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Experimental Low-Cost Blood Test Can Detect Multiple Cancers, Researchers Say

Test uses a new ultrasensitive immunoassay to detect a known clinical laboratory diagnostic protein biomarker for many common cancers

Researchers from Mass General Brigham, the Dana-Farber Cancer Institute, Harvard University’s Wyss Institute and other institutions around the world have reportedly developed a simple clinical laboratory blood test that can detect a common protein biomarker associated with multiple types of cancer, including colorectal, gastroesophageal, and ovarian cancers.

Best of all, the researchers say the test could provide an inexpensive means of early diagnosis. This assay could also be used to monitor how well patients respond to cancer therapy, according to a news release.

The test, which is still in experimental stages, detects the presence of LINE-1 ORF1p, a protein expressed in many common cancers, as well as high-risk precursors, while having “negligible expression in normal tissues,” the researchers wrote in a paper they published in Cancer Discovery titled, “Ultrasensitive Detection of Circulating LINE-1 ORF1p as a Specific Multicancer Biomarker.”

The protein had previously been identified as a promising biomarker and is readily detectable in tumor tissue, they wrote. However, it is found in extremely low concentrations in blood plasma and is “well below detection limits of conventional clinical laboratory methods,” they noted.

To overcome that obstacle, they employed an ultra-sensitive immunoassay known as a Simoa (Single-Molecule Array), an immunoassay platform for measuring fluid biomarkers.

“We were shocked by how well this test worked in detecting the biomarker’s expression across cancer types,” said lead study author gastroenterologist Martin Taylor, MD, PhD, Instructor in Pathology, Massachusetts General Hospital and Harvard Medical School, in the press release. “It’s created more questions for us to explore and sparked interest among collaborators across many institutions.”

Kathleen Burns, MD, PhD

“We’ve known since the 1980s that transposable elements were active in some cancers, and nearly 10 years ago we reported that ORF1p was a pervasive cancer biomarker, but, until now, we haven’t had the ability to detect it in blood tests,” said pathologist and study co-author Kathleen Burns, MD, PhD (above), Chair of the Department of Pathology at Dana-Farber Cancer Institute and a Professor of Pathology at Harvard Medical School, in a press release. “Having a technology capable of detecting ORF1p in blood opens so many possibilities for clinical applications.” Clinical laboratories may soon have a new blood test to detect multiple types of cancer. (Photo copyright: Dana-Farber Cancer Institute.)

Simoa’s Advantages

In their press release, the researchers described ORF1p as “a hallmark of many cancers, particularly p53-deficient epithelial cancers,” a category that includes lung, breast, prostate, uterine, pancreatic, and head and neck cancers in addition to the cancers noted above.

“Pervasive expression of ORF1p in carcinomas, and the lack of expression in normal tissues, makes ORF1p unlike other protein biomarkers which have normal expression levels,” Taylor said in the press release. “This unique biology makes it highly specific.”

Simoa was developed at the laboratory of study co-author David R. Walt, PhD, the Hansjörg Wyss Professor of Bioinspired Engineering at Harvard Medical School, and Professor of Pathology at Harvard Medical School and Brigham and Women’s Hospital.

The Simoa technology “enables 100- to 1,000-fold improvements in sensitivity over conventional enzyme-linked immunosorbent assay (ELISA) techniques, thus opening the window to measuring proteins at concentrations that have never been detected before in various biological fluids such as plasma or saliva,” according to the Walt Lab website.

Simoa assays take less than two hours to run and require less than $3 in consumables. They are “simple to perform, scalable, and have clinical-grade coefficients of variation,” the researchers wrote.

Study Results

Using the first generation of the ORF1p Simoa assay, the researchers tested blood samples of patients with a variety of cancers along with 406 individuals, regarded as healthy, who served as controls. The test proved to be most effective among patients with colorectal and ovarian cancer, finding detectable levels of ORF1p in 58% of former and 71% of the latter. Detectable levels were found in patients with advanced-stage as well as early-stage disease, the researchers wrote in Cancer Discovery.

