Lyme disease: a review of aspects of its immunology and immunopathogenesis

Neuropsychiatric Lyme Disease and Vagus Nerve Stimulation

Lyme disease, the most common tick-borne disease in the United States, is caused by infection with the spirochete Borrelia burgdorferi. While most patients with acute Lyme disease recover completely if treated with antibiotics shortly after the onset of infection, approximately 10-30% experience post-treatment symptoms and 5-10% have residual symptoms with functional impairment (post-treatment Lyme disease syndrome or PTLDS). These patients typically experience pain, cognitive problems, and/or fatigue. This narrative review provides a broad overview of Lyme disease, focusing on neuropsychiatric manifestations and persistent symptoms. While the etiology of persistent symptoms remains incompletely understood, potential explanations include persistent infection, altered neural activation, and immune dysregulation. Widely recognized is that new treatment options are needed for people who have symptoms that persist despite prior antibiotic therapy. After a brief discussion of treatment approaches, the article focuses on vagus nerve stimulation (VNS), a neuromodulation approach that is FDA-approved for depression, epilepsy, and headache syndromes and has been reported to be helpful for other diseases characterized by inflammation and neural dysregulation. Transcutaneous VNS stimulates the external branch of the vagus nerve, is minimally invasive, and is well-tolerated in other conditions with few side effects. If well-controlled double-blinded studies demonstrate that transcutaneous auricular VNS helps patients with chronic syndromes such as persistent symptoms after Lyme disease, taVNS will be a welcome addition to the treatment options for these patients.

Repurposing Disulfiram (Tetraethylthiuram Disulfide) as a Potential Drug Candidate against Borrelia burgdorferi In Vitro and In Vivo

Lyme disease caused by the Borrelia burgdorferi (Bb or B. burgdorferi) is the most common vector-borne, multi-systemic disease in the USA. Although most Lyme disease patients can be cured with a course of the first line of antibiotic treatment, some patients are intolerant to currently available antibiotics, necessitating the development of more effective therapeutics. We previously found several drugs, including disulfiram, that exhibited effective activity against B. burgdorferi. In the current study, we evaluated the potential of repurposing the FDA-approved drug, disulfiram for its borreliacidal activity. Our results indicate disulfiram has excellent borreliacidal activity against both the log and stationary phase B. burgdorferi sensu stricto B31 MI. Treatment of mice with disulfiram eliminated the B. burgdorferi sensu stricto B31 MI completely from the hearts and urinary bladder by day 28 post infection. Moreover, disulfiram-treated mice showed reduced expressions of inflammatory markers, and thus they were protected from histopathology and cardiac organ damage. Furthermore, disulfiram-treated mice showed significantly lower amounts of total antibody titers (IgM and IgG) at day 21 and total IgG2b at day 28 post infection. FACS analysis of lymph nodes revealed a decrease in the percentage of CD19+ B cells and an increase in total percentage of CD3+ T cells, CD3+ CD4+ T helpers, and naive and effector memory cells in disulfiram-treated mice. Together, our findings suggest that disulfiram has the potential to be repurposed as an effective antibiotic for treating Lyme disease.

Clinical and demographic characteristics of psychiatric patients seropositive for Borrelia burgdorferi

Purpose.

Borrelia burgdorferi (Bb) infection can affect the central nervous system and possibly lead to psychiatric disorders. We compared clinical and demographic variables in Bb seropositive and seronegative psychiatric patients and healthy controls.

Method.

Nine hundred and twenty-six consecutive psychiatric patients were screened for antibodies to Bb and compared with 884 simultaneously recruited healthy subjects.

Results.

Contrary to healthy controls, seropositive psychiatric patients were significantly younger than seronegative ones. None of the studied psychiatric diagnostic categories exhibited stronger association with seropositivity. There were no differences between seropositive and seronegative psychiatric patients in hospitalization length, proportion of previously hospitalized patients and proportion of subjects with family history of psychiatric disorders.

Conclusion.

These findings elaborate on potential association between Bb infection and psychiatric morbidity, but fail to identify any specific clinical ‘signature’ of Bb infection.

Lyme Neuroborreliosis - The Mystifying Pitfall: "Neuropathology and Current Therapeutics"

Lyme's Disease (LD) is a severe, rapidly growing, broad spectrum chronic infection caused by the bacterium 'Borrelia (B.) burgdorferi', which can be easily transmitted through the bite of certain species of ticks. The prevalence of LD is swiftly mounting in the present scenario in many countries from species to species. Although Lyme's infection is now detectable via serologic examination of early and late Lyme neuroborreliosis (LNB), the management of persistent symptoms is still fraught with quora of doubt and debate. LD is a multisystem spirochete which results after the dissemination of B. burgdorferi from a dermal inoculation site after a tick bite. Lyme's infection can easily get transmitted to the central nervous system and develop various neurological symptoms due to inflammation and an autoimmune response from body may lead to life-threatening "Lyme Borreliosis". The neurological symptoms are well mixed in presentation, late and confusing to get differentiated easily from other diseases. The use of antibiotics in post Lyme infection with neurological complications is still a topic of debate. Babesiosisstates, and human ehrlichiosis' the two other diseases, are associated with the same ticks that spread the LD. However, the prevalence of diagnosed human cases is usually much lower than that of actual cases of LD due to misdiagnosis, late diagnosis or undiagnosis at y such lateral neuroinfection stage after the tick bite. The current review focuses on the molecular neuropathology and current advancements in LD. There are very few patents or discoveries made on borrelia infection, drawing attention towards more focused and targeted research for the cure.

Respiratory modulation of cardiac vagal tone in Lyme disease

AIM: To conduct the first systematic test of the hypothesis that modulation of cardiac vagal tone is impaired in Lyme disease.

METHODS: The response of cardiac vagal tone to respiratory modulation was measured in 18 serologically positive Lyme disease patients and in 18 controls.

RESULTS: The two groups were matched in respect of age, sex, body mass, mean arterial blood pressure, mean resting heart rate and mean resting cardiac vagal tone. The mean maximum cardiac vagal tone during deep breathing in the Lyme disease patients [11.2 (standard error 1.3)] was lower than in the matched controls [16.5 (standard error 1.7); P = 0.02].

CONCLUSION: Respiratory modulation of cardiac vagal tone is impaired in Lyme disease, which suggests that Lyme disease may directly affect the vagus nerve or the brainstem.

