Plasma levels of TNF-α, IL-6, IFN-γ, IL-12, IL-17, IL-22, and IL-23 in achalasia, eosinophilic esophagitis (EoE), and gastroesophageal reflux disease (GERD).

An elevation of serum inflammatory biomarkers in achalasia patients compared with controls recently was demonstrated. It has not been determined whether the elevation of inflammatory cytokines is unique to achalasia or occurs with other diseases involving the esophagus. The primary aim of our study was to compare the differences in plasma immunological profiles (TNF- α receptor, IL-6, IFN-γ, IL-12, IL-17, IL-22, and IL-23) of patients with achalasia, eosinophilic esophagitis (EoE), and gastroesophageal reflux disease (GERD). A secondary aim of this study was to classify these same plasma cytokine profiles in the three achalasia subtypes. METHODS: Plasma from 53 patients with achalasia, 22 with EoE, and 20 with GERD (symptoms plus esophagitis or + reflux study) were analyzed. EXCLUSION CRITERIA: malignancy, autoimmune condition, immunodeficiency disorder, and treatment with steroids/immune modulating drugs. Cytokine levels were assayed via multiplex enzyme-linked immunosorbent assay (ELISA). RESULTS: Our key finding revealed significant elevations in IL- 6 (p = 0.0158) in achalasia patients compared with EoE patients. Overall, plasma inflammatory biomarker patterns were not different in the three subtypes of achalasia. CONCLUSION: There were no differences between the cytokine levels of any of the measured biomarkers between the achalasia and GERD groups suggesting that luminal stasis does increase biomarker levels for any of the cytokines examined in our study. While these results are an early first step towards clarifying some aspects of the pathogenesis of achalasia, they bring about many more questions that require further investigation and expansion. Further investigation with a larger cohort and a broader panel of biomarkers is needed.

Can Eosinophilic Esophagitis Cause Achalasia and Other Esophageal Motility Disorders?

Eosinophilic esophagitis (EoE), a disorder identified by its esophageal mucosal features, often is associated with esophageal motility abnormalities, which are manifestations of esophageal muscle dysfunction. Those motility abnormalities sometimes normalize with treatments that reduce esophageal eosinophilia, suggesting that eosinophils can cause reversible esophageal motility disturbances, perhaps by releasing myoactive and neuroactive eosinophil products. Although achalasia uncommonly is associated with EoE as currently defined, most achalasia patients have evidence of an abnormal accumulation of eosinophils and/or their degranulation products in the esophageal muscularis propria, a location inaccessible to routine endoscopic evaluation. Achalasia is an idiopathic condition resulting from destruction of neurons in the myenteric plexus of the esophagus, and degranulating eosinophils release toxic proteins capable of destroying those neurons, thereby causing the irreversible motility abnormalities of achalasia. This report reviews data on the association of esophageal eosinophilia with achalasia and other esophageal motility abnormalities. Based on this review, we propose that EoE, like eosinophilic gastroenteritis, might have mucosal-predominant and muscle-predominant forms with different clinical manifestations. A muscle-predominant form of EoE could underlie a variety of reversible and irreversible esophageal motility disorders, including achalasia. The concept that esophageal motility abnormalities might develop from a muscle-predominant form of EoE warrants serious consideration and further investigation.

Activated Eosinophils are Present in Esophageal Muscle in Patients with Achalasia of the Esophagus.