Among the 406 healthy controls, the test found detectable levels of ORF1p in only five. However, the control with the highest detectable levels, regarded as healthy when donating blood, “was six months later found to have prostate cancer and 19 months later found to have lymphoma,” the researchers wrote.

They later reengineered the Simoa assay to increase its sensitivity, resulting in improved detection of the protein in blood samples from patients with colorectal, gastroesophageal, ovarian, uterine, and breast cancers.

The researchers also employed the test on samples from 19 patients with gastroesophageal cancer to gauge its utility for monitoring therapeutic response. Although this was a small sample, they found that among 13 patients who had responded to therapy, “circulating ORF1p dropped to undetectable levels at follow-up sampling.”

“More Work to Be Done”

The Simoa assay has limitations, the researchers acknowledged. It doesn’t identify the location of cancers, and it “isn’t successful in identifying all cancers and their subtypes,” the press release stated, adding that the test will likely be used in conjunction with other early-detection approaches. The researchers also said they want to gauge the test’s accuracy in larger cohorts.

“The test is very specific, but it doesn’t tell us enough information to be used in a vacuum,” Walt said in the news release. “It’s exciting to see the early success of this ultrasensitive assessment tool, but there is more work to be done.”

More studies will be needed to valid these findings. That this promising new multi-cancer immunoassay is based on a clinical laboratory blood sample means its less invasive and less painful for patients. It’s a good example of an assay that takes a proteomic approach looking for protein cancer biomarkers rather than the genetic approach looking for molecular DNA/RNA biomarkers of cancer.

—Stephen Beale

Related Information:

Ultrasensitive Blood Test Detects ‘Pan-Cancer’ Biomarker

New Blood Test Could Offer Earlier Detection of Common Deadly Cancers

Ultrasensitive Detection of Circulating LINE-1 ORF1p as a Specific Multicancer Biomarker

Noninvasive and Multicancer Biomarkers: The Promise of LINE-1 Retrotransposons

LINE-1-ORF1p Is a Promising Biomarker for Early Cancer Detection, But More Research Is Needed

‘Pan-Cancer’ Found in Highly Sensitive Blood Test

New American Gastroenterological Association Guidelines for Managing Crohn’s Disease Suggest More Clinical Laboratory Tests and Fewer Colonoscopies

As doctors become more familiar with using biomarkers to monitor Crohn’s disease, clinical laboratories may play a greater role in that process

New evidence-based guidelines from the American Gastroenterological Association (AGA) that call for using specific biomarkers to help manage Crohn’s disease (CD) may decrease the number of invasive procedures patients must undergo and increase the role clinical laboratories play in monitoring the disease.

The new AGA guidelines “recommend using the C-reactive protein (CRP) biomarker in blood and the fecal calprotectin (FCP) biomarker in stool to measure inflammation levels and assess whether Crohn’s disease is in remission or active,” Medical News Today reported.

Crohn’s disease is a chronic inflammatory bowel disease (IBD) that causes inflammation in the digestive tract, primarily in the small and large intestine. The cause of the disease is unknown, but genetics may play a role.

Typically, CD patients must undergo repeated colonoscopies to monitor the disease’s progression or remission. This has long been standard practice. Now, however, “AGA recommends the use of biomarkers in addition to colonoscopy and imaging studies,” according to an AGA news release. This hints at a greater role for clinical laboratories in helping physicians manage patients with Crohn’s Disease.

“Patients’ symptoms do not always match endoscopic findings, so biomarkers are a useful tool to understand and monitor the status of inflammation and guide decision making in patients with Crohn’s disease,” said gastroenterologist Siddharth Singh, MD, Assistant Professor of Medicine at UC San Diego Health and a co-author of the new AGA guidelines.

The AGA’s new guidelines demonstrate how medical science is generating new insights about how multiple biomarkers can be associated for diagnosis/management of a disease in ways that change the standard of care, particularly if it can reduce invasive procedures for the patient by the use of less invasive methods (such as a venous blood draw instead of a colonoscopy).

