Red blood cells in cerebrospinal fluid as possible inhibitory factor for enterovirus RT-PCR

Assessment of the Diagnostic Utility of GeneXpert Mycobacterium tuberculosis/Rifampicin (MTB/RIF) Assay in the Suspected Cases of Tuberculous Meningitis

INTRODUCTION

Tuberculous meningitis (TBM) is a manifestation of extrapulmonary tuberculosis (EPTB) caused by Mycobacterium tuberculosis (MTB). The central nervous system is involved in about 1%-2% of all current tuberculosis (TB) cases and about 7%-8% of all EPTB. if not treated early, TBM leads to a high rate of neurological sequelae and mortality.

OBJECTIVE

This study aimed to assess the diagnostic performance of the GeneXpert MTB/rifampicin (RIF) assay in patients with TBM.

METHODS

A total of 100 suspected TBM cases were enrolled from various departments at tertiary care hospital, Bhopal, Madhya Pradesh, India, and classified as definite, possible, or probable TBM. The clinical samples were tested for microbiological and other cerebrospinal fluid (CSF) testing.

RESULTS

Out of 100 cases, 14 (14%) were classified as definite TBM, 15 (15%) were having probable TBM, and 71 (71%) were having possible TBM. Out of a total of 100 participants, all were negative for acid-fast bacilli (AFB) staining. Of the 100 cases, 11 (11%) were positive by mycobacterium growth indicator tube (MGIT) culture, of which only four (36.36%) were positive by GeneXpert MTB/RIF. GeneXpert MTB/RIF detected three (3%) cases that were negative by MGIT culture. Ten (90.9%) of the 11 MGIT-positive culture isolates were found to be RIF sensitive while one (9.1%) was found to be RIF resistant. Three cases tested positive/sensitive by the GeneXpert MTB/RIF but negative by MGIT culture. Six (85%) of the seven GeneXpert MTB/RIF positive cases were RIF sensitive while one (15%) was RIF resistant. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were 36.36% (95% Confidence Interval (CI) (10.93% to 69.21%)), 96.63% (95% CI (90.46% to 99.30%)), 57.14% (95% CI (25.50% to 83.85%)), 92.47% (95% CI (88.70% to 95.06%)) and 90% (95% CI (82.38% to 95.10%)) for GeneXpert MTB/RIF assay, compared with MGIT culture as the reference standard.

CONCLUSION

Our study found that the sensitivity is lower when compared to culture, so using GeneXpert MTB/RIF alone is not recommended. Overall performance of GeneXpert MTB/RIF assay is noteworthy. The GeneXpert MTB/RIF assay is a potentially accepted test for obtaining an earlier diagnosis, and if it tested positive, the treatment should begin immediately. However, culture must be performed in GeneXpert MTB/RIF negative cases.

Comprehensive RNA analysis of CSF reveals a role for CEACAM6 in lung cancer leptomeningeal metastases

Non-small cell lung cancer (NSCLC) metastatic to the brain leptomeninges is rapidly fatal, cannot be biopsied, and cancer cells in the cerebrospinal fluid (CSF) are few; therefore, available tissue samples to develop effective treatments are severely limited. This study aimed to converge single-cell RNA-seq and cell-free RNA (cfRNA) analyses to both diagnose NSCLC leptomeningeal metastases (LM), and to use gene expression profiles to understand progression mechanisms of NSCLC in the brain leptomeninges. NSCLC patients with suspected LM underwent withdrawal of CSF via lumbar puncture. Four cytology-positive CSF samples underwent single-cell capture (n = 197 cells) by microfluidic chip. Using robust principal component analyses, NSCLC LM cell gene expression was compared to immune cells. Massively parallel qPCR (9216 simultaneous reactions) on human CSF cfRNA samples compared the relative gene expression of patients with NSCLC LM (n = 14) to non-tumor controls (n = 7). The NSCLC-associated gene, CEACAM6, underwent in vitro validation in NSCLC cell lines for involvement in pathologic behaviors characteristic of LM. NSCLC LM gene expression revealed by single-cell RNA-seq was also reflected in CSF cfRNA of cytology-positive patients. Tumor-associated cfRNA (e.g., CEACAM6, MUC1) was present in NSCLC LM patients' CSF, but not in controls (CEACAM6 detection sensitivity 88.24% and specificity 100%). Cell migration in NSCLC cell lines was directly proportional to CEACAM6 expression, suggesting a role in disease progression. NSCLC-associated cfRNA is detectable in the CSF of patients with LM, and corresponds to the gene expression profile of NSCLC LM cells. CEACAM6 contributes significantly to NSCLC migration, a hallmark of LM pathophysiology.

