Is There Any Evidence for a Viral Cause in Achalasia?

BACKGROUND Achalasia, as an incurable disease is defined by the lack of normal esophageal peristalsis and loss of lower esophageal sphincter relaxation due to impaired myenteric neural plexus. The exact cause of myenteric neural cells degeneration in achalasia is still unknown. One hypothesis is that certain neurotropic viruses and autoimmune factors cause the inflammatory response in myenteric network, which consequently destroy neural cells. This study was designed to find the evidence of viral causes of achalasia. METHODS In this case-control study, 52 patients with achalasia and 50 controls referred to Shariati Hospital, were evaluated for the genome of neurotropic viruses, HPV, and adenovirus by polymerase chain reaction (PCR) and reverse transcription (RT) PCR techniques. RESULTS Genome assessment of neurotropic DNA viruses turned out negative in the patients, however, the genome of HSV-1 (Herpes simplex virus) was found in tissues of six controls. No neurotropic RNA viruses were observed in the tissue samples and whole blood of both the patients and controls. Among non-neurotropic viruses, adenovirus genome was positive in tissues of two out of 52 patients and three out of 50 controls. In addition, one out of 52 patients and two out of 50 controls were positive for HPV infection in tissues. CONCLUSION We could not detect any significant relationship between achalasia and HPV, adenovirus, and neurotropic viruses in the cases. Nevertheless, it does not exclude the hypothesis of either an alternate viral species or resolved viral infection as the etiology of achalasia.