The AGA published its new guidelines in the journal Gastroenterology titled, “AGA Clinical Practice Guideline on the Role of Biomarkers for the Management of Crohn’s Disease.”

Ashwin Ananthakrishnan MD

“Based on this guideline, biomarkers are no longer considered experimental and should be an integral part of inflammatory bowel disease care,” Ashwin Ananthakrishnan MD (above), a gastroenterologist at Massachusetts General Hospital and co-author of the guidelines, told Medical News Today. Under the new AGA guidelines, clinical laboratories will play a greater role in helping patients monitor their disease. (Photo copyright: Massachusetts General Hospital.)

Patient’s Needs Determine Biomarker vs Endoscopy Monitoring

AGA’s new guidelines could give patients a more comfortable, cost-effective, and possibly more efficient treatment plan to manage their Crohn’s disease. That’s even true if a patient’s Crohn’s disease is in remission.

With these new guidelines, Crohn’s disease patients in remission would only need their biomarkers to be checked every six to 12 months. Patients with active symptoms would need their biomarkers checked roughly every two to four months.

Biomarker testing can be seen as a useful addition to Crohn’s disease care rather than a full replacement of other forms of care. For example, the new AGA guidelines do not fully omit imaging studies and colonoscopies from treatment. Rather, they are recommended in treatment plans based on the patient’s needs.

In their Gastroenterology paper, the AGA authors wrote, “A biomarker-based monitoring strategy involves routine assessment of symptoms and noninvasive biomarkers of inflammation in patients with CD in symptomatic remission to inform ongoing management. In this situation, normalization of biomarkers is an adequate treatment target—asymptomatic patients with normal biomarkers would continue current management without endoscopy, whereas those with elevated biomarkers would undergo endoscopy.”

Fecal Matter Biomarkers

In speaking with Medical News Today on the benefits of using fecal biomarkers to assess a patient’s disease maintenance, gastroenterologist Jesse Stondell, MD, an Associate Clinical Professor at UC Davis Health, said, “If we start a patient on therapy, they’re not responding appropriately, they’re still having a lot of symptoms, we can check that fecal calprotectin test and get a very quick sense of if things are working or not.

“If the calprotectin is normal, it could be reassuring that there may be other reasons for their symptoms, and that the medicine’s working. But if they have symptoms, and a calprotectin is elevated, that’s a signal that we have to worry the medicine is not working. And that we need to change therapy in that patient,” he added.

“This is a win for Crohn’s disease patients,” Ashwin Ananthakrishnan, MD, a gastroenterologist at Massachusetts General Hospital and co-author of the AGA’s new guidelines, told Medical News Today. “Biomarkers are usually easier to obtain, less invasive, more cost-effective than frequent colonoscopies, and can be assessed more frequently for tighter disease control and better long-term outcomes in Crohn’s disease.”

Clinical laboratories should expect these guidelines to increase demand for the processing of blood or fecal matter biomarker testing. As Crohn’s disease monitoring becomes more dependent on biomarker testing, clinical labs will play a critical role in that process.

—Ashley Croce

Related Information:

Fewer Colonoscopies? New Crohn’s Guidelines Emphasize Blood, Stool Tests as Management Tool

AGA Clinical Practice Guideline on the Role of Biomarkers for the Management of Crohn’s Disease

Biomarker- vs Endoscopy-Based Monitoring Strategy in Crohn’s Disease

First Comprehensive Guideline on Using Biomarkers for Monitoring Crohn’s Disease

National Library of Medicine: Crohn’s Disease

Crohn’s Disease Is on the Rise

Healthcare Experts See Links Between COVID-19 and RSV as Tripledemic Pressures Ease on Hospitals and Clinical Laboratories

Some medical experts suggest an ‘immunity gap’ related to COVID-19 mitigation measures, while others point to alternative theories

Surge in fall/winter SARS-CoV-2, influenza (flu), and respiratory syncytial virus (RSV) hospitalizations and ensuing clinical laboratory test referrals—dubbed by some public health experts as a “tripledemic”—appear to have eased in the US, according to stats from the US Centers for Disease Control and Prevention (CDC), Becker’s Hospital Review reported. However, scientists are still left with questions about why the RSV outbreak was so pronounced.

