Interest of the PCR in the diagnosis of herpes simplex virus oesophagitis
Abstract number: P551
Leveque N., Frobert E., Guedec R., Lukaszewiez A., Brixi Benmansour H., Andréoletti L., Brodard V., Diebold M.D.
Objective: Type 1 Herpes Simplex virus is the second infectious aetiological cause of oesophagitis after Candida albicans. HSV1 oesophagitis generally occurs in immunocompromised patient causing odynophagia, retrosternal pain or dysphagia. Its current diagnosis consists in the histological examination of oesophageal lesions sampled during the endoscopy. The potential advantage of the HSV1 specific PCR assay in the diagnosis strategy of the herpetic oesophagitis remains to be assessed.
Patients and Methods: Nineteen biopsies demonstrating an evocative histological aspect of herpetic oesophagitis (presence of plurinuclear squamous cells with vitreous aspect of the nuclei) confirmed by specific immunohistochemical assay using an anti-HSV1 antibody (Dako®), and seventeen biopsies of oesophagitis without any histological proof of herpetic infection were retrospectively selected. After the dewaxing phase, DNA was extracted using DNA Blood kit (Qiagen®) and was then quantified using a spectrophotometer. A qualitative GAPDH DNA PCR was performed in order to check the good quality of the DNA extracts and the absence of PCR inhibitors before testing the samples by "Herpes consensus" kit (Argène®) for a qualitative detection of HSV DNA. For each HSV1 positive sample, HSV1 viral load levels were measured by in-house real time PCR system and expressed by the results were expressed as the number of HSV DNA copies/mg of extracted DNA (Frobert and Al, Antiviral Res., 2008).
Results: Eighteen of the nineteen HSV1 oesophagitis histologically proven were confirmed by the HSV1 specific PCR displaying a number of genomic DNA copies ranging from 11 to 3.42×106 per mg of extracted DNA. Two negative biopsies by histological examination were tested positive by PCR. Their measured viral loads were respectively of 197 and 146 copies/mg of extracted DNA.
Conclusion: These preliminary data indicated a good correlation between the histological and the virological molecular diagnosis of HSV1-induced oesophagitis. The quantification of HSV1-DNA in oesophageal biopsies with a histological positive diagnosis may allow establishing a viral load threshold, estimated here at 1000 copies of genome/mg of extracted DNA, beyond which an aetiological diagnosis of herpetic oesophagitis could be performed even in the absence of histological evidence. However, the threshold of HSV-DNA load levels remains to be assessed in further larger prospective studies.
|Session name:||19th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Helsinki, Finland, 16 - 19 May 2009|
|Back to top|