Genome-wide association study for cytokines and immunoglobulin G in swine

Increased disease resistance through improved immune capacity would be beneficial for the welfare and productivity of farm animals. To identify genomic regions responsible for immune capacity traits in swine, a genome-wide association study was conducted. In total, 675 pigs were included. At 21 days of age, all piglets were vaccinated with modified live classical swine fever vaccine. Blood samples were sampled when the piglets were 20 and 35 days of age, respectively. Four traits, including Interferon-gamma (IFN-γ) and Interleukin 10 (IL-10) levels, the ratio of IFN-γ to IL-10 and Immunoglobulin G (IgG) blocking percentage to CSFV in serum were measured. All the samples were genotyped for 62,163 single nucleotide polymorphisms (SNP) using the Illumina porcineSNP60k BeadChip. After quality control, 46,079 SNPs were selected for association tests based on a single-locus regression model. To tackle the issue of multiple testing, 10,000 permutations were performed to determine the chromosome-wise and genome-wise significance level. In total, 32 SNPs with chromosome-wise significance level (including 4 SNPs with genome-wise significance level) were identified. These SNPs account for 3.23% to 13.81% of the total phenotypic variance individually. For the four traits, the numbers of significant SNPs range from 5 to 15, which jointly account for 37.52%, 82.94%, 26.74% and 24.16% of the total phenotypic variance of IFN-γ, IL-10, IFN-γ/IL-10, and IgG, respectively. Several significant SNPs are located within the QTL regions reported in previous studies. Furthermore, several significant SNPs fall into the regions which harbour a number of known immunity-related genes. Results herein lay a preliminary foundation for further identifying the causal mutations affecting swine immune capacity in follow-up studies.

Role of immunologic cross-reactivity in neurological diseases

Although the immune system evolved to protect the host from foreign infection, it can sometimes recognize and attack host tissues, a phenomenon known as autoimmunity. In addition to genetic factors, environmental elements such as viruses and bacteria are thought to play a role in the development of autoimmune diseases. The major hypothesized mechanism by which infection with these agents can lead to autoimmunity is termed molecular mimicry. Here, immune responses initiated against foreign antigens are cross-reactive with self-antigens. This is thought to occur especially if the foreign antigen is similar in structure or amino acid sequence to the self-antigen. In this review, we explore evidence for the role of molecular mimicry in neurological diseases.

Lyme nephritis

OBJECTIVE

To review what is known and highlight knowledge gaps regarding Lyme nephritis (LN).

DATA SOURCES

Publications identified via PubMed using the keywords "Borrelia burgdorferi," "Borreliosis," "glomerulonephritis," "protein-losing nephropathy," "autoimmunity," and "retriever," and as generated by investigators working in the fields of Borreliosis and immune-mediated glomerulonephritis.

HUMAN DATA SYNTHESIS

Postborrelial immune-mediated glomerulonephritis was described recently in 6 people; 3 responded to antimicrobials/steroids, 1 to antimicrobials/angiotensin-converting enzyme inhibitor/warfarin, 1 required hemodialysis but became hemodialysis independent after 5 months and treatment with antimicrobials, steroids, plasmapheresis, immunoglobulin, and 1 did not respond to steroids and angiotensin-converting enzyme inhibitor and still requires hemodialysis.

VETERINARY DATA SYNTHESIS

Lyme nephritis is seen in <1-2% of Lyme seropositive dogs, with an average onset at 5-6 years. Labrador and Golden Retrievers are predisposed to this condition. Prior or concurrent lameness is described in 9-28% cases. Historical presentations include acute progressive protein-losing nephropathy with membranoproliferative glomerulonephritis, tubular necrosis/regeneration, and interstitial nephritis, but possibly milder forms exist. Complications include thromboembolic events, hypertension, effusive disease, and oliguric/anuric renal failure. Diagnostic tests help stage disease and rule out other causes. Renal biopsy is advocated early, when intervention may help, and to prove if immune-complex disease exists. Treatment includes standard therapy for protein-losing nephropathy, long-term antimicrobials, and perhaps immunosuppressive therapy.

CONCLUSIONS

There is no experimental model of LN to study predisposing factors, pathogenesis, onset, progression, treatment, or prevention. There are no predictive tests to identify the few individuals at highest risk, therefore all seropositive dogs should be screened and monitored for proteinuria. Lyme nephritis mimics other forms of protein-losing nephropathy and sometimes Leptospirosis. Renal biopsy helps show if immune-complex disease exists, but may not prove LN specifically. More studies are warranted on dogs with Lyme-specific immune-complex deposition to evaluate risk factors, understand pathogenesis, variability of expression, and to validate treatment and prevention protocols.

The effects of ingested mammalian blood factors on vector arthropod immunity and physiology

The blood feeding behavior of disease-transmitting arthropods creates a unique intersection between vertebrate and invertebrate physiology. Here, we review host blood-derived factors that persist through blood digestion to affect the lifespan, reproduction, and immune responses of some of the most common arthropod vectors of human disease.

Chronic or late lyme neuroborreliosis: analysis of evidence compared to chronic or late neurosyphilis

Whether spirochetes persist in affected host tissues and cause the late/chronic manifestations of neurosyphilis was the subject of long-lasting debate. Detection of Treponema pallidum in the brains of patients with general paresis established a direct link between persisting infection and tertiary manifestations of neurosyphilis. Today, the same question is in the center of debate with respect to Lyme disease. The goal of this review was to compare the established pathological features of neurosyphilis with those available for Lyme neuroborreliosis. If the main tertiary forms of neurosyphilis also occur in Lyme neuroborreliosis and Borrelia burgdorferi can be detected in brain lesions would indicate that the spirochete is responsible for the neuropsychiatric manifestations of late/chronic Lyme neuroborreliosis. The substantial amounts of data available in the literature show that the major forms of late/chronic Lyme neuroborreliosis (meningovascular and meningoencephalitis) are clinically and pathologically confirmed. Borrelia burgdorferi was detected in association with tertiary brain lesions and cultivated from the affected brain or cerebrospinal fluid. The accumulated data also indicate that Borrelia burgdorferi is able to evade from destruction by the host immune reactions, persist in host tissues and sustain chronic infection and inflammation. These observations represent evidences that Borrelia burgdorferi in an analogous way to Treponema pallidum is responsible for the chronic/late manifestations of Lyme neuroborreliosis.Late Lyme neuroborreliosis is accepted by all existing guidelines in Europe, US and Canada. The terms chronic and late are synonymous and both define tertiary neurosyphilis or tertiary Lyme neuroborreliosis. The use of chronic and late Lyme neuroborreliosis as different entities is inaccurate and can be confusing. Further pathological investigations and the detection of spirochetes in infected tissues and body fluids are strongly needed.