Some healthcare experts point to an “immunity gap” tied to the COVID-19 pandemic, while others suggest alternative theories such as temporary immunodeficiency brought on by COVID-19. In most cases, RSV causes “mild, cold-like symptoms,” but the CDC states it also can cause serious illness, especially for infants, young children, and older adults, leading to emergency room visits, hospitalizations, and an increased demand for clinical laboratory testing.

Pulmonology Advisor reported that the disease typically peaks between December and February, but hospitalizations this season hit their peak in November with numbers far higher than in previous years. In addition to infants and older adults, children between five and 17 years of age were “being hospitalized far in excess of their numbers in previous seasons,” the publication reported.

Asuncion Meijas MD, PhD

“Age by itself is a risk factor for more severe disease, meaning that the younger babies are usually the ones that are sick-sick,” pediatrician Asuncion Mejias, MD, PhD (above), a principal investigator with the Center for Vaccines and Immunity at Nationwide Children’s Hospital in Columbus, Ohio, told MarketWatch. Now, she added, “we are also seeing older kids, probably because they were not exposed to RSV the previous season.” Clinical laboratories in hospitals caught the brunt of those RSV inpatient admissions. (Photo copyright: Nationwide Children’s Hospital.)

Did COVID-19 Cause Immunity Gap and Surge in Respiratory Diseases?

CDC data shows that hospitalization rates linked to RSV have steadily declined since hitting their peak of 5.2 per 100,000 people in mid-November. In contrast, hospitalizations linked to the flu peaked in late November and early December at 8.7 per 100,000. Hospitalizations linked to COVID 19—which still exceed those of the other respiratory diseases—reached a plateau of 9.7 per 100,000 in early December, then saw an uptick later that month before declining in the early part of January, 2023, according to the CDC’s Respiratory Virus Hospitalization Surveillance Network (RESP-NET) dashboard.

Surveillance by the CDC’s National Center for Immunization and Respiratory Diseases (NCIRD) revealed a similar pattern: An early peak in weekly numbers for emergency room visits for RSV, followed by a spike for influenza and steadier numbers for COVID-19.

So, why was the RSV outbreak so severe?

Respiratory diseases tend to hit hardest in winter months when people are more likely to gather indoors. Beyond that, some experts have cited social distancing and masking requirements imposed in 2020 and 2021 to limit the spread of COVID 19. These measures, along with school closures, had the side effect of reducing exposure to influenza and RSV.

“It’s what’s being referred to as this ‘immunity gap’ that people have experienced from not having been exposed to our typical respiratory viruses for the last couple of years, combined with reintroduction to indoor gatherings, indoor venues, indoor school, and day care without any of the mitigation measures that we had in place for the last couple of years,” infectious disease expert Kristin Moffitt, MD, of Boston Children’s Hospital told NPR.

Term ‘Immunity Debt’ Sparks Controversy

Other experts have pushed back against the notion that pandemic-related public health measures are largely to blame for the RSV upsurge. Many have objected to the term “immunity debt,” a term Forbes reported on in November.

“Immunity debt is a made-up term that did not exist until last year,” pediatrician Dave Stukus, MD, wrote on Twitter. Stukus is a Professor of Clinical Pediatrics in the Division of Allergy and Immunology at Nationwide Children’s Hospital in Columbus, Ohio.

An article published by Texas Public Radio (TPR) suggests further grounds for skepticism, stating that “the immunity debt theory doesn’t seem to hold up to scrutiny.”

Pediatrician and infectious disease expert Theresa Barton, MD, of UT Health San Antonio noted that there was also a big RSV surge in summer of 2021.

