Expression of suppressor of cytokine signaling in peripheral blood monocular cells of patients with Vogt-Koyanagi-Harada disease

Abstract

To investigate suppressor of cytokine signaling (SOCS) mRNA and protein expression in peripheral blood mononuclear cells (PBMC) of patients with Vogt-Koyanagi-Harada (VKH) disease. Blood samples were taken from 15 VKH patients with active uveitis, 17 quiescent patients and 16 healthy individuals. IFN-gamma, IL-12 and IL-4 in the serum were measured by ELISA. PBMC were subjected to analysis of SOCS mRNA and protein expression using quantitative RT-PCR and western blot, respectively. The level of IL-4 in the serum of VKH patients and in controls were (28.40 +/- 5.93) ng/L, (34.5 +/- 9.47) ng/L and (11.25 +/- 4.43) ng/L, IL-12 were (24.33 +/- 8.55) ng/L, (11.53 +/- 6.11) ng/L and (5.19 +/- 2.43) ng/L, IFN-gamma were (18.05 +/- 2.23) ng/L, (15.53 +/- 2.63) ng/L and (1.61 +/- 3.47) ng/L, respectively. The level of IFN-gamma, IL-12 and IL-4 were all significantly higher in the serum of VKH patients than in controls(P < 0.01). IL-4 in quiescent patients was higher than in active patients (P < 0.01), IL-12 and IFN-gamma were lower in quiescent patients was higher than in active patients (P < 0.01, P < 0.05). Cytokine inducible SH2 containing protein (CIS) mRNA, SOCS1 mRNA, SOCS2 mRNA, SOCS3 mRNA and SOCS5 mRNA levels in PBMC of VKH patients with active uveitis are 0.72, 4.92, 1.09, 0.75 and 1.15 folds than that in healthy volunteers, respectively. They are 1.15, 2.25, 1.40, 0.69 and 1.16 folds in static patients, respectively. Marked decreased expression of CIS protein is detected in both active and quiescent patients with no significant difference between two groups (both P < 0.01). SOCS1 protein is up-regulated significantly in active patients compares to in quiescent patients nor in healthy volunteers (P < 0.01, P < 0.05). SOCS3 protein is significantly decreased in patients than in controls (both P < 0.05). SOCS5 protein is much higher in patients than in controls (both P < 0.01), and even higher in quiescent patients than in active episode (P < 0.05). Up regulation of SOCS1 and SOCS5 expression and down-regulation of SOCS3 and CIS may correlate with the development of a Th1 mediated immune response in VKH disease. There is insidious inflammation in VKH patients with clinically quiescent uveitis, and this may be one of the causes of persistence and recurrences of uveitis.