The pathogenesis of lyme neuroborreliosis: from infection to inflammation

Neuronal loss or dysfunction in patients with early Lyme neuroborreliosis: a proton magnetic resonance spectroscopy study of the brain

Background

We hypothesized that since Borrelia burgdorferi causes systemic inflammation and infects the brain, it may lead to alterations in cerebral metabolism, as measured by ¹H-magnetic resonance spectroscopy (¹H-MRS). The purpose of our study was to determine whether ¹H-MRS could detect brain metabolite alterations in patients with early Lyme neuroborreliosis (LNB) in normal-appearing brain tissue on the conventional magnetic resonance imaging (MRI).

Methods

Twenty-six patients diagnosed with early LNB and twenty-six healthy volunteers as a control group have been involved in the study. All of them underwent routine MRI protocol using 3.0-T MRI scanner. ¹H-MRS examinations were performed with repetition time (TR) = 2000 ms, and echo time (TE) = 135 ms. Single voxels were positioned in the anterior and posterior parts of the right and left frontal lobes.

Results

We found a statistically significant decrease of the N-acetylaspartate/creatine ratio within the anterior part of the right and left frontal lobes (p ≤ 0.001 and p = 0.001 respectively) and in the posterior part of the right and left frontal lobes (p ≤ 0.001 and 0.031) in the patients with LNB.

Conclusion

A significant reduction in NAA/Cr ratio in comparison with the controls suggests the presence of diffuse neuronal loss in patients with early LNB.

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.

Association of small fiber neuropathy and post treatment Lyme disease syndrome

OBJECTIVES

To examine whether post-treatment Lyme disease syndrome (PTLDS) defined by fatigue, cognitive complaints and widespread pain following the treatment of Lyme disease is associated with small fiber neuropathy (SFN) manifesting as autonomic and sensory dysfunction.

METHODS

This single center, retrospective study evaluated subjects with PTLDS. Skin biopsies for assessment of epidermal nerve fiber density (ENFD), sweat gland nerve fiber density (SGNFD) and functional autonomic testing (deep breathing, Valsalva maneuver and tilt test) were performed to assess SFN, severity of dysautonomia and cerebral blood flow abnormalities. Heart rate, end tidal CO2, blood pressure, and cerebral blood flow velocity (CBFv) from middle cerebral artery using transcranial Doppler were monitored.

RESULTS

10 participants, 5/5 women/men, age 51.3 ± 14.7 years, BMI 27.6 ± 7.3 were analyzed. All participants were positive for Lyme infection by CDC criteria. At least one skin biopsy was abnormal in all ten participants. Abnormal ENFD was found in 9 participants, abnormal SGNFD in 5 participants, and both abnormal ENFD and SGNFD were detected in 4 participants. Parasympathetic failure was found in 7 participants and mild or moderate sympathetic adrenergic failure in all participants. Abnormal total CBFv score was found in all ten participants. Low orthostatic CBFv was found in 7 participants, three additional participants had abnormally reduced supine CBFv.

CONCLUSIONS

SFN appears to be associated with PTLDS and may be responsible for certain sensory symptoms. In addition, dysautonomia related to SFN and abnormal CBFv also seem to be linked to PTLDS. Reduced orthostatic CBFv can be associated with cerebral hypoperfusion and may lead to cognitive dysfunction. Autonomic failure detected in PTLDS is mild to moderate. SFN evaluation may be useful in PTLDS.

[Bilateral diaphragmatic palsy due to Lyme neuroborreliosis]

INTRODUCTION

Lyme disease is not uncommon and can sometimes progress to neurological complications. We report here an unusual case of bilateral diaphragmatic paralysis secondary to Lyme neuroborreliosis.

CASE REPORT

A 79-year-old man was admitted to the intensive care unit for acute respiratory distress requiring intubation and the long-term use of nocturnal non-invasive ventilation. Three months beforehand he had been bitten by a tick and developed erythema migrans which was treated with Doxycycline for 10 days. This clinical presentation became complicated a few days later by the progressive onset of severe dyspnoea. At admission, chest radiography revealed bilateral elevation of the diaphragm. Pulmonary function tests revealed a severe restrictive disorder aggravated by decubitus. A diaphragmatic electromyogram showed bilateral axonal polyneuropathy of the phrenic nerves. IgG and IgM antibodies to Borrelia burgdorferi were detectable in serum and cerebrospinal fluid, leading to the diagnosis of Lyme disease. He was treated with intravenous ceftriaxone 2g per day for 21 days, leading to a substantial improvement in symptoms.

