Immunologic factors Onset of<unk>  can broadly be described as a failure of the ocular immune system and the disease results from inflammation and tissue destruction.<unk>  is driven by the Th17 T cell sub-population that bear T-cell receptors specific for proteins found in the eye. These are often not deleted centrally whether due to ocular antigen not being presented in the thymus (therefore not negatively selected) or a state of anergy is induced to prevent self targeting. Autoreactive T cells must normally be held in check by the suppressive environment produced by microglia and dendritic cells in the eye. These cells produce large amounts of TGF beta and other suppressive cytokines, including IL-10, to prevent damage to the eye by reducing inflammation and causing T cells to differentiate to inducible T reg cells. Innate immune stimulation by bacteria and cellular stress is normally suppressed by myeloid suppression while inducible Treg cells prevent activation and clonal expansion of the autoreactive Th1 and Th17 cells that possess potential to cause damage to the eye. Whether through infection or other causes, this balance can be upset and autoreactive T cells allowed to proliferate and migrate to the eye. Upon entry to the eye, these cells may be returned to an inducible Treg state by the presence of IL-10 and TGF-beta from microglia. Failure of this mechanism leads to neutrophil and other leukocyte recruitment from the peripheral blood through IL-17 secretion. Tissue destruction is mediated by non-specific macrophage activation and the resulting cytokine cascades. Serum TNF-α is significantly elevated in cases while IL-6 and IL-8 are present in significantly higher quantities in the aqueous humour in patients with both quiescent and active<unk> . These are inflammatory markers that non-specifically activate local macrophages causing tissue damage. Genetic factors The cause of non-infectious<unk>  is unknown but there are some strong genetic factors that predispose disease onset including HLA-B27 and the PTPN22 genotype. Infectious agents Recent evidence has pointed to reactivation of herpes simplex, varicella zoster and other viruses as important causes of developing what was previously described as idiopathic anterior<unk> . Bacterial infection is another significant contributing factor in developing<unk> .
Uveitis
Glaucoma
Sinusitis
Laryngitis
Rhinitis
Aortitis
Pharyngitis
Uveoparotitis