A Novel Biomarker in Diabetic Macular Edema with Serous Retinal Detachment: Serum Chitinase-3-Like Protein 1.

PURPOSE: To determine whether serum chitinase-3-like protein 1 (CHI3L1) and interleukin-6 (IL-6) levels correlate with serous retinal detachment (SRD) in diabetic macular edema (DME) using spectral-domain optical coherence tomography (SD-OCT).

METHODS: In this cross-sectional case-control study, 394 patients (treatment-naive DME patients, n = 218; diabetic patients without DME, n = 96; nondiabetic controls, n = 80) were included in the study. Eyes were classified according to SD-OCT features of DME: SRD, cystoid macular edema (CMO), and diffuse retinal thickness (DRT). Serum concentrations of CHI3L1 and IL-6 were analyzed using enzyme-linked immunosorbent assay.

RESULTS: Serum CHI3L1 and IL-6 levels were significantly higher in DME with SRD compared to patients with CMO and DRT (p < 0.001 for all groups). Multivariate regression analysis showed that CHI3L1 and IL-6 had a stronger influence on the presence of SRD in DME (r = 1.162, p = 0.026, and r = 1.242, p = 0.016, respectively). Serum concentration of CHI3L1 was significantly correlated with that of IL-6 (r = 0.386, p = 0.0015).

CONCLUSIONS: Our data suggest that serum concentrations of CHI3L1 and IL-6 are involved in the process of SRD in DME. CHI3L1 can be investigated further as a new diagnostic biomarker for DME with SRD.