BACKGROUND The aim of this study was to undertake a histological evaluation of the presence of eosinophils in esophageal muscle in patients with achalasia before treatment with peroral endoscopic myotomy (POEM), with clinical follow-up at one year. MATERIAL AND METHODS Before treatment, esophageal biopsies including mucosa and esophageal muscle were obtained from 28 patients with achalasia. Nine patients who had undergone esophagectomy for esophageal carcinoma were included in the control group. The Eckardt Score was used to evaluate the clinical symptoms of achalasia. Histology of routinely processed tissue sections was used to perform eosinophil cell counts (0 to +++), and immunohistochemistry was used to detect expression of eosinophil major basic protein (MBP), eosinophil-derived neurotoxin (EDN), and S100 protein in cases of achalasia (n=28) and controls (n=9). The findings in patients with achalasia were compared before and one year following POEM. RESULTS Esophageal tissue from patients with achalasia showed eosinophils infiltrating into the muscularis externa in 85.7% (24/28), into the muscularis propria in 28.6% (8/28), and in 89% (25/28) there were few remaining myenteric ganglion cells, before POEM. The extent of inflammation was similar in all regions of the esophagus and between subtypes of achalasia. At one year following POEM, the Eckardt Scores between the former eosinophil (0) group and the eosinophil (+++) group were significantly different (Z=3.50, P=0.030). CONCLUSIONS Achalasia of the esophagus was associated with infiltration of the esophageal muscle by activated eosinophils and a decrease in the density of ganglion cells in the myenteric esophageal plexus.

Circulating antimyenteric autoantibodies in Tunisian patients with idiopathic achalasia.

The physiopathology of idiopathic achalasia is still unknown. The description of circulating antimyenteric autoantibodies (CAA), directed against enteric neurons in sera of patients, suggests an autoimmune process. Recent data showed controversies according to the existence and the significance of CAA. The aims of this study were to investigate whether CAA are detected in Tunisian patients with idiopathic achalasia and to look for associated clinical or manometrical factors with CAA positivity. Twenty-seven patients with idiopathic achalasia and 57 healthy controls were prospectively studied. CAA were assessed by indirect immunofluorescence on intestinal monkey tissue sections. Western blot on primate cerebellum protein extract and dot technique with highly purified recombinant neuronal antigens (Hu, Ri, and Yo) were further used to analyze target antigens of CAA. CAA were significantly increased in achalasia patients compared with controls when considering nuclear or cytoplasmic fluorescence patterns. (33% vs. 12%, P = 0.03 and 48% vs. 23%, P = 0.001 respectively). By immunoblot analysis, CAA did not target neuronal antigens, however 52/53 and 49 kDa bands were consistently detected. CAA positivity was not correlated to specific clinical features. The results are along with previous studies demonstrating high CAA prevalence in achalasia patients. When reviewing technical protocols and interpretation criteria, several discrepancies which could explain controversies between studies were noted.

Synopsis of investigations into proposed theories on the etiology of achalasia.

The current state of research into the etiology of achalasia only allows for speculation. To date, several studies have been performed investigating genetic, immune, and infectious disease mechanisms; however, none of these have been conclusive. Further research into this topic is warranted given the severity of the disease, and it may be possible that all of these mechanisms are involved in the pathophysiology of the disease.

The prevalence of autoimmune disease in patients with esophageal achalasia.

Achalasia is a rare disease of the esophagus that has an unknown etiology. Genetic, infectious, and autoimmune mechanisms have each been proposed. Autoimmune diseases often occur in association with one another, either within a single individual or in a family. There have been separate case reports of patients with both achalasia and one or more autoimmune diseases, but no study has yet determined the prevalence of autoimmune diseases in the achalasia population. This paper aims to compare the prevalence of autoimmune disease in patients with esophageal achalasia to the general population. We retrospectively reviewed the charts of 193 achalasia patients who received treatment at Toronto's University Health Network between January 2000 and May 2010 to identify other autoimmune diseases and a number of control conditions. We determined the general population prevalence of autoimmune diseases from published epidemiological studies. The achalasia sample was, on average, 10-15 years older and had slightly more men than the control populations. Compared to the general population, patients with achalasia were 5.4 times more likely to have type I diabetes mellitus (95% confidence interval [CI] 1.5-19), 8.5 times as likely to have hypothyroidism (95% CI 5.0-14), 37 times as likely to have Sjögren's syndrome (95% CI 1.9-205), 43 times as likely to have systemic lupus erythematosus (95% CI 12-154), and 259 times as likely to have uveitis (95% CI 13-1438). Overall, patients with achalasia were 3.6 times more likely to suffer from any autoimmune condition (95% CI 2.5-5.3). Our findings are consistent with the impression that achalasia's etiology has an autoimmune component. Further research is needed to more conclusively define achalasia as an autoimmune disease.