Peripheral nervous system manifestations of lyme borreliosis

Lyme disease is a tick-borne illness that has protean neurologic manifestations involving both the central and peripheral nervous system. The peripheral nervous system manifestations of Lyme borreliosis can be divided chronologically into acute and chronic forms. Within weeks after disease onset, approximately 15% of untreated patients develop an acute Lyme meningoradiculoneuritis with headache, fever, radicular pain, weakness, and sensory loss, often associated with cranial neuropathy, usually facial palsy. Cerebrospinal fluid typically shows lymphocytic pleocytosis, high protein, and normal glucose. Diagnosis is made by recognition of characteristic clinical features with a history of preceding exposure and confirmed by serologic evidence of exposure to B. burgdorferi or by antibody or PCR evidence of cerebrospinal fluid infection. Months to years after onset, rare patients may develop chronic polyradiculoneuropathy presenting with sensory symptoms or radicular pain. Diagnosis is confirmed by a history of exposure, previous systemic or acute neurologic manifestations of Lyme borreliosis, and serologic evidence of infection. Pathology of acute or chronic Lyme radiculoneuropathy reveals axonal degeneration with perivascular mononuclear infiltration. Eradication of the organism can be achieved with 2 to 4 weeks of ceftriaxone for both acute and chronic Lyme neuroborreliosis. Isolated facial palsy without evidence of cerebrospinal fluid infection can be treated with oral antibiotics such as doxycycline. Prognosis after therapy is good, but neurologic recovery is slower for chronic than acute Lyme radiculoneuropathy.

Alzheimer's disease - a neurospirochetosis. Analysis of the evidence following Koch's and Hill's criteria

It is established that chronic spirochetal infection can cause slowly progressive dementia, brain atrophy and amyloid deposition in late neurosyphilis. Recently it has been suggested that various types of spirochetes, in an analogous way to Treponema pallidum, could cause dementia and may be involved in the pathogenesis of Alzheimer's disease (AD). Here, we review all data available in the literature on the detection of spirochetes in AD and critically analyze the association and causal relationship between spirochetes and AD following established criteria of Koch and Hill. The results show a statistically significant association between spirochetes and AD (P = 1.5 × 10-17, OR = 20, 95% CI = 8-60, N = 247). When neutral techniques recognizing all types of spirochetes were used, or the highly prevalent periodontal pathogen Treponemas were analyzed, spirochetes were observed in the brain in more than 90% of AD cases. Borrelia burgdorferi was detected in the brain in 25.3% of AD cases analyzed and was 13 times more frequent in AD compared to controls. Periodontal pathogen Treponemas (T. pectinovorum, T. amylovorum, T. lecithinolyticum, T. maltophilum, T. medium, T. socranskii) and Borrelia burgdorferi were detected using species specific PCR and antibodies. Importantly, co-infection with several spirochetes occurs in AD. The pathological and biological hallmarks of AD were reproduced in vitro by exposure of mammalian cells to spirochetes. The analysis of reviewed data following Koch's and Hill's postulates shows a probable causal relationship between neurospirochetosis and AD. Persisting inflammation and amyloid deposition initiated and sustained by chronic spirochetal infection form together with the various hypotheses suggested to play a role in the pathogenesis of AD a comprehensive entity. As suggested by Hill, once the probability of a causal relationship is established prompt action is needed. Support and attention should be given to this field of AD research. Spirochetal infection occurs years or decades before the manifestation of dementia. As adequate antibiotic and anti-inflammatory therapies are available, as in syphilis, one might prevent and eradicate dementia.

Musculoskeletal features of Lyme disease: understanding the pathogenesis of clinical findings helps make appropriate therapeutic choices

Patients with Lyme disease, that is, active infection with Borrelia burgdorferi, experience many types of musculoskeletal complaints, with different explanatory mechanisms. Appropriate therapy depends on understanding the underlying cause of the complaint and addressing that specific root cause. In the case of active infection the dosage, duration, drug, and method of administration of antibiotics should be determined by the state of the infection and history of prior therapy, according to the established and validated recommendations of the Infectious Disease Society of America. Many patients have musculoskeletal complaints not attributable to active infection; some patients have residual complaints following a documented infection that has been adequately treated with antibiotics previously, and others never had true B. burgdorferi infection in the first place. For such patients, antibiotics are not warranted and in fact may be physically and emotionally harmful. Complaints following an episode of Lyme disease are not necessarily due to ongoing infection, especially adequately treated. Consideration of other diagnoses may suggest use of other effective modalities, including physical therapy and emotional support. Appropriate ordering and interpretation of the various validated seroconfirmatory tests available to study B. burgdorferi infection are critical, as these tests are often misapplied and misconstrued in pursuit of strategies aimed at eliminating patients' suffering. Although seronegative Lyme disease has been reported, seronegativity in a reputable laboratory makes the likelihood of Lyme arthritis very low. On the other hand, a positive result from certain unvalidated laboratories or novel assays proves nothing and should not be viewed as substantiating the diagnosis.

Mapping quantitative trait loci for cytokines in the pig

Increased disease resistance through improved general immune capacity would be beneficial for the welfare and productivity of farm animals. Cytokines are essential diagnostic parameters in veterinary practice. To identify quantitative trait loci (QTL) for cytokine levels in serum in the pig, Interferon-gamma (IFN-γ) and Interleukin 10 (IL-10) levels and the ratio of IFN-γ to IL-10 were measured in a composite pig population, before and after challenge with modified live CSF (classical swine fever) vaccine. Through interval mapping using the variance component approach and the permutation test, 11 QTL (five for IFN-γ, two for IL-10 and four for the ratio of IFN-γ to IL-10) with significance levels of P < 0.10 were identified, of which five were significant at the P < 0.05 level. The most significant QTL (P < 0.01) was found on chromosome 16, with effect on the ratio of IFN-γ to IL-10. Within these QTL regions, a number of known genes were revealed and their potential relationships to the studied traits were discussed. Some of these genes may serve as candidate genes for these traits in swine.

