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

Abstract

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-γ using Taqman^® real-time polymerase chain reaction. Data are expressed as cytokine fold change corresponding to ratio of interferon-γ messenger RNA copies produced in antigen stimulated versus unstimulated cells. Results. The interferon-γ 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.

Key Words::

• Achalasia
• Herpes simplex virus type 1
• immune response
• interferon-γ

Acknowledgements

This work was supported by a fellowship grant from the Research & Development Office, Central Services Agency, Northern Ireland.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.