Immune trigeminal sensory neuropathy with esophageal achalasia: improvement with long-term immunotherapy.

We report a patient who developed subacute facial-predominant numbness and anhidrosis, oral incoordination, and esophageal achalasia with resultant cachexia. Great auricular nerve biopsy showed extensive epineurial perivascular inflammatory infiltrates. Sensation, sweating, and swallowing improved with pulse intravenous methylprednisolone given over 5 years. We suggest that the patient's deficits, including achalasia, were due to an immune-mediated sensory and autonomic neuropathy and that, in such cases, pathologic studies of the great auricular nerve may be diagnostically informative.

Lymphocytic Esophagitis With Predominance of CD4 T Cells and Expansion of Th1 Cells Is Associated With Achalasia.

OBJECTIVES: Although histologic features in biopsies suggesting a possibility of achalasia would be helpful diagnostically, such features remain unknown. The goal of this study was to explore the prevalence, histologic features, and immunophenotype of lymphocytic esophagitis (LyE) in achalasia biopsies. METHODS: The study group consisted of 57 patients with achalasia. Controls comprised 52 patients with severe gastroesophageal reflux disease (GERD) and normal esophageal motility. CD4/CD8 immunophenotype of lymphocytes was analyzed by immunohistochemistry. RESULTS: LyE was identified in 30% (17/57) of patients with achalasia and 6% (3/52) of patients with GERD, indicating a strong association with achalasia (odds ratio, 6.94; 95% confidence interval, 1.90-25.38). LyE was focal in 59% (10/17) of the cases and diffuse in 41% (7/17). CD4 T-cell predominance over CD8 T cells was observed in 88% of patients with achalasia and LyE. T helper 1 (Th1) cells, but not T helper 2 cells, were expanded in CD4 T cells; in the absence of evident infection, this was compatible with the role of Th1 cells in organ-specific autoimmunity. CONCLUSIONS: Achalasia should be considered in the differential diagnosis of clinical entities associated with CD4-predominant LyE. Additional studies to explore the significance of Th1 cells in achalasia-associated LyE are warranted.

Lower esophageal sphincter muscle of patients with achalasia exhibits profound mast cell degranulation.

BACKGROUND: Eosinophils and mast cells are key effectors of allergy. When they accumulate in the esophagus, their myoactive, pro-inflammatory, and cytotoxic products potentially could cause achalasia-like motility abnormalities and neuronal degeneration. We hypothesized that there is an allergy-mediated form of achalasia. METHODS: LES muscle samples obtained during Heller myotomy from patients with achalasia or EGJ outflow obstruction (EGJOO) and from organ donor controls were immunostained for tryptase. Eosinophil and mast cell density, and mast cell degranulation were assessed. LES muscle was evaluated by qPCR for genes mediating smooth muscle Ca2+ handling and contraction. KEY RESULTS: There were 13 patients (7 men, median age 59; 10 achalasia, 3 EGJOO) and 7 controls (4 men, median age 42). Eosinophils were infrequent in LES muscle, but mast cells were plentiful. Patients and controls did not differ significantly in LES mast cell density. However, 12 of 13 patients exhibited profound LES mast cell degranulation involving perimysium and myenteric plexus nerves, while only mild degranulation was seen in 2 of 7 controls. Hierarchical clustering analysis of qPCR data revealed two "mototype" LES gene expression patterns, with all type II patients in one mototype, and type I and III patients in the other. CONCLUSIONS & INFERENCES: LES muscle of patients with achalasia or EGJOO exhibits striking mast cell degranulation, and patients with different achalasia manometric phenotypes exhibit different LES patterns of expression for genes mediating Ca2+ handling and muscle contraction. Although these findings are not definitive, they support our hypothesis that achalasia can be allergy-driven.