Anti-neural antibody reactivity in patients with a history of Lyme borreliosis and persistent symptoms

Some Lyme disease patients report debilitating chronic symptoms of pain, fatigue, and cognitive deficits despite recommended courses of antibiotic treatment. The mechanisms responsible for these symptoms, collectively referred to as post-Lyme disease syndrome (PLS) or chronic Lyme disease, remain unclear. We investigated the presence of immune system abnormalities in PLS by assessing the levels of antibodies to neural proteins in patients and controls. Serum samples from PLS patients, post-Lyme disease healthy individuals, patients with systemic lupus erythematosus, and normal healthy individuals were analyzed for anti-neural antibodies by immunoblotting and immunohistochemistry. Anti-neural antibody reactivity was found to be significantly higher in the PLS group than in the post-Lyme healthy (p<0.01) and normal healthy (p<0.01) groups. The observed heightened antibody reactivity in PLS patients could not be attributed solely to the presence of cross-reactive anti-borrelia antibodies, as the borrelial seronegative patients also exhibited elevated anti-neural antibody levels. Immunohistochemical analysis of PLS serum antibody activity demonstrated binding to cells in the central and peripheral nervous systems. The results provide evidence for the existence of a differential immune system response in PLS, offering new clues about the etiopathogenesis of the disease that may prove useful in devising more effective treatment strategies.

The role of infections in autoimmune disease

Autoimmunity occurs when the immune system recognizes and attacks host tissue. In addition to genetic factors, environmental triggers (in particular viruses, bacteria and other infectious pathogens) are thought to play a major role in the development of autoimmune diseases. In this review, we (i) describe the ways in which an infectious agent can initiate or exacerbate autoimmunity; (ii) discuss the evidence linking certain infectious agents to autoimmune diseases in humans; and (iii) describe the animal models used to study the link between infection and autoimmunity.

The failure of immune response evasion by linear plasmid 28-1-deficient Borrelia burgdorferi is attributable to persistent expression of an outer surface protein

Infectivity and persistence by Borrelia burgdorferi, the etiologic agent of Lyme disease, rely stringently on regulatory events. Among these is the downregulation of lipoprotein antigen expression, exemplified by outer surface protein C (OspC), at the advent of specific immunity in the mammalian host. B. burgdorferi spirochetes that lack the linear plasmid 28-1 (lp28-1) succumb to the host's immune response. We thus explored the notion that these two phenomena were related--that lp28-1(-) organisms fail to downregulate ospC and thus are cleared following the appearance of anti-OspC antibody in the murine host. The lp-28-1(-) isolate and a wild-type (wt) isolate bearing the complete set of plasmids were grown in dialysis membrane chambers that were implanted into rat peritoneal cavities. Analysis of mRNA and protein from these cultures showed that OspC expression levels by lp28-1(-) organisms are abnormally high in vivo. A time course analysis of ospC expression in tissues following infection indicates also that temporal diminution of the dominant antigen OspC is impaired in lp28-1(-) spirochetes. Finally, passive transfer of monoclonal OspC-specific antibody into SCID mice 8 days postinfection cleared lp28-1(-) spirochetes, yet the wt organisms persisted in a majority of animals. These findings indicate that incomplete repression of OspC by lp28-1(-) organisms renders them susceptible to immune-mediated clearance. The lp28-1 plasmid must harbor one or more genes involved in OspC downregulation.

Serum reactivity against Borrelia burgdorferi OspA in patients with rheumatoid arthritis

Lyme arthritis and rheumatoid arthritis share common clinical features and synovial histology. It is unclear whether they also share similar pathogenesis. Previous studies have shown that the severity and duration of Lyme arthritis correlate directly with serum concentrations of antibody against outer surface protein A (OspA) of the causative pathogen Borrelia burgdorferi. We tested the sera of 68 subjects with rheumatoid arthritis, 147 subjects with other autoimmune diseases, and 44 healthy subjects who had never had Lyme disease, as well as sera of 16 patients who had Lyme disease, for reactivity against the B. burgdorferi OspA protein. The sera of about a quarter of the rheumatoid arthritis patients and a 10th of the autoimmune disease and Lyme disease patients reacted against OspA antigen. Of 50 rheumatoid arthritis patients who could be evaluated for disease severity, a 28-joint count disease activity score of >2.6 was noted for 11 of 15 (73%) patients whose sera reacted against OspA antigen and 13 of 35 (37%; P < 0.05) whose sera were nonreactive. Serum reactivity against OspA antigen is associated with the pathogenesis of rheumatoid arthritis.

Borrelia burgdorferi-induced monocyte chemoattractant protein-1 production in vivo and in vitro

Matrix metalloproteinase 9 (MMP-9) is selectively upregulated in erythema migrans (EM) lesions with acute Lyme disease. This study explored whether upregulation of MMP-9 was associated with monocyte chemoattractant protein 1 (MCP-1) production, and Borrelia burgdorferi (B. burgdorferi) could induce MCP-1 production in vivo and in vitro. The results indicated that expression of MCP-1 was significantly increased in U937 cells by B. burgdorferi. The activity of MMP-9 could be elevated by recombinant MCP-1 (rMCP-1) in U937 cells. MMP-9 was not upregulated by B. burgdorferi in fibroblasts. However, the expression of MCP-1 was significantly increased in the presence of B. burgdorferi in fibroblasts. The level of MCP-1 in EM lesions and in serum of patients with acute Lyme disease was also significantly elevated compared to that for healthy controls. The secreted MCP-1 may affect the production of MMP-9 in fibroblasts and/or macrophages.

The function of programmed cell death 1 and its ligands in regulating autoimmunity and infection

The programmed cell death 1 (PD-1) surface receptor binds to two ligands, PD-L1 and PD-L2. Studies have shown that PD-1-PD-L interactions control the induction and maintenance of peripheral T cell tolerance and indicate a previously unknown function for PD-L1 on nonhematopoietic cells in protecting tissues from autoimmune attack. PD-1 and its ligands have also been exploited by a variety of microorganisms to attenuate antimicrobial immunity and facilitate chronic infection. Here we examine the functions of PD-1 and its ligands in regulating antimicrobial and self-reactive T cell responses and discuss the therapeutic potential of manipulating this pathway.