CONCLUSION

In the presence of unilateral or bilateral diaphragmatic paralysis of undetermined aetiology, it seems relevant to perform Lyme serology in the blood and, in positive cases, to follow up with a lumbar puncture in order to detect intrathecal IgG synthesis.

Limitations and Confusing Aspects of Diagnostic Testing for Neurologic Lyme Disease in the United States

In the United States, laboratories frequently offer multiple different assays for testing of cerebrospinal fluid (CSF) samples to provide laboratory support for the diagnosis of central nervous system Lyme disease (CNSLD). Often included among these diagnostic tests are the same enzyme immunoassays and immunoblots that are routinely used to detect the presence of antibodies to Borrelia burgdorferi in serum. However, performing these assays on CSF alone may yield positive results simply from passive diffusion of serum antibodies into the CSF. In addition, such tests are only U.S. Food and Drug Administration cleared and well validated for testing serum, not CSF. When performed using CSF, positive results from these assays do not establish the presence of intrathecal antibody production to B. burgdorferi and therefore should not be offered. The preferred test to detect intrathecal production of antibodies to B. burgdorferi is the antibody index assay, which corrects for passive diffusion of serum antibodies into CSF and requires testing of paired serum and CSF collected at approximately the same time. However, this assay also has limitations and should only be used to establish a diagnosis of CNSLD in conjunction with patient exposure history, clinical presentation, and other laboratory findings.

The Emerging Role of Microbial Biofilm in Lyme Neuroborreliosis

Lyme borreliosis (LB) is the most common tick-borne disease caused by the spirochete Borrelia burgdorferi in North America and Borrelia afzelii or Borrelia garinii in Europe and Asia, respectively. The infection affects multiple organ systems, including the skin, joints, and the nervous system. Lyme neuroborreliosis (LNB) is the most dangerous manifestation of Lyme disease, occurring in 10-15% of infected individuals. During the course of the infection, bacteria migrate through the host tissues altering the coagulation and fibrinolysis pathways and the immune response, reaching the central nervous system (CNS) within 2 weeks after the bite of an infected tick. The early treatment with oral antimicrobials is effective in the majority of patients with LNB. Nevertheless, persistent forms of LNB are relatively common, despite targeted antibiotic therapy. It has been observed that the antibiotic resistance and the reoccurrence of Lyme disease are associated with biofilm-like aggregates in B. burgdorferi, B. afzelii, and B. garinii, both in vitro and in vivo, allowing Borrelia spp. to resist to adverse environmental conditions. Indeed, the increased tolerance to antibiotics described in the persisting forms of Borrelia spp., is strongly reminiscent of biofilm growing bacteria, suggesting a possible role of biofilm aggregates in the development of the different manifestations of Lyme disease including LNB.

Imaging in Lyme neuroborreliosis

Abstract

Lyme neuroborreliosis (LNB) is a tick-borne spirochetal infection with a broad spectrum of imaging pathology. For individuals who live in or have travelled to areas where ticks reside, LNB should be considered among differential diagnoses when clinical manifestations from the nervous system occur. Radiculitis, meningitis and facial palsy are commonly encountered, while peripheral neuropathy, myelitis, meningoencephalitis and cerebral vasculitis are rarer manifestations of LNB. Cerebrospinal fluid (CSF) analysis and serology are key investigations in patient workup. The primary role of imaging is to rule out other reasons for the neurological symptoms. It is therefore important to know the diversity of possible imaging findings from the infection itself. There may be no imaging abnormality, or findings suggestive of neuritis, meningitis, myelitis, encephalitis or vasculitis. White matter lesions are not a prominent feature of LNB. Insight into LNB clinical presentation, laboratory test methods and spectrum of imaging pathology will aid in the multidisciplinary interaction that often is imperative to achieve an efficient patient workup and arrive at a correct diagnosis. This article can educate those engaged in imaging of the nervous system and serve as a comprehensive tool in clinical cases.

Key Points

• Diagnostic criteria for LNB emphasise exclusion of an alternative cause to the clinical symptoms.

• MRI makes a crucial contribution in the diagnosis and follow-up of LNB.

• MRI may have normal findings, or show neuritis, meningitis, myelitis, encephalitis or vasculitis.

• White matter lesions are not a prominent feature of LNB.