An immunohistochemical study of the myenteric plexus in idiopathic achalasia.

BACKGROUND: Achalasia is a primary esophageal motor disorder characterized by degenerative changes of the myenteric plexus. The pathophysiologic abnormalities may be the final result of several intermeshing mechanisms, and more than one single factor may cause the motor abnormalities. AIMS: To report our experience in investigating the myenteric plexus of achalasia patients undergoing esophagomyotomy. PATIENTS AND METHODS: Tissue samples from 12 patients undergoing Heller myotomy for achalasia were evaluated and compared with esophageal tissue specimens from 7 controls. Enteric neurons and interstitial cells of Cajal (ICC) were assessed by immunohistochemical methods, and the presence of vasoactive intestinal polypeptide ergic fibers and of CD3 lymphocytes. The possible presence of herpesvirus was also assessed by immunohistochemistry, whereas that of papillomavirus was assessed by in-situ hybridization. RESULTS: Compared with controls, achalasia patients displayed a significant decrease of both enteric neurons and ICC. Immunoreactivity for vasoactive intestinal polypeptide was completely absent in each patient. CD3 staining disclosed myenteric plexitis in 5 (42%) patients; no control patient had plexitis. All patients were completely negative for the presence of both herpes simplex virus and human papillomavirus. CONCLUSIONS: The enteric nervous system of the lower esophageal sphincter area is impaired in patients with "idiopathic achalasia," and the abnormalities involve ICC and neurons in many patients. The triggering factors for these abnormalities are, however, still unknown.

Enhanced reactivity of peripheral blood immune cells to HSV-1 in primary achalasia.

OBJECTIVE: Achalasia is the best characterized oesophageal motor disorder but the etiology is unknown. The pathology is characterized by a decrease in nitric oxide-producing neurons and the presence of an activated T-cell inflammatory infiltrate in the myenteric plexus that are reactive to HSV-1 viral antigens. These findings are not present in normal controls. The current study compared the reactivity of peripheral blood mononuclear cells (PBMCs) between patients with primary achalasia and normal controls to determine if PBMCs of patients exhibit a similar heightened reactivity to the virus. MATERIAL AND METHODS: Whole blood culture experiments were conducted with heparinized peripheral venous blood obtained from 151 patients with primary achalasia and 118 healthy controls. Whole blood was cultured in the presence of ultraviolet inactivated HSV-1 or conditioned cell culture media. Reactivity of mononuclear cells to viral antigens was quantified by measuring expression of the cytokine gene interferon-gamma using Taqman real-time polymerase chain reaction. Data are expressed as cytokine fold change corresponding to ratio of interferon-gamma messenger RNA copies produced in antigen stimulated versus unstimulated cells. RESULTS: The interferon-gamma fold change was higher in cases 61.33 (20.54-217.00) than controls 49.67 (10.05-157.05). Mean fold change difference between cases and controls was 1.66 times (95% confidence interval 1.17-2.34, p = 0.004). CONCLUSIONS: These results indicate that the PBMCs of patients with primary achalasia show an enhanced immune response to HSV-1 antigens. The data suggest that there is persistent stimulation of immune cells by herpes simplex virus type 1 (HSV-1) or HSV-1 like antigen moieties.

Neural autoantibody profile of primary achalasia.

