Single genetic test can identify multiple pathogens and can be used by the UCSF clinical laboratory team to help physicians identify difficult to diagnose diseases
Continuing improvements in gene sequencing technologies and analytical software tools are enabling clinical laboratorians to diagnosis patients who have challenging symptoms. One such example is a new genomic test developed by researchers at University California, San Francisco (UCSF). The single test analyzes both RNA and DNA to detect almost any type of pathogen that may be the cause of specific illnesses.
The test uses a genomic sequencing technique known as metagenomics next-generation sequencing (mNGS). It works by sequencing genetic material found in blood, tissue, or body fluid samples and compares the sequenced data against a broad database of known pathogens to seek a match. Instead of looking for just one pathogen at a time, mNGS analyzes all of the nucleic acids, RNA, and DNA present in a sample simultaneously to detect nearly all pathogens, including viruses, bacteria, fungi, and parasites.
The mNGS test is not intended to replace existing clinical laboratory tests, but to help physicians diagnose an illness in cases where patients are experiencing severe symptoms, and where initial, commonplace tests are ineffective. In such cases, medical professionals require additional information to achieve a proper diagnosis.
“Our technology is deceptively simple,” said Charles Chiu, MD, PhD (above), professor of laboratory medicine and infectious diseases at UCSF and senior author of the studies in a news release. “By replacing multiple tests with a single test, we can take the lengthy guesswork out of diagnosing and treating infections.” The new technology may help physicians diagnose patients who have challenging symptoms and where current clinical laboratory testing is ineffective at identifying specific pathogens. (Photo copyright: University California San Francisco.)
Diagnostic Armamentarium for Physicians
According to an article published by the American Society for Microbiology (ASM) titled, “Metagenomic Next Generation Sequencing: How Does It Work and Is It Coming to Your Clinical Microbiology Lab?” mNGS is “running all nucleic acids in a sample, which may contain mixed populations of microorganisms, and assigning these to their reference genomes to understand which microbes are present and in what proportions. The ability to sequence and identify nucleic acids from multiple different taxa [plural for taxon] for metagenomic analysis makes this a powerful new platform that can simultaneously identify genetic material from entirely different kingdoms of organisms.”
The researchers developed the mNGS test years ago and it has produced promising results, including:
Diagnosing cases of encephalitis in transplant recipients to yellow fever in their organ donors.
Helping to identify the cause of a meningitis outbreak in Mexico among surgical patients.
Detecting a case of leptospirosis in a patient who was in a medically induced coma, which prompted doctors to prescribe penicillin and resulted in the full recovery of the patient.
Identifying the cause of neurological infections such as meningitis and encephalitis. The test successfully diagnosed 86% of neurological infections in more than 4,800 spinal fluid samples.
“Our mNGS test performs better than any other category of test for neurologic infections,” said Charles Chiu, MD, PhD, professor of laboratory medicine and infectious diseases at UCSF and senior author of the two studies, in a UCSF news release. “The results support its use as a critical part of the diagnostic armamentarium for physicians who are working up patients with infectious diseases.”
FDA Breakthrough Device Designation
The UCSF test has not yet been approved by the federal Food and Drug Administration (FDA), but it was granted a “breakthrough device” designation by the agency. This classification authorizes labs to use the test as a valid diagnosis method due to its potential ability to benefit patients.
Chiu told NBC News that the test costs about $3,000 per sample and fewer than 10 labs routinely use it due to several issues.
“Traditionally, it’s been used as a test of last resort, but that’s primarily because of issues involving, for instance, the cost of the test, the fact that it’s only available in specialized reference laboratories, and it also is quite laborious to run,” he said.
This type of lab testing is not feasible for most hospitals as it is costly and complicated, and because physicians may need assistance from clinical laboratory personnel who have the appropriate expertise to properly read test results.
“This just is not something that a clinical lab will be doing until somebody commercially puts it in a box with an easy button,” Susan Butler-Wu, PhD, associate professor of clinical pathology at the University of Southern California (USC), told NBC News. “It’s not a one-stop shop. It just can be helpful as an additional tool.”
Although the technology has some limitations, Chiu says the research performed by his team “raises the possibility that we perhaps should be considering running this test earlier” in symptomatic patients. He hopes the test will be used on a widespread basis in hospitals to diagnose various illnesses in the future.
“We need to get the cost down and we need to get the turnaround times down as well,” he told NBC.
Definitive Tool for Pathogen Detection
To increase access to the technology, Chiu and his colleagues founded Delve Bio, which is now the exclusive provider of the mNGS tool created at UCSF. In December, the company announced the commercial launch of Delve Detect, a metagenomic test for infectious diseases. According to its website, Delve Detect “offers genomic testing of cerebrospinal fluid (CSF) for more than 68,000 pathogens, with 48-hour turnaround time and metagenomics experts readily available to discuss results.”
“These findings support including mNGS as a core tool in the clinical workup for CNS [central nervous system] infections,” said Steve Miller, MD, PhD, UCSF volunteer clinical professor, laboratory medicine, and chief medical officer of Delve Bio in the UCSF news release. “mNGS offers the single most unbiased, complete and definitive tool for pathogen detection. Thanks to its ability to quickly diagnose an infection, mNGS helps guide management decisions and treatment for patients with meningitis and encephalitis, potentially reducing healthcare costs down the line.”