The chemokine CXCL13 in cerebrospinal fluid in children with Lyme neuroborreliosis

Anti-Borrelia antibodies in the cerebrospinal fluid (CSF) are required for definite diagnosis of Lyme neuroborreliosis (LNB). However, children often present with early LNB, and antibody production in the CSF may not be demonstrated. Recent studies have suggested the chemokine CXCL13 to be an early marker for LNB. The aim of the study was to evaluate CXCL13 for laboratory diagnosis in pediatric LNB patients and to evaluate the association with pleocytosis in CSF, clinical features, and recovery. CSF samples were collected from LNB patients, classified as definite LNB (n = 44) or possible LNB (n = 22), and controls classified as non-LNB (n = 102) or other specific diagnoses (n = 23). CSF samples were analyzed with the recomBead CXCL13 assay (Mikrogen Diagnostik, Germany), cut-off 160 pg/mL. CXCL13 was significantly higher in LNB patients compared to controls (p < 0.001). Among LNB patients, 58/66 had elevated CXCL13, and among controls, 111/125 had CXCL13 levels under cut-off (sensitivity 88%, specificity 89%). In LNB patients with pleocytosis but no detectable anti-Borrelia antibodies in CSF (possible LNB), CXCL13 was elevated in 16/22 (73%). A weak correlation between CXCL13 and pleocytosis in CSF was found in LNB patients (Rho = 0.46, p < 0.01), but no differences in CXCL13 levels in relation to specific clinical features. In conclusion, CXCL13 is elevated in CSF in children with LNB, showing acceptable sensitivity and specificity. In patients with possible LNB, CXCL13 was elevated in a majority of cases (73%) and is suggested as a complementary diagnostic tool in pediatric LNB patients. CXCL13 was not associated with specific clinical features or recovery.

Occurrence of erythema migrans in children with Lyme neuroborreliosis and the association with clinical characteristics and outcome - a prospective cohort study

Background

Erythema migrans (EM) is the most common manifestation of Lyme borreliosis (LB), caused by the spirochete Borrelia burgdorferi sensu lato. The infection can disseminate into the nervous system and cause Lyme neuroborreliosis (LNB), the second most frequent LB manifestation in children. The aim of this prospective cohort study is to describe the occurrence of EM among children with LNB and to evaluate possible differences in clinical characteristics or outcome between LNB patients with and without EM.

Method

Children being evaluated for LNB in southeast Sweden during the period 2010–2014 underwent a clinical examination, laboratory testing and filled out a questionnaire regarding duration and nature of symptoms, EM and the child’s health. Children were classified according to European guidelines for LNB. Clinical recovery was evaluated at a 2-month follow-up.

Results

The occurrence of EM among children with LNB was 37 out of 103 (36%). Gender, age, observed tick bite, clinical features, duration of neurological symptoms or clinical outcome did not differ significantly between LNB patients with or without EM. However, facial nerve palsy was significantly more common among children with EM in the head and neck area.

Conclusion

EM occurred in 36% of children with LNB and the location on the head and neck was more common among children with facial nerve palsy. EM was not associated with other specific clinical characteristics or outcome. Thus, the occurrence of EM in children with LNB cannot be useful as a prognostic factor for clinical outcome. This aspect has not previously been highlighted but seems to be relevant for the paediatrician in a clinical setting.

Electronic supplementary material

The online version of this article (10.1186/s12887-018-1163-2) contains supplementary material, which is available to authorized users.

Primary Human Microglia Are Phagocytically Active and Respond to Borrelia burgdorferi With Upregulation of Chemokines and Cytokines

