Comparing the application of mNGS after combined pneumonia in hematologic patients receiving hematopoietic stem cell transplantation and chemotherapy: A retrospective analysis

Torque Teno Virus: Lights and Shades

Torque Teno Virus (TTV) is a highly prevalent non-pathogenic DNA virus whose plasma levels may be related to the host's immune status. TTV gained attention about 25 years ago, but its replication is not fully understood, nor is its relationship with the host's immune system. Despite this lack of knowledge, TTV is currently being investigated as a functional biomarker of the immune system in patients with immunological damage and inflammatory diseases. Monitoring TTV viral load over time may help clinicians in making therapeutic decisions regarding immunosuppression as well as the likelihood of infectious complications. This review summarizes what we do and do not know about this enigmatic virus.

Diagnostic value and clinical use of metagenomic next-generation sequencing for invasive pulmonary aspergillosis

OBJECTIVE

To compare the diagnostic efficacy of metagenomic next generation sequencing (mNGS) with traditional fungal culture, (1,3)-β-D glucan (G) test, and galactomannan (GM) test in diagnosing invasive pulmonary aspergillosis (IPA) and to explore the advantages and disadvantages of mNGS for IPA diagnosis.

METHODS

A retrospective analysis was conducted on 136 patients admitted to the Department of Respiratory and Critical Care Medicine of Affiliated Hospital of Putian University from March 2018 to March 2020. Among them, there were 66 patients with IPA (IPA group) and 70 without (non-IPA group). Baseline data, inflammatory factors, cytokines, and specimens such as bronchoalveolar lavage fluid (BALF) and blood of these patients were collected. Fungal culture test, G test, GM test and mNGS test were performed. Information included for analysis encompassed patients' host factors, clinical features, chest scanning images, laboratory test results, and treatment outcome.

RESULTS

There was no statistical difference in the baseline data or inflammatory factors in patients between the IPA group and the non-IPA group. Further analysis showed that the sensitivity of mNGS in diagnosing IPA was 53.03%, which was higher than that of traditional fungal culture test (27.27%), G test (31.82%), and GM test (34.85%). Notably, when combining fungal culture, G test, GM test, and mNGS, the sensitivity increased to 69.70%, with a specificity of 97.14%. The sensitivity of the combined test was higher than that any of the tests alone for diagnosing IPA.

CONCLUSION

mNGS test offers superior diagnostic performance for IPA in comparison to traditional tests, particularly for testing samples like bronchoalveolar lavage fluid and bronchial secretions. The test result remains valuable even after aspergillus treatment. In addition, the use of mNGS in conjunction with other traditional tests, such as fungal culture test, G test, and GM test, can enhance the diagnostic efficacy for IPA.

Clinical and diagnostic values of metagenomic next-generation sequencing for infection in hematology patients: a systematic review and meta-analysis

OBJECTIVES

This meta-analysis focused on systematically assessing the clinical value of mNGS for infection in hematology patients.

METHODS

We searched for studies that assessed the clinical value of mNGS for infection in hematology patients published in Embase, PubMed, Cochrane Library, Web of Science, and CNKI from inception to August 30, 2023. We compared the detection positive rate of pathogen for mNGS and conventional microbiological tests (CMTs). The diagnostic metrics, antibiotic adjustment rate and treatment effective rate were combined.

RESULTS

Twenty-two studies with 2325 patients were included. The positive rate of mNGS was higher than that of CMT (blood: 71.64% vs. 24.82%, P < 0.001; BALF: 89.86% vs. 20.78%, P < 0.001; mixed specimens: 82.02% vs. 28.12%, P < 0.001). The pooled sensitivity and specificity were 87% (95%CI: 81-91%) and 59% (95%CI: 43-72%), respectively. The reference standard/neutropenia and research type/reference standard may be sources of heterogeneity in sensitivity and specificity, respectively. The pooled antibiotic adjustment rate according to mNGS was 49.6% (95% CI: 41.8-57.4%), and the pooled effective rate was 80.9% (95% CI: 62.4-99.3%).

CONCLUSION

mNGS has high positive detection rates in hematology patients. mNGS can guide clinical antibiotic adjustments and improve prognosis, especially in China.

