Shedding of HSV-1, HSV-2, CMV, and EBV in the saliva of hematopoietic stem cell transplant recipients at Fundación HOMI - Hospital de la Misericordia, Bogotá, D.C

Oral microbial changes and oral disease management before and after the treatment of hematological malignancies: a narrative review

OBJECTIVES

Patients with hematological malignancies have dynamic changes in oral microbial communities before and after treatment. This narrative review describes the changes in oral microbial composition and diversity, and discusses an oral microbe-oriented strategy for oral disease management.

MATERIALS AND METHODS

A literature search was performed in PubMed/Medline, Web of Science, and Embase for articles published between 1980 and 2022. Any articles on the changes in oral microbial communities in patients with hematological malignancies and their effects on disease progression and prognosis were included.

RESULTS

Oral sample detection and oral microbial sequencing analysis of patients with hematological malignancies showed a correlation between changes in oral microbial composition and diversity and disease progression and prognosis. The possible pathogenic mechanism of oral microbial disorders is the impairment of mucosal barrier function and microbial translocation. Probiotic strategies, antibiotic strategies, and professional oral care strategies targeting the oral microbiota can effectively reduce the risk of oral complications and the grade of severity in patients with hematological malignancies.

CLINICAL RELEVANCE

This review provides dentists and hematologists with a comprehensive understanding of the host-microbe associated with hematologic malignancies and oral disease management advice.

Novel impacts of saliva with regard to oral health

The maintenance of balanced oral homeostasis depends on saliva. A readily available and molecularly rich source of biological fluid, saliva fulfills many functions in the oral cavity, including lubrication, pH buffering, and tooth mineralization. Saliva composition and flow can be modulated by different factors, including circadian rhythm, diet, age, drugs, and disease. Recent events have revealed that saliva plays a central role in the dissemination and detection of the SARS-CoV-2 coronavirus. A working knowledge of saliva function and physiology is essential for dental health professionals.

Oral shedding of CMV and HSV-1 in hematopoietic stem cell transplantation patients

OBJECTIVES

To evaluate the oral shedding of herpesviruses in patients undergoing hematopoietic stem cell transplantation (HSCT) and correlate it with oral mucositis (OM).

METHODS

Saliva samples were collected before the HSCT and on day D + 8. Multiplex Polymerse Chain Reaction (PCR) was performed to detect herpes simplex virus (HSV)-1 and HSV-2, Epstein-Barr virus (EBV), Cytomegalovirus (CMV), Variella-zoster virus (VZV), and human herpesvirus (HHV)-6, HHV-7, and HHV-8. OM was assessed according to WHO criteria.

RESULTS

Thirty one patients were enrolled, in which 20 of 31 (64.5%) were males; median age was 50 (21-70) years; 16 of 31 (51.6%) underwent allo-HSCT; and 15 of 31 (48.4%) underwent auto-HSCT. On D + 8, OM grades III and IV were observed in 8 of 31 (25.8%) patients. In the first salivary collection, EBV was found in 24 of 31 (77.4%), followed by HHV-6 (7/31, 22.6%) and HHV-7 (8/31 25.8%). In the second collection, EBV was found in 24 of 27(89%), followed by HSV-1 (8/27, 30%) and CMV, HHV-6, and HHV-7 (5/27, 18.5%, each one). On D + 8, OM grades II and IV were associated with the presence of HSV-1. HSV-1 was also associated with worsening degrees of OM on D + 15.

CONCLUSION

The presence of HSV-1 and CMV in oral samples was more frequent on day D + 8 after HSCT. HSV-1 detection was associated with severity and worsening of OM. HSV-1 and CMV seem to be associated with oral dysbiosis due to HSCT.

Isolation of the Human Cytomegalovirus from bodily fluids

In vitro studies on the pathogenesis of the human cytomegalovirus (HCMV) are conducted regularly using laboratory adapted strains that lose some characteristics during the adaptation process. Since HCMV is excreted from bodily fluids during infection or reactivation, this work aimed to isolate and culture HCMV from the MRC-5 human cells found in the urine, bronchoalveolar lavage, saliva, and plasma samples of pediatric patients with probable or confirmed infection. The samples were inoculated on cell cultures either for 14 days or until a cytopathic effect (CPE) of 80 % was observed. The cell lysates and supernatants were used to perform successive viral passages. Besides HCMV, the herpes simplex virus was detected from all the saliva samples. Inoculation of the HCMV positive sera induced cell clustering and immediate monolayer damage that restricted their use. One sample of bronchoalveolar lavage induced a CPE after inoculation like that of the HCMV reference strains (Towne and Merlin), which was consequently propagated and titrated. A second viral isolate derived from the urine sample of a patient with congenital infection did not demonstrate a CPE, although presence of the virus had been confirmed using PCR. The viral isolates were examined and found to be negative for adenoviruses or enteroviruses. Despite the evident difficulty encountered for the isolation and harvesting of the HCMV, this work shows that it was possible to obtain a low passage viral strain using a modified shell vial method and inoculation protocol with extended follow-up and confirmation.

Epstein-Barr Virus Epidemiology, Serology, and Genetic Variability of LMP-1 Oncogene Among Healthy Population: An Update

The Epstein-Barr virus (EBV) is a DNA lymphotropic herpesvirus and the causative agent of infectious mononucleosis. EBV is highly prevalent since it affects more than 90% of individuals worldwide and has been linked to several malignancies including PTLDs, which are one of the most common malignancies following transplantation. Among all the EBV genes, most of the recent investigations focused on studying the LMP-1 oncogene because of its high degree of polymorphism and association with tumorigenic activity. There are two main EBV genotypes, Type 1 and 2, distinguished by the differences in the EBNA-2 gene. Further sub genotyping can be characterized by analyzing the LMP-1 gene variation. The virus primarily transmits through oral secretions and persists as a latent infection in human B-cells. However, it can be transmitted through organ transplantations and blood transfusions. In addition, symptoms of EBV infection are not distinguishable from other viral infections, and therefore, it remains questionable whether there is a need to screen for EBV prior to blood transfusion. Although the process of leukoreduction decreases the viral copies present in the leukocytes, it does not eliminate the risk of EBV transmission through blood products. Here, we provide a review of the EBV epidemiology and the genetic variability of the oncogene LMP-1. Then, we underscore the findings of recent EBV seroprevalence and viremia studies among blood donors as a highly prevalent transfusion transmissible oncovirus.

Diagnosis of human herpes virus 1 and 2 (HHV-1 and HHV-2): use of a synthetic standard curve for absolute quantification by real time polymerase chain reaction

The use of quantitative real time polymerase chain reaction (qPCR) for herpesvirus detection has improved the sensitivity and specificity of diagnosis, as it is able to detect shedding episodes in the absence of clinical lesions and diagnose clinical specimens that have low viral loads. With an aim to improve the detection and quantification of herpesvirus by qPCR, synthetic standard curves for human herpesvirus 1 and 2 (HHV-1 and HHV-2) targeting regions gD and gG, respectively, were designed and evaluated. The results show that synthetic curves can replace DNA standard curves in diagnostic herpes qPCR.