The Lyme disease causing bacterium Borrelia burgdorferi has an affinity for the central nervous system (CNS) and has been isolated from human cerebral spinal fluid by 18 days following Ixodes scapularis tick bite. Signaling from resident immune cells of the CNS could enhance CNS penetration by B. burgdorferi and activated immune cells through the blood brain barrier resulting in multiple neurological complications, collectively termed neuroborreliosis. The ensuing symptoms of neurological impairment likely arise from a glial-driven, host inflammatory response to B. burgdorferi. To date, however, the mechanism by which the bacterium initiates neuroinflammation leading to neural dysfunction remains unclear. We hypothesized that dead B. burgdorferi and bacterial debris persist in the CNS in spite of antibiotic treatment and contribute to the continuing inflammatory response in the CNS. To test our hypothesis, cultures of primary human microglia were incubated with live, antibiotic-killed and antibiotic-killed sonicated B. burgdorferi to define the response of microglia to different forms of the bacterium. We demonstrate that primary human microglia treated with B. burgdorferi show increased expression of pattern recognition receptors and genes known to be involved with cytoskeletal rearrangement and phagocytosis including MARCO, SCARB1, PLA2, PLD2, CD14, and TLR3. In addition, we observed increased expression and secretion of pro-inflammatory mediators and neurotrophic factors such as IL-6, IL-8, CXCL-1, and CXCL-10. Our data also indicate that B. burgdorferi interacts with the cell surface of primary human microglia and may be internalized following this initial interaction. Furthermore, our results indicate that dead and sonicated forms of B. burgdorferi induce a significantly larger inflammatory response than live bacteria. Our results support our hypothesis and provide evidence that microglia contribute to the damaging inflammatory events associated with neuroborreliosis.

Cerebrospinal Fluid B-lymphocyte Chemoattractant CXCL13 in the Diagnosis of Acute Lyme Neuroborreliosis in Children

BACKGROUND

Current markers of Lyme neuroborreliosis (LNB) in children have insufficient sensitivity in the early stage of disease. The B-lymphocyte chemoattractant CXCL13 in the cerebrospinal fluid (CSF) may be useful in diagnosing LNB, but its specificity has not been evaluated in studies including children with clinically relevant differential diagnoses. The aim of this study was to elucidate the diagnostic value of CSF CXCL13 in children with symptoms suggestive of LNB.

METHODS

Children with symptoms suggestive of LNB were included prospectively into predefined groups with a high or low likelihood of LNB based on CSF pleocytosis and the detection of Borrelia antibodies or other causative agents. CSF CXCL13 levels were compared between the groups, and receiver-operating characteristic analyses were performed to indicate optimal cutoff levels to discriminate LNB from non-LNB conditions.

RESULTS

Two hundred and ten children were included. Children with confirmed LNB (n=59) and probable LNB (n=18) had higher CSF CXCL13 levels than children with possible LNB (n=7), possible peripheral LNB (n=7), non-Lyme aseptic meningitis (n=12), non-meningitis (n=91) and negative controls (n=16). Using 18 pg/mL as a cutoff level, both the sensitivity and specificity of CSF CXCL13 for LNB (confirmed and probable) were 97%. Comparing only children with LNB and non-Lyme aseptic meningitis, the sensitivity and specificity with the same cutoff level were 97% and 83%, respectively.

CONCLUSION

CSF CXCL13 is a sensitive marker of LNB in children. The specificity to discriminate LNB from non-Lyme aseptic meningitis may be more moderate, suggesting that CSF CXCL13 should be used together with other variables in diagnosing LNB in children.

Chemokine CXC Ligand 13 in Cerebrospinal Fluid Can Be Used as an Early Diagnostic Biomarker for Lyme Neuroborreliosis: A Meta-Analysis

Lyme neuroborreliosis (LNB), which is the most common neurological manifestation of Lyme disease (LD), seriously impairs both the central and peripheral nervous systems. Current LNB diagnostic methods and criteria are not very effective. Recently, several studies have indicated that a high concentration of the chemokine CXC ligand 13 (CXCL13) in cerebrospinal fluid (CSF) could be used as a new biomarker for the diagnosis of LNB. Thus, we carried out a meta-analysis to systematically analyze the data from these studies to evaluate the value of CXCL13 as an LNB biomarker. After searching for articles in several databases, including PubMed, Embase, the Cochrane Library, and the China National Knowledge Infrastructure (CNKI), we included 7 articles in the meta-analysis with a total of 1299 patients with LNB or other neuroinflammatory diseases. From these 1299 patients, 343 patients with LNB served as the experimental group and 956 patients with other neuroinflammatory diseases or healthy individuals served as the control group. The analyses were performed using Meta-Disc1.4 statistical software. Based on the pooled specificity, sensitivity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and summary receiver operating characteristic curve, we found that CXCL13 indeed has a high sensitivity and specificity for diagnosing LNB, which means that it can be used as a new diagnostic biomarker for the diagnosis of LNB.

