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Several recent developments in Lyme disease treatment and diagnosis may pave the way forward for combating disease that persists following missed or delayed diagnoses or remains following standard treatment. These include combination therapy to address “persister” bacteria and diagnostic tests that test directly for the pathogen and/or indirectly test for host response, according to experts who presented at a 2-day National Academies of Science, Engineering and Medicine workshop on infection-associated chronic illnesses.
Research has shown that 60% of people who are infected and not treated during the early or early disseminated stages of Lyme disease go on to develop late Lyme arthritis, said John Aucott, MD, director of the Johns Hopkins Lyme Disease Clinical Research Center in Baltimore. And in the real world, there’s an additional category of patients: Those who are misdiagnosed and develop infection-related persistent symptoms – such as fatigue, brain fog/cognitive dysfunction, and musculoskeletal problems – that don’t match the “textbook schematic” involving late Lyme arthritis and late neurologic disease.
Moreover, of patients who are treated with protocols recommended by the Infectious Diseases Society of America (IDSA), about 15% go on to develop persistent symptoms at 6 months – again, symptoms that don’t match textbook manifestations and do match symptoms of other infection-associated chronic illnesses. As a “research construct,” this has been coined posttreatment Lyme disease (PTLD), he said at the workshop, “Toward a Common Research Agenda in Infection-Associated Chronic Illnesses.”
(On a practical level, it is hard to know clinically who has early disseminated disease unless they have multiple erythema migrans rashes or neurologic or cardiac involvement, he said after the meeting.)
All this points to the need for tests that are sensitive and specific for diagnosis at all stages of infection and disease, he said in a talk on diagnostics. Currently available tests – those that fit into the widely used two-tiered enzyme-linked immunosorbent assay, Western Blot serology testing – have significant limitations in sensitivity and specificity, including for acute infection when the body has not generated enough antibodies, yet treatment is most likely to succeed.
Move toward combination therapy research
Lyme disease is most commonly treated with doxycycline, and that’s problematic because the antibiotic is a microstatic whose efficacy relies on immune clearance of static bacteria, said Monica E. Embers, PhD, director of vector-borne disease at the Tulane National Primate Research Center and associate professor of immunology at Tulane University, New Orleans.
“But we know that Borrelia burgdorferi has the capability to evade the host immune response in almost every way possible. Persistence is the norm in an immunocompetent host ... [and] dormant bacteria/persisters are more tolerant of microstatic antibiotics,” she said.
Other considerations for antibiotic efficacy include the fact that B. burgdorferi survives for many months inside ticks without nutrient replenishment or replication, “so dormancy is part of their life cycle,” she said. Moreover, the bacteria can be found deep in connective tissues and joints.
The efficacy of accepted regimens of antibiotic treatment has been “a very contentious issue,” she said, noting that guidelines from the International Lyme and Associated Diseases Society “leave open the possibility for antibiotic retreatment when a chronic infection is judged to be a possible cause [of ongoing symptoms].”
The development of persister B. burgdorferi in the presence of antibiotics has been well studied in vitro, which has limitations, Dr. Embers said. But her group specializes in animal models and has shown persistence of antimicrobial-tolerant B. burgdorferi in tick-inoculated rhesus macaques 8-9 months after treatment with oral doxycycline.
“We [also] saw persistence of mild-moderate inflammation in the brain, peripheral nerves, spinal cord, joints and skeletal muscle, and in the heart,” Dr. Embers said, who coauthored a 2022 review of B. burgdorferi antimicrobial-tolerant persistence in Lyme disease and PTLD.
Her work has also shown that ceftriaxone, which is recommended by IDSA for patients with clinically evident neurological and/or cardiac involvement, does not clear infection in mice. “In general, single drugs have not been capable of clearing the infection, yet combinations show promise,” she said.
Dr. Embers has combed large drug libraries looking for combinations of antibiotics that employ different mechanisms of action in hopes of eliminating persister spirochetes. Certain combinations have shown promise in mice and have been tested in her rhesus macaque model; data analyses are underway.