“That was sort of the great unmasking, and everybody got viral illnesses,” she told TPR. “Now we’re past that. We’ve already been through that. We should have some immunity from that and we’re having it again.”

She added that “the hospital is filled with babies who are less than a year of age who have RSV infection. Those children weren’t locked down in 2020.”

The story also noted that not all Americans complied with social distancing or masking guidelines.

“We’re not seeing [less viral illness in] states in the United States that were less strict compared to states that were stricter during mask mandates and things like that. All the states are being impacted,” Barton told TPR.

Perfect Storm of Demand for Clinical Laboratory Testing

Barton suggested that COVID-19 might have compromised people’s immune systems in ways that made them more susceptible to other respiratory diseases. For example, a study published in Nature Immunology, titled, “Immunological Dysfunction Persists for Eight Months following Initial Mild-to-Moderate SARS-CoV-2 Infection,” found that some patients who survived COVID-19 infection developed post-acute long COVID (LC, aka, COVID syndrome) which lasted longer than 12 weeks. And that “patients with LC had highly activated innate immune cells, lacked naive T and naive B cells, and showed elevated expression of type I IFN (IFN-β) and type III IFN (IFN-λ1) that remained persistently high at eight months after infection.”  

Experts speaking to The Boston Globe said that multiple factors are likely to blame for the severity and early arrival of the RSV outbreak. Pediatric hospitalist and infectious disease specialist Chadi El Saleeby, MD, of Massachusetts General Hospital, said the severity of some cases might be tied to simultaneous infection with multiple viruses.

Clinical laboratories experienced a perfect storm of infectious disease testing demands during this tripledemic. Hopefully, with the arrival of spring and summer, that demand for lab tests will wane and allow for a return to a normal rate of traditional laboratory testing.

Stephen Beale

Related Information:

This Year’s RSV Surge: Bigger, Earlier, and Affecting Older Patients than Previous Seasonal Outbreaks

Experts Explain the ‘Perfect Storm’ of Rampant RSV and Flu

Flu, COVID-19 and RSV are All Trending Down for the First Time in Months

COVID, Flu, RSV Declining in Hospitals As ‘Tripledemic’ Threat Fades

COVID-19 May Be to Blame for the Surge in RSV Illness Among Children. Here’s Why.

Is Immunity Debt or Immunity Theft to Blame for Children’s Respiratory Virus Spike?

Don’t Blame ‘Immunity Debt’ If You Get Sick This Winter

Claims of an Immunity Debt in Children Owe Us Evidence

Some are Blaming ‘Immunity Debt’ for the ‘Tripledemic’—But Experts Disagree

Rapid Tests for COVID, RSV and the Flu are Available in Europe. Why Not in the US?

University of Utah Study Points to Genetic Link for High Risk of Stillbirth

Researchers at the university suggested their findings could lead to new genetic tests that could be offered by medical laboratories

New research conducted at the University of Utah suggests that clinical laboratories may someday be able to deploy genetic tests to indicate whether a couple has a higher-than-average risk of stillbirth.

This is yet another example of how researchers are cracking DNA’s code to understand how certain gene variants may affect the healthcare of offspring. The knowledge produced by this research, as confirmed by additional studies, may lead to genetic markers that medical laboratories can use to diagnose the risk of stillbirth using the parent’s DNA.

The researchers published their study in the British Journal of Obstetrics and Gynaecology (BJOG), titled “Familial Aggregation of Stillbirth: A Pedigree Analysis of a Matched Case–Control Study.”

Jessica Page, MD

“Stillbirth is one of those problems that is so tragic and life-changing,” said study co-author Jessica Page, MD (above). “It is especially frustrating when you don’t have a good answer for why it happens. This knowledge may give us the opportunity to change how we risk stratify people and reduce their risk through prevention.” Should this research be validated, clinical laboratories may soon have new genetics tests to help doctors identify risk for stillbirth. (Photo copyright: Intermountain Healthcare.)

Can Stillbirth be Prevented?

