Seroprevalence of Human Herpes Simplex, Hepatitis B and Epstein-Barr Viruses in Children with Acute Lymphoblastic Leukemia in Southern Iran

Investigating causes and risk factors of pre-chemotherapy viremia in acute lymphoblastic leukemia pediatric patients

BACKGROUND

Leukemia patients are immune-compromised even before starting chemotherapy because the malignant cells invade the bone marrow and destroy WBC precursors. Leukemic patients are more susceptible to infection by a wide range of microorganisms. Viral infections and reactivations are common and may result in severe complications. The aim of this study is to investigate different causes of viremia in ALL pediatric patients as well as the clinical and the laboratory characteristics associated with viral infections.

METHODS

Qualitative real-time PCR was used to detect (polyoma BK, parvo B19 and herpes simplex virus) DNA in the blood of ALL patients and routine hospital records were used to provide the data of hepatitis B & C virus infection.

RESULTS

Polyoma BK was the most common detected virus (51.2%) followed by herpes simplex (30.2%). Viremia by single virus was found in 16 (37.2%) cases, while viremia by multiple viruses was found in 15 (34.8%) cases. The most frequent co-detected viruses were herpes simplex and polyoma BK (11.6%) followed by herpes simplex, parvo B19 and polyoma BK (9.3%).

CONCLUSION

There is a high frequency of viremia by single virus and viremia by multiple viruses at the time of diagnosis of acute lymphoblastic leukemia in pediatric patients admitted to South Egypt Cancer Institute (SECI) compared to studies in other regions. Polyoma BK is the most common detected virus and is mainly associated with lymphopenia. It was also significantly associated with herpes simplex viremia. HCV infection was associated with increased incidence of CNS leukemia.

A three year Seroepidemiological and molecular study of Epstein -Barr virus infection among different age groups with hematological malignancies in a Tertiary care centre of North India ( 2017 -2019)

Purpose

Epstein-Barr virus (EBV) is a member of the family Gamma Herpes viridae and is usually implicated in malignancies like non-Hodgkin's lymphoma, Hodgkin's lymphoma and Burkitt's lymphoma. The present study was designed with the aim to estimate the seroprevalence of EBV in people with hematological malignancies and further follow up was planned by viral load quantitation by Real time PCR in positive cases.

Methods

The current study was planned for a period of three years and a total of 272 serum samples were tested from patients with hematological malignancies namely; HL, NHL, ALL, CLL. Serological testing was performed for the presence of IgM and IgG antibodies against EBV viral capsid antigen. Sera of the patients found positive for IgM was further subjected to viral DNA extraction and Real Time Quantitative PCR was performed by a commercial kit.

Results

The overall seropositivity rate was 89.2% for EBV IgG antibodies and 56.1% for IgM antibodies. The seroprevalence for anti-EBV VCA IgM was found to be highest in the age group <10 years (34.8%) and 11-22 years (20.4%). Of the 109 EBV positive strains by PCR, 27.3% were HL, 35.2% NHL, 24.3% ALL and 13.7% were CLL. The mean viral load was 68.7 × 10⁷ copies/ml DNA.

Conclusion

Our study showed a higher seroprevalence and a definite causal relationship of EBV in lymphoma patients. Young adults showed a higher risk of hematological malignancies as compared to elder population. This study can prove to be an essential guide and aid to the primary care physicians in identifying the possible risk factors and seroprevalence in various age groups of EBV malignancy patients for their proper follow up and referral to higher speciality centres.

Sequence Variations of Epstein-Barr Virus-Encoded Small Noncoding RNA and Latent Membrane Protein 1 in Hematologic Tumors in Northern China

OBJECTIVE

To investigate the relationship between hematologic tumors and Epstein-Barr virus (EBV)-encoded small noncoding RNA (EBER) variations as well as latent membrane protein 1 (LMP1) variations.

METHODS

Patients with leukemia and myelodysplastic syndrome (MDS) were selected as subjects. Genotypes 1/2 and genotypes F/f were analyzed using the nested PCR technology, while EBER and LMP1 subtypes were analyzed by the nested PCR and DNA sequencing.

