Systemic biomarkers of retinopathy of prematurity in preterm babies.

Purpose: Retinopathy of prematurity (ROP) progression is an inter-play of various perinatal and neonatal angiogenic and inflammatory cytokines. A small subset of ROP progresses to ROP requiring treatment. The present study was conducted with the aim to determine whether levels of IL-6, IL-8 and VEGF in serum and urine at the time of first ROP screening visit could be a biomarker for the prediction of development of treatable ROP.

Method: Prospective single-center observational study of preterm babies screened for ROP. Blood and urine samples were collected as a part of routine sampling at initial ROP screening visit and stored at -80 °C for further processing. The babies were followed up and grouped into 'Group A' comprising of 35 babies who developed treatable ROP and 'Group B' comprising of 36 babies with regressed ROP or no ROP. The evaluation of blood and urine samples was done for IL6, IL8 and VEGF by solid-phase sandwich RayBio® Human ELISA kit.

Results: The median serum values for IL-6, IL-8 and VEGF in Group A and Group B were 5.8 pg/ml (IQR 1.5,128.5) and 8.7 pg/ml (IQR 1.5,30.5), 55.9 pg/ml (IQR 28.0, 392.9) and 27.0 pg/ml (IQR 20.5,444.9) and 26.6 pg/ml (IQR 6.3, 39.4) and 30.0 pg/ml (IQR9.2,70.3), respectively. Group A had significantly increased levels of IL-8 (p < 0.05). However, AUROC curve for serum IL-8 demonstrated suboptimal discriminating ability.

Conclusion: Babies developing ROP requiring treatment had significantly increased levels of IL-8 in the serum at the time of initial screening. However, it could not serve as predictor for treatable ROP.