The pathogenesis of lyme neuroborreliosis: from infection to inflammation

Th1 and Th17 but no Th2-related cytokine spectrum in the cerebrospinal fluid of children with Borrelia-related facial nerve palsy

Background

Chemokines and cytokines in cerebrospinal fluid (CSF) and serum have been extensively studied in adults with neuroborreliosis (NB), whereas there are limited data about the pediatric population. In adults, T helper type 1 (Th1) and Th17-related cytokines were observed during acute NB. In children, the Th2 response is thought to moderate the disease course. The aim of this study was to determine the chemokine-cytokine profile in children with acute NB displaying Borrelia-related peripheral facial nerve palsy (PFNP).

Methods

Luminex multiple bead technology was used for the detection of twelve cytokines and chemokines in the CSF and serum of three groups: 1) children with Borrelia-related PFNP (B_PFNP); 2) children with non-borrelial “idiopathic” PFNP (NI_PFNP); and 3) age-related controls.

Results

In B_PFNP, cytokines-chemokines related to a non-specific pro-inflammatory activity and specific Th1/Th17 responses were detected in CSF, and elevated IL-7 and IL-10 levels were observed in serum and CSF compared to NI_PFNP and to controls. In NI_PFNP, CSF findings were similar to controls; however, higher levels of IL-7 and MCP-1 were observed in serum. Higher IL-8, IL-15 and MCP-1 levels were detected in CSF compared to serum in all groups. MCP-1 and IL-8 levels in CSF were strikingly higher in B_PFNP compared to the other two groups, while IL-15 levels in CSF showed no difference. In addition, in controls, increased IL-4 level was found in CSF compared to serum.

Conclusion

The chemokine-cytokine profile in the CSF of children with acute NB was similar to previous studies in adults. Our data suggests that higher levels of IL-4, IL-15 and MCP-1 levels in CSF compared to serum in controls might represent a potentially protective cytokine milieu in the CNS compartment.

The multifaceted responses of primary human astrocytes and brain microvascular endothelial cells to the Lyme disease spirochete, Borrelia burgdorferi

The vector-borne pathogen, Borrelia burgdorferi, causes a multi-system disorder including neurological complications. These neurological disorders, collectively termed neuroborreliosis, can occur in up to 15% of untreated patients. The neurological symptoms are probably a result of a glial-driven, host inflammatory response to the bacterium. However, the specific contributions of individual glial and other support cell types to the pathogenesis of neuroborreliosis are relatively unexplored. The goal of this project was to characterize specific astrocyte and endothelial cell responses to B. burgdorferi. Primary human astrocytes and primary HBMEC (human brain microvascular endothelial cells) were incubated with B. burgdorferi over a 72-h period and the transcriptional responses to the bacterium were analyzed by real-time PCR arrays. There was a robust increase in several surveyed chemokine and related genes, including IL (interleukin)-8, for both primary astrocytes and HBMEC. Array results were confirmed with individual sets of PCR primers. The production of specific chemokines by both astrocytes and HBMEC in response to B. burgdorferi, including IL-8, CXCL-1, and CXCL-10, were confirmed by ELISA. These results demonstrate that primary astrocytes and HBMEC respond to virulent B. burgdorferi by producing a number of chemokines. These data suggest that infiltrating phagocytic cells, particularly neutrophils, attracted by chemokines expressed at the BBB (blood-brain barrier) may be important contributors to the early inflammatory events associated with neuroborreliosis.

Cytokines and chemokines at the crossroads of neuroinflammation, neurodegeneration, and neuropathic pain

Cytokines and chemokines are proteins that coordinate the immune response throughout the body. The dysregulation of cytokines and chemokines is a central feature in the development of neuroinflammation, neurodegeneration, and demyelination both in the central and peripheral nervous systems and in conditions of neuropathic pain. Pathological states within the nervous system can lead to activation of microglia. The latter may mediate neuronal and glial cell injury and death through production of proinflammatory factors such as cytokines and chemokines. These then help to mobilize the adaptive immune response. Although inflammation may induce beneficial effects such as pathogen clearance and phagocytosis of apoptotic cells, uncontrolled inflammation can result in detrimental outcomes via the production of neurotoxic factors that exacerbate neurodegenerative pathology. In states of prolonged inflammation, continual activation and recruitment of effector cells can establish a feedback loop that perpetuates inflammation and ultimately results in neuronal injury. A critical balance between repair and proinflammatory factors determines the outcome of a neurodegenerative process. This review will focus on how cytokines and chemokines affect neuroinflammation and disease pathogenesis in bacterial meningitis and brain abscesses, Lyme neuroborreliosis, human immunodeficiency virus encephalitis, and neuropathic pain.

Correlates of perceived health-related quality of life in post-treatment Lyme encephalopathy

BACKGROUND

Marked functional impairment has been reported by patients with post-treatment Lyme disease syndrome (PTLDS).

OBJECTIVE

We sought to identify the clinical features that contribute most strongly to the impaired health status associated with PTLDS.

METHODS

Enrolled patients had a well-documented history of Lyme disease, prior treatment with at least 3 weeks with intravenous ceftriaxone, a positive IgG Western blot, and objective problems with memory. An index score to capture aggregate cognitive functioning, Short-Form 36 physical and mental component summary scores, and scores on other clinical and demographic measures were examined. Multiple linear regressions were performed to determine significant predictors of perceptions of impaired life functioning as delineated by the Short-Form 36.

RESULTS

Fatigue was the most important contributor to perceived impairments in overall physical functioning, and fatigue and depression significantly predicted perceived impairments in overall mental functioning.

