Role of Multidrug Resistance Proteins in Nonresponders to Immunomodulatory Therapy for Noninfectious Uveitis

Immunosuppressive therapy for Vogt-Koyanagi-Harada disease: a retrospective study and review of literature

BACKGROUND

Vogt-Koyanagi-Harada (VKH) disease is an idiopathic autoimmune disease which targets melanin-containing tissues such as the uvea, meninges, ear and skin. This typically presents in the eye with acute findings of granulomatous anterior uveitis, diffuse choroidal thickening, multiple focal areas of sub-retinal fluid and, in severe cases, optic nerve involvement with bullous serous retinal detachment can occur. Early initiation of treatment has been advocated to prevent progression to the chronic stage of the disease, which can result to a sunset glow fundus with devastatingly poor visual outcome. Treatment is usually initiated with corticosteroids followed by an early introduction of immunosuppressive treatment (IMT) to achieve immediate response after disease presentation, although the choice of IMT for VKH can vary.

MAIN FINDINGS

We conducted a retrospective case-series to investigate the management trend of treating VKH over a 20-year period. Twenty-six patients were included and we found a shift from steroid monotherapy to combined IMT/low-dose steroid for the management of acute initial-onset of VKH in the last 10 years. Our average time from diagnosis to initiation of IMT was 2.1 months. 81% (21 of 26 patients) of our patients treated with combined IMT/steroid were able to achieve disease stability with significant good visual outcome at 24 months (Median VA_pre-IMT = 0.3 Logmar vs VA_post-IMT = 0.0 Logmar, p = 0.0001). MMF monotherapy was the most common IMT used and it was well-tolerated by our patients. Even so, 50% of our patients who were treated with MMF did not achieve disease control. We then performed a literature review to identify any IMT which could be superior in the treatment of VKH. We also share our experience (where applicable) on the various treatment options found from the literature review.

SHORT CONCLUSION

Our study found that patients with VKH who were treated with combined IMT/low-dose steroids achieved significantly better visual improvement at 24 months compared to steroid monotherapy. We frequently chose MMF and this appears to be well tolerated by our patients. Since its introduction, anti-TNF agents are increasingly becoming a popular choice of treatment for VKH as these have been shown to be safe and effective. However, more data is required to provide evidence that anti-TNF agents can be used as first-line treatment and as monotherapy.

Roles of CSF2 as a modulator of inflammation during retinal degeneration

Colony-stimulating factor 2 (CSF2) is a potent cytokine that stimulates myeloid cells, such as dendritic cells and macrophages. We have been analyzing the roles of microglia in retinal degeneration through the modulation of inflammation in the eye, and examined the roles of CSF2 in this process. Both subunits of the CSF2 receptor are expressed in microglia, but no evidence suggesting the involvement of CSF2 in inflammation in the degenerating eye has been reported. We found that Csf2 transcripts were induced in the early phase of in vitro mouse adult retina culture, used as degeneration models, suggesting that CSF2 induction is one of the earliest events occurring in the pathology of retinal degeneration. The administration of CSF2 into the retina after systemic NaIO₃ treatment increased the number of microglia. To examine the roles of CSF2 in retinal inflammation, we overexpressed CSF2 in retinal explants. Induction of CSF2 activated microglia and Müller glia, and the layer structure of the retina was severely perturbed. CC motif chemokine ligand 2 (Ccl2) and C-X-C motif chemokine ligand 10 (Cxcl10), both of which are expressed in activated microglia, were strongly induced by the expression of CSF2 in the retina. The addition of CSF2 to primary retinal microglia and the microglial cell lines MG5 and BV2 showed statistically significant increase in Ccl2 and Il1b transcripts. Furthermore, CSF2 induced proliferation, migration, and phagocytosis in MG5 and/or BV2. The effects of CSF2 on microglia were mild, suggesting that CSF2 induced strong inflammation in the context of the retinal environment.