Avellis syndrome due to borreliosis

Avellis syndrome is a rare form of alternating hemiparesis that is usually because of atherosclerosis. We report a 67-year-old man who developed paresthesiae of the left arm, dysphagia and dysphonia. The clinical picture, magnetic resonance imaging and cerebrospinal fluid findings were consistent with Avellis syndrome caused by brain stem arteritis because of late stage Borrelia burgdorferi infection, an extremely unusual aetiology for Avellis syndrome; this may well be the first such instance. It may be unrecognized in elderly patients with other risk factors for cerebrovascular disease.

The impact of immunosuppression on erythema migrans. A retrospective study of clinical presentation, response to treatment and production of Borrelia antibodies in 33 patients

BACKGROUND

Little is known about the potential influence of immunosuppression on erythema migrans, the hallmark of early Lyme borreliosis.

METHODS

We performed a retrospective study to assess the impact of immunosuppression on erythema migrans in 33 patients with a malignant or autoimmune disease, chronic infection, or immunosuppressive therapy for organ transplantation. Only patients with active disease status and/or current immunosuppressive therapy were included. Pre-treatment clinical parameters, such as presentation of the skin lesion and presence of extracutaneous signs and symptoms, the disease course during a median follow-up of 9 months after therapy and serum anti-Borrelia burgdorferi antibodies before therapy and by the end of follow-up in the 33 immunosuppressed patients were statistically compared with 75 otherwise healthy patients with erythema migrans. The 75 control patients were matched for sex, age and antibiotic therapy.

RESULTS

With the exception of the site of erythema migrans lesions, which were found more often on the trunk than on the legs in the immunosuppressed patients (vice versa in immunocompetent patients), we found no significant differences for all investigated parameters between the two groups.

CONCLUSIONS

It appears that immunosuppression does not influence clinical presentation, response to therapy, or production of anti-B. burgdorferi antibodies of patients with erythema migrans. It is thus not necessary to treat immunosuppressed patients with erythema migrans differently from immunocompetent patients.

Borrelia burgdorferi–Traveling incognito?

We outline in this review how Borrelia burgdorferi, the causative agent of Lyme disease, moves from the tick to the vertebrate host, and what molecules are potentially involved in this challenging commute. The survival strategies utilized by the spirochete during transmission and the initial stages of infection are discussed.

Identification of Borrelia burgdorferi outer surface proteins

Several Borrelia burgdorferi outer surface proteins have been identified over the past decade that are up-regulated by temperature- and/or mammalian host-specific signals as this spirochete is transmitted from ticks to mammals. Given the potential role(s) that these differentially up-regulated proteins may play in B. burgdorferi transmission and Lyme disease pathogenesis, much attention has recently been placed on identifying additional borrelial outer surface proteins. To identify uncharacterized B. burgdorferi outer surface proteins, we previously performed a comprehensive gene expression profiling analysis of temperature-shifted and mammalian host-adapted B. burgdorferi. The combined microarray analyses revealed that many genes encoding known and putative outer surface proteins are down-regulated in mammalian host-adapted B. burgdorferi. At the same time, however, several different genes encoding putative outer surface proteins were found to be up-regulated during the transmission and infection process. Among the putative outer surface proteins identified, biochemical and surface localization analyses confirmed that seven (Bb0405, Bb0689, BbA36, BbA64, BbA66, BbA69, and BbI42) are localized to the surface of B. burgdorferi. Furthermore, enzyme-linked immunosorbent assay analysis using serum from tick-infested baboons indicated that all seven outer surface proteins identified are immunogenic and that antibodies are generated against all seven during a natural infection. Specific antibodies generated against all seven of these surface proteins were found to be bactericidal against B. burgdorferi, indicating that these newly identified outer surface proteins are prime candidates for analysis as second-generation Lyme disease vaccinogens.

A small molecule alpha 4 beta 1 antagonist prevents development of murine Lyme arthritis without affecting protective immunity

After infection with Borrelia burgdorferi, humans and mice under certain conditions develop arthritis. Initiation of inflammation is dependent on the migration of innate immune cells to the site of infection, controlled by interactions of a variety of adhesion molecules. In this study, we used the newly synthesized compound S18407, which is a prodrug of the active drug S16197, to analyze the functional importance of alpha4beta1-dependent cell adhesion for the development of arthritis and for the antibacterial immune response. S16197 is shown to interfere specifically with the binding of alpha4beta(1 integrin to its ligands VCAM-1 and fibronectin in vitro. Treatment of B. burgdorferi-infected C3H/HeJ mice with the alpha4beta1 antagonist significantly ameliorated the outcome of clinical arthritis and the influx of neutrophilic granulocytes into ankle joints. Furthermore, local mRNA up-regulation of the proinflammatory mediators IL-1, IL-6, and cyclooxygenase-2 was largely abolished. Neither the synthesis of spirochete-specific Igs nor the development of a Th1-dominated immune response was altered by the treatment. Importantly, the drug also did not interfere with Ab-mediated control of spirochete load in the tissues. These findings demonstrate that the pathogenesis, but not the protective immune response, in Lyme arthritis is dependent on the alpha4beta1-mediated influx of inflammatory cells. The onset of inflammation can be successfully targeted by treatment with S18407.

Histopathological Studies of Experimental Lyme Disease in the Dog

Experimental borrelia infection was induced in 62 specific--pathogen-free beagle dogs by exposure to Ixodes scapularis ticks harbouring the spirochaete Borrelia burgdorferi. Clinical signs of Lyme disease occurred in 39/62 dogs, the remaining 23 being subclinically infected. Clinical signs consisted of one to six episodes of transitory lameness with joint swelling and pain, most commonly affecting the elbow or shoulder joints. The polymerase chain reaction and culture demonstrated that the dogs remained infected for up to 581 days. At necropsy, gross findings consisted of lymphadenopathy in the area of tick attachment. Microscopical changes consisted of effusive fibrinosuppurative inflammation or nonsuppurative inflammation, or both, affecting synovial membranes, joint capsules and associated tendon sheaths. Plasma cells dominated areas of chronic inflammation, with CD3(+) T cells being present in lesser numbers. Microscopical signs of arthritis were polyarticular and more widespread than indicated by clinical signs, and most of the subclinically affected animals also had synovitis. In areas of tick attachment to the skin, hyperkeratosis and a mixture of suppurative and nonsuppurative dermatitis were encountered. Lymphadenopathy in superficial lymph nodes resulted from follicular and parafollicular hyperplasia. In 14/62 dogs, lymphoplasmacytic periarteritis and perineuritis were noted, resembling lesions found in human Lyme disease and syphilis, in which an underlying microangiopathy has been proposed.

