Human herpesvirus-8 infection in Tunisian adult acute leukemia patients.

Background: Human herpesvirus 8 (HHV-8) has been linked to the development of Kaposi's sarcoma (KS)and multiple other hematologic malignant disorders. However, the role of HHV-8 in acute leukemia patients is unknown. Objectives: The objective of this study was to determine the prevalence of HHV-8 in Tunisian acute leukemia patients and in healthy blood donors. Methods: An indirect immunofluorescence test was used to detect the presence of anti-HHV8 antibodies. Nested PCR was used for the detection of HHV-8 DNAemia in samples of plasma. Results: The seroprevalence of HHV-8 was significantly higher in acute leukemia patients (21,4% ,15/70) than in healthy blood donors (7,1%, 5/70), (p= 0.02). Gender, type of disease, status of disease, prior blood transfusion, and outcome were not associated with HHV-8 seroprevalence. However, among acute leukemia patients, HHV-8 seroprevalence was statistically associated with older age > 40 years of age, (p=0.002). HHV-8 DNAemia was detected (1,4%) in only one patient of acute myeloid leukemia (AML) and none of the healthy blood donors. Conclusions: The seroprevalence of HHV-8 infection in Tunisian adult acute leukemia patients was three times as high compared to healthy blood donors, suggesting that patients with acute leukemia might be at increased risk of HHV-8 infection.

Pooling Nasopharyngeal Swab Specimens to Improve Testing Capacity for SARS-CoV-2 by Real-Time RT-PCR.

BACKGROUND: The detection of SARS-CoV-2 using qRT-PCR with the pooling of samples can reduce workload and costs especially when the prevalence rate of COVID-19 in a population is low. To analyse the effect of pooling samples on the sensitivity of RT-qPCR for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection, we compared the cycle threshold (Ct) values of pools of 5 and 10 that tested positive with Ct values of individual samples that tested positive in that pool. Twenty positive nasopharyngeal (NP) specimens with low to high viral load were selected and pooled individually with four and nine negative NP. RESULTS: In NP specimens, the sensitivity of pools of 5 and 10 were 90 and 85%, compared to individual sample testing, respectively. The RT-qPCR sensitivity of pools of 5 and 10 against individual testing were not significantly different (p > 0.05). Detection of positive samples with low Ct values (< 36) was consistently achieved in pools of 5 and 10. However, there were higher false negatives when samples with high ct values (> 36) were pooled and tested. The mean Ct values obtained with the 5-sample pooled testing exceeded individual sample testing by 1.85 ± 1.09 cycles, while Ct values obtained with the 10-sample pooling exceeded individual sample testing by 3.4 ± 1.65 cycles. CONCLUSIONS: In a low prevalence setting, testing capacity can be increased by pooling 5 or 10 samples, but the risk of additional false negatives needs to be considered.

Cytomegalovirus Glycoprotein Polymorphisms and Increasing Viral Load in Non-Transplant Patients with Hematological Malignancies Undergoing Chemotherapy: A Prospective Observational Study.

INTRODUCTION: Cytomegalovirus (CMV) predisposes to several clinical complications and is a major cause of morbidity and mortality in immunocompromised patients, including patients with hematological malignancies (HM). The present study was carried out to determine the distribution of CMV glycoprotein B, N, and O (gB, gN, and gO) genotypes and their potential effect on its viral load and on clinical outcomes in a cohort of Tunisian non-hematopoietic stem cell transplant (HSCT) patients with HM undergoing chemotherapy. METHODS: CMV viral load was evaluated by real-time quantitative PCR. The gB, gN, and gO genotypes of the CMV strains were analyzed by multiplex nested PCR and sequencing. RESULTS: This prospective study involved 60 clinical isolates obtained from 60 non-HSCT patients with HM undergoing chemotherapy. Mixed CMV gB, gN, and gO genotypes were the predominant glycoprotein genotypes in 31%, 41.4%, and 46.4% of patients, respectively. Mixed gB genotypes were associated with higher initial levels of CMV load (p = 0.001), increased rate of fever (0.025), and co-infection with other herpesviruses (HHVs) (p = 0.024) more frequently than in single gB genotype. Mixed gN genotypes were more associated with severe lymphopenia (ALC < 500/µL) (p = 0.01) and increased risk of death (p = 0.042) than single gN genotype. Single gO2b genotype had also a more unfavorable outcome (p = 0.009) than the other single gO genotype. Mixed gO genotypes were associated with female gender (p = 0.015), acute leukemia disease (p = 0.036), initial high level of CMV viral load (at least 1000 copies/mL) (p = 0.029), skin rash (p = 0.01) more frequently than in single gO genotype. The gO1a/gN3b linkage was associated with an increased initial viral load (p = 0.012). CONCLUSION: Infection with mixed CMV genotypes was common and multiple gB, gN, and gO genotypes were associated with clinical manifestation and higher viral load.