CONCLUSIONS

Because fatigue and depression contribute prominently to reports of impaired physical functioning and mental functioning among patients with PTLDS, clinicians should assess patients for these symptoms and consider targeting these symptoms in the selection of treatment interventions. Future controlled studies should examine the effectiveness of such agents for patients with PTLDS.

Rapid progressive bilateral hearing loss due to granulomatous otitis media in Lyme disease

We report on a patient with Lyme disease who presented with chronic bilateral otitis media and cranial neuropathy with rapid progressive hearing loss. After ceftriaxone and high-dose intravenous immunoglobulins, the disease was controlled only with methylprednisolone and cyclophosphamide. The relationship between Lyme disease and granulomatous vasculitis is discussed. Lyme disease should be kept in mind in the differential diagnosis of various otolaryngological and neurological presentations.

Risk factors for a non-favorable outcome after treated European neuroborreliosis

AIM

To identify possible risk factors for reduced health-related quality of life (HRQoL) and fatigue after treated Lyme neuroborreliosis (LNB).

METHODS

We included 50 patients with LNB and analyzed associations between their demographic, clinical, and laboratory characteristics at baseline and outcome at 30 months assessed by the self-report questionnaires Short Form-36 (SF-36) and Fatigue Severity Scale (FSS).

RESULTS

Lower scores in the SF-36 domain Physical Component Summary were associated with pretreatment symptom duration >6 weeks (B = -11.0, P = 0.001) and non-complete recovery at 4 months (B = -5.5, P = 0.037) (R(2) = 0.35). Lower scores in the SF-36 domain Mental Component Summary were associated with non-complete recovery at 4 months (B = -8.9, P = 0.01 (R(2) = 0.14). Higher FSS scores were associated with pretreatment symptom duration >6 weeks (B = 1.4, P = 0.006), high scores on the composite clinical score pretreatment (B = 0.1, P = 0.003), and non-complete recovery at 4 months (B = 1.6, P = 0.005) (R(2) = 0.46). No laboratory test results were associated with these predefined outcomes.

CONCLUSIONS

Delayed treatment start, more symptoms and findings before treatment, and non-complete recovery at 4 months after treatment are possible predictors of a poorer HRQoL and more fatigue 30 months after treated LNB. We did not find age, gender, educational level, involvement of the central nervous system, coexisting diseases, or cerebrospinal fluid findings to be associated with reduced HRQoL or fatigue. Our findings should be replicated in future studies before any conclusions can be drawn.

Ixodes ricinus ticks infected with the causative agent of Lyme disease, Borrelia burgdorferi sensu lato, have higher energy reserves

Ticks use their energy reserves to maintain their water balance, search for hosts and transmit tick-borne pathogens. However, the influence of tick-borne pathogens on the energy reserves of the tick vector has not been well studied. The relationship between Borrelia burgdorferi sensu lato (s.l.) infection status and fat content in questing Ixodes ricinus nymphs was examined. Nymphs were sampled from the field. Their body mass and fat content were measured, and their Borrelia genospecies infection status (using reverse line blot analysis), and spirochete load (using quantitative PCR) were analysed. Of the 900 nymphs tested, 21.2% were infected with a variety of Borrelia genospecies. Borrelia-infected nymphs had 12.1% higher fat content than uninfected ticks after correcting for body size. For the subset of Borrelia-infected nymphs, no relationship was found between spirochete load and fat content and bioenergetics calculations suggest that Borrelia spirochetes consume a negligible fraction of the tick energy reserves. While the mechanism that causes the association between Borrelia infection and higher fat content in I. ricinus nymphs remains unknown, the present study complements our previous findings that Borrelia-infected nymphs had higher survival times under desiccating conditions and walked less within a humidity gradient.

Lyme neuroborreliosis

Lyme neuroborreliosis (LNB) designates the nervous system disorders caused by the tick-borne spirochete Borrelia burgdorferi (Bb). The clinical syndromes are usually distinct and are classified as early and the rare late or chronic LNB. Early LNB occurs 3-6 weeks after infection most frequently as a lymphocytic meningoradiculoneuritis (LMR). Symptoms are mainly due to a painful sensory radiculitis and a multifocal motor radiculo-neuritis. Fifty percent have cranial nerve involvement predominantly uni- or bilateral facial nerve palsies. Meningitic symptoms occur primarily in children. Nerve biopsies, autopsies, animal models, and nerve conduction studies showed that the pathology is a lymphocytic perineuritis leading to multisegmental axonal injury of nerve roots, spinal ganglia, and distal nerve segments. Due to meningeal and root inflammation cerebrospinal fluid (CSF) shows lymphocytic inflammation. The only evidence that Bb causes peripheral neuropathy without CSF inflammation is seen in patients with acrodermatitis chronica atrophicans (ACA), a chronic dermatoborreliosis. In the rare chronic or late LNB the pathology and thus the clinical presentation is primarily due to chronic meningitis and meningovascular CNS involvement, whereas the peripheral nervous system is not primarily affected. In early and late LNB the diagnosis is based on a characteristic clinical appearance and CSF inflammation with Bb-specific intrathecal antibody production. Both conditions, but not the ACA-associated neuropathy, respond to antibiotic therapy.

CXCL13 may improve diagnosis in early neuroborreliosis with atypical laboratory findings

Background

Current guidelines regarding Lyme neuroborreliosis [LNB] require the presence of intrathecal Borrelia burgdorferi-specific antibody production for the definite diagnosis of LNB. However, about 20% of early stage infections present without an elevated antibody index. Moreover, intrathecal B. burgdorferi specific antibody synthesis may persist long after successful therapy of LNB. Recently published data indicate that CXCL13 seems to be a promising diagnostic tool for early stage LNB. In addition, CXCL13 might be suitable for treatment monitoring.