Borrelia burgdorferi basic membrane protein A could induce chemokine production in murine microglia cell line BV2

Lyme neuroborreliosis is a nervous system infectious disease caused by Borrelia burgdorferi (B. burgdorferi). It has been demonstrated that cytokines induced by B. burgdorferi are related to Lyme neuroborreliosis. Microglia is known as a key player in the immune responses that occur within the central nervous system. In response to inflammation, it will be activated and generate cytokines and chemokines. Experiments in vitro cells have showed that B. Burgdorferi membrane protein A (BmpA), a major immunogen of B. Burgdorferi, could induce Lyme arthritis and stimulate human and murine lymphocytes to produce inflammatory cytokines. In our study, the murine microglia BV2 cell line was used as a cell model to explore the stimulating effects of recombinant BmpA (rBmpA); Chemokine chip, ELISA and QPCR technology were used to measure the production of chemokines from microglial cells stimulated by rBmpA. Compared with the negative control group, CXCL2, CCL22, and CCL5 concentrations in the cell supernatant increased significantly after the rBmpA stimulation; the concentration of these chemokines increased with rBmpA concentration increasing; the mRNA expression levels of chemokines (CXCL2, CCL22, and CCL5) in murine BV2 cells increased significantly with 10 μg/mL and 20 μg/mL rBmpA stimulation; CXCL13 was not change after the rBmpA stimulation. Our study shows that chemokines, such as CXCL2, CCL22, and CCL5 were up-regulated by the rBmpA in the BV2 cells. The production of chemokines in Lyme neuroborreliosis may be mainly from microglia cells and the rBmpA may be closely related with the development of Lyme neuroborreliosis.

Bibrachial plegia due to Lyme radiculopoliomyelitis-myelitis

Nervous system involvement occurs in up to 15% of patients with Lyme disease, most commonly manifested as cranial neuropathy, lymphocytic meningitis, and or radiculoneuritis. We describe a patient with subacute radiculopoliomyelitis-myelitis matching the selective involvement of the anterior horns and roots of the cervical spinal cord seen on MRI and on electrodiagnostic studies. We demonstrate positive CSF Lyme antibodies and document a near-complete recovery with antibiotics. This case highlights the importance of recognizing an atypical presentation of Lyme disease in the setting of initial radiculitis and or myelitis, particularly given the potential for favorable outcomes with appropriate treatment.

A Borrelia afzelii Infection Increases Larval Tick Burden on Myodes glareolus (Rodentia: Cricetidae) and Nymphal Body Weight of Ixodes ricinus (Acari: Ixodidae)

Several microorganisms have been shown to manipulate their host or vector to enhance their own transmission. Here we examined whether an infection with Borrelia afzelii affects its transmission between its bank vole (Myodes glareolus, Schreber, 1780) host and tick vector. Captive-bred bank voles were inoculated with B. afzelii or control medium, after which host preference of Ixodes ricinus L. nymphs was determined in a Y-tube olfactometer. Thereafter, infected and uninfected bank voles were placed in a semifield arena containing questing larvae to measure larval tick attachment. Engorged larvae were collected from these bank voles, molted into nymphs, weighed, and analyzed for infection by PCR.Nymphs were attracted to the odors of a bank vole compared to ambient air and preferred the odors of an infected bank vole over that of an uninfected bank vole. In the semifield arena, infected male bank voles had greater larval tick burdens then uninfected males, while similar larval tick burdens were observed on females regardless of infection status. Nymphal ticks that acquired a B. afzelii infection had higher body weight than nymphs that did not acquire an infection regardless of the infection status of the vole. These results show that a B. afzelii infection in bank voles increases larval tick burden and that a B. afzelii infection in larvae increases nymphal body weight. This finding provides novel ecological insights into the enzootic cycle of B. afzelii.

Effects of dexamethasone and meloxicam on Borrelia burgdorferi-induced inflammation in glial and neuronal cells of the central nervous system

Background

Lyme neuroborreliosis (LNB), caused by the spirochete Borrelia burgdorferi (Bb), affects both the central and peripheral nervous systems. Previously, we reported that in a model of acute LNB in rhesus monkeys, treatment with the anti-inflammatory drug dexamethasone significantly reduced both pleocytosis and levels of cerebrospinal fluid (CSF) immune mediators that were induced by Bb. Dexamethasone also inhibited the formation of inflammatory, neurodegenerative, and demyelinating lesions in the brain and spinal cord of these animals. In contrast, these signs were evident in the infected animals that were left untreated or in those that were treated with meloxicam, a non-steroidal anti-inflammatory drug.