Co-infections of human herpesviruses (CMV, HHV-6, HHV-7 and EBV) in non-transplant acute leukemia patients undergoing chemotherapy.

BACKGROUND: Human herpesviruses (HHVs) remain latent after primary infection and can be reactivated in response to immunosuppression and chemotherapy. Little is known about their incidence, potential relationships, risk factors and clinical impact in non-transplant leukemia patients. This study investigated prospectively incidence, risk factors, clinical impact and possible association of HHVs-(1-7) infections in patients with newly diagnosed acute leukemia. METHODS: Study design involved longitudinal sampling before chemotherapy and in different phases of chemotherapy: post-induction, post-remission, and post-salvage during 2016-2018. A total of 734 plasma samples from 95 patients were analyzed by a qualitative, multiplex PCR for HHVs detection and a quantitative real-time PCR was used for cytomegalovirus (CMV) quantification. HHVs-(1-6) IgG and IgM antibodies were tested using immunoassays. Risk factors were analyzed by binary logistic regression and relationships between viruses were analyzed using the Chi-square or Fisher's exact test as appropriate. RESULTS: The overall seroprevalences of HHV-(1-6) IgG were high (> 80%). At least one herpes viral agent was detected in 60 patients (63.3%). CMV was the most commonly detected virus in the different phases of chemotherapy (19.4%), followed by HHV-6 (9.7%), HHV-7 (5.2%) and EBV (2.7%). HSV-1/2 and VZV DNA were not detected. Twenty-seven patients (28.4%) had more than one virus detected in the follow-up, with 23 who were co-infected. CMV/HHV-6 was the most frequent co-infection (69.5%, 16/23). HHV-6 infection (p = 0.008) was identified as a risk factor for CMV infection while salvage treatment (p = 0.04) and CMV infection (p = 0.007) were found to be independent risk factors for HHV-6 infection. CMV co-infection was associated with severe lymphopenia with an absolute lymphocyte count (ALC) (< 500/µL) (p = 0.009), rash (p = 0.011), pneumonia (p = 0.016) and opportunistic infections [bacteremia, p < 0.001 and invasive fungal infection, (p = 0.024)] more frequently than CMV mono-viral infections. CONCLUSIONS: Our data suggest that co-infection with HHVs, especially CMV and HHV-6, may contribute to the development of serious clinical manifestations with profound lymphopenia, pneumonia rash and increased risk for bacterial and fungal co-infections. These findings may suggest the synergistic effect of HHVs associated infection.

Observational study of vaccine effectiveness 20 years after the introduction of universal hepatitis B vaccination in Tunisia.

OBJECTIVES: The objectives of this study were to estimate the national prevalence of hepatitis B infection in Tunisia using data from a nationwide survey, to compare results with those obtained in 1996 survey and to evaluate the impact of vaccination twenty years after its introduction. METHODS: A National household-based cross sectional and serological survey was undertaken in 2015 from randomly selected districts using two-stage sampling. Data collection was performed using standardized and pretested questionnaires and collected blood samples were tested for markers of hepatitis B virus infection. RESULTS: National point prevalence of Hepatitis B surface antigen was 1.7% (95% CI [1.6-1.9%]). The highest prevalence was found in the Center and South regions with respectively 2.3% (95% CI [2.0-2.7%]) and 2.2% (95% CI [1.8-2.8%]). Vaccine effectiveness (VE) was 88.6% (95% CI [81.5-93.0%]) and was higher among population aged less than 20 years 96.1% (95% CI [70.1-99.5%]) than those aged more than 20 years 59.0% (95% CI [32.0-75.3%]). VE was 85.6% (95% CI [65.8-93.9%]) is hyper-endemic areas and 89.1% (95% CI [80.3-94.0%]) in meso-endemic and hypo-endemic areas. CONCLUSIONS: The prevalence of Hepatitis B surface antigen decreased compared to previous estimations and classify Tunisia as a low endemic country as result to the introduction of vaccination since 1995.