Jessica Page, MD, an assistant professor in the Department of Obstetrics and Gynecology at the University of Utah School of Medical and co-author of the 2022 study, was lead author of a 2018 study that estimated nearly one-fourth of stillbirths are preventable.

“Stillbirth rate reduction has been slow in the US and we think many stillbirths may be potentially preventable,” she said in a university press release. “This is motivating us to look for those genetic factors so we can achieve more dramatic rate reduction.”

According to the press release, the University of Utah researchers found that stillbirth “can be inherited and tends to be passed down through male members of the family. That risk preferentially comes from the mother’s or father’s male relatives—their brothers, fathers, grandfathers, uncles, or male cousins. But the odds of a couple losing a baby to stillbirth are even greater when the condition comes from the father’s side of the family.”

The researchers made this discovery by analyzing data from the Utah Population Database (UPDB), which contains information on eight million people who were born in the state or have other connections there. The database is maintained by the Huntsman Cancer Institute at the University of Utah. It includes genealogical information and health records that allowed the researchers to trace incidence of stillbirths across multiple generations of families.

The researchers examined 9,404 stillbirth cases between 1978 and 2019, along with 18,808 live births that served as controls. They identified 390 multi-generational families with high numbers of stillbirths. Within that group, they looked at incidence of stillbirth among first-, second-, and third-degree relatives of stillborn babies. They then compared those numbers with data from unaffected families.

“We were able to evaluate multigenerational trends in fetal death as well as maternal and paternal lineages to increase our ability to detect a familial aggregation of stillbirth,” said genetic epidemiologist Tsegaselassie Workalemahu, PhD, lead author of the study. “Not many studies have examined inherited genetic risk for stillbirth because of a lack of data. The Utah Population Database allows for a more rigorous evaluation than has been possible in the past.”

Workalemahu described the research as “an important step toward identifying specific genes that increase the risk of stillbirth, which could one day lead to better diagnosis and prevention,” according to the university press release.

One caveat, the press release notes, is that Utah’s population is disproportionately of northern European descent. “Future studies will need to determine whether the trends hold true among people of different races and ethnicities,” it stated.

Call for More Testing

The University of Utah study is part of a larger effort to gain a greater understanding of the causes of stillbirths.

“Researchers and national obstetric groups, including the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine, have called on doctors and hospitals to offer a stillbirth evaluation, a systematic assessment that includes placental exams, genetic testing, and autopsies,” states a recent story from ProPublica.

The story notes that “more than 20,000 pregnancies in the US end in stillbirth,” and in one in three of those cases, the cause is not determined.

Drucilla Roberts, MD, an obstetric and perinatal pathologist at Massachusetts General Hospital (MGH), told ProPublica that at a minimum, “the placenta should definitely be evaluated in every stillbirth.” But citing CDC data, the story notes that this is done in only 65% of stillbirths, and autopsies are performed in less than 20%.

“Experts blame the low rates on several factors,” the story states. “Because an autopsy often is performed in the days following a stillbirth, doctors and nurses have to ask families soon after they receive news of the death if they would like one. Many families can’t process the loss, let alone imagine their baby’s body being cut open. What’s more, many doctors aren’t trained in the advantages of an autopsy, or in communicating with parents about the exam.”

One consequence, ProPublica notes, is that clinicians are ill-equipped to advise patients on how to reduce risk in future pregnancies. The story describes the case of Karen Gibbins, MD, a maternal-fetal medicine specialist and an assistant professor of obstetrics and gynecology at the Oregon Health and Science University (OHSU) in Portland.

An Opportunity for Pathologists

Gibbins’ son was stillborn in 2018. She asked for an autopsy and learned that her son “had a rare disease caused by her antibodies attacking the cells in his liver,” the story states. When she became pregnant again, her doctor prescribed antibody infusions and she later gave birth to a healthy son. “If we had not had that autopsy, my third child would have died as well,” she told ProPublica.