RESULTS

Type 1 was more dominant than type 2, found in 59 out of 82 (72%) leukemia and in 31 out of 35 (88.6%) MDS, while type F was more prevalent than type f in leukemia (83/85, 97.6%) and MDS (29/31, 93.5%) samples. The distribution of EBV genotypes 1/2 was not significantly different among leukemia, MDS, and healthy donor groups, neither was that of EBV genotypes F/f. EB-6m prototype was the dominant subtype of EBER in leukemia and MDS (73.2% [30/41] and 83.3% [10/12], respectively). The frequency of EB-6m was lower than that of healthy people (96.7%, 89/92), and the difference was significant (p < 0.05). China 1 subtype was the dominant subtype of LMP1 in leukemia and MDS (70% [28/40] and 90% [9/10], respectively), and there was no significant difference in the distribution of LMP1 subtypes among the 3 groups (p > 0.05).

CONCLUSION

The distribution of EBV 1/2, F/f, EBER, and LMP1 subtypes in leukemia and MDS was similar to that in the background population in Northern China, which means that these subtypes may be rather region-restricted but not associated with leukemia and MDS pathogenesis.

Molecular Epidemiology of Epstein-Barr virus (EBV) in Patients with Hematologic Malignancies

Background:

Epstein-Barr virus (EBV) is associated with different malignant diseases, such as Hodgkin lymphoma (HL) and lymphoproliferative disorders. Patients with hematologic malignancies by variable severity could be suspected for the infection with different types of this virus. This preliminary study reported the genotyping and related viral load of Epstein-Barr virus in Iranian patients with hematologic malignancies for estimation of possible factors affecting malignancy.

Methods:

Peripheral blood mononuclear cells (PBMC) of HL (n=20), NHL (n=29), acute lymphocytic leukemia (ALL) (n=18) and chronic lymphocytic leukemia (CLL) (n=12) were obtained. After DNA extraction, a nested-PCR and a conventional-PCR targeting EBNA-2 and EBNA-3C genes were performed. A real-time PCR assay for viral load quantitation carried out. Standard curve analysis used for evaluation of amplification specificity.

Results:

Of 79 included patients, 34 (43%) were EBV positive. There were 23.5% (8/34), 38.2% (13/34), 23.5% (8/34), 14.8% (5/34) in HL, NHL, ALL and CLL groups, respectively. Also, the main genotype was genotype I (91.2%) which it follows by 8.8% (3/34) genotype II. The real-time PCR assay showed the mean viral load ± std. deviation was 2.75×10⁵ ± 1.202×10⁶ copies/μg DNA and the higher viral load was seen in NHL patients.

Conclusion:

This preliminary investigation in Iran shows that the main EBV genotype into our region probably is genotype I (91.2%) which it is similar to others. We could not find any statistically significant association between the virus infection and viral load with any specific disease and patients’ demographic data.

A systematic review and meta-analysis of the association between childhood infections and the risk of childhood acute lymphoblastic leukaemia

Background:

To determine whether childhood infections were associated with the development of childhood acute lymphoblastic leukaemia (ALL).

Methods:

We included studies that assessed any infection in childhood prior to the diagnosis of ALL in children aged 0–19 years compared to children without cancer. The primary analysis synthesised any infection against the odds of ALL, and secondary analyses assessed the frequency, severity, timing of infections, and specific infectious agents against the odds of ALL. Subgroup analyses by data source were investigated.

Results:

In our primary analysis of 12 496 children with ALL and 2 356 288 children without ALL from 38 studies, we found that any infection was not associated with ALL (odds ratio (OR)=1.10, 95% CI: 0.95–1.28). Among studies with laboratory-confirmed infections, the presence of infections increased the odds of ALL by 2.4-fold (OR=2.42, 95% CI: 1.54–3.82). Frequency, severity, and timing of infection were not associated with ALL.

Conclusions:

The hypothesis put forward by Greaves and others about an infectious aetiology are neither confirmed nor refuted and the overall evidence remains inadequate for good judgement. The qualitative difference in the subgroup effects require further study, and future research will need to address the challenges in measuring infectious exposures.

