It must be noted that, although research on other extraocular autoimmune disorders can be very informative, the eye is an immune-privileged site that actively regulates and directs immune responses that take place in its “territory.”
53 The immune privilege of the eye limits tissue damage after an episode of immune activation and allows allogenic, unmatched corneal transplantation. It implies strong intraocular tolerance, which is achieved through production of the anti-inflammatory cytokine TGF-β and through the presence of different subsets of Tregs in the ocular surface tissues.
54 However, when immune privilege is faced with a serious challenge, it fails dismally to prevent severe destruction and permanent structural damage in uncontrolled uveitis.
55 In those occasions, immune therapy might be beneficial. However, the cytokine patterns in uveitis seem to be nonredundant, and tailored immune therapy might be required. Indeed in the present study, levels of the B-cell chemoattractant CXCL13 were significantly higher in patients with VKH disease and IGU than in patients with BD, HLA-B27-associated uveitis, and sarcoidosis. These findings suggest that B lymphocytes may be pathogenetically important in uveitis associated with VKH disease and IGU and that CXCL13 levels in AH might be a useful biomarker for this pathology. Interestingly, several reports described predominance of B lymphocytes in the uveal inflammatory infiltrate in granulomatous uveitic entities, such as sympathetic ophthalmia,
56–59 multifocal choroiditis
60 and progressive subretinal fibrosis.
61 Additionally, B lymphocytes were identified in choroidal inflammatory infiltrate in two cases of VKH disease with “sunset glow fundus.”
62 B lymphocyte aggregates were described in the uvea of one patient with end-stage VKH disease.
63 These findings suggest that treatment with rituximab, an antibody against CD20 leading to depletion of B lymphocytes, might be effective in patients with VKH disease and IGU. Several clinical trials have demonstrated the effectiveness of rituximab in treating signs and symptoms of multiple autoimmune diseases.
26,64 Recently, rituximab was reported to be effective in the treatment of 2 cases with diffuse subretinal fibrosis
65 and one case of resistant VKH disease.
66