Case presentation

We report on a 39-year-old male patient from southern Germany, who has been suffering from subfebrile body temperatures and meningeal headache for six weeks. On the second day after hospital admission he developed peripheral palsy of the VII. cranial nerve. Cerebrospinal fluid (CSF) analysis showed granulocytic pleocytosis, elevated total protein and blood-CSF barrier dysfunction. Differential diagnostics for granulocytic pleocytosis were unremarkable. Only a second lumbar puncture, on day 6 after admission, revealed a lymphocytic pleocytosis. Serologic testing pointed to clear intrathecal Borrelia specific IgG antibody production. Interestingly, no anti-OspC antibodies were detectable. DNA of the rare Borrelia garinii OspA-type 7 could be amplified from the first CSF sample. The monitoring of CXCL13 in all CSF samples documented a fast decrease from 5000 pg/ml to 450 pg/ml after appropriate antibiotic treatment.

Conclusion

CXCL13 is a novel biomarker with high sensitivity and specificity for acute LNB. Our data show, that CXCL13 might be helpful in unclear cases and support the presumption that it might be a valuable tool for treatment monitoring. Anti-OspC antibody negativity is a rare observation, given the need of OspC for infection of the human hosts. Most likely this is due to a lack of sensitivity of OspC immunoblots that are unable to detect rare OspC variants.

Acetate supplementation reduces microglia activation and brain interleukin-1β levels in a rat model of Lyme neuroborreliosis

BACKGROUND

We have found that acetate supplementation significantly reduces neuroglia activation and pro-inflammatory cytokine release in a rat model of neuroinflammation induced with lipopolysaccharide. To test if the anti-inflammatory effect of acetate supplementation is specific to a TLR4-mediated injury, we measured markers of neuroglia activation in rats subjected to B. burgdorferi-induced neuroborreliosis that is mediated in large part by a TLR2-type mechanism.

METHODS

In this study, rats were subjected to Lyme neuroborreliosis following an intravenous infusion of B. burgdorferi (B31-MI-16). Acetate supplementation was induced using glyceryl triacetate (6g/kg) by oral gavage. Immunohistochemistry, qPCR, and western blot analyses were used to measure bacterial invasion into the brain, neuroglial activation, and brain and circulating levels of interleukin 1β. Statistical analysis was performed using one-way analysis of variance (ANOVA) followed by a Tukey's post hoc tests or using a Student's t test assuming unequal variances when appropriate.

RESULTS

We found that acetate supplementation significantly reduced microglia activation by 2-fold as determined by immunohistochemical and western blot analysis. Further, acetate supplementation also reduced the expression of the pro-inflammatory cytokine IL-1β by 2-fold as compared to controls. On the other hand, the inoculation of rats with B. burgdorferi had no effect on astroglial activation as determined by immunocytochemistry and western blot analysis despite significant increases in circulation levels of antigen toward B. burgdorferi and presence of the bacteria in the central nervous system.

CONCLUSIONS

These results suggest that microglial activation is an essential component to neuroborreliosis and that acetate supplementation may be an effective treatment to reduce injury phenotype and possibly injury progression in Lyme neuroborreliosis.

Pattern and motion-related visual-evoked potentials in neuroborreliosis: follow-up study

Visual-evoked potentials (VEPs) were used for objective testing of visual functions during treatment courses of Lyme neuroborreliosis (LNB) in adult patients in the Czech Republic. In 30 LNB patients with originally delayed VEP latencies, pattern-reversal (R-VEP) and motion onset (M-VEP) VEPs were repeatedly examined within 1 to 8 years. Six patients had Lyme optic neuritis (ON), five of them displayed prolonged latencies in both R-VEPs and M-VEPs, and one had only abnormal R-VEPs. The VEP recovery to normal latency values was in three of them. In the group of 24 LNB patients without ON, 14 patients displayed prolonged latencies only to motion stimuli, and 10 patients had abnormal latencies in both R-VEPs and M-VEPs. During the follow-up period, 7 patients displayed shortening to normal latencies. In 5 patients, VEPs latencies improved only partially, and in the remaining 12 patients, VEPs did not improve at all. This study provides objective evidence that in LNB, most of the patients without clinically manifesting ON display optic pathway involvement-predominantly magnocellular system/dorsal stream function changes. In patients with ON, however, mainly the parvocellular system is affected. About half of the patients without ON improved with a relatively long-time course of latency shortening.

Population Dynamics of Borrelia burgdorferi in Lyme Disease

Many chronic inflammatory diseases are known to be caused by persistent bacterial or viral infections. A well-studied example is the tick-borne infection by the gram-negative spirochaetes of the genus Borrelia in humans and other mammals, causing severe symptoms of chronic inflammation and subsequent tissue damage (Lyme Disease), particularly in large joints and the central nervous system, but also in the heart and other tissues of untreated patients. Although killed efficiently by human phagocytic cells in vitro, Borrelia exhibits a remarkably high infectivity in mice and men. In experimentally infected mice, the first immune response almost clears the infection. However, approximately 1 week post infection, the bacterial population recovers and reaches an even larger size before entering the chronic phase. We developed a mathematical model describing the bacterial growth and the immune response against Borrelia burgdorferi in the C3H mouse strain that has been established as an experimental model for Lyme disease. The peculiar dynamics of the infection exclude two possible mechanistic explanations for the regrowth of the almost cleared bacteria. Neither the hypothesis of bacterial dissemination to different tissues nor a limitation of phagocytic capacity were compatible with experiment. The mathematical model predicts that Borrelia recovers from the strong initial immune response by the regrowth of an immune-resistant sub-population of the bacteria. The chronic phase appears as an equilibration of bacterial growth and adaptive immunity. This result has major implications for the development of the chronic phase of Borrelia infections as well as on potential protective clinical interventions.