Application of plasma metagenomic next-generation sequencing improves prognosis in hematology patients with neutropenia or hematopoietic stem cell transplantation for infection

Introduction

Metagenomic next-generation sequencing (mNGS) is a novel technique for detecting pathogens. This retrospective study evaluated the diagnostic value of mNGS using plasma for infections in hematology patients and its impact on clinical treatment and prognosis in different subgroups of hematology patients.

Methods

A total of 153 hematology patients with suspected infection who underwent mNGS using plasma were enrolled in the study. Their clinical histories, conventional microbiological test (CMT) results, mNGS results, treatment and prognosis were retrospectively analyzed.

Results

In 153 plasma samples, mNGS yielded a higher positivity rate than CMT (total: 88.24% vs. 40.52%, P<0.001; bacteria: 35.95% vs. 21.57%, P < 0.01; virus: 69.93% vs. 21.57%, P<0.001; fungi: 20.26% vs. 7.84%, P<0.01). mNGS had a higher positivity rate for bacteria and fungi in the neutropenia group than in the non-neutropenia group (bacteria: 48.61% vs. 24.69%, P<0.01; fungi: 27.78% vs. 13.58%, P<0.05). mNGS demonstrated a greater advantage in the group of patients with hematopoietic stem cell transplantation (HSCT). Both the 3-day and 7-day efficacy rates in the HSCT group were higher than those in the non-HSCT group (3-day: 82.22% vs. 58.65%, P < 0.01; 7-day: 88.89% vs. 67.31%, P < 0.01), and the 28-day mortality rate was lower in the HSCT group than in the non-HSCT group (6.67% vs. 38.89%, P < 0.000). The neutropenia group achieved similar efficacy and mortality rates to the non-neutropenia group (7-day efficiency rate: 76.39% vs. 71.43%, P > 0.05; mortality rate: 29.17% vs. 29.63%, P > 0.05) with more aggressive antibiotic adjustments (45.83% vs. 22.22%, P < 0.01).

Conclusion

mNGS can detect more microorganisms with higher positive rates, especially in patients with neutropenia. mNGS had better clinical value in patients with hematopoietic stem cell transplantation (HSCT) or neutropenia, which had a positive effect on treatment and prognosis.

BALF metagenomic next-generation sequencing analysis in hematological malignancy patients with suspected pulmonary infection: clinical significance of negative results

Purpose

Metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid (BALF) is gradually being used in hematological malignancy (HM) patients with suspected pulmonary infections. However, negative results are common and the clinical value and interpretation of such results in this patient population require further analysis.

Methods

Retrospective analysis of 112 HM patients with suspected pulmonary infection who underwent BALF mNGS and conventional microbiological tests. The final diagnosis, imaging findings, laboratory results and treatment regimen of 29 mNGS-negative patients were mainly analyzed.

Results

A total of 83 mNGS positive and 29 negative patients (15 true-negatives and 14 false-negatives) were included in the study. Compared to false-negative patients, true-negative patients showed more thickening of interlobular septa on imaging (p < 0.05); fewer true-negative patients had acute respiratory symptoms such as coughing or sputum production (p < 0.05) clinically; On the aspect of etiology, drug-related interstitial pneumonia (6/15, 40%) was the most common type of lung lesion in true-negative patients; on the aspect of pathogenesis, false-negative patients mainly missed atypical pathogens such as fungi and tuberculosis (8/14, 57.1%). Regarding treatment, delayed anti-infection treatment occurred after pathogen missing in mNGS false-negative patients, with the longest median time delay observed for anti-tuberculosis therapy (13 days), followed by antifungal therapy (7 days), and antibacterial therapy (1.5 days); the delay in anti-tuberculosis therapy was significantly longer than that in antibacterial therapy (p < 0.05).

Conclusion

For HMs patients with imaging showing thickening of interlobular septa and no obvious acute respiratory symptoms, lung lesions are more likely caused by drug treatment or the underlying disease, so caution should be exercised when performing BALF mNGS. If BALF mNGS is negative but infection is still suspected, atypical pathogenic infections should be considered.