EP 41. Corneal confocal microscopy in chronic inflammatory demyelinating polyneuropathies

Abstract

Objective There is an unmet need for better diagnostic tools to further delineate clinical subsets of heterogeneous chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN) to facilitate treatment decisions. Corneal confocal microscopy (CCM) is a non-invasive and reproducible nerve imaging technique. This study evaluates the potential of CCM as a diagnostic surrogate in CIDP and MMN. Methods In a cross-sectional prospective approach 182 patients and healthy controls were studied using CCM to quantify corneal nerve damage and immune cell infiltration. Results Patients with CIDP and MMN had a reduction in corneal nerve fiber (CNF) measures and an increase in corneal immune cell infiltrates. In CIDP, CNF parameters decreased with increasing duration of disease. The number of dendritic cells in proximity to corneal nerve fibers was increased in patients with early disease and correlated with the degree of motor affection. A further reduction in CNF parameters and an increase in non-dendritic cells was observed in patients with painful neuropathy. In CIDP patients with anti-neuronal antibodies the number of non-dendritic cells was increased. Interpretation Our findings suggest that corneal nerve fiber loss may reflect severity of neuropathy and quantification of distinct cells around the CNF plexus may help in stratifying CIDP subtypes, clinical course and disease activity. However, further longitudinal studies are required before CCM can be considered as a valid surrogate end point for patients with CIDP and MMN.