European neuroborreliosis: quality of life 30 months after treatment

OBJECTIVES

The prognosis after Lyme neuroborreliosis (LNB) is debated. The aim of this study was to assess health-related Quality of Life (QoL) and neurological symptoms 30 months after treatment in European patients with LNB.

MATERIALS AND METHODS

In a prospective case-control designed study, we investigated 50 well-characterized patients with LNB who had participated in a treatment trial for LNB 30 months earlier and 50 matched control persons with the health QoL questionnaire Short-Form 36 (SF-36), the Fatigue Severity Scale (FSS), the Montgomery and Åsberg Depression Rating Scale (MADRS), the Starkstein Apathy Scale (SAS), and the Mini Mental State (MMS). Clinical and demographic data were collected by semi-structured interviews and clinical neurological examination.

RESULTS

Lyme neuroborreliosis-treated patients scored lower than control persons in the SF-36 domains physical component summary (PCS) (44 vs 51 P < 0.001) and mental component summary (MCS) (49 vs 54 P = 0.010). They also scored lower than control persons in all the SF-36 subscales, except for bodily pain, and on FSS (3.5 vs 2.1 P < 0.001), but not on MMS (28 vs 29 P = 0.106). There was a difference in MADRS (3.1 vs 0. 8 P = 0.003) and SAS (13 vs 11 P = 0.016), but the scores were low in both groups. Fatigue was the most frequently reported symptom among LNB-treated patients (50%). Patients who reported complete recovery (56%) after LNB had similar QoL scores as the controls.

CONCLUSION

European persons treated for LNB have poorer health-related QoL and have more fatigue than persons without LNB.

European neuroborreliosis: neuropsychological findings 30 months post-treatment

BACKGROUND

The aim of this study was to compare neuropsychological (NP) functioning in patients with Lyme neuroborreliosis (LNB) 30months after treatment to matched controls.

METHODS

We tested 50 patients with LNB and 50 controls with the trail-making test (TMT), Stroop test, digit symbol test, and California Verbal Learning test (CVLT). A global NP sumscore was calculated to express the number of low scores on 23 NP subtasks.

RESULTS

Mean scores were lower amongst LNB-treated patients than amongst controls on tasks assessing attention/executive functions: (Stroop test 4: 77.6 vs. 67.0, P=0.015), response/processing speed (TMT 5: 23.4 vs. 19.2, P=0.004), visual memory (digit symbol recall: 6.6 vs. 7.2, P=0.038), and verbal memory (CVLT list B: 4.68 vs. 5.50, P=0.003). The proportion of patients and controls with NP sumscores within one SD from the mean in the control group (defined as normal) and between one and two SD (defined as deficit) were similar, but more LNB-treated patients than controls had a sumscore more than two SD from the mean (defined as impairment) (8 vs. 1, P=0.014).

CONCLUSIONS

As a group, LNB-treated patients scored lower on four NP subtasks assessing processing speed, visual and verbal memory, and executive/attention functions, as compared to matched controls. The distribution of NP dysfunctions indicates that most LNB-treated patients perform comparable to controls, whilst a small subgroup have a debilitating long-term course with cognitive problems.

[Ocular Lyme disease occurring during childhood: five case reports]

INTRODUCTION

Lyme borreliosis (LB) is the most common human tick-borne disease in the Northern hemisphere. The various ophthalmologic manifestations of Lyme borreliosis (LB) during childhood are discussed in this paper.

PATIENTS AND METHODS

Six children with LB-associated ocular manifestations were treated between 2000 and 2010 in the ophthalmology department of Strasbourg University Hospital (an endemic area). Medical history, ocular and systemic clinical findings, determinations of antibodies related to Borrelia, as well as exclusion of other causes were the diagnosis criteria.

RESULTS

Two cases of uveitis, two cases of abducens palsies, one case of optical neuropathy, and one case of orbital myositis associated with LB were diagnosed. Systemic findings, such as arthritis, rash, or erythema migrans were mentioned in all cases. Two children also complained of severe knee arthritis. Determination of antibodies was positive in all patients. They were all treated with antibiotics adjusted to individual circumstances and some of them (two cases of uveitis and one of optic neuropathy) also had anti-inflammatory treatment. Resolution of ocular signs, with no relapse, was observed in all patients within two to 12 weeks.

CONCLUSION

For any unexplained ocular symptom, even in children, LB should be taken into account, especially in endemic areas. Such patients should undergo serological testing. If the clinical presentation is suggestive of LB, a course of oral antibiotics should be used. All in all, permanent defects are extremely rare during the childhood period, even following long-term manifestation at an early age.