Epstein-Barr virus and regulatory T cells in Egyptian paediatric patients with acute B lymphoblastic leukaemia

OBJECTIVE

Acute B lymphoblastic leukaemia (B-ALL) is the most common type of childhood malignancy worldwide but little is known of its origin. Recently, many studies showed both a high incidence of Epstein-Barr virus (EBV) infection and high levels of CD4⁺CD25⁺Foxp3⁺(Treg cells) in children with B-ALL. In our study, we investigated the possible relationship between EBV infection and the onset of B-ALL, and its relation to expression of CD4⁺, CD25^high+Foxp3+ T regulatory cells.

SUBJECT AND METHODS

We analysed expression and mean fluorescence intensity (MFI) of Treg cells in peripheral blood of 45 children with B-ALL and in 40 apparently healthy children as a control, using flow cytometry. Serum anti-EBV viral capsid antigen (VCA) IgG, anti-EBV nuclear antigen (EBNA) IgG (for latent infection) and anti-EBV VCA IgM (for acute infection) were investigated using ELISA.

RESULTS

Analysis of the Treg cells population in patients and controls revealed that expression of CD4⁺ CD25^high+ T lymphocytes was higher in patients than in controls (mean±SD 15.7±4.1 and 10.61±2.6 in patients and controls, respectively, and MFI of Foxp3 was 30.1±7.1 and 16.7±3.7 in patients and controls, respectively (p<0.001)). There was a high incidence of latent EBV infection in patients (31%) compared with controls (10%) while the incidence of acute infection was 12% in patients and 0% in the control group. To study the role of latent EBV infection in the pathogenesis of acute B-ALL, OR was calculated (OR=4.06, coefficient index 1.2-13.6).

CONCLUSIONS

These findings suggest a possible role for Treg cells and EBV in the pathogenesis of B-ALL. Further studies are needed on the possible mechanisms of tumour genesis related to Treg cells and EBV in children with B-ALL.

Infection and childhood leukemia: review of evidence

OBJECTIVE

To analyze studies that evaluated the role of infections as well as indirect measures of exposure to infection in the risk of childhood leukemia, particularly acute lymphoblastic leukemia.

METHODS

A search in Medline, Lilacs, and SciELO scientific publication databases initially using the descriptors "childhood leukemia" and "infection" and later searching for the words "childhood leukemia" and "maternal infection or disease" or "breastfeeding" or "daycare attendance" or "vaccination" resulted in 62 publications that met the following inclusion criteria: subject aged ≤ 15 years; specific analysis of cases diagnosed with acute lymphoblastic leukemia or total leukemia; exposure assessment of mothers' or infants' to infections (or proxy of infection), and risk of leukemia.

RESULTS

Overall, 23 studies that assessed infections in children support the hypothesis that occurrence of infection during early childhood reduces the risk of leukemia, but there are disagreements within and between studies. The evaluation of exposure to infection by indirect measures showed evidence of reduced risk of leukemia associated mainly with daycare attendance. More than 50.0% of the 16 studies that assessed maternal exposure to infection observed increased risk of leukemia associated with episodes of influenza, pneumonia, chickenpox, herpes zoster, lower genital tract infection, skin disease, sexually transmitted diseases, Epstein-Barr virus, and Helicobacter pylori.

CONCLUSIONS

Although no specific infectious agent has been identified, scientific evidence suggests that exposure to infections has some effect on childhood leukemia etiology.

Childhood cancers: what is a possible role of infectious agents?

The etiology of childhood cancers has been studied for more than 40 years. However, most if not all cancers occurring in children are attributed to unknown causes. This review is focused on the role of infections in cancer development and progression in children. The main infectious agents include human herpesviruses, polyoma viruses, and human papilloma viruses. It is known that infections can lead to carcinogenesis through various mechanisms, and most likely act in addition to genetic and environmental factors. Given the importance of the infectious etiology of childhood cancers, clinical implications and possible prevention strategies are discussed.

