Correlation between serum cytokine expression and clinical characteristics in patients with autoimmune retinopathy

Objective  To investigate the expressions of serum cytokines in patients with autoimmune retinopathy (AIR), and their association with disease diagnosis as well as clinical features.

Methods  A prospective case-control study was conducted.A total of 90 eyes of 45 AIR patients were consecutively collected in Beijing Tongren Hospital from September 2018 to December 2023.Additionally, age-matched 43 controls (86 eyes) were enrolled, consisting of 21 patients (42 eyes) with retinitis pigmentosa as a disease control group and 22 healthy subjects (44 eyes) as a normal control group.The main clinical outcome measures included best-corrected visual acuity (BCVA), mean deviation (MD) of visual field, central retinal thickness and the maximal response amplitude and implicit time of full-field electroretinography (ff-ERG). A total of 21 serum cytokines were detected by Luminex multiple cytokines assay or ELISA.Differences in serum cytokine concentrations of among groups, the correlation between cytokine levels and clinical outcomes, and the contribution of cytokines to the diagnosis of AIR were analyzed.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Beijing Tongren Hospital (No.TRECKY2018-048). Written informed consent was obtained from each subject.

Results  In AIR patients, the expression levels of Th1-type cytokines or receptors (including interferon-γ[IFN-γ], interleukin [IL]-8, C-X-C motif chemokine ligand [CXCL]9, and CXCL10) and Th17-type cytokines (including IL-17 and IL-6) were elevated.There were statistically significant overall differences in pro-inflammatory cytokines/chemokines (IL-6, IL-8, CXCL10, IL-10, IFN-γ, IL-17, C-X3-C motif chemokine ligand 1 [CX3CL]1, CXCL9) among the three groups ( H=10.823, 10.816, 9.633, 10.103, 23.670, 16.493, 9.050, 9.253; all P<0.05). Compared with the disease control group and the healthy control group, the IFN-γ level was significantly increased in the AIR group (both P=0.001). Compared with the healthy control group, the serum levels of IL-6, IL-8, CXCL10, IL-10, IL-17, and CXCL9 in the AIR group were significantly elevated (all P<0.05). The serum level of CX3CL1 was significantly higher in the AIR group than in the disease control group ( P=0.039). The serum level of IFN-γ was significantly higher in the AIR group than in the healthy control and disease control groups, but no association with AIR diagnosis was found ( OR=1.402, 95% CI: 0.710-2.870, P=0.245). Multilevel mixed-effects regression modeling analysis showed that the serum levels of IL-8 and CXCL9 in AIR patients were positively correlated with LogMAR BCVA ( β=0.028, P=0.033; β=0.023, P=0.003). The C-C motif chemokine ligand 11 level was positively correlated with implicit time of ERG a-wave ( β=13.950, P<0.001). The tumor necrosis factor-α level was positively correlated with MD value of visual field ( β=6.310, P=0.002). Granulocyte-macrophage colony-stimulating factor was negatively correlated with the amplitude of ERG a-wave and granulocyte colony-stimulating factor was negatively correlated with ERG b-wave amplitude ( β=-152.700, P<0.001; β=-14.790, P=0.003).

Conclusions  Serum Th1 and Th17-type cytokines/chemokines may be involved in the pathogenesis of AIR and are related to disease severity.

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