Molecular and pathological investigations of the central nervous system in Borrelia burgdorferi-infected dogs

Although neurological signs have been reported sporadically in dogs with systemic Lyme disease, it is unknown if neuroborreliosis occurs in dogs. The current study systematically evaluates canine brains for evidence of Borrelia burgdorferi infection. Twelve Beagles were experimentally challenged with B. burgdorferi-infected ticks at 18 weeks of age, and 2 unexposed dogs served as controls. One of the uninfected dogs and 6 infected dogs were each given 5 daily immunosuppressive doses of dexamethasone starting at 153 days post-infection. Eleven dogs were confirmed as infected by skin punch biopsy polymerase chain reaction (PCR) and serology. Neurological signs were not seen in any dogs through the end of the 190-day study. Whole blood, serum, cerebrospinal fluid (CSF), and brains from all dogs were collected. DNA was extracted from blood, CSF, and brain and evaluated by PCR for B. burgdorferi. Formalin-fixed brain tissue was examined by histopathology, immunohistochemistry, and PCR. Immunohistochemical staining for B. burgdorferi antigen was negative in all cases. The CSF analysis was normal, and PCR was uniformly negative for B. burgdorferi in all dogs. Six of the 11 (45%) infected dogs had mild to moderate lymphoplasmacytic choroid plexitis, which was more pronounced in the immunosuppressed dogs. The lack of B. burgdorferi DNA and immunohistochemical evidence of organisms, including within the choroid plexus lesions, suggests that B. burgdorferi does not have a direct role in the etiopathogenesis of canine central nervous system pathology.

Lyme disease: Part I. Advances and perspectives

Lyme disease (LD) is an increasingly recognized multisystem, insect-borne zoonosis. Prevalent worldwide, it has a variety of presentations at different stages of infection. The characteristic rash with central clearing known as erythema chronicum migrans, or simply erythema migrans, appears in its first stage. Typical features may be absent, and important variations are evident among cases seen in different parts of the world. LD may be difficult to diagnose clinically; knowledge about its epidemiology and transmission may be of assistance when the diagnosis is unclear. Based upon our experience with LD and a comprehensive literature review, we provide an update of LD epidemiology, pathophysiology, and management. We also cover the three clinical stages of LD that parallel those of syphilis, another spirochetal disease.

Neuroborreliosis: pathogenesis, symptoms, diagnosis and treatment

Lyme disease is the most common human tick-borne disease in the northern hemisphere. This article describes the current knowledge of several aspects of Lyme neuroborreliosis. The epidemiology is reviewed first, with special respect to the difference between European and American disease. Then, the current knowledge about the pathogenesis of Lyme neuroborreliosis is presented, with emphasis on immune evasion strategies. Furthermore, the clinical picture of acute Lyme neuroborreliosis and the frequently discussed post-Lyme disease syndrome are critically discussed. The commonly used diagnostic strategies, as well as the relevance of the lymphocyte transformation test, CD57+/CD3- cell count and CXCL13, are presented. Finally, the therapeutic options are described to give a balanced overview of all aspects of this disease.

Lyme Neuroborreliosis in 2 Horses

Lyme neuroborreliosis—characterized as chronic, necrosuppurative to nonsuppurative, perivascular to diffuse meningoradiculoneuritis—was diagnosed in 2 horses with progressive neurologic disease. In 1 horse, Borrelia burgdorferi sensu stricto was identified by polymerase chain reaction amplification of B burgdorferi sensu stricto–specific gene targets ( ospA, ospC, flaB, dbpA, arp). Highest spirochetal burdens were in tissues with inflammation, including spinal cord, muscle, and joint capsule. Sequence analysis of ospA, ospC, and flaB revealed 99.9% sequence identity to the respective genes in B burgdorferi strain 297, an isolate from a human case of neuroborreliosis. In both horses, spirochetes were visualized in affected tissues with Steiner silver impregnation and by immunohistochemistry, predominantly within the dense collagenous tissue of the dura mater and leptomeninges.

[Multiple ischemic strokes due to Borrelia garinii meningovasculitis]

The most frequent clinical manifestation of borreliosis in Switzerland is erythema migrans, with about 2500 patients each year. Neurological manifestations are rare, mostly hyperalgesic radiculitis (Bannwarth syndrome), aseptic meningitis or cranial nerve involvement. We report the first Swiss patient with meningovasculitis due to neuroborreliosis, with recurrent multiple ischemic strokes in multiple vascular territories. The treatment with ceftriaxone stopped the progression, but the patient is still suffering from severe invalidating cognitive disorders. We also comment on the pathophysiology and review the literature of other clinical cases.

Entzündliche Erkrankungen

Unter einer Meningitis versteht man eine Entzündung von Pia mater und Arachnoidea. Das Erregerspektrum ist weit und reicht von Bakterien, die hämatogen-metastatisch, fortgeleitet oder durch offene Hirnverletzung zur eitrigen Meningitis führen, über Viren zu Pilzen und Parasiten. Insbesondere bei den unbehandelt häufig letal verlaufenden eitrigen Meningitiden ist eine rasche Diagnose mit Erregernachweis notwendig. Unverzüglich ist daraufhin eine spezifische, der regionalen Resistenzentwicklung angepasste Therapie einzuleiten. Die meningeale Affektion im Rahmen einer Listeriose oder Tuberkulose verdient aufgrund des klinischen Bildes, des Verlaufs und der spezifischen Therapie besondere Beachtung. Die fungalen Infektionen werden, da klinisch häufig als Meningoenzephalitis imponierend, in Abschn. 33.3 abgehandelt.

