Subclinical Corneal Nerve Fiber Damage and Immune Cell Activation in Systemic Lupus Erythematosus: A Corneal Confocal Microscopy Study.

Purpose: The purpose of this study was to evaluate the utility of corneal confocal microscopy (CCM) in identifying small nerve fiber damage and immune cell activation in patients with systemic lupus erythematosus (SLE). Methods: This cross-sectional comparative study included 39 consecutive patients with SLE and 30 healthy control participants. Central corneal sensitivity was assessed using a Cochet-Bonnet contact corneal esthesiometer and a laser scanning CCM (Heidelberg, Germany) was used to quantify corneal nerve fiber density (CNFD), nerve branch density (CNBD), nerve fiber length (CNFL), and Langerhans cell (LC) density. Results: Age was comparable among patients with SLE (33.7 ± 12.7) and controls (35.0 ± 13.7 years, P = 0.670) and the median duration of disease was 3.0 years (2.0-10.0 years). CNBD (P = 0.003) and CNFL (P = 0.019) were lower and mature LC density (P = 0.002) was higher, but corneal sensitivity (P = 0.178) and CNFD (P = 0.198) were comparable in patients with SLE compared with controls. The SELENA-SLEDAI score correlated with CNFD (ρ = -0.319, P = 0.048) and CNFL (ρ = -0.373, P = 0.019), and the total and immature LC densities correlated with CNBD (ρ = -0.319. P = 0.048, and ρ = -0.328, P = 0.041, respectively). Immature LC density was higher (P = 0.025), but corneal sensitivity and nerve fiber parameters were comparable between patients with (33%) and without neuropsychiatric symptoms and SLE. Conclusions: Corneal confocal microscopy identifies distal corneal nerve fiber loss and increased immune cell density in patients with SLE and corneal nerve loss was associated with disease activity. Translational Relevance: Corneal confocal microscopy may enable the detection of subclinical corneal nerve loss and immune cell activation in SLE.