This mNGS test may prove to have the potential to greatly improve medical care for some infections and possibly expedite the detection of new viral threats. It is probable that clinical laboratories will soon be learning about and performing more tests of this nature in the future.
Findings may lead to new clinical laboratory biomarkers for predicting risk of developing MS and other autoimmune diseases
Scientists continue to find new clinical laboratory biomarkers to detect—and even predict risk of developing—specific chronic diseases. Now, in a recent study conducted at the University of California San Francisco (UCSF), researchers identified antibodies that develop in about 10% of Multiple Sclerosis (MS) patients’ years before the onset of symptoms. The researchers reported that of those who have these antibodies, 100% develop MS. Thus, this discovery could lead to new blood tests for screening MS patients and new ways to treat it and other autoimmune diseases as well.
The UCSF researchers determined that, “in about 10% [of] cases of multiple sclerosis, the body begins producing a distinctive set of antibodies against its own proteins years before symptoms emerge,” Yahoo Life reported, adding that “when [the patients] are tested at the time of their first disease flare, the antibodies show up in both their blood and cerebrospinal fluid.”
That MS is so challenging to diagnose in the first place makes this discovery even more profound. And knowing that 100% of a subset of MS patients who have these antibodies will develop MS makes the UCSF study findings quite important.
“This could be a useful tool to help triage and diagnose patients with otherwise nonspecific neurological symptoms and prioritize them for closer surveillance and possible treatment,” Colin Zamecnik, PhD, scientist and research fellow at UCSF, told Yahoo Life.
“From the largest cohort of blood samples on Earth, we obtained blood samples from MS patients years before their symptoms began and profiled antibodies against self-autoantibodies that are associated with multiple sclerosis diagnosis,” Colin Zamecnik, PhD (above), scientist and research fellow at UCSF, told Yahoo Life. “We found the first molecular marker of MS that appears up to five years before diagnosis in their blood.” These findings could lead to new clinical laboratory tests that determine risk for developing MS and other autoimmune diseases. (Photo copyright: LinkedIn.)
UCSF Study Details
According to the MS International Foundation Atlas of MS, there are currently about 2.9 million people living with MS worldwide, with about one million of them in the US. The disease is typically diagnosed in individuals 20 to 50 years old, mostly targeting those of Northern European descent, Yahoo Life reported.
To complete their study, the UCSF scientists used the Department of Defense Serum Repository (DoDSR), which is comprised of more than 10 million individuals, the researchers noted in their Nature Medicine paper.
From that group, the scientists identified 250 individuals who developed MS, spanning a period of five years prior to showing symptoms through one year after their symptoms first appeared, Medical News Today reported. These people were compared to 250 other individuals in the DoDSR who have no MS diagnosis but who all had similar serum collection dates, ages, race and ethnicities, and sex.
“The researchers validated the serum results against serum and cerebrospinal fluid results from an incident MS cohort at the University of California, San Francisco (ORIGINS) that enrolled patients at clinical onset. They used data from 103 patients from the UCSF ORIGINS study,” according to Medical News Today. “They carried out molecular profiling of autoantibodies and neuronal damage in samples from the 500 participants, measuring serum neurofilament light chain measurement (sNfL) to detect damage to nerve cells.
“The researchers tested the antibody patterns of both MS and control participants using whole-human proteomeseroreactivity which can detect autoimmune reactions in the serum and CSF,” Medical News Today noted.
Many who developed MS had an immunogenicity cluster (IC) of antibodies that “remained stable over time” and was not found in the control samples. The higher levels of sNfL in those with MS were discovered years prior to the first flare up, “indicating that damage to nerve cells begins a long time before symptom onset,” Medical News Today added.
“This signature is a starting point for further immunological characterization of this MS patient subset and may be clinically useful as an antigen-specific biomarker for high-risk patients with clinically or radiologically isolated neuroinflammatory syndromes,” the UCSF scientists wrote in Nature Medicine.
“We believe it’s possible that these patients are exhibiting cross reactive response to a prior infection, which agrees with much current work in the literature around multiple sclerosis disease progression,” Zamecnik told Yahoo Life.
It “validates and adds to prior evidence of neuro-axonal injury occurring in patients during the MS preclinical phase,” the researchers told Medical News Today.
Implications of UCSF’s Study
UCSF’s discovery is a prime example of technology that could soon work its way into clinical use once additional studies and research are done to support the findings.
The researchers believe their research could lead to a simple blood test for detecting MS years in advance and discussed how this could “give birth to new treatments and disease management opportunities,” Neuroscience News reported.
Current MS diagnosis requires a battery of tests, such as lumbar punctures for testing cerebrospinal fluid, magnetic resonance imaging (MRI) scans of the spinal cord and brain, and “tests to measure speed and accuracy of nervous system responses,” Medical News Today noted.
“Given its specificity for MS both before and after diagnosis, an autoantibody serology test against the MS1c peptides could be implemented in a surveillance setting for patients with high probability of developing MS, or crucially at a first clinically isolated neurologic episode,” the UCSF researchers told Medical News Today.
The UCSF discovery is another example of nascent technology that could work its way into clinical use after more research and studies. Microbiologists, clinical laboratories, and physicians tasked with diagnosing MS and other autoimmune diseases should find the novel biomarkers the researchers identified most interesting, as well as what changed with science and technology that enabled researchers to identify these biomarkers for development.