Early production of IL-22 but not IL-17 by peripheral blood mononuclear cells exposed to live Borrelia burgdorferi: the role of monocytes and interleukin-1

If insufficiently treated, Lyme borreliosis can evolve into an inflammatory disorder affecting skin, joints, and the CNS. Early innate immunity may determine host responses targeting infection. Thus, we sought to characterize the immediate cytokine storm associated with exposure of PBMC to moderate levels of live Borrelia burgdorferi. Since Th17 cytokines are connected to host defense against extracellular bacteria, we focused on interleukin (IL)-17 and IL-22. Here, we report that, despite induction of inflammatory cytokines including IL-23, IL-17 remained barely detectable in response to B. burgdorferi. In contrast, T cell-dependent expression of IL-22 became evident within 10 h of exposure to the spirochetes. This dichotomy was unrelated to interferon-γ but to a large part dependent on caspase-1 and IL-1 bioactivity derived from monocytes. In fact, IL-1β as a single stimulus induced IL-22 but not IL-17. Neutrophils display antibacterial activity against B. burgdorferi, particularly when opsonized by antibodies. Since neutrophilic inflammation, indicative of IL-17 bioactivity, is scarcely observed in Erythema migrans, a manifestation of skin inflammation after infection, protective and antibacterial properties of IL-22 may close this gap and serve essential functions in the initial phase of spirochete infection.

Lyme neuroborreliosis in children

Lyme neuroborreliosis (LNB) represents the second most frequent manifestation of Lyme disease (LD) in Europe after cutaneous involvement. In the USA, LNB represents the third most frequent manifestation of LD after cutaneous involvement and arthritis. The scope of this article is, in the light of recent publications, to review the specific manifestations of LNB in children including predictive models, and to discuss diagnosis criteria, new diagnostic tools and new therapeutic options. Differences in disease patterns between the USA and Europe are also highlighted.

The crystal structures of two salivary cystatins from the tick Ixodes scapularis and the effect of these inhibitors on the establishment of Borrelia burgdorferi infection in a murine model

We have previously demonstrated that two salivary cysteine protease inhibitors from the Borrelia burgdorferi (Lyme disease) vector Ixodes scapularis- namely sialostatins L and L2 - play an important role in tick biology, as demonstrated by the fact that silencing of both sialostatins in tandem results in severe feeding defects. Here we show that sialostatin L2 - but not sialostatin L - facilitates the growth of B. burgdorferi in murine skin. To examine the structural basis underlying these differential effects of the two sialostatins, we have determined the crystal structures of both sialostatin L and L2. This is the first structural analysis of cystatins from an invertebrate source. Sialostatin L2 crystallizes as a monomer with an 'unusual' conformation of the N-terminus, while sialostatin L crystallizes as a domain-swapped dimer with an N-terminal conformation similar to other cystatins. Deletion of the 'unusual' N-terminal five residues of sialostatin L2 results in marked changes in its selectivity, suggesting that this region is a particularly important determinant of the biochemical activity of sialostatin L2. Collectively, our results reveal the structure of two tick salivary components that facilitate vector blood feeding and that one of them also supports pathogen transmission to the vertebrate host.

[Neuroborreliosis]

Neuroborreliosis is easily diagnosed by means of clinical symptoms and laboratory findings. Guiding symptoms are radicular pain and pareses of the extremities and the facial nerve. There is a great number of further less frequently occurring neurological symptoms, which can be attributed to a borrelial infection only by appropriate investigations of the CSF. Radiculitis is cured adequately by oral doxycycline while symptoms of the central nervous system are probably better treated intravenously by ceftriaxone, cefotaxime or penicillin G. Post-Lyme syndrome is a diffuse description of non-specific complaints, which are not the explicit result of a former infection with B. burgdorferi. As further antibiotics do not help and the CSF is unremarkable in most patients, a persistent infection with B. burgdorferi s.l. in all probability can be excluded.

The chemokine CXCL13 is a key regulator of B cell recruitment to the cerebrospinal fluid in acute Lyme neuroborreliosis

Background

The chemokine CXCL13 is known to dictate homing and motility of B cells in lymphoid tissue and has been implicated in the formation of ectopic lymphoid tissue in chronic inflammation. Whether it influences B cell trafficking during acute infection, is largely unclear. In previous studies, we showed that (I) CXCL13 levels are markedly increased in the B cell-rich cerebrospinal fluid (CSF) of patients with acute Lyme neuroborreliosis (LNB), and (II) CXCL13 is released by monocytes upon recognition of borrelial outer surface proteins by Toll-like receptor 2. Here, we assessed the role of CXCL13 - in comparison to other chemokines - in the recruitment of B cells to the CSF of patients with acute LNB.

Methods

Measurement of chemokines was done by ELISA. B cells were isolated from whole blood using magnetic cell separation (MACS). For migration experiments, a modified Boyden chamber assay was used and the migrated B cells were further analysed by FACS. The migration was inhibited either by preincubation of the CSF samples with neutralizing antibodies, heating to 60°C, removal of proteins >3 kDa, or by pre-treatment of the B cells with pertussis toxin. The principal statistical tests used were one-way analysis of variance and Bonferroni test (chemokine measurements) as well as paired Student's t-test (migration experiments).

Results

Measurements of chemokine levels revealed an increase in three of the four known major B cell chemoattractants CXCL13, CCL19 and CXCL12 in LNB CSF. The CXCL13 CSF:serum ratio, as a measure of the chemotactic gradient, was substantially higher than that of CCL19 and CXCL12. Moreover, the chemotactic activity of LNB CSF was reduced up to 56% after preincubation with a neutralizing CXCL13 antibody, while combined preincubation with antibodies against CXCL13, CCL19, and CXCL12 did not lead to further reduction. Since treatment with pertussis toxin, heating to 60°C, and removal of proteins >3 kDa abrogated the chemotactic activity, further not yet identified chemokines seem to be involved in B cell recruitment to LNB CSF.

Conclusion

Combined, our study suggests a key role of CXCL13 in B cell migration to sites of infection as shown here for the CSF of LNB patients.

