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BackgroundAutoimmune Autonomic Ganglionopathy (AAG) is a rare, immune-mediated condition characterised by subacute pandysautonomia. 50% have auto-antibodies to the ganglionic nicotinic acetylcholine receptor (gAChR), affecting synaptic transmission at autonomic ganglia.MethodsWe describe 13 patients (5 female, median age 47) presenting with widespread autonomic failure, confirmed on cardiovascular, sudomotor and pupillometry testing at the National Hospital for Neurology and Neurosurgery (NHNN), and high gAChR antibody levels (>200 pm) measured by radioimmunoprecipitation assay at Oxford University.ResultsOf the 13 patients, 8 had other autoimmune conditions, 3 had antecedent infection and 3 were paraneoplastic. All had orthostatic hypotension, gastro-intestinal and urinary symptoms, 11 had documented pupillary abnormalities (9 mixed sympathetic and parasympathetic deficits, 2 subclinical sympathetic deficits), 11 had secretomotor dysfunction, 8 had generalised/partial anhidrosis, 8 had sexual dysfunction and 7 had evidence of small fibre dysfunction on neurophysiology.Ten received immunomodulatory treatment; 6 plasma exchange and 4 combination treatment including intravenous immunoglobulin, mycophenolate and rituximab. Earlier treatment was associated with greater clinical response.DiscussionPatients with AAG and high gAChR antibody levels have widespread dysfunction of the autonomic nervous system, which can respond dramatically to immunomodulation. Further research is needed to develop robust clinical biomarkers to guide treatment and monitor response.

Background and ObjectivesSudomotor impairment has been recognized as a key feature in differentiating Parkinson disease (PD) and multiple system atrophy–parkinsonian type (MSA-P), with the latter characterized by diffuse anhidrosis in prospective study, including patients in late stage of disease. We aimed to evaluate morphologic and functional postganglionic sudomotor involvement in patients with newly diagnosed MSA-P and PD to identify possible biomarkers that might be of help in differentiating the 2 conditions in the early stage.MethodsOne hundred patients with parkinsonism within 2 years from onset of motor symptoms were included in the study. At the time of recruitment, questionnaires to assess nonmotor, autonomic, and small fiber symptoms were administered, and patients underwent postganglionic sudomotor function assessment by the dynamic sweat test and punch skin biopsy from the distal leg. Skin samples were processed for indirect immunofluorescence with a panel of antibodies, including noradrenergic and cholinergic markers. The density of intraepidermal, sudomotor, and pilomotor nerve fibers was measured on confocal images with dedicated software. A follow-up visit 12 months after recruitment was performed to confirm the diagnosis.ResultsWe recruited 57 patients with PD (M/F 36/21, age 63.5 ± 9.4 years) and 43 patients with MSA-P (M/F 27/16, age 62.3 ± 9.0 years). Clinical scales and questionnaires showed a more severe clinical picture in patients with MSA-P compared to those with PD. Sweating output and intraepidermal, pilomotor, and sudomotor nerve densities, compared to controls, were lower in both groups but with a greater impairment in patients with MSA-P. Pilomotor and sudomotor nerve density correlated with sweating function and with nonmotor clinical symptoms. A composite sudomotor parameter defined as the arithmetic product of sweat production multiplied by the density of sudomotor fibers efficiently separated the 2 populations; the receiver operating characteristics curve showed an area under the curve of 0.83.DiscussionDynamic sweat test and the quantification of cutaneous autonomic nerves proved to be a sensitive morpho-functional approach to assess the postganglionic component of the sudomotor pathway, revealing a more severe involvement in MSA-P than in PD early in the disease course. This approach can be applied to differentiate the 2 conditions early.Classification of EvidenceThis study provides Class II evidence that postganglionic sudomotor morpho-functional assessment accurately distinguish patients with PD from patients with MSA-P.