Search for evidence of three viral agents in radicular (periapical) cysts with immunohistochemistry

Keratinizing odontogenic cysts with a spectrum of verrucoid morphology: investigation of a potential role of human papillomavirus

OBJECTIVE

The role of human papillomavirus (HPV) in keratinizing odontogenic cysts (OC) has only rarely been studied. We describe the clinicopathologic findings in a series of OCs that had unusual keratinization patterns and were investigated for a possible HPV etiology.

STUDY DESIGN

Tissue samples from 29 patients with keratinizing OCs were studied for light microscopic features suggestive of HPV infection and by an HPV DNA polymerase chain reaction assay.

RESULTS

The mean age at presentation was 31.1 years; 79.3% of the OCs occurred in the mandible and 46.4% were associated with an impacted tooth. The phenotypic characteristics koilocytes, hypergranulosis, and a verrucous pattern of the cyst-lining epithelium were observed in 69%, 62.1%, and 17.2% of cases, respectively. These histomorphologic features did not, however, correlate with HPV infection.

CONCLUSIONS

HPV does not appear to play a role in keratinizing OCs and is not responsible for the wart-like histomorphologic features that may be seen in these lesions.

Viruses in pulp and periapical inflammation: a review

The presence of viruses in endodontic disease has been studied in the last decade. Their presence is associated with periapical radiolucency and with clinical findings, such as pain. The aim of this review is to analyze the scientific evidence currently published about viruses in pulp and periapical inflammation, and its possible clinical implications. A literature review was carried out using the Medline/Pubmed database. The search was performed, in English and Spanish, using the following keyword combinations: virus AND endodontic; virus AND periapical; virus AND pulpitis; herpesvirus AND periapical; papillomavirus AND periapical. We subsequently selected the most relevant studies, which complied with the search criterion. A total of 21 articles were included, of which 18 detected the present of viruses in the samples. In 3 of the studies, viral presence was not found in the samples studied. The Epstein-Barr virus was found in about 41 % of cases compared to controls, in which it was present in about 2 %. The main association between viruses and endodontic pathosis is between Cytomegalovirus and Epstein-Barr virus; these are found in 114 of the 406 samples of different endodontic pathosis. Some evidence supports that the Epstein-Barr virus is present in a significant number of endodontic diseases, without exact knowledge of their action in these diseases.

Identification of herpesviruses types 1 to 8 and human papillomavirus in acute apical abscesses

INTRODUCTION

It has been suggested that viruses, especially herpesviruses, can play a role in the pathogenesis of marginal and apical periodontitis. This study aimed to detect herpesviruses types 1 to 8, namely herpes simplex virus (HSV-1/2), varicella zoster virus (VZV), Epstein-Barr virus (EBV), human cytomegalovirus (HCMV), human herpesvirus-6 (HHV-6), human herpesvirus-7 (HHV-7), and human herpesvirus-8 (HHV-8) as well as human papillomavirus (HPV) in acute apical abscesses.

METHODS

Twenty-four samples were taken by aspiration of the purulent exudate from acute apical abscesses. DNA extracted from clinical samples served as a template in single or nested polymerase chain reaction (PCR) assays for the detection of the target viruses.

RESULTS

Control PCR reactions with β-globin gene primers revealed that all samples but one had detectable human DNA. Of the 23 abscess samples positive for the β-globin gene, 14 (61%) were positive for at least one of the target human viruses. Thirteen (56.5%) cases had herpesvirus: HHV-8 occurred in 11 (48%), VZV and HHV-6B in two (9%), and HHV-7 and HSV-1/2 in one (4%). EBV and HCMV were not present in any of the examined samples. HPV was detected in three (13%) abscess samples. Viral coinfection was found in five cases, with one case harboring three of the targeted viruses.

CONCLUSION

A large number of abscess samples were positive for at least one target virus. Unexpectedly, HHV-8 was for the first time detected and in a high prevalence. Papillomavirus and other herpesviruses were also found for the first time in endodontic abscesses. Although these findings suggest an association, the specific role of viruses in the pathogenesis of acute apical abscesses awaits further clarification.

Human cytomegalovirus is present in odontogenic cysts

INTRODUCTION

Recent studies suggest that some viruses, including human cytomegalovirus (CMV), may be involved in the pathogenesis of periapical lesions. Since periapical cysts (PCs) represent the next stage in the evolution of periapical granuloma, it seemed reasonable to investigate the presence of CMV in PCs and any possible relationship between its presence and the clinical features of those cysts, as well as to compare the results obtained with corresponding findings in non-inflammatory lesions, like odontogenic keratocysts (OKCs).