Clinical and laboratory detection of nonpolio enteroviruses among different age groups of aseptic meningitis patients in Alexandria, Egypt

BACKGROUND

Viral meningitis is the most common type of meningitis. Worldwide, nonpolio enteroviruses (NPEVs) account for 23%-60% of all cases of viral meningitis. We aimed to detect NPEV among aseptic meningitis cases using reverse transcription-polymerase chain reaction (RT-PCR) and evaluate molecular testing versus clinical and laboratory parameters.

PATIENTS AND METHODS

A 2-year prospective study was conducted for all clinically suspected meningitis patients, who underwent lumbar puncture in Alshatby University and Alexandria Fever Hospitals. Clinical manifestations were reviewed; cytological, microbiological, and biochemical examinations were done. One-step RT-PCR for NPEV was introduced to a routine workflow using Pan-Enterovirus primers.

RESULTS

Out of 2519 patients, 994 (40%) patients were found to have positive cerebrospinal fluid findings, out of which 716 (72%) patients had positive findings of aseptic meningitis. Ninety-four samples were randomly selected and divided across four age groups: neonates, infants, children, and adults. The significant difference was found among adult patients regarding fever, vomiting, headache, signs of meningeal irritation, cranial nerve affection, and focal neurological deficits (p ≤ .05). Seven cases (7.4%) were found to be NPEV positive by RT-PCR. Positive NPEV PCR samples were shown to be statistically significant among neonates (p ≤ .05). The statistical significance was found among the NPEV group regarding the length of hospital stay and duration of IV antibiotic intake while no statistical significance was found with any clinical or laboratory findings.

CONCLUSION

RT-PCR was reliable to identify NPEV while clinical and laboratory findings were inconclusive. NPEV showed low incidence and slight seasonal variation which rings the bell to investigate other causes of viral meningitis throughout the year.

Diagnostic characteristics of Xpert MTB/RIF assay for the diagnosis of tuberculous meningitis and rifampicin resistance in Southern Brazil

BACKGROUND

The timely diagnosis of tuberculous meningitis (TBM) is challenging. Molecular diagnostic tools are necessary for TBM, particularly in low- and middle-income countries.

OBJECTIVES

We aimed to calculate the diagnostics characteristics of Xpert MTB/RIF for the detection of Mycobacterium tuberculosis in the cerebrospinal fluid (CSF) and the frequency of rifampicin (RIF)-resistance in the CSF samples.

METHODS

A total of 313 consecutive CSF samples were studied and categorized into TBM definite, probable, possible, or not TBM cases based on the clinical, laboratory, and imaging data.

RESULTS

For the definite TBM cases (n=7), the sensitivity, specificity, efficiency, and positive likelihood ratio were 100, 97, 97, and 38%, respectively. However, for the TBM definite associated with the probable cases (n=24), the sensitivity decreased to 46%. All CSF samples that were Xpert MTB/RIF-positive were RIF susceptible.

CONCLUSION

Xpert MTB/RIF showed high discriminating value among the microbiology-proven TBM cases, although the values for the probable and possible TBM cases were reduced. Xpert MTB/RIF contributes significantly to the diagnosis of TBM, mainly when coupled with the conventional microbiological tests and clinical algorithms.

Human adenovirus meningoencephalitis: a 3-years' overview

Human adenovirus (HAdV) has been recognized as a significant viral pathogen implicated in neurological diseases, particularly in immunocompromised patients. However, its involvement in meningoencephalitis remains unclear. The aim of this study was to investigate HAdV and other viral co-infections in the cerebrospinal fluid (CSF) of patients suspected of having either meningoencephalitis or encephalitis. A total of 373 CSF samples from patients under clinical suspicion of neurological viral infection were included in this study. HAdV was investigated by conventional or multiplex real-time PCR, for different time periods. The frequency of HAdV central nervous system (CNS) infection was 1.08%, predominating in female patients with a predisposing condition, and presented with HAdV encephalitis. HAdV CNS infection was found to occur during the months of autumn and winter. The frequency of HAdV detected in CSF positive samples increased after the change in the diagnostic method from conventional to multiplex real-time PCR. There were no specific NMRI or EEG characteristics and two CSF samples with HAdV encephalitis had normal CSF WBC count. There were two cases of co-infection with HIV; no other co-infections with enterovirus or herpes family viruses were detected. All patients had good outcome. Although HAdV is rarely observable in CNS infectious syndromes, it must be investigated particularly in immunocompromised patients.