Other research teams, such as that of Ying Zhang, MD, PhD, at Johns Hopkins, have similarly been screening combinations of antibiotics and other compounds, identifying candidates for further testing.
During a question and answer period, Dr. Embers said her team is also investigating the pathophysiology and long-term effects of tick-borne coinfections, including Bartonella, and is pursuing a hypothesis that infection with Borrelia allows Bartonella to cause more extensive disease and persist longer. “I think Lyme is at the core because of its ability to evade and suppress the immune response so effectively.”
Diagnostic possibilities, biomarkers for PTLD
Direct diagnostic tests for microbial nucleic acid and proteins “are promising alternatives for indirect serologic tests,” Dr. Aucott said. For instance, in addition to polymerase chain reaction tests, which “are making advances,” it may be possible to target the B. burgdorferi peptidoglycan for antigen detection.
Researchers have shown that peptidoglycan, a component of the B. burgdorferi cell envelope, is a persistent antigen in the synovial fluid of patients with Lyme arthritis who have been treated with oral and intravenous antibiotics, and that it likely contributes to inflammation.
“Maybe the infection is gone but parts of the bacteria are still there that are driving inflammation,” said Dr. Aucott, also associate professor of medicine at John Hopkins.
Researchers have also been looking at the host response to B. burgdorferi – including cytokines, chemokines, and autoantibiodies – to identify biomarkers for PTLD and to identify patients during posttreatment follow-up who are at increased risk of developing PTLD, with the hope of someday intervening. Persistently high levels of interleukin-23, CCL19, and interferon-alpha have each been associated in different studies with persistent symptoms after treatment, Dr. Aucott said.
In addition, metabolomics research is showing that patients with PTLD have metabolic fingerprints that are different from those who return to good health after treatment, and it may be possible to identify an epigenetic signature for Lyme disease. A project sponsored by the Defense Advanced Research Projects Agency called ECHO (Epigenetic Characterization and Observation) aims to identify epigenetic signatures of exposures to various threats, including B. burgdorferi.
“At the very proximal end of [indirectly testing for host response], there are modifications of the DNA that can occur in response to infectious insults ... and that changed DNA changes RNA expression and protein synthesis,” Dr. Aucott explained. DARPA’s project is “exciting because their goal [at DARPA] is to have a diagnostic test quickly as a result of this epigenetics work.”
Imaging research is also fast offering diagnostic opportunities, Dr. Aucott said. Levels of microglial activation on brain PET imaging have been found to correlate with PTLD, and a study at Johns Hopkins of multimodal neuroimaging with functional MRI and diffusion tensor imaging has shown distinct changes to white matter activation within the frontal lobe of patients with PTLD, compared with controls.
The NASEM workshop did not collect or require disclosures of its participants.
Several recent developments in Lyme disease treatment and diagnosis may pave the way forward for combating disease that persists following missed or delayed diagnoses or remains following standard treatment. These include combination therapy to address “persister” bacteria and diagnostic tests that test directly for the pathogen and/or indirectly test for host response, according to experts who presented at a 2-day National Academies of Science, Engineering and Medicine workshop on infection-associated chronic illnesses.
Research has shown that 60% of people who are infected and not treated during the early or early disseminated stages of Lyme disease go on to develop late Lyme arthritis, said John Aucott, MD, director of the Johns Hopkins Lyme Disease Clinical Research Center in Baltimore. And in the real world, there’s an additional category of patients: Those who are misdiagnosed and develop infection-related persistent symptoms – such as fatigue, brain fog/cognitive dysfunction, and musculoskeletal problems – that don’t match the “textbook schematic” involving late Lyme arthritis and late neurologic disease.
Moreover, of patients who are treated with protocols recommended by the Infectious Diseases Society of America (IDSA), about 15% go on to develop persistent symptoms at 6 months – again, symptoms that don’t match textbook manifestations and do match symptoms of other infection-associated chronic illnesses. As a “research construct,” this has been coined posttreatment Lyme disease (PTLD), he said at the workshop, “Toward a Common Research Agenda in Infection-Associated Chronic Illnesses.”
