Corneal Immune Cells Are Increased in Patients With Multiple Sclerosis

PURPOSE: Corneal confocal microscopy (CCM) is an ophthalmic imaging technique that has been used to identify increased corneal immune cells in patients with immune-mediated peripheral neuropathy. Given that multiple sclerosis has an immune-mediated etiology, we have compared corneal immune cell (IC) density and near-nerve distance in different subtypes of patients with multiple sclerosis (MS) to controls. METHODS: This is a blinded, cross-sectional study conducted at a tertiary hospital. Patients with clinically isolated syndrome (CIS) (n = 9), relapsing-remitting multiple sclerosis (RRMS) (n = 43), secondary progressive multiple sclerosis (SPMS) (n = 22), and control subjects (n = 20) underwent CCM. The total, mature, and immature corneal IC density and their nearest nerve distance were quantified. RESULTS: The total IC density was higher in patients with MS (P = 0.02), RRMS (P = 0.01), and SPMS (P = 0.04) but not CIS (P = 0.99) compared to controls. Immature IC density was higher in patients with MS (P = 0.03) and RRMS (P = 0.02) but not SPMS (P = 0.10) or CIS (P = 0.99) compared to controls. Mature IC density (P = 0.15) did not differ between patients with MS and controls. The immature IC near-nerve distance was significantly greater in patients with MS (P = 0.001), RRMS (P = 0.007), and SPMS (P = 0.002) compared to controls. Immature IC density correlated with the Symbol Digit Modalities Test (r = –0.281, P = 0.02) and near-nerve distance correlated with the Expanded Disability Status Scale (r = 0.289, P = 0.005). CONCLUSIONS: In vivo CCM demonstrates an increase in immature IC density and the near-nerve distance in patients with MS. These observations merit further studies to assess the utility of CCM in assessing neuroimmune alterations in MS. TRANSLATIONAL RELEVANCE: Multiple sclerosis is an immune-mediated neurodegenerative disease. Dendritic cells mediate communication between the innate and adaptive immune systems. We have used in vivo CCM to show increased corneal ICs and suggest it may act as an imaging biomarker for disease status in patients with MS.