This parent’s comment about the value of the autopsy done after her son’s stillbirth identifies an opportunity for the pathology profession. For several decades, health plans have become ever more reluctant to pay for autopsies. Yet, pathologists know the value that autopsies can provide.

The immediate value comes from revealing useful insights about all the health conditions of the deceased. The long-term value comes from the ability to gather the findings across a large number of autopsies that can contribute to new knowledge about health conditions that physicians use to improve the diagnoses of different health conditions.

Thus, with the publication of this peer-reviewed study about the connection between genetic variations and stillbirth, there is the opportunity for some of the nation’s pathology societies to advocate for funding a pilot program to fund more autopsies of stillborn babies, specifically to add more knowledge about the role of gene mutations as a causative factor in stillbirths.

Stephen Beale

Related Information:

Increased Risk for Stillbirth Passed Down Through Fathers, Male Relatives

Familial Aggregation of Stillbirth: A Pedigree Analysis of a Matched Case–Control Study

Potentially Preventable Stillbirth in a Diverse U.S. Cohort

Raising the Bar on Stillbirth Research

Study Finds Genes Might Play Major Factor in Stillbirths

Risk of Stillbirth Linked to Father’s Family History, Study Suggests

After a Stillbirth, an Autopsy Can Provide Answers. Too Few of Them Are Being Performed

Her Child Was Stillborn at 39 Weeks. She Blames a System That Doesn’t Always Listen to Mothers

Researchers in Boston Find COVID-19 Spike Protein Lingers in Long COVID-19 Patients

Viral reservoir could be behind persistence, says study, which also suggests a blood biomarker could be found for clinical laboratory testing

Microbiologists and virologists working closely with physicians treating long COVID-19 patients will gain new insights in a study that found coronavirus spike protein in COVID-19 patients’ blood up to 12 months after diagnosis. The researchers believe their findings could be used to develop a clinical laboratory biomarker for long COVID-19.

Researchers at Brigham and Women’s Hospital and Massachusetts General Hospital said medical experts are not sure why some people have unwelcome symptoms weeks and months after a positive COVID-19 diagnosis, while others clear the infection without lingering effects.

The scientists believe if this work is validated, clinical laboratories might gain an assay to use in the diagnosis of long COVID-19.

“The diagnosis and management of post-acute sequelae of COVID-19 (PASC) poses an ongoing medical challenge. … Strikingly, we detect SARS-CoV-2 spike antigen in a majority of PASC patients up to 12 months post-diagnosis, suggesting the presence of an active persistent SARS-CoV-2 viral reservoir,” the researchers wrote in their published study, which can be found on the preprint server medRxiv, titled, “Persistent Circulating SARS-CoV-2 Spike Is Associated with Post-Acute COVID-19 Sequelae.”

David Walt, PhD

“The half-life of spike protein in the body is pretty short, so its presence indicates that there must be some kind of active viral reservoir,” said David Walt, PhD (above), Professor of Pathology, Brigham and Women’s Hospital, and lead author of the study that found coronavirus spike protein in long COVID patients. The study findings indicate a potential clinical laboratory biomarker for long COVID-19. (Photo copyright: Brigham and Women’s Hospital.)

Viral Reservoir Possibly Behind Long COVID-19

The study suggests that SARS-CoV-2 finds a home in the body, particularly the gastrointestinal tract, “through viral reservoirs, where it continues to release spike protein and trigger inflammation,” Medical News Today reported.

Lead author of the study David Walt, PhD, Professor of Pathology, Brigham and Women’s Hospital and the Hansjörg Wyss Professor Biologically Inspired Engineering at Harvard Medical School, told The Guardian he “was motivated to carry out the study after earlier research by his colleagues detected genetic material from the COVID virus (viral RNA) in stool samples from children with multisystem inflammatory syndrome (a rare but serious condition that often strikes around four weeks after catching COVID) as well as spike protein and a marker of gut leakiness in their blood.”

