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Introduction Autoimmune autonomic ganglionopathy is a rare treatable disease presenting with subacute pandysautonomia. 50% have ganglionic acetylcholine receptor (gAChR) antibodies. We hypothesised autonomic phenotype and innervation would differ in gAChR-positive and gAChR-negative patients presenting with subacute autonomic failure.Methods 20 gAChR-positive and 34 gAChR-negative patients underwent cardiovascular autonomic testing, pupillometry, salivary testing and skin biopsies at distal leg and thigh to quantify intraepidermal and pilomotor innervation using pan-neuronal, cholinergic, and adrenergic markers.Results gAChR-positive patients had greater orthostatic hypotension (median systolic blood pressure fall 76 vs 58mmHg), lower heart rate variability with deep breathing (3 vs 6bpm) and Valsalva ratio (1.04 vs 1.33), more frequent sympathetic and parasympathetic pupillary deficits (89 vs 33%) and xerostomia (86 vs 35%), P≤0.01. All gAChR-positive and no gAChR-negative patients demonstrated pupil fatigue. gAChR-negative patients had greater adrenergic pilomotor denervation (0 vs 5 fibres/mm at leg, 0 vs 16 fibres/mm at thigh, P<.05). Four gAChR-positive and one gAChR-negative patient had repeat biopsies after immunotherapy. Improvements in cutaneous innervation correlated with clinical recovery.Conclusions gAChR-positive patients had a characteristic phenotype with severe pandysautonomia, prominent cholinergic deficits and pupillary fatigue. Most gAChR-negative patients had sympathetic predominant autonomic failure, with more severe cutaneous adrenergic denervation. We found encouraging evidence for clinical recovery and regeneration after immunotherapy in both groups.shiwen.koay@nhs.net