The etiology and pathogenesis of primary achalasia are both unknown. Postulated mechanisms include autoimmune, viral-immune, and central neurodegenerative. The aim of this study is to investigate the serum profile of neural autoantibodies in patients with primary achalasia. Coded sera from 70 patients with primary achalasia and 161 healthy control subjects, matched in sex, age, and smoking habits, were screened for antibodies targeting neuronal, glial, and muscle autoantigens. No specific myenteric neuronal antibody was identified. However, the overall prevalence of neural autoantibodies in patients with primary achalasia was significantly higher than in healthy control subjects (25.7 vs. 4.4%, P < 0.0001). Most noteworthy was the 21.4% frequency of glutamic acid decarboxylase-65 antibody in patients with achalasia (versus 2.5% in control subjects), in the absence of diabetes or companion antibodies predictive of type 1 diabetes. This profile of autoantibodies suggests an autoimmune basis for a subset of primary achalasia.

Triosephosphate isomerase, carbonic anhydrase, and creatinine kinase-brain isoform are possible antigen targets in patients with achalasia.

BACKGROUND: Idiopathic achalasia is an uncommon esophageal motor disorder. The disease involves interaction between inflammatory and autoimmune responses. However, the antigens related to the disease are still unknown. AIM: To identify the possible antigen targets in muscle biopsies from lower esophageal sphincter (LES) of achalasia patients. METHODS: Esophageal biopsies of patients with type I and type II achalasia and esophagogastric junction outflow obstruction (EGJOO) were analyzed. Lower esophageal sphincter muscle biopsy from a Healthy organ Donor (HD) was included as control for two-dimensional gel electrophoresis. Immunoblotting of muscle from LES lysate with sera of type I, type II achalasia, or type III achalasia, sera of EGJOO and sera of healthy subjects (HS) was performed. The target proteins of the serum were identified by mass spectrometry Matrix-assited laser desorption/ionization time-of-flight (MALDI-TOF). KEY RESULTS: The proteomic map of muscle from LES tissue lysates of type I, and type II achalasia, EGJOO, and HD were analyzed and divided into three important regions. We found a difference in the concentration of certain spots. Further, we observed the serum reactivity of type I achalasia and type II achalasia against 45 and 25 kDa bands of type I achalasia tissue. Serum of type III achalasia and EGJOO mainly recognized 25 kDa band. Bands correspond to triosephosphate isomerase (TPI) (25 kDa), carbonic anhydrase (CA) (25 kDa) and creatinine kinase-brain (CKB) isoform (45 kDa). CONCLUSIONS AND INFERENCES: We identify three antigen targets, TPI, CA, and CKB isoform, which are recognized by sera from patients with achalasia.

An increased proportion of inflammatory cells express tumor necrosis factor alpha in idiopathic achalasia of the esophagus.

Achalasia is a motility disorder characterized by the absence of coordinated peristalsis and incomplete relaxation of the lower esophageal sphincter. The etiology remains unclear although dense inflammatory infiltrates within the myenteric plexus have been described. The nature of these infiltrating cells is unknown. The aim of this study was to evaluate the expression of proinflammatory cytokines - namely, tumor necrosis factor alpha and interleukin-2 - in the distal esophageal muscle in patients with achalasia. Lower esophageal sphincter muscle from eight patients undergoing myotomy or esophagectomy for achalasia of the esophagus were obtained at the time of surgery. Control specimens consisted of similar muscle taken from eight patients undergoing operation for cancer or Barrett's esophagus. The expression of tumor necrosis factor alpha and interleukin-2 were assessed by immunohistochemistry. The total number of inflammatory cells within the myenteric plexus were counted in five high power fields. The percentage of infiltrating cells expressing tumor necrosis factor alpha or interleukin-2 was calculated. Clinical data including demographics, preoperative lower esophageal sphincter pressure, duration of symptoms, and dysphagia score (1 = no dysphagia to 5 = dysphagia to saliva) were obtained through electronic medical records. Statistical comparisons between the groups were made using the unpaired t-test, Fisher's exact test, or Mann-Whitney U test, with a two-tailed P-value less than 0.05 being considered significant. The total number of inflammatory cells was found to be similar between the groups. A significantly higher proportion of inflammatory cells expressed tumor necrosis factor alpha in achalasia as compared with controls (22 vs. 11%; P= 0.02). A similar percentage of infiltrating cells expressed interleukin-2 (40 vs. 41%; P= 0.87). Age, gender, preoperative lower esophageal sphincter pressure, or dysphagia score were not correlated to expression of these cytokines. There was, however, a significant inverse correlation between duration of symptoms and the proportion of inflammatory cells expressing tumor necrosis factor alpha in achalasia (P= 0.007). In conclusion, a higher proportion of infiltrating inflammatory cells expressed tumor necrosis factor alpha in achalasia. Furthermore, this proportion appears to be highest early in the disease process. Further studies are required to more clearly delineate the role of tumor necrosis factor alpha in the pathogenesis of this idiopathic disease.