Long COVID—also known as long-haul COVID, post-COVID-19, or its technical name, post-acute sequelae of COVID-19 or PASC—can involve health problems continuing weeks, months, or even years after a positive diagnosis, according to the federal Centers for Disease Control and Prevention (CDC).

Symptoms of long COVID, according to the researchers, include:

  • fatigue,
  • loss of smell,
  • memory loss,
  • gastrointestinal distress, and
  • shortness of breath. 

“If someone could somehow get to that viral load and eliminate it, it might lead to resolution of symptoms,” Walt told the Boston Globe, which noted that the researchers may explore a clinical trial involving antiviral drugs for treatment of long COVID-19.

Clues from Earlier Studies on Long COVID-19

Medical conditions that persisted following a COVID-19 infection have been studied for some time. In fact, in an earlier study, Walt and others found children who developed a multisystem inflammation syndrome weeks after being infected by SARS-CoV-2, according to their 2021 paper published in The Journal of Clinical Investigation, titled, “Multisystem Inflammatory Syndrome in Children Is Driven by Zonulin-Dependent Loss of Gut Mucosal Barrier.”

Although these earlier studies provided clues, the cause of PASC remains unclear, the researchers noted. They planned to take a more precise look at PASC biology by using appropriate sampling and patient recruitment.

“Disentangling the complex biology of PASC will rely on the identification of biomarkers that enable classification of patient phenotypes. Here, we analyze plasma samples collected from PASC and COVID-19 patients to determine the levels of SARS-CoV-2 antigens and cytokines and identify a blood biomarker that appears in the majority of PASC patients,” the researchers wrote.

Finding a Marker of a Persistent Infection

The researchers used plasma samples from 63 people with a previous SARS-CoV-2 diagnosis (37 also had PASC), Medical News Today reported. Over a 12-month period, the researchers’ findings included:

  • Detection in 65% of PASC samples of full-length spike, S1 spike, and nucleocapsid throughout the year of testing.
  • Spike detected in 60% of PASC patient samples, and not found in the COVID-19 samples.

In an interview with Scientific American, bioengineer Zoe Swank PhD, post-doctoral researcher, Brigham and Women’s Hospital, and co-author of the study, said, “Our main hypothesis is that the spike protein is not causing the symptoms, but it’s just a marker that is released because you still have infection of some cells with SARS-CoV-2.” 

In that article, Swank shared the scientists’ intent to do more research involving hundreds of samples over the course of the COVID-19 pandemic from many hospitals and people.

COVID-19 Not the Only Virus That Hangs On

Having a long-haul COVID-19 marker is a “game-changer,” according to an infectious disease expert who was not involved in the study.

“There has not so far been a clear, objective marker that is measurable in the blood of people experiencing long COVID-19,” Michael Peluso, MD, Assistant Professor, Medicine, University of California San Francisco, told Scientific American. “I hope their findings will hold up. It really would make a difference for a lot of people if a marker like this could be validated,” he added.

However, COVID-19 is not the only virus that could persist. Ebola also may linger in areas that skirt the immune system, such as the eye interior and central nervous system, according to a World Health Organization fact sheet.

Thus, medical laboratory leaders may want to follow the Brigham and Women’s Hospital research to see if the scientists validate their finding, discover a biomarker for long-haul COVID-19, and pursue a clinical trial for antiviral drugs. Such discoveries could have implications for how diagnostic professionals work with physicians to care for long COVID patients.   

Donna Marie Pocius

Related Information:

Persistent Circulating SARS-CoV-2 Spike Is Associated with Post-Acute COVID-19 Sequelae

Long COVID: “Viral Reservoir” of Spike Protein May Explain Long-Term Symptoms

Are Pockets of COVID in the Gut Causing Long-Term Symptoms?

CDC: COVID-19: Long-Term Effects

Boston Researchers May Have Found Biomarker for Long COVID

Multisystem Inflammatory Syndrome in Children Is Driven by Zonulin-Dependent Loss of Gut Mucosal Barrier

People with Long COVID May Still Have Spike Proteins in Their Blood

WHO: Ebola Virus Disease

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