Metagenomic analysis and identification of emerging pathogens in blood from healthy donors

Prevalence and investigation of Cytomegalovirus (HCMV) in blood donors from the main blood establishment in Rio de Janeiro/Brazil

BACKGROUND

Human Cytomegalovirus (HCMV) remains a significant cause of morbidity and mortality among pregnant women and immunocompromised patients. HCMV transmission can occur through blood transfusions and typically results in asymptomatic infections in newborns and young individuals or causes symptoms like infectious mononucleosis when symptomatic infections arise. HCMV infection poses a notable risk to transfusion recipients, particularly in vulnerable groups such as premature newborns and immunosuppressed patients. The risk persists even after prophylaxis ends, especially in patients who undergo organ transplantation and receive blood or blood products from a seropositive donor while being seronegative themselves (D+/R-).

MATERIALS AND METHODS

Here, we investigated the serological and molecular prevalence of HCMV among 980 blood donors from the main blood bank in Rio de Janeiro, Brazil, using chemiluminescence and real-time PCR (TaqMan). The data underwent univariate, bivariate, and multivariate statistical analyses using the SPSS program, version 20.0.

RESULTS

The average age of donors was 38.53 years, with a majority being male (53.9 %). The prevalence of cytomegalovirus was 88.5 %, and HCMV DNA was detected in 1.2 % of the samples.

DISCUSSION

Given that there are approximately 100,000 blood donations per year, this prevalence rate is considerably high compared to that in developed countries. These findings underscore the critical need for ongoing surveillance and molecular testing to ensure the safety of blood supplies.

High seroprevalence of CMV among Algerian hemodialysis patients and the general population: Intermediate-risk patients for post-transplant CMV infection

INTRODUCTION

Cytomegalovirus (CMV) is a virus of the herpesviridae family. CMV infection is associated with increased morbidity and mortality in immunocompromised subjects such as hemodialysis patients and transplant recipients. The aim of our study was to determine the serological status of potential kidney recipients and donors in order to assess the risk of post-transplant CMV infection and disease.

PATIENTS AND METHODS

We included 135 and 200 potential kidney transplant donors and recipients, respectively, who were tested for anti-CMV IgM and IgG by chemiluminescence on IMMULITE 2000 XPI®.

RESULTS

The prevalence of anti-CMV IgG was 95.50 % (95 % CI [92.63 %-98.37 %]) in hemodialysis patients and 96.30 % (95 % CI [93.12 %-99.48 %]) in potential kidney donors. The difference between the two groups was not significant (p = 0.721). Anti-CMV IgM were only detected in the sera of 13 hemodialysis patients and 3 healthy subjects. In both groups, the highest rate of anti-CMV IgG positivity was observed in subjects aged over 50 years (100 %), followed by those aged between 18 and 30 years old, with a slightly higher seroprevalence in men than in women.

CONCLUSION

Our results suggest a high prevalence of anti-CMV IgG in potential kidney donors and recipients (D+/R+), who could be classified as an intermediate risk group for post-transplant CMV infection and/or disease.

Full annotation of viral metagenomics in different components from Chinese blood donors using next-generation sequencing

BACKGROUND

Emerging viruses in the blood of healthy/qualified donors can seriously affect transfusion safety. However, the virus characteristics in different healthy blood donors and blood components are still not fully understood.

MATERIALS AND METHODS

Buffy coat (BC) and plasma specimens were collected from 32 whole blood donors, and platelet (PLT) and BC specimens from 30 apheresis platelet donors to explore the full annotation of viral metagenomics in different blood components from Chinese blood donors using next-generation sequencing technology.

RESULTS

The study detected 56 viruses in the plasma and BC groups of whole blood donors. The plasma group had a significantly higher viral abundance and more types of viruses than the BC group. We detected 20 viruses in the PLT and BC groups of apheresis platelet donors. Viral abundance and types were significantly lower in the BC group than in the PLT group. According to β-diversity analysis, the plasma group had a significantly different community structure and composition than the BC group.

DISCUSSION

Viral nucleic acid is found in the blood of healthy Chinese blood donors, with the highest concentration in plasma, which could explain the distribution of viruses in the blood of healthy individuals.

Cerebral toxoplasmosis in HIV-infected patients: a review

Toxoplasma gondii infection in the central nervous system commonly occurs among immunodeficient patients. Its prevalence is high in countries with a high burden of HIV and low coverage of antiretroviral drugs. The brain is one of the predilections for T. gondii infection due to its low inflammatory reaction, and cerebral toxoplasmosis occurs solely due to the reactivation of a latent infection rather than a new infection. Several immune elements have recently been recognized to have an essential role in the immunopathogenesis of cerebral toxoplasmosis. Although real-time isothermal amplification, next-generation sequencing, and enzyme-linked aptamer assays from blood samples have been the recommended diagnostic tools in some in-vivo studies, a combination of clinical symptoms, serology examination, and neuroimaging are still the daily standard for the presumptive diagnosis of cerebral toxoplasmosis and early anti-toxoplasma administration. Clinical trials are needed to find a new therapy that is less likely to affect folate synthesis, have neuroprotective properties, or cure the latent phase of infection. The development of a vaccine is being extensively tested in animals, but its efficacy and safety for humans are still not proven.

