Serum cytokine alteration is associated with optic neuropathy in human primary open angle glaucoma

PURPOSE: The purpose of this study is to compare human serum levels of T_H1 and T_H2 cytokines between 2 stages of primary open-angle glaucoma (POAG) and nonglaucomatous controls. METHODS: Thirty-two patients with primary POAG and 26 normal control subjects were enrolled into this study. The 32 patients with POAG were divided into 2 subgroups according to their mean defect (MD) with MD better than -12dB and worse than -12dB on the visual field. Enzyme-linked immunosorbent assay was used to assay for the levels of TH1 cytokines serum soluble interleukin-2 receptor (sIL-2R), interleukin (IL)-2, IL-12p40, IL-12p70, IL-23, tumor necrosis factor (TNF)-alpha, interferon-gamma, and TH2 cytokines IL-4, IL-6 in the peripheral serum. RESULTS: Patients with mild glaucomatous neuropathy exhibited significant elevations in IL-4 (P<0.0001) and IL-6 (P=0.0302) compared with the controls, whereas higher concentrations of IL-4 (P<0.0001) and IL-6 (P=0.0084) were found in patients with severe glaucomatous neuropathy. The level of IL-12p70 was significantly increased in both the MD 12dB (P<0.0001) and MD <12dB (P<0.0001) groups. A significant decrease in TNF-alpha levels were observed in MD <12dB group compared with the controls (P=0.0464), and TNF-alpha levels in MD <12dB group were lower than MD 12dB group (P=0.0328). No significant differences in serum concentrations of IL-2, sIL-2R IL-12p40, IL-23 and interferon-gamma were found between MD <12dB group, MD 12dB group, and control group. CONCLUSIONS: Significant alterations of serum TH1 and TH2 cytokines are associated with glaucoma, suggesting the possibility that abnormal immune environments contribute to the glaucomatous neuropathy of POAG.