Microglia in infectious diseases of the central nervous system

Microglia are the resident macrophage population in the central nervous system (CNS) parenchyma and, as such, are poised to provide a first line of defense against invading pathogens. Microglia are endowed with a vast repertoire of pattern recognition receptors that include such family members as Toll-like receptors and phagocytic receptors, which collectively function to sense and eliminate microbes invading the CNS parenchyma. In addition, microglial activation elicits a broad range of pro-inflammatory cytokines and chemokines that are involved in the recruitment and subsequent activation of peripheral immune cells infiltrating the infected CNS. Studies from several laboratories have demonstrated the ability of microglia to sense and respond to a wide variety of pathogens capable of colonizing the CNS including bacterial, viral, and fungal species. This review will highlight the role of microglia in microbial recognition and the resultant antipathogen response that ensues in an attempt to clear these infections. Implications as to whether microglial activation is uniformly beneficial to the CNS or in some circumstances may exacerbate pathology will also be discussed.

Inflammation and central nervous system Lyme disease

Lyme disease, caused by the bacterium Borrelia burgdorferi, can cause multi-systemic signs and symptoms, including peripheral and central nervous system disease. This review examines the evidence for and mechanisms of inflammation in neurologic Lyme disease, with a specific focus on the central nervous system, drawing upon human studies and controlled research with experimentally infected rhesus monkeys. Directions for future human research are suggested that may help to clarify the role of inflammation as a mediator of the chronic persistent symptoms experienced by some patients despite antibiotic treatment for neurologic Lyme disease.

Microglia are mediators of Borrelia burgdorferi-induced apoptosis in SH-SY5Y neuronal cells

Inflammation has long been implicated as a contributor to pathogenesis in many CNS illnesses, including Lyme neuroborreliosis. Borrelia burgdorferi is the spirochete that causes Lyme disease and it is known to potently induce the production of inflammatory mediators in a variety of cells. In experiments where B. burgdorferi was co-cultured in vitro with primary microglia, we observed robust expression and release of IL-6 and IL-8, CCL2 (MCP-1), CCL3 (MIP-1α), CCL4 (MIP-1β) and CCL5 (RANTES), but we detected no induction of microglial apoptosis. In contrast, SH-SY5Y (SY) neuroblastoma cells co-cultured with B. burgdorferi expressed negligible amounts of inflammatory mediators and also remained resistant to apoptosis. When SY cells were co-cultured with microglia and B. burgdorferi, significant neuronal apoptosis consistently occurred. Confocal microscopy imaging of these cell cultures stained for apoptosis and with cell type-specific markers confirmed that it was predominantly the SY cells that were dying. Microarray analysis demonstrated an intense microglia-mediated inflammatory response to B. burgdorferi including up-regulation in gene transcripts for TLR-2 and NFκβ. Surprisingly, a pathway that exhibited profound changes in regard to inflammatory signaling was triggering receptor expressed on myeloid cells-1 (TREM1). Significant transcript alterations in essential p53 pathway genes also occurred in SY cells cultured in the presence of microglia and B. burgdorferi, which indicated a shift from cell survival to preparation for apoptosis when compared to SY cells cultured in the presence of B. burgdorferi alone. Taken together, these findings indicate that B. burgdorferi is not directly toxic to SY cells; rather, these cells become distressed and die in the inflammatory surroundings generated by microglia through a bystander effect. If, as we hypothesized, neuronal apoptosis is the key pathogenic event in Lyme neuroborreliosis, then targeting microglial responses may be a significant therapeutic approach for the treatment of this form of Lyme disease.

Lyme disease, which is transmitted to humans through the bite of a tick, is currently the most frequently reported vector-borne illness in the northern hemisphere. Borrelia burgdorferi is the bacterium that causes Lyme disease and it is known to readily induce inflammation within a variety of infected tissues. Many of the neurological signs and symptoms that may affect patients with Lyme disease have been associated with B. burgdorferi-induced inflammation in the central nervous system (CNS). In this report we investigated which of the primary cell types residing in the CNS might be functioning to create the inflammatory environment that, in addition to helping clear the pathogen, could simultaneously be harming nearby neurons. We report findings that implicate microglia, a macrophage cell type in the CNS, as the key responders to infection with B. burgdorferi. We also present evidence indicating that this organism is not directly toxic to neurons; rather, a bystander effect is generated whereby the inflammatory surroundings created by microglia in response to B. burgdorferi may themselves be toxic to neuronal cells.

Possible role of glial cells in the onset and progression of Lyme neuroborreliosis

BACKGROUND

Lyme neuroborreliosis (LNB) may present as meningitis, cranial neuropathy, acute radiculoneuropathy or, rarely, as encephalomyelitis. We hypothesized that glia, upon exposure to Borrelia burgdorferi, the Lyme disease agent, produce inflammatory mediators that promote the acute cellular infiltration of early LNB. This inflammatory context could potentiate glial and neuronal apoptosis.

METHODS

We inoculated live B. burgdorferi into the cisterna magna of rhesus macaques and examined the inflammatory changes induced in the central nervous system (CNS), and dorsal root nerves and ganglia (DRG).

RESULTS

ELISA of the cerebrospinal fluid (CSF) showed elevated IL-6, IL-8, CCL2, and CXCL13 as early as one week post-inoculation, accompanied by primarily lymphocytic and monocytic pleocytosis. In contrast, onset of the acquired immune response, evidenced by anti-B. burgdorferi C6 serum antibodies, was first detectable after 3 weeks post-inoculation. CSF cell pellets and CNS tissues were culture-positive for B. burgdorferi. Histopathology revealed signs of acute LNB: severe multifocal leptomeningitis, radiculitis, and DRG inflammatory lesions. Immunofluorescence staining and confocal microscopy detected B. burgdorferi antigen in the CNS and DRG. IL-6 was observed in astrocytes and neurons in the spinal cord, and in neurons in the DRG of infected animals. CCL2 and CXCL13 were found in microglia as well as in endothelial cells, macrophages and T cells. Importantly, the DRG of infected animals showed significant satellite cell and neuronal apoptosis.

