucial role in specific viral intraocular inflammation 
and influence IOP levels. Remarkable similarities but also significant 
differences of immune mediator concentrations are apparent in PSS compared to 
FU. High concentrations of IL-1RA, IL-8, IL-10, and IP-10 correlate with active 
inflammation in PSS, while FU may trigger chronic inflammation. Our data also 
substantiated a very similar composition of cytokines in those patients from the 
PSS group suffering from ocular hypertension and thus offers a potential 
explanation model for a negative correlation between mediators and IOP.