Cytometric Evaluation of Cytokine Factors in Serum and Vitreous from Endophthalmitis Patients: Correlated Elevation in Neutrophil Markers

<b>Background</b>: Endophthalmitis is a rare, sight-threatening condition resulting from infection inside the eye. This study more accurately characterises the cytokines upregulated in human endophthalmitis, and for the first time demonstrates a correlation with cytokine elevation in the serum. <b>Methods</b>: We recruited 39 patients, 17 with endophthalmitis and 22 controls. We compared cytokine expression quantified through cytometric bead assays for both vitreous and serum. <b>Conclusions:</b> The cytokine profile in the vitreous of patients with infectious endophthalmitis was suggestive of a highly inflammatory environment, as 23/26 cytokines examined were significantly elevated. In the patient sera, MMP-9, MPO, Calprotectin, NGAL, SAA (HVIP1), and MCP-1 (HIP1) were all significantly elevated in endophthalmitis samples, which was unexpected as pathology was thought to be localised with minimal systemic effects. Overall, many of the observed cytokines in endophthalmitis are associated with neutrophil responses, and we believe that this deserves further investigation with a view to developing immunomodulatory therapies to prevent endophthalmitis or improve clinical outcomes. Furthermore, our novel demonstration that cytokine elevation associated with endophthalmitis can be demonstrated in serum may allow for novel and rapid interventions.