Hierarchical Cluster Analysis of Serum and Vitreous Cytokines in Intermediate, Posterior and Panuveitis

Abstract

Purpose : To assess the association between serum and vitreous cytokines and ocular inflammation among patients enrolled in the Multicenter Uveitis Steroid Treatment (MUST) trial using hierarchal cluster analysis heatmaps.

Methods : Serum and vitreous specimens were obtained from patients with active intermediate or posterior/panuveitis, who were randomized to the fluocinolone acetonide implant arm of the MUST trial (NCT00132691) as part of an ancillary study “The Vitreous Proteome and Inflammatory Mediators in Ocular Inflammatory Disease” (NCT00331331) done at the National Eye Institute. Both serum and vitreous samples were obtained at the time of fluocinolone acetonide implant surgery. Multiplex cytokine analysis was performed to measure 27 biomarkers of inflammation in the serum and vitreous samples. Hierarchical clustering heatmaps were performed on log-transformed cytokine levels using the webtool ClustVis (https://biit.cs.ut.ee/clustvis/).

Results : 36 eyes are included in the analysis (14 intermediate uveitis, 22 posterior/panuveitis) with a mean age of 45.5 years (range 22-70), 79% were female. Unbiased hierarchical cluster analysis demonstrated a group of 12 eyes with higher levels of clinical activity (11 of 12 eyes with >1+ vitreous haze) correlating with increased vitreous levels of pro-inflammatory cytokines MIP-1a, IL-1b, IL-12, TNF-alpha, VEGF, MIP-1b, IL-6, IL-8, and IL-9 with relatively lower serum levels of pro-inflammatory cytokines. There was no significant clustering based on diagnosis of intermediate versus posterior/panuveitis or etiologic diagnoses.

Conclusions : Hierarchical cluster analysis demonstrates increased levels of pro-inflammatory vitreous cytokine levels associated with higher levels of clinically activity in intermediate, posterior, and panuveitis. There was no significant clustering based on clinical type of uveitis. In addition, the cluster analysis dendrogram demonstrates patterns of cytokine expression differ between serum and vitreous and provides insight into the functional interplay of cytokine signaling.

This is a 2020 ARVO Annual Meeting abstract.