To investigate which
cytokines,
chemokines and
growth factors are involved in the immunopathogenesis of idiopathic
uveitis, and whether
cytokine profiles are associated with. Serum and aqueous humor (AH) samples of 75 patients with idiopathic
uveitis were analyzed by multiplex immunoassay. Infectious controls consisted of 16 patients with
ocular toxoplasmosis all confirmed by intraocular fluid analyses. Noninfectious controls consisted of 7 patients with
Behçet disease related
uveitis and 15 patients with
sarcoidosis related
uveitis. The control group consisted of AH and serum samples from 47 noninflammatory control patients with age-related
cataract. In each sample, 27 immune mediators ±
IL-21 and
IL-23 were measured. In idiopathic
uveitis, 13 of the 29 mediators, including most proinflammatory and vascular mediators such as
IL-6,
IL-8,
IL-12,
G-CSF,
GM-CSF, MCP-1, IP-10, TNF-α and
VEGF, were significantly elevated in the aqueous humor when compared to all controls. Moreover,
IL-17, IP-10, and
IL-21, were significantly elevated in the serum when compared to all controls. We clustered 4 subgroups of idiopathic
uveitis using a statistical analysis of hierarchical unsupervised classification, characterized by the order of magnitude of concentrations of intraocular
cytokines. The pathogenesis of idiopathic
uveitis is characterized by the presence of predominantly proinflammatory
cytokines and
chemokines and
vascular endothelial growth factor with high expression levels as compared to other causes of
uveitis. There are indications for obvious Th-1/ IL21-Th17 pathways but also IL9-Th9 and increased IFN-γ-inducing
cytokine (
IL12) and IFN-γ-inducible
CXC chemokine (IP-10). The combined data suggest that immune mediator expression is different among idiopathic
uveitis. This study suggests various clusters among the idiopathic
uveitis group rather than one specific
uveitis entity.