CONCLUSION

Our results support the notion that innate responses of glia to B. burgdorferi initiate/mediate the inflammation seen in acute LNB, and show that neuronal apoptosis occurs in this context.

Remaining complaints 1 year after treatment for acute Lyme neuroborreliosis; frequency, pattern and risk factors

BACKGROUND AND PURPOSE

To chart remaining complaints 1 year after treatment for neuroborreliosis, and to identify risk factors for a non-favorable outcome.

METHODS

We followed patients treated for neuroborreliosis prospectively, and assessed outcome by a composite clinical score. The impact on outcome of clinical, demographic and laboratory factors were analyzed by univariate analyses and logistic regression.

RESULTS

Out of 85 patients 41 (48%) had remaining complaints; 14 had objective findings and 27 subjective symptoms. Remaining complaints were associated with pre-treatment symptom duration >or=6 weeks (OR = 4.062, P = 0.044), high pre-treatment cerebrospinal fluid (CSF) cell count (OR = 1.005, P = 0.001), and female gender (OR = 3.218, P = 0.025). Presence of CSF oligoclonal bands (OCBs) was not analyzed in the logistic regression model due to many missing observations, but was found to be more frequent both pre-treatment (P = 0.004) and after 12 months (P = 0.015) among patients with remaining complaints as compared to patients with complete recovery. Further evaluation showed that objective remaining findings, and not subjective symptoms, were associated with pre-treatment symptom duration >or=6 weeks. No difference in outcome was observed between patients treated with IV ceftriaxone and patients treated with oral doxycycline.

CONCLUSION

Remaining complaints are common after neuroborreliosis. The majority of the complaints are subjective. Pre-treatment symptom duration >or=6 weeks, high pre-treatment CSF cell count, and female gender seem to be risk factors for remaining complaints. Presence of CSF OCBs may also predict a non-favorable outcome, but this should be further studied. Whether subjective and objective complaints are associated with different risk factors is also an issue for future studies.

Laboratory data in children with Lyme neuroborreliosis, relation to clinical presentation and duration of symptoms

The occurrence of IgM and IgG antibodies against Borrelia burgdoferi in serum and cerebrospinal fluid (CSF) and intrathecal synthesis of antibodies (antibody index) were studied in relation to clinical presentation and the duration of symptoms before diagnosis in 146 children diagnosed with neuroborreliosis. Lymphocytic meningitis was demonstrated in 141 of these children. Levels of white blood cells (WBC) and protein in CSF correlated significantly to numbers of d with symptoms. Children were divided into 3 clinical groups: A (n = 37): only cranial neuropathy; B (n = 68): both cranial neuropathy and other neurological symptoms; C (n = 41): neurological symptoms without cranial neuropathy. Levels of WBC and protein in CSF as well as the proportion of children with antibodies in serum and CSF were generally lowest in group A, intermediate in group B and highest in group C. The proportion of children with antibodies in serum and CSF and a positive antibody index was also related to duration of symptoms; the antibody index was present in 51% of children with symptoms < or = 7 d, and in 80% of children with symptoms > 7 d (p<0.01). The clinical presentation and duration of symptoms must be considered when interpreting laboratory data in children with suspected neuroborreliosis.

Lyme neuroborreliosis: manifestations of a rapidly emerging zoonosis

Lyme disease has a worldwide distribution and is the most common vector-borne disease in the United States. Incidence, clinical manifestations, and presentations vary by geography, season, and recreational habits. Lyme neuroborreliosis (LNB) is neurologic involvement secondary to systemic infection by the spirochete Borrelia burgdorferi in the United States and by Borrelia garinii or Borrelia afzelii species in Europe. Enhanced awareness of the clinical presentation of Lyme disease allows inclusion of LNB in the imaging differential diagnosis of facial neuritis, multiple enhancing cranial nerves, enhancing noncompressive radiculitis, and pediatric leptomeningitis with white matter hyperintensities on MR imaging. The MR imaging white matter appearance of successfully treated LNB and multiple sclerosis display sufficient similarity to suggest a common autoimmune pathogenesis for both. This review highlights differences in the epidemiology, clinical manifestations, diagnosis, and management of Lyme disease in the United States, Europe, and Asia, with an emphasis on neurologic manifestations and neuroimaging.

Management of neuroborreliosis in European adult patients

OBJECTIVES

To survey present knowledge and controversies in European neuroborreliosis.

MATERIAL AND METHODS

The article is based on available literature, own experience, and a speech held by the authors. together on the Norwegian annual neurological meeting.

RESULTS

Diagnosis of neuroborreliosis is based on clinical neurological findings, laboratory support of borrelia infection, and indications of causality between neurological findings and borreliosis. In the absence of means to identify B. burgdorferi, antibody tests are used for laboratory diagnosis. Two to three weeks courses of IV penicillin or ceftriaxone are highly effective in neuroborreliosis. Oral doxycyclin is probably equally effective. Remaining symptoms five years after treatment for neuroborreliosis are reported in 25-50% of patients.

CONCLUSIONS

We suggest two levels of diagnostic accuracy; definite and possible neuroborreliosis. These case definitions are proposed to make the basis for treatment decisions. The prognosis of neuroborreliosis and pathophysiology of post-treatment conditions need further studies. Extensive treatments with antibiotics are not recommended.