[Achalasia and Guillain-Barré syndrome]. / Achalasie und Guillain-Barré-Syndrom.

A 47-year-old patient with a history of Guillain-Barré syndrome three years prior to evaluation and a severe persisting sensory neuronopathy, complained of dysphagia especially for solid food. He also had severe, intermittent retrosternal pain. Radiological and manometric studies showed the typical features of achalasia. Treatment with botulinum toxin injection improved the dysphagia but not the retrosternal pain. An autoimmune response triggered by an infection is discussed as one possible cause of ganglion cell degeneration within the myenteric plexus in patients with achalasia. Such a hypothesis is supported by our observation showing the simultaneous occurrence of achalasia, sensory neuronopathy, and Guillain-Barré syndrome.

Achalasia and associated esophageal cancer risk: What lessons can we learn from the molecular analysis of Barrett's-associated adenocarcinoma?

Idiopathic achalasia and Barrett's esophagus (BE) are preneoplastic conditions of the esophagus. BE increases the risk of esophageal adenocarcinoma (EAC), while achalasia is associated with both EAC and esophageal squamous cell carcinoma (ESCC). However, while the molecular mechanisms underlying the transformation of esophageal epithelial cells in BE are relatively well characterized, less is known regarding these processes in achalasia. Nevertheless, both conditions are associated with chronic inflammation and BE can occur in achalasia patients, and it is likely that similar processes underlie cancer risk in both diseases. The present review will discuss possible lessons that we can learn from the molecular analysis of BE for the study of achalasia-associated cancer and contrast findings in BE with those in achalasia. First, we will describe cellular fate during development of BE, EAC, and ESCC, and consider the inflammatory status of the epithelial barrier in BE and achalasia in terms of its contribution to carcinogenesis. Next, we will summarize current data on genetic alterations and molecular pathways involved in these processes. Lastly, the plausible role of the microbiota in achalasia-associated carcinogenesis and its contribution to abnormal lower esophageal sphincter (LES) functioning, the maintenance of chronic inflammatory status and influence on the esophageal mucosa through carcinogenic by-products, will be discussed.

Achalasia: virus-induced euthanasia of neurons?

Achalasia, a motor disorder of the esophagus, is characterized by myenteric plexitis leading to neuronal loss. Cytotoxic T cells, isolated from the lower esophageal sphincter of achalasia patients, respond to human herpes virus-1 (HSV-1) with gamma-IFN (and to a lesser extent IL-2) production and clonal proliferation. In addition, HSV-1 DNA was demonstrated in the vast majority of patients, but also in controls. These exciting data suggest that achalasia is an immune-mediated inflammatory disease in which a (latent) infection with HSV-1 leads to persistent immune activation and self-destruction of esophageal neurons, most likely in genetic susceptible subjects only.

T cells in the myenteric plexus of achalasia patients show a skewed TCR repertoire and react to HSV-1 antigens.