La maladie de Lyme du point de vue de l’ophtalmologue

The first case of Lyme disease was described more than 25 years ago in the city of Lyme, Connecticut (USA) and although the responsible pathogenic organism is known (Borrelia Burgdorferi) as well as its vector (a tick from the Ixode genus), it is still underdiagnosed and often poorly known by practitioners. The symptomatology is classically divided into three phases depending on the time between the tick bite and the first symptoms. However, in a number of cases this clinical division of the disease is not easily applied. We describe three cases of atypical ocular manifestations to illustrate this problem. Recently developed laboratory tests help confirm the diagnosis but should not be used without a good knowledge of the disease. This study aims to emphasize the difficulty of diagnosis and the importance of appropriate treatment and to avoid potentially permanent complications.

Quantitative analysis of Borrelia burgdorferi gene expression in naturally (tick) infected mouse strains

Adaptation of Borrelia burgdorferi in the vector and vertebrate host is mediated by mechanisms that regulate differential expression of outer surface lipoproteins (Osps). In this study, real time PCR was applied to quantify tissue-specific expression of four linear plasmid (lp54)-encoded (ospA, zs7.a36, zs7.a66 zs7.a68) and one circular plasmid (cp26)-encoded (ospC) gene from B. burgdorferi sensu stricto, in a natural setting of tick-infected immunodeficient (C.B-17 SCID) and immunocompetent (BALB/c and AKR/OlaHsd) mice for up to 120 days post-infection (p.i.). Early during infection (day 30 p.i.) high numbers of spirochetes were found in the heart and joint, but not the ear and spleen tissues of disease-susceptible SCID mice. In disease-susceptible AKR mice spirochetes colonized the ear and joint tissues, but were undetectable in tissues of disease-resistant BALB/c mice. Later in infection (day 120 p.i.), spirochetes had expanded (approximately 1,000-fold) in all SCID tissues tested but were undetectable in AKR and BALB/c mice. Of the five genes analyzed, only zs7.a36 transcripts were detected in various tissues of all infected mouse strains, though at differing levels, whereas ospC transcripts were only found in tissue specimens of SCID mice. Furthermore, gene expression of ospC and zs7.a36 appears to be differentially regulated in distinct organs of individual mice. In contrast, transcripts for ospA, zs7.a66, and zs7.a68 were not detected in any of the mouse strains, independent of their immune status and/or the severity of their infection/inflammatory responses. Late during infection (day 120 p.i.), transcription of zs7.a36 and ospC was down-regulated in the tissues of SCID mice despite expansion of spirochetes. This type of quantitative analysis may be helpful to further disclose principles of pathogenesis of Lyme borreliosis and to design strategies for its therapeutic treatment.

A DNA vaccine encoding the outer surface protein C from Borrelia burgdorferi is able to induce protective immune responses

The outer surface protein C (OspC) of Borrelia burgdorferi, the spirochete that causes Lyme disease, is a promising candidate for a vaccine against borreliosis. BALB/c and C3H/HeJ mice were immunized either with recombinant OspC protein or with plasmid DNA encoding OspC fused to the human tissue plasminogen activator leader sequence (pCMV-TPA/ZS7). The influence of the route of administering the DNA and the use of oligodeoxynucleotides containing CpG-motifs on the development of the immune response was investigated. In both mouse strains, protein as well as gene-gun immunization induced Th2 type responses, whereas needle injection of plasmid DNA resulted in Th1 type antibody production. Co-injection of CpG-motifs did not significantly modify the response type in any immunization group, as indicated by only marginal changes of antibody subclass distribution. The protection rate after challenge with 10(4) B. burgdorferi organisms per mouse was between 80% and 100% for all groups. These results demonstrate, for the first time, that a DNA vaccine encoding OspC of B. burgdorferi is suitable for inducing protection against Lyme borreliosis.

Susceptibility to experimental Lyme arthritis correlates with KC and monocyte chemoattractant protein-1 production in joints and requires neutrophil recruitment via CXCR2

The development of experimental Lyme arthritis has been correlated with the expression of a number of chemokines and cytokines, however, none of these have been measured directly from the arthritic joint. We examined the temporal expression of IL-1beta, IL-4, IL-6, IL-10, IL-12p70, GM-CSF, IFN-gamma, TNF-alpha, macrophage inflammatory protein-2, KC, macrophage inflammatory protein-1alpha, and monocyte chemoattractant protein-1 directly from the tibiotarsal joint in arthritis-resistant C57BL/6 (B6) and -susceptible C3H/He (C3H) mice. Only the chemokines KC and monocyte chemoattractant protein-1 were differentially expressed in joints of B6 and C3H mice and correlated with the development of Lyme arthritis. Infection of CXCR2(-/-) mice on either genetic background resulted in a significant decrease in the development of pathology, although infection of CCR2(-/-) mice had little or no effect. Neutrophils in CXCR2(-/-) mice were marginalized within blood vessels and could not enter the joint tissue. These results suggest that chemokine-mediated recruitment of neutrophils into the infected joint is a key requirement for the development of experimental Lyme arthritis.

'Lyme disease': ancient engine of an unrecognized borreliosis pandemic?

Unexpectedly we have found large numbers of chronically ill Borrelia burgdorferi PCR- and seropositive patients in Houston, Texas, a zoonotically 'non-endemic' area. In order to understand this finding prior to sufficient data availability, we chose to examine critically currently accepted but troublesome 'Lyme disease' concepts. Our method was to analyze each foundation 'Lyme disease' premise within the context of available medical and veterinary literature, then to reconstruct the disease model consistent with the preponderance of that data. We find the present conceptualization of the illness seriously truncated, with a high likelihood of two distinct but connected forms of human B. burgdorferi infection. The yet-unrecognized form appears to have a broader clinical presentation, wider geographic distribution, and vastly greater prevalence. We conclude that 'Lyme disease' currently acknowledges only its zoonosis arm and is a limited conceptualization of a far more pervasive and unrecognized infection state that must be considered a global epidemic.