(On a practical level, it is hard to know clinically who has early disseminated disease unless they have multiple erythema migrans rashes or neurologic or cardiac involvement, he said after the meeting.)
All this points to the need for tests that are sensitive and specific for diagnosis at all stages of infection and disease, he said in a talk on diagnostics. Currently available tests – those that fit into the widely used two-tiered enzyme-linked immunosorbent assay, Western Blot serology testing – have significant limitations in sensitivity and specificity, including for acute infection when the body has not generated enough antibodies, yet treatment is most likely to succeed.
Move toward combination therapy research
Lyme disease is most commonly treated with doxycycline, and that’s problematic because the antibiotic is a microstatic whose efficacy relies on immune clearance of static bacteria, said Monica E. Embers, PhD, director of vector-borne disease at the Tulane National Primate Research Center and associate professor of immunology at Tulane University, New Orleans.
“But we know that Borrelia burgdorferi has the capability to evade the host immune response in almost every way possible. Persistence is the norm in an immunocompetent host ... [and] dormant bacteria/persisters are more tolerant of microstatic antibiotics,” she said.
Other considerations for antibiotic efficacy include the fact that B. burgdorferi survives for many months inside ticks without nutrient replenishment or replication, “so dormancy is part of their life cycle,” she said. Moreover, the bacteria can be found deep in connective tissues and joints.
The efficacy of accepted regimens of antibiotic treatment has been “a very contentious issue,” she said, noting that guidelines from the International Lyme and Associated Diseases Society “leave open the possibility for antibiotic retreatment when a chronic infection is judged to be a possible cause [of ongoing symptoms].”
The development of persister B. burgdorferi in the presence of antibiotics has been well studied in vitro, which has limitations, Dr. Embers said. But her group specializes in animal models and has shown persistence of antimicrobial-tolerant B. burgdorferi in tick-inoculated rhesus macaques 8-9 months after treatment with oral doxycycline.
“We [also] saw persistence of mild-moderate inflammation in the brain, peripheral nerves, spinal cord, joints and skeletal muscle, and in the heart,” Dr. Embers said, who coauthored a 2022 review of B. burgdorferi antimicrobial-tolerant persistence in Lyme disease and PTLD.
Her work has also shown that ceftriaxone, which is recommended by IDSA for patients with clinically evident neurological and/or cardiac involvement, does not clear infection in mice. “In general, single drugs have not been capable of clearing the infection, yet combinations show promise,” she said.
Dr. Embers has combed large drug libraries looking for combinations of antibiotics that employ different mechanisms of action in hopes of eliminating persister spirochetes. Certain combinations have shown promise in mice and have been tested in her rhesus macaque model; data analyses are underway.
Other research teams, such as that of Ying Zhang, MD, PhD, at Johns Hopkins, have similarly been screening combinations of antibiotics and other compounds, identifying candidates for further testing.
During a question and answer period, Dr. Embers said her team is also investigating the pathophysiology and long-term effects of tick-borne coinfections, including Bartonella, and is pursuing a hypothesis that infection with Borrelia allows Bartonella to cause more extensive disease and persist longer. “I think Lyme is at the core because of its ability to evade and suppress the immune response so effectively.”
Diagnostic possibilities, biomarkers for PTLD
Direct diagnostic tests for microbial nucleic acid and proteins “are promising alternatives for indirect serologic tests,” Dr. Aucott said. For instance, in addition to polymerase chain reaction tests, which “are making advances,” it may be possible to target the B. burgdorferi peptidoglycan for antigen detection.
Researchers have shown that peptidoglycan, a component of the B. burgdorferi cell envelope, is a persistent antigen in the synovial fluid of patients with Lyme arthritis who have been treated with oral and intravenous antibiotics, and that it likely contributes to inflammation.
“Maybe the infection is gone but parts of the bacteria are still there that are driving inflammation,” said Dr. Aucott, also associate professor of medicine at John Hopkins.
Researchers have also been looking at the host response to B. burgdorferi – including cytokines, chemokines, and autoantibiodies – to identify biomarkers for PTLD and to identify patients during posttreatment follow-up who are at increased risk of developing PTLD, with the hope of someday intervening. Persistently high levels of interleukin-23, CCL19, and interferon-alpha have each been associated in different studies with persistent symptoms after treatment, Dr. Aucott said.