Methods

To address the differential anti-inflammatory effects of dexamethasone and meloxicam in the central nervous system (CNS), we evaluated the potential of these drugs to alter the levels of Bb-induced inflammatory mediators in culture supernatants of rhesus frontal cortex (FC) explants, primary rhesus astrocytes and microglia, and human oligodendrocytes. We also ascertained the potential of dexamethasone to modulate Bb-induced apoptosis in rhesus FC explants. As meloxicam is a known COX-2 inhibitor, we evaluated whether meloxicam altered the levels of COX-2 as induced by live Bb in cell lysates of primary rhesus astrocytes and microglia.

Results

Dexamethasone but not meloxicam significantly reduced the levels of several Bb-induced immune mediators in culture supernatants of FC explants, astrocytes, microglia, and oligodendrocytes. Dexamethasone also had a protective effect on Bb-induced neuronal and oligodendrocyte apoptosis in rhesus FC explants. Further, meloxicam significantly reduced the levels of Bb-induced COX-2 in microglia, while both Bb and meloxicam were unable to alter the constitutive levels of COX-2 in astrocytes.

Conclusions

These data indicate that dexamethasone and meloxicam have differential anti-inflammatory effects on Bb-induced inflammation in glial and neuronal cells of the CNS and help explain the in vivo findings of significantly reduced inflammatory mediators in the CSF and lack of inflammatory neurodegenerative lesions in the brain and spinal cord of Bb-infected animals that were treated with dexamethasone but not meloxicam. Signaling cascades altered by dexamethasone could serve as possible therapeutic targets for limiting CNS inflammation and tissue damage in LNB.

MicroRNA and mRNA Transcriptome Profiling in Primary Human Astrocytes Infected with Borrelia burgdorferi

Lyme disease is caused by infection with the bacterium Borrelia burgdorferi (Bb), which is transmitted to humans by deer ticks. The infection manifests usually as a rash and minor systemic symptoms; however, the bacteria can spread to other tissues, causing joint pain, carditis, and neurological symptoms. Lyme neuroborreliosis presents itself in several ways, such as Bell's palsy, meningitis, and encephalitis. The molecular basis for neuroborreliosis is poorly understood. Analysis of the changes in the expression levels of messenger RNAs and non-coding RNAs, including microRNAs, following Bb infection could therefore provide vital information on the pathogenesis and clinical symptoms of neuroborreliosis. To this end, we used cultured primary human astrocytes, key responders to CNS infection and important components of the blood-brain barrier, as a model system to study RNA and microRNA changes in the CNS caused by Bb. Using whole transcriptome RNA-seq, we found significant changes in 38 microRNAs and 275 mRNAs at 24 and 48 hours following Bb infection. Several of the RNA changes affect pathways involved in immune response, development, chromatin assembly (including histones) and cell adhesion. Further, several of the microRNA predicted target mRNAs were also differentially regulated. Overall, our results indicate that exposure to Bb causes significant changes to the transcriptome and microRNA profile of astrocytes, which has implications in the pathogenesis, and hence potential treatment strategies to combat this disease.

Cerebrospinal fluid cytokines in Lyme neuroborreliosis

Background

Lyme neuroborreliosis (LNB) is one of the manifestations of Lyme disease. Although it is known that immune reaction of LNB patients is dominated by Th1 and Th2 responses and patients have elevated numbers of B cells in their cerebrospinal fluid (CSF), not all the cells involved in inflammation and cytokine secretion have been characterized. The current diagnostics of LNB is based on intrathecal production of antibodies. In recent years, the measurement of chemokine CXCL13 concentration from the CSF has been introduced as a new promising diagnostic tool for LNB to complement the antibody-based diagnostic methods. A few other cytokines have also been analyzed as possible diagnostic markers. However, multiplex analyses simultaneously evaluating the concentrations of a large number of different cytokines in the CSF of LNB patients have been lacking thus far. Extensive cytokine profiling CSF samples of LNB patients would also help in understanding the complex immunopathogenesis of LNB.

Methods

CSF samples were analyzed from 43 LNB patients, 19 controls, 18 tick-borne encephalitis patients, and 31 multiple sclerosis patients. In addition, CSF samples from 23 LNB patients obtained after the antibiotic treatment were examined. Altogether, the concentrations of 49 different cytokines were determined from all of the samples. The concentrations of 48 different cytokines were analyzed by magnetic bead suspension array using the Bio-Plex Pro Human Cytokine 21- and 27-plex panels, and the concentration of CXCL13 was analyzed by an ELISA based method.

