Inflammatory aetiology of primary oesophageal achalasia: an immunohistochemical and ultrastructural study of Auerbach's plexus

AIM: Achalasia is a disease of the oesophagus characterized by increased lower oesophageal sphincter (LOS) tone, absence of LOS relaxation with swallowing and aperistalsis of the body of the oesophagus. The aetiology and pathogenesis of idiopathic achalasia is still controversial. METHODS AND RESULTS: We examined 16 oesophageal biopsies and one low oesophagectomy specimen from patients with achalasia. The control group was composed of five autopsy cases with no history of oesophageal disorders, three cases of diffuse oesophageal spasm, one of gastro-oesophageal reflux disease and one patient with oesophageal carcinoma. Sections were immunostained for neurofilaments NF70 and NF200, S100 protein and neurone-specific enolase. Biopsies with inflammatory infiltrates, were in addition immunostained with antibodies against leucocyte common antigen as well as for CD20, CD43, CD68 and CD45RO. All biopsies were examined after plastic embedding, and electron microscopy (EM) was performed on samples containing autonomic plexus. An inflammatory infiltrate of varying intensity was present along the nerve fascicles and around ganglion cells in 90% of the cases of achalasia. T-lymphocytes predominated in all these cases. The autonomic nerves showed loss of fibres and degenerative changes which were discernible only by EM. Although there was no convincing neuronal loss or signs of active neuronal degeneration in biopsied cases, the oesophagectomy specimen revealed total absence of neurones and significant loss of nerve fibres. The control group showed normal plexuses and no inflammation. CONCLUSION: Degeneration and significant loss of nerve fibres associated with predominant T-cell lymphocytic inflammatory infiltrate around the myenteric plexus support the concept for the inflammatory, probably autoimmune, aetiology of autonomic nervous system injury in primary achalasia.