Increased expression of B-lymphocyte chemoattractant, but not pro-inflammatory cytokines, in muscle tissue in rhesus chronic Lyme borreliosis

Inflammation in skeletal muscle is a consistent feature of Lyme borreliosis, both in the human disease and experimental models. This study had two goals: to evaluate the expression of selected pro-inflammatory and chemokine genes in skeletal muscle in the Rhesus model of Lyme disease, and to identify unexpected cytokine genes involved in Lyme myositis. Two different techniques for measuring cytokine messenger RNA (mRNA) levels were used to achieve these goals: gene expression microarrays and. real-time RT-PCR (Taqman). Muscle from necropsies and biopsies were used, and were obtained from both infected and uninfected non-human primates (NHPs). Although many cytokines were found expressed in muscle tissue, pro-inflammatory cytokines commonly associated with inflammation were not consistently upregulated in infected muscles relative to uninfected muscles. However, B-lymphocyte chemoattractant (BLC), a chemokine implicated in the trafficking of B-cells into tissue, was increased in expression. This study is the first to extensively characterize cytokine gene expression in chronically inflamed tissue in Lyme borreliosis.

Host-pathogen interactions and the pathogenesis of murine Lyme disease

Lyme disease results from persistent infection with the spirochete Borrelia burgdorferi. A combination of bacterial factors and host factors contributes to the development of inflammatory disease. Studies from the past year have provided insight into both sides of this host-pathogen interplay. We now have a better appreciation of the bacterial genes and products that are involved in pathology and the components of the host response that participate in disease development.

Standardised in vitro susceptibility testing of Borrelia burgdorferi against well-known and newly developed antimicrobial agents--possible implications for new therapeutic approaches to Lyme disease

Lyme disease represents a disorder of potentially chronic proportions, and relatively little is known about the in vivo pharmacodynamic interactions of antimicrobial agents with borreliae. So far, evidence-based drug regimens for the effective treatment of Lyme disease have not been definitively established. Moreover, therapeutic failures have been reported for almost every suitable antimicrobial agent currently available. Resistance to treatment and a protracted course of the disease, therefore, continue to pose problems for clinicians in the management of patients suffering from chronic Lyme disease. Further characterisation of the antibiotic susceptibility pattern and a better understanding of the interactions of B. burgdorferi with antimicrobial agents are urgently needed and continue to be crucial owing to considerable differences in the experimental conditions and test methods applied. The development of easily performed, new techniques for the sensitivity testing of B. burgdorferi provides the opportunity to study factors affecting the bacteriostatic and bactericidal action of recently introduced chemotherapeutic agents under more standardised conditions. For the first time, these studies provide direct evidence that, in addition to beta-lactams, macrolides, and tetracyclines which are recommended for stage-dependent treatment of Lyme borreliosis, other recently introduced substances, such as fluoroquinolones, everninomycins, and the ketolide family of antimicrobial agents, also show enhanced in vitro activity against borreliae. Some of these compounds, if effective in vivo as well, may prove to be useful agents in the treatment of certain manifestations of Lyme disease. As such, their potential role should be evaluated further by in vivo experiments and clinical trials. Finally, these antimicrobial agents may turn out to be very effective therapeutic alternatives on account of their oral availability, favourable pharmacodynamic profiles, and high tissue levels in cases where beta-lactames or tetracyclines cannot be administered without detrimental side-effects.

[Rheumatologic manifestations of Lyme borreliosis]

PURPOSE

Lyme borreliosis is a multisystemic infection caused by the spirochaete Borrelia burgdorferi. In European endemic areas like northeast France, articular manifestations are, after neuroborreliosis, the most frequent extra-cutaneous features observed. Among the pathogenic species of Borrelia, Borrelia burgdorferi sensu stricto is the most frequently identified during Lyme arthritis, but others species also seem to be involved.

CURRENT KNOWLEDGE AND KEY POINTS

The diagnosis of Lyme arthritis is usually based on combined clinical data and serological laboratory tests. In atypical forms, detection of bacterial DNA could be useful. While mechanisms involved in acute Lyme arthritis are beginning to be better understood, the pathogenesis of chronic arthritis, which concerns about 10% of the patients, remains unknown. Two hypotheses are proposed to explain the prolonged evolution of the articular disease: a chronic persistence of Borrelia burgdorferi, which evades the host immune system within the joint and/or an autoimmune mechanism by molecular mimicry. The antibiotic therapy is codified in acute arthritis, but is not really adapted in chronic Lyme arthritis or post-Lyme syndrome.

FUTURE PROSPECTS AND PROJECTS

To prevent the disease, the vaccine available in the United States does not offer complete protection and is not useful in Europe since the species heterogeneity is important for the outer surface protein A. A better understanding of Lyme disease pathogenesis can subsequently lead to new therapeutic or preventive approaches.

Impaired bactericidal activity and host resistance to Listeria monocytogenes and Borrelia burgdorferi in rats administered an acute oral regimen of ethanol

A rat model was used to examine how ethanol ingestion may interfere with antimicrobial immunity both in vitro and in vivo. Nonimmune Long-Evans rats were given a short-course treatment orally with excessive amounts of ethanol. Their spleens were removed at the time of sacrifice, and separate spleen cell suspensions were prepared and tested in vitro for their ability to kill two bacterial pathogens, Listeria monocytogenes and Borrelia burgdorferi. After the bacteria were mixed separately with various concentrations of spleen cells, it was found that spleen cells from the ethanol-treated rats killed fewer bacteria than matching pair-fed controls, based on counts of the number of cultured CFU (for Listeria) or based on microscopic examination (for Borrelia). For the in vivo studies, ethanol-treated and control rats were infected intraperitoneally with Listeria, and then, 1 to 3 days later, they were assessed for systemic infection based on the numbers of organisms present in their livers and spleens. Numbers of bacterial CFU for both organs were significantly higher in the group fed ethanol for the first 2 days after listerial challenge. These results support the concept that acute exposure to high levels of ethanol can impair host defense mechanisms, especially those expressed at the cellular level, which could lead to increased susceptibility to certain types of infections.

An unusual case of anti-Borrelia burgdorferi immunoglobulin G seroconversion caused by administration of intravenous gammaglobulins

Administration of gammaglobulins to individuals without specific anti-Borrelia burgdorferi antibodies may lead to immunoglobulin G (IgG) conversion as detected by enzyme-linked immunosorbent assay (ELISA). In some cases however, complementary techniques such as Western blot or avidity will be of prime importance in distinguishing the start of an infection from the passive immunization induced by the gammaglobulins. In all cases, the key element before reaching conclusions in relation to any of these investigations remains the confrontation between the clinical context and the biological findings. This is the scenario that has been followed in our observation.