Relationship between cervical disease and infection with human papillomavirus types 16 and 18, and herpes simplex virus 1 and 2

Persistent infection with high-risk HPV, particularly Type HPV 16 and 18, is necessary in the development of cervical cancer, but apart from HPV infection, other causative factors of most cervical cancers remain unknown. The aim of this study was to determine the prevalence of HPV 16 and HPV 18 and HSV 1 and HSV 2 in cervical samples, and to assess the role of HSVs in cervical carcinogenesis. Two hundred thirty-three healthy controls and 567 cases (333 of cervicitis, 210 of cervical intraepithelial neoplasia, and 24 of squamous cell carcinoma) in cervical exfoliative cells were tested for HPV 16, HPV 18, HSV 1, and HSV 2 DNA using the triplex real-time polymerase chain reaction method. In contrast to healthy women, positive rate of HPV is related significantly to cervical lesions (odds ratios (ORs) = 4.1, P < 0.01 for cervical intraepithelial neoplasia; ORs = 24.9, P < 0.01 for squamous cell carcinoma), but not cervicitis (ORs = 2.3, P > 0.05). HSV 2 prevalence in cervical intraepithelial neoplasia and squamous cell carcinoma was higher than in healthy women (ORs = 4.9, P < 0.05 for cervical intraepithelial neoplasia; ORs = 4.7, P < 0.05 for squamous cell carcinoma). HSV 2 coinfection with HPV in cervical intraepithelial neoplasia and squamous cell carcinoma was strongly higher than in healthy women (ORs = 34.2, P < 0.01 for cervical intraepithelial neoplasia; ORs = 61.1, P < 0.01 for squamous cell carcinoma). The obtained results indicated that the presence of HPV is associated closely with cervical cancer, and that HSV 2 infection or co-infection with HPV might be involved in cervical cancer development, while HSV 1 might not be involved.

A novel multiplex real-time PCR assay for the detection and quantification of HPV16/18 and HSV1/2 in cervical cancer screening

Infection with human papillomavirus (HPV), particularly HPV16 and HPV18, is the main cause of invasive cervical cancer, although other factors such as herpes simplex virus (HSV) may act in conjunction with HPV in this context. To explore the possibility of developing a system for rapid diagnosis and clinical screening of cervical cancer, we developed a multiplex real-time PCR assay that can simultaneously detect and quantify HPV16/18 and HSV1/2. To evaluate its possibilities and practical uses, 177 samples collected from patients with suspected HPV and HSV infection in exfoliated cervical cells, genital herpes or labial herpes were tested by multiplex real-time PCR and compared with results obtained by DNA sequencing. Each virus was detected over a range from 1.0 × 10(1) to 1.0 × 10(7) copies/reaction. The clinical sensitivity was 100% for HPV16/18 and HSV1/2. The clinical specificity was 97.1% for HPV16, 98.1% for HPV18, 97.0% for HSV1 and 96.0% for HSV2. The kappa value was 0.96 for HPV16, 0.92 for HPV18, 0.94 for HSV1 and 0.93 for HSV2, when DNA sequencing was used as the reference standard. In summary, this novel multiplex real-time PCR allows the rapid and specific detection of HPV16/18 and HSV1/2, as well as coinfection with HPV and HSV, in clinical samples. In the future, this multiplex real-time PCR assay will assist in cervical cancer screening, viral treatment evaluation and epidemiological studies in which high throughput analysis is required.

Incidence of Epstein-Barr virus in pediatric leukemia in the Sudan

BACKGROUND

Results of several studies have suggested a probable etiologic association between Epstein-Barr virus (EBV) and leukemias; therefore, the aim of this study was to investigate the association of EBV in childhood leukemia.

METHODS

A direct isothermal amplification method was developed for detection of the latent membrane protein 1 (LMP1) of EBV in the peripheral blood of 80 patients with leukemia (54 had lymphoid leukemia and 26 had myeloid leukemia) and of 20 hematologically healthy control subjects.

RESULTS

EBV LMP1 gene transcripts were found in 29 (36.3%) of the 80 patients with leukemia but in none of the healthy controls (P < .0001). Of the 29 EBV(+) cases, 23 (79.3%), 5 (17.3%), and 1 (3.4%) were acute lymphoblastic leukemia, acute myeloid leukemia, and chronic myeloid leukemia, respectively.

CONCLUSION

EBV LMP1 gene transcriptional activity was observed in a significant proportion of patients with acute lymphoblastic leukemia. EBV infection in patients with lymphoid leukemia may be a factor involved in the high incidence of pediatric leukemia in the Sudan.