Long-lasting clinical and autonomic effects of plasma ganglionic acetylcholine antibodies removal and immunosuppressive therapy in a patient with autoimmune Pure Autonomic Failure

Autoimmune autonomic ganglionopathy: Ganglionic acetylcholine receptor autoantibodies

Autoimmune Autonomic Ganglionopathy (AAG) is a rare immune-mediated disease of the autonomic nervous system. The incidence of AAG is unknown and diagnosis is often difficult due to the multicompartmental nature of the autonomic nervous system - sympathetic, parasympathetic and enteric components - with variable severity and number of components affected. Diagnostic confidence is increased when ganglionic acetylcholine receptor (gnACHR) autoantibodies are detected. Three gnACHR autoantibody diagnostic assays have been described (two binding assays, one receptor immunomodulation assay), but cross-validation between assays is limited. The prevalence of gnACHR autoantibodies in AAG is not known, with application of different clinical and laboratory criteria in the few studies of AAG cohorts and large retrospective laboratory studies of positive gnACHR autoantibodies lacking adequate clinical characterisation. Furthermore, the rate of unexpected gnACHR autoantibody positivity in conditions without overt autonomic dysfunction (false positive results) adds to the complexity of their interpretation. We review the pathophysiology of gnACHR autoantibodies and assays for their detection, with immunomodulation and high titer radioimmunoprecipitation results likely offering better AAG disease identification.

Profile of autonomic dysfunctions in patients with primary brain tumor and possible autoimmunity

OBJECTIVE

Cerebral lesion due to different neurological conditions could be complicated by autonomic dysfunction, reported in the literature as a sympathetic hyperactivity. The mechanisms of dysautonomia still remains partial. The aim of the study was to assess the profile of autonomic dysfunction in patient with primary brain tumors, with attempt to estimate the additional factors in pathogenesis of dysautonomia.

MATERIAL AND METHODS

Neurological examinations, the Low's autonomic disorder questionnaire, electrophysiological autonomic tests (Heart Rate Variability test at rest and during deep breathing, spectral analysis of R-R intervals, sympathetic skin response test), studies of peripheral nerves, blood sampling collection for antibodies were done in 33 patients with recognized primary brain tumors.

RESULTS

The averaged Low's Questionnaire score in the patients group was significantly higher than in the controls, systolic blood pressure was increased, heart rate tended to be higher without significance, but heart rate variability was severe low, LF/HF ratio also tended to be higher in the patients group. In SSR test the amplitude of responses from hand and foot was significantly lower without changes in their latencies. We found changes in the electrophysiological tests of peripheral nerves, and positive anti-neural antibodies in 5 patients.

CONCLUSIONS

The results of the study indicated to the sympathetic nervous system hyperactivity in patients with primary brain tumors. Local brain lesion with high intracranial pressure, additional peripheral nerve damage probably in the course of autoimmunity, and direct influence of autoimmunity to the central part of autonomic nervous system are possible in the pathogenesis of dysautonomia.