Aims: Considering the phenotypical consequences and association of C4 copy number variation (CNV) with various autoimmune diseases, we aimed to examine C4 CNVs for 1027 patients with Vogt-Koyanagi-Harada (VKH) syndrome and 2083 controls.
Methods: C4 CNVs were examined by real-time PCR for 1027 patients with VKH and 2083 controls. Peripheral blood mononuclear cells (PBMC) were prepared from venous blood by Ficoll-Hypaque density-gradient centrifugation for cell culture. Cytokine production was examined by ELISA.
Results: The expression of total C4 in serum was significantly decreased in patients with VKH as compared with controls (p=0.0010). A significant positive association between C4 expression with C4 CNVs was found (p=0.0023, r(2)=0.92). CNV analysis identified significantly decreased frequencies of more than two copies of C4A or more than four copies of total C4 in patients with VKH (Pc=1.42×10(-3) to 3.56×10(-4), OR=0.67 to 0.70). Linkage analysis showed the independent association of C4 with VKH syndrome from human leucocyte antigen (HLA)-DR4. No significant association was observed concerning type 1 T helper cell (Th1) cytokines and Th17 cytokine production by stimulated PBMCs and C4A copy number.
Conclusions: Our findings indicate a decreased expression of serum C4 and a decreased frequency of high C4 gene copy number in patients with VKH.
Trial registration number: Chinese Clinical Trial Registration Number: ChiCTR-CCC-12002184.
Keywords: Immunology; Inflammation.
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