METHODS

Samples of 33 PCs and 10 OKCs, obtained at the time of surgery, were used for the detection of CMV DNA by polymerase chain reaction. Presence of the virus was correlated with clinical and radiographic features of the cysts.

RESULTS

CMV was detected in 18 PCs (54.5%) and six OKCs (60%). The presence of CMV was more frequent in cyst samples collected from patients who reported previous episodes of acute infection. The presence of sinus tract was more frequent in CMV-positive cysts and CMV presence was less frequent in a group of cysts showing signs of acute inflammation at the time of sample collection. The mean sizes of CMV-positive and CMV-negative PCs were almost the same; CMV-positive OKCs were slightly larger than CMV-negative OKCs. None of these results proved to be statistically significant.

CONCLUSION

The presence of CMV in the cystic wall is a common feature of both inflammatory and non-inflammatory odontogenic cysts. Although this study has not proved that CMV affects pathogenesis of odontogenic cysts, such a possibility could not be ruled out.

Cytomegalovirus and Epstein-Barr virus active infection in periapical lesions of teeth with intact crowns

Herpesviruses seem to play an important role in the pathogenesis of aggressive periodontitis and may also contribute to periapical pathosis. This study determined the presence of human cytomegalovirus, Epstein-Barr virus, and herpes simplex virus productive infection in five symptomatic periapical lesions of teeth having intact crowns and calcified necrotic pulps. Periapical samples were collected in conjunction with periapical surgery and kept frozen until virological examination. Reverse transcription-polymerase chain reaction was used in herpesviral identification. RNA was isolated from periapical tissue by a guanidinium isothiocyanate-acid phenol procedure. cDNAs were generated from highly conserved regions of the test viruses using a preamplification kit. Sensitivity and validity of the PCR-primers were determined according to established methods. Amplification products were identified using gel electrophoresis. Human cytomegalovirus and Epstein-Barr virus dual transcription was detected in all five periapical lesions studied. Herpes simplex virus transcript was not identified in any lesion. The present data suggest that human cytomegalovirus or Epstein-Barr virus activation participate in the pathogenesis of symptomatic periapical lesions. We hypothesize that periapical active herpesvirus infection impairs local defenses, thereby inducing overgrowth of endodontopathic bacteria and the clinical flare-up of inflammation.

Cytomegalovirus and Epstein-Barr virus DNA transcription in endodontic symptomatic lesions

OBJECTIVES

Productive Herpesviridae infections are implicated in the etio-pathogenesis of aggressive periodontitis. However, virtually nothing is known about a possible role of herpesviruses in pulpal and periapical pathosis. This study employed a cDNA analysis to determine transcription of human cytomegalovirus (HCMV), Epstein-Barr virus (EBV) and herpes simplex virus (HSV) in 14 recalcitrant periapical lesions and in 2 periapical healthy control sites.

METHODS

Periapical samples were collected in conjunction with periapical surgery and kept frozen until virologic examination. RNA was isolated from periapical tissue by using a guanidinium isothiocyanate-acid phenol procedure (TRIZOL LS Reagent, GIBCO BRL, Rockville, MD). cDNAs were amplified by means of oligonucleotides targeting highly conserved regions of the test viruses and the RT-PCR-100 amplification kit (Sigma-Aldrich, St Louis, MO). Standardization of PCR primer sensitivity and validation was carried out according to established methods. Amplification products were identified by agarose gel electrophoresis.

RESULTS

HCMV transcript was detected in 12 of 13 symptomatic and in 1 asymptomatic periapical lesion. EBV transcript was demonstrated in 8 of the 13 symptomatic lesions but not in the asymptomatic periapical lesion. HCMV and EBV dual transcription occurred at higher frequency in periapical lesions showing radiographic bone destruction of 5 mm x 7 mm or larger than in smaller size lesions (P = 0.03; Chi-squared test). No HCMV or EBV transcription was identified in the 2 healthy control sites. HSV transcript was not detected in any study site.

CONCLUSION

The present data suggest that HCMV or EBV infections participate in the pathogenesis of periapical symptomatic lesions. Herpesviruses may produce periapical pathosis as a direct result of viral infection and replication, or as a consequence of virally induced impairment of the host defense and subsequent increased virulence of resident bacterial pathogens.