OBJECTIVE: The loss of myenteric neurons in the lower esophageal sphincter (LES) characterizes achalasia, an esophageal motor disorder. Because the presence of lymphocytic infiltrates suggests an immuno-mediated mechanism ongoing at the sites of disease, we investigated the T-cell receptor (TCR) repertoire and the ability to recognize human herpes virus type 1 (HSV-1) antigens of LES-infiltrating T lymphocytes in achalasia patients. METHODS: Fifty-nine patients with idiopathic achalasia and 38 heart-beating cadaveric multiorgan donors (controls) were studied. By flow cytometry evaluation and CDR3 length spectratyping analysis, the lymphocytes of 18 patients and 15 controls were analyzed, whereas 41 patients and 23 controls were employed for functional assays. RESULTS: Achalasia patients were characterized by a significantly higher esophagus lymphocytic infiltrate than controls (24.71%+/- 3.11 and 9.54%+/- 1.34, respectively; P < 0.05), mainly represented by CD3+CD8+ T cells. The characterization of TCR beta chain repertoire of CD3+ cells showed the expression of a limited number of TCR beta variable (BV) gene families (from two to five out of 26), with highly restricted spectratypes, suggesting a disease-associated oligoclonal selection of T cells. Furthermore, lymphocytes from achalasia LES specifically responded to exposure to HSV-1 antigens in vitro as showed by increased proliferation and Th-1 type cytokines release. CONCLUSIONS: These data suggest that the oligoclonal lymphocytic infiltrate within the LES of achalasia patients may represent the trace of an immune-inflammatory reaction triggered by HSV-1 antigens and that the Th1-type cytokines released by the activated lymphocytes may contribute to establish the neuronal damage accounting for the clinical features of idiopathic achalasia.

Reduction of interstitial cells of Cajal (ICC) associated with neuronal nitric oxide synthase (n-NOS) in patients with achalasia.

BACKGROUND: The etiology of achalasia is still unknown. The current theories of chronic inflammation leading to autoimmune response with destruction and loss of the inhibitory myenteric ganglion cells enlighten its pathogenesis in a limited way only. Interstitial cells of Cajal (ICC) have been shown to be involved in nitrergic neurotransmission of the lower esophageal sphincter (LES). AIM: To investigate the significance of ICC and neuronal nitric oxide synthase (n-NOS) in esophageal wall tissue of patients undergoing surgery for achalasia. METHODS: In 53 patients with a median age of 45 (6-78) yr undergoing surgery for achalasia, the immunoreactivity of ICC (CD117/c-kit) and n-NOS was assessed. In 42 patients, biopsies were taken from the LES high-pressure zone during Heller myotomy, whereas in 11 patients with end-stage achalasia and a decompensated megaesophagus, the complete esophagus was resected. A semiquantitative analysis was carried out and ICC and n-NOS impairments were classified into four grades. Staining intensity was correlated with preoperative clinical, radiologic, and manometric findings and with long-term postoperative Eckardt score. RESULTS: Grade III/IV ICC reduction (severe reduction to complete loss) was seen in 59.5% of all biopsy specimens of the LES high-pressure zone. Patients with grade III/IV ICC reduction had a significantly longer duration of achalasia symptoms (3 [0-43] yr) than patients with minor to marked (grade I/II) impairment (1 [0-16] yr, P= 0.028). A majority (72.5%) of tissue samples revealed severe reduction to complete loss of n-NOS immunoreactivity. The preoperative Eckardt score was statistically significantly different between patients with grade I/II and those with grade III/IV n-NOS reductions (P= 0.031). CD117 (c-kit) positivity was statistically significantly correlated with n-NOS staining intensity (correlation coefficient r= 0.781, P < 0.0001). CONCLUSION: The present results suggest that in the pathogenesis of achalasia, especially in the development of the LES high-pressure zone, depletion of ICC networks and potential changes in the electrical activity of smooth muscle cells may play a crucial role. The reduction in CD117-positive ICC in a few patients also seemed to be of relevance, even if the cells of Auerbach's plexus were unscathed. The associated reduced NOS release might underlie the profound ICC impairment and could possibly be responsible for the lack of LES relaxation, because of missing inhibitory neurotransmission. It is unclear, however, whether the ICC loss is primarily caused by the accelerated attrition of mature cells or their impaired regeneration.