Validation of Mycobacterium tuberculosis real-time polymerase chain reaction for diagnosis of tuberculous meningitis using cerebrospinal fluid samples: a pilot study

Background

Timely diagnosis of tuberculous meningitis (TBM) remains challenging. Molecular diagnostic tools are necessary, particularly in low- and middle-income countries. There is no approved commercial polymerase chain reaction (PCR) assay that can be used to detect Mycobacterium tuberculosis in non-respiratory samples, such as the cerebrospinal fluid (CSF). We aimed to validate the threshold cycle (Ct) cut-off points; calculate the operational characteristics of real-time PCR for detection of M. tuberculosis (MTb qPCR) in the CSF; and the inhibitory affect of CSF red blood cells (RBC) and total proteins on MTb qPCR.

Methods

A total of 334 consecutive participants were enrolled. Based on clinical, laboratory and imaging data, cases of suspected TBM were categorized as definite, probable, possible or not TBM cases. Receiver operating characteristic curve analysis was used to select the best discriminating Ct value.

Results

For TBM cases categorized as definite or probable (n=21), the Ct validated for CSF (≤39.5) improved the diagnostic performance of MTb qPCR on CSF samples. The sensitivity was 29%, specificity was 95%, positive predictive value was 26%, negative predictive value was 95%, efficiency was 90% and positive likelihood was 5.3. The CSF RBC and total protein did not affect the positivity of the MTb qPCR.

Conclusions

These data support the validation of a highly specific but low sensitive MTb qPCR assay for the TBM diagnosis using CSF samples. MTb qPCR contributes significantly to the diagnosis, mainly when associated with conventional microbiology tests and clinical algorithms.

Evaluation of the Luminex ARIES HSV 1&2 Assay and Comparison with the FTD Neuro 9 and In-house Real-Time PCR Assays for Detecting Herpes Simplex Viruses

Background

Human herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are responsible for a plethora of human diseases, of which cutaneous and mucocutaneous infections are the most prevalent. In its most severe form, HSV infection can cause meningitis/encephalitis. We compared the Luminex ARIES HSV 1&2 assay (Luminex Corp., Austin, TX, USA), an automated sample-to-result molecular solution, to two non-automated HSV DNA assays.

Methods

A total of 116 artificial controls were used to determine the analytical performance of the ARIES assay. Controls were prepared by spiking universal transport medium (UTM) and cerebrospinal fluid (CSF) samples from patients who tested negative for HSV by an in-house HSV-1 and -2 DNA assay with reference materials (SeraCare Life Sciences, MA, USA; ZeptoMetrix Corp., MA, USA). Another 117 clinical samples were then used to compare the clinical performance of the ARIES assay with those of an in-house assay and the FTD Neuro 9 assay (Fast Track Diagnostics, Junglinster, Luxembourg).

Results

The analytical sensitivity (95% limit of detection) of the ARIES assay was 318 copies/mL (UTM samples) and 935 copies/mL (CSF samples) for HSV-1 strain 96 and 253 copies/mL (UTM samples) and 821 copies/mL (CSF samples) for HSV-2 strain 09. No cross-reactivity was observed in samples spiked with 14 non-HSV microorganisms. Compared with the reference result (agreement between the in-house and FTD Neuro 9 results), the ARIES assay had overall concordance rates of 98.2% (111/113) and 100% (113/113) for HSV-1 and HSV-2, respectively.

Conclusions

The ARIES assay appears to be an excellent alternative for rapid detection and differentiation of HSV in skin and genital infections, meningitis, and encephalitis.

Expression of TRPM8 in human reactive lymphoid tissues and mature B-cell neoplasms

Transient receptor potential melastatin 8 (TRPM8) is a member of the transient receptor potential superfamily of Ca²⁺ channels. The aim of the present study was to clarify TRPM8 expression in reactive lymphoid tissues and mature B-cell neoplasms. Reactive and neoplastic lymphoid tissues were used to evaluate TRPM8 expression by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). TRPM8⁺ cells were frequently detected in the follicular light zone and marginal zone of reactive lymphoid tissues. Double immunostaining revealed that TRPM8⁺ cells co-expressed cluster of differentiation (CD) 38, CD79a, CD138, interferon regulatory factor 4/melanoma associated antigen (mutated) 1, B cell CLL/lymphoma 6 and transmembrane activator and CAML interactor. TRPM8⁺ neoplastic cells were frequently detected in plasma cell myeloma. The positive band of TRPM8 mRNA was confirmed by RT-PCR in cases of myeloma. The present study is, to the best of our knowledge, the first to demonstrate the expression of TRPM8 in reactive lymphoid tissues and mature B-cell neoplasms, revealing that TRPM8 is frequently expressed in pre-plasmablasts, plasmablasts, plasma cells and mature B-cell lymphomas that are likely to differentiate into plasma cells.