Vogt-Koyanagi-Harada Syndrome in a Canadian First Nations Population

TET2-mediated upregulation of 5-hydroxymethylcytosine in LRRC39 promoter promotes Th1 responses in association with downregulated Treg response in Vogt-Koyanagi-Harada disease

DNA 5-Hydroxymethylcytosine (5-hmC), an oxidative reaction mediated by the ten-eleven translocation (TET) family, has been reported to play an essential role in the progression of auto-inflammatory and autoimmune diseases. By far, little is known about the effect of DNA 5-hmC and the TET family on the development of Vogt-Koyanagi-Harada (VKH) disease. In this study, we discovered that the global DNA 5-hmC level and the TET activity were elevated in association with the up-regulated expression of TET2 at both mRNA and protein levels in CD4⁺T cells from active VKH patients compared to healthy controls. Integrated analysis of DNA 5-hmC pattern and transcription profile of CD4⁺ T cells revealed that 6 candidate target genes were involved in the development of VKH disease. The promoter 5-hmC and mRNA levels of leucine rich repeat containing 39 (LRRC39) were verified to be elevated in active VKH patients. Functional experiments showed that TET2 could up-regulate LRRC39 mRNA expression by increasing the promoter 5-hmC level of LRRC39 in CD4⁺ T cells from active VKH patients. Up-regulated LRRC39 expression could increase the frequencies of IFN-γ⁺ and IL-17⁺ CD4⁺ T cells as well as the secretions of IFN-γ and IL-17 in association with the decreased frequency of CD4⁺CD25⁺FOXP3⁺ regulatory T (Treg) cells and the reduced production of IL-10. Additionally, restoration of LRRC39 rescued TET2-silencing-mediated reduced frequency of IFN-γ⁺ CD4⁺ T cells and increased frequency of CD4⁺CD25⁺FOXP3⁺ Treg cells. Collectively, our study reveals a novel axis, TET2-5-hmC-LRRC39-Th1/Treg responses axis, in the pathogenesis of VKH and provides a potential target for further investigation into the epigenetic therapy of this disease.

Uveitis Patterns and Severity: An Epidemiologic Study from a Tertiary Care Private Referral Center in Buenos Aires, Argentina

PURPOSE

To report uveitis' spectrum in a private practice cohort in the city of Buenos Aires, Argentina.

METHODS

Retrospective review at Instituto de la Visión (November 2011-October 2015). Standard demographics, ethnicity and Native American aboriginal ancestry were recorded.

RESULTS

Among 212 patients, median age 45 (6-97), 10% pediatric, 35% bilateral, 72% non-idiopathic, 36% infectious. Anterior uveitis presented in 50%, followed by posterior (32%), intermediate (9%) and panuveitis (8%). Frequent visits (≥ 6 per year) needed by 29%: posterior, non-idiopathic disease with 79% systemic immunosuppression requirement was their main presentation. Native American aboriginal ancestry was reported by 22.64% of the whole cohort and 37% of frequent visits' subgroup.

CONCLUSIONS

Unilateral, non-idiopathic, non-infectious anterior uveitis was the most frequent presentation, in agreement with reports coming from western developed cities. The multi-racial Argentinian population with specific Native American aboriginal ancestry might contribute to certain forms of posterior uveitis and their response to treatment.