Serum factor VIII levels in ocular inflammatory disease

Abstract

Purpose : The protein factor VIII (FVIII) plays an important role in the coagulation cascade, leading to normal hemostasis. FVIII is produced primarily by hepatic sinusoidal endothelial cells and monocytes, whereas most other coagulation factors are produced by hepatocytes. Because it is secreted primarily by vascular endothelial cells, FVIII has been evaluated as a potential marker for vascular endothelial damage secondary to vasculitis. Alkaabi et al (2013) evaluated patients with Behçets disease and found elevated FVIII levels in those with active disease, compared to both healthy controls and patients with inactive disease. FVIII levels have also been studied in patients with retinal vasculitis. Elevated FVIII levels have been reported in patients with Susac syndrome. Probst et al (2004) found elevated FVIII levels in 79% of patients with ocular Behçets disease. In this study, we evaluated serum FVIII levels in patients with a variety of ocular inflammatory diseases.

Methods : A retrospective chart review was performed on all patients who had serum FVIII level obtained in the setting of active ocular inflammatory disease. Active disease was defined as the need for additional anti-inflammatory therapy at the visit where the FVIII level was obtained.

Results : 38 patients were included in the study. Thirteen of the 38 patients had elevated FVIII levels. Patients with known systemic inflammatory disease were more likely to have elevated FVIII, X² = 5.96, p = 0.015, relative risk (RR) = 2.86. Patients with a diagnosis of retinal vasculitis were also more likely to have elevated FVIII compared to patients with other types of ocular inflammatory disease, X² = 4.80, p = 0.029, RR = 2.78.

Conclusions : While a standard work-up is obtained in all patients with ocular inflammatory disease, most patients eventually fall into a category of ‘idiopathic’ inflammation, despite there being likely differences in the pathophysiologic mechanisms of these diseases. In our sample, patients with known systemic inflammatory disease and patients with a classification of retinal vasculitis were more likely to have elevated FVIII. As FVIII is produced outside of the eye primarily by vascular endothelial cells, elevated levels may indicate a component of systemic vascular endothelial damage and vasculitis. This information may be helpful in better differentiating and classifying ocular inflammatory disease.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.