Epigenetic Manipulation of Psychiatric Behavioral Disorders Induced by Toxoplasma gondii

Toxoplasma gondii is known to have a complex life cycle and infect almost all kinds of warm-blooded animals around the world. The brain of the host could be persistently infected by cerebral cysts, and a variety of psychiatric disorders such as schizophrenia and suicide have been reported to be related with latent toxoplasmosis. The infected animals showed fear reduction and a tendency to be preyed upon. However, the mechanism of this “parasites manipulation” effects have not been elucidated. Here, we reviewed the recent infection prevalence of toxoplasmosis and the evidence of mental and behavioral disorders induced by T. gondii and discussed the related physiological basis including dopamine dysregulation and gamma-aminobutyric acid (GABA) pathway and the controversial opinion of the necessity for cerebral cysts existence. Based on the recent advances, we speculated that the neuroendocrine programs and neurotransmitter imbalance may play a key role in this process. Simultaneously, studies in the evaluation of the expression pattern of related genes, long noncoding RNAs (lncRNAs), and mRNAs of the host provides a new point for understanding the mechanism of neurotransmitter dysfunction induced by parasite manipulation. Therefore, we summarized the animal models, T. gondii strains, and behavioral tests used in the related epigenetic studies and the responsible epigenetic processes; pinpointed opportunities and challenges in future research including the causality evidence of human psychiatric disorders, the statistical analysis for rodent-infected host to be more vulnerable preyed upon; and identified responsible genes and drug targets through epigenetics.

METAVIROME COMPOSITION OF BRAZILIAN BLOOD DONORS POSITIVE FOR THE ROUTINELY TESTED BLOOD-BORNE INFECTIONS

Viral metagenomics is widely applied to characterize emerging viral pathogens but it can also reveal the virome composition in health and disease. The evaluation of the virome in healthy blood donors can provide important knowledge on possible transfusion threats. Currently, there is still a paucity of information regarding the virome of blood donors who test positive for routinely tested blood-borne infections. Such analysis may reveal co-infections which in turn appear to be crucial for transfusion medicine and for patient management. The aim of this study was to evaluate the metavirome in blood donors who tested positive for routinely tested blood-borne infections, the information for which is important for transfusion medicine and blood donor management. For this purpose, we analyzed 18 blood donations obtained from HIV and HBV-infected blood donors from the Brazilian Amazon (Amapa state) and 11 HIV, HBV, HCV, syphilis and Chagas disease - positive blood donations obtained from blood donors sampled in South Brazil (Rio Grande do Sul state). We additionally included a control group of 20 blood donors obtained from Southeast Brazil (State of São Paulo). Samples were assembled in pools and sequenced by the Illumina NovaSeq 6000 platform. To link a given virus with geographic region or type of blood donor, we performed supervised machine learning classification (fingerprint analysis). The virome of both locations was predominantly composed of commensal viruses. However, in HBV-infected blood donors from the Brazilian Amazon, the Human Pegivirus-1 (HPgV-1) reads were prevailing, while in HIV-infected donors from the same location, the torque teno virus (TTV) reads expressive abundance. In blood donors from South Brazil, the most abundant reads were classified as Human endogenous retrovirus K (HERV-K). Putative emerging viruses like the Human gemykibivirus-2 (HuGkV-2) were exclusively identified in samples from the Brazilian Amazon. The fingerprint analysis demonstrated that the HERV-K, TTV-7, 13, and 15 were statistically important for the infected blood donors, while TTV-5, 12 and 20 were linked to geographic localization. Our study revealed differences in the viral composition among blood donors who tested positive for routinely tested blood-borne infections from two different Brazilian regions and indicated the presence of putative emerging viruses in samples obtained from the Amazon. Together our results show that the presence of specific commensal viruses may be related donor infection status but additional investigations including larger study groups and samples from other Brazilian regions are needed to confirm this hypothesis.

Metagenomic next-generation sequencing to identify pathogens and cancer in lung biopsy tissue

BACKGROUND

Lung biopsy tissue samples can be used for infection detection and cancer diagnosis. Metagenomic next-generation sequencing (mNGS) has the potential to further improve diagnosis.

METHODS

From July 2018 to May 2020, lung biopsy samples of 133 patients with suspected pulmonary infection or abnormal imaging findings were collected and subjected to clinical microbiological testing, Illumina and Nanopore sequencing to identify pathogens. The neural networks were pretrained by extracting features of human reads from 2,095 metagenomic next-generation sequencing results, and the human reads of lung biopsy samples were entered into the validated pipeline to predict the risk of cancer.

FINDINGS

Based on the pathogen-cancer detection pipeline, the Illumina platform showed 77·6% sensitivity and 97·6% specificity compared to the composite reference standard for infection diagnosis. However, the Nanopore platform showed 34·7% sensitivity and 98·7% specificity. mNGS identified more fungi, which was confirmed by subsequent pathological examination. M. tuberculosis complex was weakly detected. For cancer detection, compared with histology, the Illumina platform showed 83·7% sensitivity and 97·6% specificity, diagnosing an additional 36 cancer patients, of whom half had abnormal imaging findings (pulmonary shadow, space-occupying lesions, or nodules).

INTERPRETATION

For the first time, we have established a pipeline to simultaneously detect pathogens and cancer based on Illumina sequencing of lung biopsy tissue. This pipeline efficiently diagnosed cancer in patients with abnormal imaging findings.

FUNDING

This work was supported by the National Key Research and Development Program of China and National Natural Science Foundation of China.