In addition, metabolomics research is showing that patients with PTLD have metabolic fingerprints that are different from those who return to good health after treatment, and it may be possible to identify an epigenetic signature for Lyme disease. A project sponsored by the Defense Advanced Research Projects Agency called ECHO (Epigenetic Characterization and Observation) aims to identify epigenetic signatures of exposures to various threats, including B. burgdorferi.
“At the very proximal end of [indirectly testing for host response], there are modifications of the DNA that can occur in response to infectious insults ... and that changed DNA changes RNA expression and protein synthesis,” Dr. Aucott explained. DARPA’s project is “exciting because their goal [at DARPA] is to have a diagnostic test quickly as a result of this epigenetics work.”
Imaging research is also fast offering diagnostic opportunities, Dr. Aucott said. Levels of microglial activation on brain PET imaging have been found to correlate with PTLD, and a study at Johns Hopkins of multimodal neuroimaging with functional MRI and diffusion tensor imaging has shown distinct changes to white matter activation within the frontal lobe of patients with PTLD, compared with controls.
The NASEM workshop did not collect or require disclosures of its participants.
Several recent developments in Lyme disease treatment and diagnosis may pave the way forward for combating disease that persists following missed or delayed diagnoses or remains following standard treatment. These include combination therapy to address “persister” bacteria and diagnostic tests that test directly for the pathogen and/or indirectly test for host response, according to experts who presented at a 2-day National Academies of Science, Engineering and Medicine workshop on infection-associated chronic illnesses.
Research has shown that 60% of people who are infected and not treated during the early or early disseminated stages of Lyme disease go on to develop late Lyme arthritis, said John Aucott, MD, director of the Johns Hopkins Lyme Disease Clinical Research Center in Baltimore. And in the real world, there’s an additional category of patients: Those who are misdiagnosed and develop infection-related persistent symptoms – such as fatigue, brain fog/cognitive dysfunction, and musculoskeletal problems – that don’t match the “textbook schematic” involving late Lyme arthritis and late neurologic disease.
Moreover, of patients who are treated with protocols recommended by the Infectious Diseases Society of America (IDSA), about 15% go on to develop persistent symptoms at 6 months – again, symptoms that don’t match textbook manifestations and do match symptoms of other infection-associated chronic illnesses. As a “research construct,” this has been coined posttreatment Lyme disease (PTLD), he said at the workshop, “Toward a Common Research Agenda in Infection-Associated Chronic Illnesses.”
(On a practical level, it is hard to know clinically who has early disseminated disease unless they have multiple erythema migrans rashes or neurologic or cardiac involvement, he said after the meeting.)
All this points to the need for tests that are sensitive and specific for diagnosis at all stages of infection and disease, he said in a talk on diagnostics. Currently available tests – those that fit into the widely used two-tiered enzyme-linked immunosorbent assay, Western Blot serology testing – have significant limitations in sensitivity and specificity, including for acute infection when the body has not generated enough antibodies, yet treatment is most likely to succeed.
Move toward combination therapy research
Lyme disease is most commonly treated with doxycycline, and that’s problematic because the antibiotic is a microstatic whose efficacy relies on immune clearance of static bacteria, said Monica E. Embers, PhD, director of vector-borne disease at the Tulane National Primate Research Center and associate professor of immunology at Tulane University, New Orleans.
“But we know that Borrelia burgdorferi has the capability to evade the host immune response in almost every way possible. Persistence is the norm in an immunocompetent host ... [and] dormant bacteria/persisters are more tolerant of microstatic antibiotics,” she said.
Other considerations for antibiotic efficacy include the fact that B. burgdorferi survives for many months inside ticks without nutrient replenishment or replication, “so dormancy is part of their life cycle,” she said. Moreover, the bacteria can be found deep in connective tissues and joints.