Future vaccines: recent advances and future prospects

The 20th century has witnessed the introduction of over 20 vaccines that prevent or even conquer diseases such as smallpox, polio, and measles. The continued threat of infectious diseases demands the creation of many more vaccines, especially against common respiratory and gastrointestinal pathogens. Thanks to recent advances in molecular biology, immunology, and adjuvant technology, the next decade likely will bring a vaccine for HIV/AIDS also. We enter the 21st century with a tempered optimism, proud of past achievements, but mindful of the challenges that lie ahead.

Natural antibody affects survival of the spirochete Borrelia burgdorferi within feeding ticks

Natural antibodies are those immunoglobulin molecules found in mammalian serum that arise in the absence of exposure to environmental pathogens and may comprise an early host defense against invading pathogens. The spirochete Borrelia burgdorferi first encounters natural antibodies when its arthropod vector, Ixodes scapularis, begins feeding on a mammalian host. Natural antibodies may therefore have an impact on pathogens within blood-sucking vectors, prior to pathogen transmission to the mammal. In this study, we investigated whether natural antibodies influenced the number and/or phenotype of B. burgdorferi organisms within feeding I. scapularis nymphs. Using a competitive PCR, we found that ticks ingesting a blood meal from B-cell-deficient mice, which lack all immunoglobulins, contained fivefold more spirochete DNA than ticks feeding on control mice. Spirochete DNA levels could be reduced to that of controls with passive transfer of normal mouse serum or polyclonal immunoglobulin M (IgM), but not IgG, into B-cell-deficient mice prior to placement of infected ticks. At 48 h of tick feeding, 90% of spirochetes within salivary glands of ticks removed from B-cell-deficient mice were found by confocal immunofluorescence microscopy to express outer surface protein A (OspA), compared to only 5% of salivary gland spirochetes from ticks detached from control mice. Taken together, these results show that ingestion of natural antibodies limits the spirochete burden within feeding ticks. Because OspA is normally downregulated when spirochetes moved from the tick midgut to the salivary gland, our findings suggest that OspA-expressing midgut spirochetes may be particularly susceptible to the borrelicidal effects of these molecules.

Erythema migrans after ceftriaxone treatment of aseptic meningitis caused by Borrelia burgdorferi

Erythema migrans is the characteristic exanthem of Lyme disease. The rash initially occurs at the site of inoculation; subsequently satellite lesions can occur. We describe an adolescent girl in whom the rash appeared after the initiation of ceftriaxone therapy for aseptic meningitis. We suggest that the occurrence of rash in this patient was a result of liberated toxin from local bacterial lysis.

H9724, a monoclonal antibody to Borrelia burgdorferi's flagellin, binds to heat shock protein 60 (HSP60) within live neuroblastoma cells: a potential role for HSP60 in peptide hormone signaling and in an autoimmune pathogenesis of the neuropathy of Lyme disease

Although Borrelia burgdorferi, the causative agent of Lyme disease, is found at the site of many disease manifestations, local infection may not explain all its features. B. burgdorferi's flagellin cross-reacts with a component of human peripheral nerve axon, previously identified as heat shock protein 60 (HSP60). The cross-reacting epitopes are bound by a monoclonal antibody to B. burgdorferi's flagellin, H9724. Addition of H9724 to neuroblastoma cell cultures blocks in vitro spontaneous and peptide growth-factor-stimulated neuritogenesis. Withdrawal of H9724 allows return to normal growth and differentiation. Using electron microscopy, immunoprecipitation and immunoblotting, and FACS analysis we sought to identify the site of binding of H9724, with the starting hypotheses that the binding was intracellular and not identical to the binding site of II-13, a monoclonal anti-HSP60 antibody. The current studies show that H9724 binds to an intracellular target in cultured cells with negligible, if any, surface binding. We previously showed that sera from patients with neurological manifestations of Lyme disease bound to human axons in a pattern identical to H9724's binding; these same sera also bind to an intracellular neuroblastoma cell target. II-13 binds to a different HSP60 epitope than H9724: II-13 does not modify cellular function in vitro. As predicted, II-13 bound to mitochondria, in a pattern of cellular binding very different from H9724, which bound in a scattered cytoplasmic, nonorganelle-related pattern. H9724's effect is the first evidence that HSP60 may play a role in peptide-hormone-receptor function and demonstrates the modulatory potential of a monoclonal antibody on living cells.

Lyme disease and current aspects of immunization

Lyme disease is a tick-borne multisystem disease that affects primarily the skin, nervous system, heart and joints. At least three species of Borrelia burgdorferi sensu lato, namely Borrelia burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii, can cause the disease. This review will focus mainly on the pathophysiology of Lyme arthritis, the long-term outcome of Lyme disease, and the recently licensed vaccine against Lyme disease.

CD4+ T helper 1 cells facilitate regression of murine Lyme carditis

Murine Lyme borreliosis, caused by infection with the spirochete Borrelia burgdorferi, results in acute arthritis and carditis that regress as a result of B. burgdorferi-specific immune responses. B. burgdorferi-specific antibodies can attenuate arthritis in mice deficient in both B cells and T cells but have no effect on carditis. Because macrophages comprise the principal immune cell in carditis, T-cell responses that augment cell-mediated immunity may be important for carditis regression. To investigate this hypothesis, we examined the course of Lyme carditis in mice selectively deficient in B cells or alphabeta T cells. Our results show that carditis regresses in B-cell-deficient B10.A(k) mice but not in alphabeta T-cell-deficient mice, independently of the mouse strain background. Despite prominent macrophage infiltrates, hearts from B. burgdorferi-infected alphabeta T-cell-deficient mice had less mRNA for tumor necrosis factor alpha as measured by reverse transcription-PCR compared to infected control mice. Anti-inflammatory cytokine mRNA levels were equivalent. Adoptive transfer of gamma interferon-secreting CD4+ T cells into infected alphabeta T-cell-deficient mice promoted carditis resolution. These results show that alphabeta T cells can promote resolution of murine Lyme carditis and are the first demonstration of a beneficial role for CD4+ T helper 1 cells in this disease.