The efficacy of accepted regimens of antibiotic treatment has been “a very contentious issue,” she said, noting that guidelines from the International Lyme and Associated Diseases Society “leave open the possibility for antibiotic retreatment when a chronic infection is judged to be a possible cause [of ongoing symptoms].”
The development of persister B. burgdorferi in the presence of antibiotics has been well studied in vitro, which has limitations, Dr. Embers said. But her group specializes in animal models and has shown persistence of antimicrobial-tolerant B. burgdorferi in tick-inoculated rhesus macaques 8-9 months after treatment with oral doxycycline.
“We [also] saw persistence of mild-moderate inflammation in the brain, peripheral nerves, spinal cord, joints and skeletal muscle, and in the heart,” Dr. Embers said, who coauthored a 2022 review of B. burgdorferi antimicrobial-tolerant persistence in Lyme disease and PTLD.
Her work has also shown that ceftriaxone, which is recommended by IDSA for patients with clinically evident neurological and/or cardiac involvement, does not clear infection in mice. “In general, single drugs have not been capable of clearing the infection, yet combinations show promise,” she said.
Dr. Embers has combed large drug libraries looking for combinations of antibiotics that employ different mechanisms of action in hopes of eliminating persister spirochetes. Certain combinations have shown promise in mice and have been tested in her rhesus macaque model; data analyses are underway.
Other research teams, such as that of Ying Zhang, MD, PhD, at Johns Hopkins, have similarly been screening combinations of antibiotics and other compounds, identifying candidates for further testing.
During a question and answer period, Dr. Embers said her team is also investigating the pathophysiology and long-term effects of tick-borne coinfections, including Bartonella, and is pursuing a hypothesis that infection with Borrelia allows Bartonella to cause more extensive disease and persist longer. “I think Lyme is at the core because of its ability to evade and suppress the immune response so effectively.”
Diagnostic possibilities, biomarkers for PTLD
Direct diagnostic tests for microbial nucleic acid and proteins “are promising alternatives for indirect serologic tests,” Dr. Aucott said. For instance, in addition to polymerase chain reaction tests, which “are making advances,” it may be possible to target the B. burgdorferi peptidoglycan for antigen detection.
Researchers have shown that peptidoglycan, a component of the B. burgdorferi cell envelope, is a persistent antigen in the synovial fluid of patients with Lyme arthritis who have been treated with oral and intravenous antibiotics, and that it likely contributes to inflammation.
“Maybe the infection is gone but parts of the bacteria are still there that are driving inflammation,” said Dr. Aucott, also associate professor of medicine at John Hopkins.
Researchers have also been looking at the host response to B. burgdorferi – including cytokines, chemokines, and autoantibiodies – to identify biomarkers for PTLD and to identify patients during posttreatment follow-up who are at increased risk of developing PTLD, with the hope of someday intervening. Persistently high levels of interleukin-23, CCL19, and interferon-alpha have each been associated in different studies with persistent symptoms after treatment, Dr. Aucott said.
In addition, metabolomics research is showing that patients with PTLD have metabolic fingerprints that are different from those who return to good health after treatment, and it may be possible to identify an epigenetic signature for Lyme disease. A project sponsored by the Defense Advanced Research Projects Agency called ECHO (Epigenetic Characterization and Observation) aims to identify epigenetic signatures of exposures to various threats, including B. burgdorferi.
“At the very proximal end of [indirectly testing for host response], there are modifications of the DNA that can occur in response to infectious insults ... and that changed DNA changes RNA expression and protein synthesis,” Dr. Aucott explained. DARPA’s project is “exciting because their goal [at DARPA] is to have a diagnostic test quickly as a result of this epigenetics work.”
Imaging research is also fast offering diagnostic opportunities, Dr. Aucott said. Levels of microglial activation on brain PET imaging have been found to correlate with PTLD, and a study at Johns Hopkins of multimodal neuroimaging with functional MRI and diffusion tensor imaging has shown distinct changes to white matter activation within the frontal lobe of patients with PTLD, compared with controls.
The NASEM workshop did not collect or require disclosures of its participants.
FROM A NATIONAL ACADEMIES OF SCIENCE, ENGINEERING AND MEDICINE WORKSHOP