Results

Distinct cytokine profiles which were able to distinguish LNB patients from controls, tick-borne encephalitis patients, multiple sclerosis patients, and LNB patients treated with antibiotics were identified. LNB patients had elevated concentrations of all major T helper cell type cytokines (Th1, Th2, Th9, Th17, and Treg) in their CSF.

Conclusions

Despite the great differences in the CSF cytokine profiles of different patient groups, CXCL13 still remained as the best marker for LNB. However, IL-1ra might also be helpful as a marker for the antibiotic treatment response. Concerning the immunopathogenesis, this is the first report suggesting the involvement of Th9 cells in the immune response of LNB.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0745-x) contains supplementary material, which is available to authorized users.

Lipid peroxidation in the pathogenesis of neuroborreliosis

This study analyzed the onset of lipid peroxidation (LPO) in neuroborreliosis and the effects of ceftriaxone therapy on LPO. Twenty-two patients with early neuroborreliosis and 22 healthy subjects were studied. LPO in the cerebrospinal fluid (CSF), as well as the plasma and urine was estimated by the levels of reactive aldehydes: 4-hydroxynonenal (4-HNE), 4-hydroxyhexenal, malondialdehyde, and 4-oxononenal, F2-isoprostanes and A4/J4-neuroprostanes (NPs). The plasma level of 4-HNE-protein adducts arachidonic acid (AA), docosahexaenoic acid (DHA) and vitamin E was determined. Additionally, enzymatic activities of phospholipase A2 (PLA2), platelet-activating factor acetylhydrolase (PAF-AH) and glutathione peroxidase (GSH-Px) were determined. A decrease of AA, DHA levels and GSH-Px activity in plasma was associated with a significant increase of aldehydes in the CSF, plasma and urine. Similarly, the increase of F2-isoprostanes and NPs in the CSF and plasma was associated with the decreased activity of PLA2 and PAF-AH. Ceftriaxone therapy cured patients and reduced the levels of F2-isoprostanes, NPs and reactive aldehydes. However, the activities of PLA2 and PAF-AH increased. Pathophysiological association of neuroborreliosis with systemic LPO was revealed. Effective antibiotic therapy attenuated LPO. Biomarkers of LPO could be useful to monitor the onset of neuroborreliosis and show the effectiveness of pharmacotherapy.

Did Garin and Bujadoux Actually Report a Case of Lyme Radiculoneuritis?

Although a 1922 report by Garin and Bujadoux is widely regarded as describing the first case of neurologic Lyme borreliosis, the many highly atypical features raises the question of whether the paper deserves the historic recognition that it has received.

A 1922 report by Garin and Bujadoux is widely regarded as describing the first case of neurologic Lyme borreliosis. Although the patient reported had a tick bite followed by the development of a rash and radiculoneuritis, there were a number of highly atypical features, raising the question of whether the patient, in fact, had neurologic Lyme borreliosis. The paper may not deserve the historic recognition that it has received.

Anti-inflammatory effects of dexamethasone and meloxicam on Borrelia burgdorferi-induced inflammation in neuronal cultures of dorsal root ganglia and myelinating cells of the peripheral nervous system

Background

Lyme neuroborreliosis (LNB), caused by the spirochete Borrelia burgdorferi (Bb), could result in cognitive impairment, motor dysfunction, and radiculoneuritis. We hypothesized that inflammation is a key factor in LNB pathogenesis and recently evaluated the effects of dexamethasone, a steroidal anti-inflammatory drug, and meloxicam a non-steroidal anti-inflammatory drug (NSAID), in a rhesus monkey model of acute LNB. Dexamethasone treatment significantly reduced the levels of immune mediators, and prevented inflammatory and/or neurodegenerative lesions in the central and peripheral nervous systems, and apoptosis in the dorsal root ganglia (DRG). However, infected animals treated with meloxicam showed levels of inflammatory mediators, inflammatory lesions, and DRG cell apoptosis that were similar to that of the infected animals that were left untreated.

Methods

To address the differential anti-inflammatory effects of dexamethasone and meloxicam on neuronal and myelinating cells of the peripheral nervous system (PNS), we evaluated the potential of these drugs to alter the levels of Bb-induced inflammatory mediators in rhesus DRG cell cultures and primary human Schwann cells (HSC), using multiplex enzyme-linked immunosorbent assays (ELISA). We also ascertained the ability of these drugs to modulate cell death as induced by live Bb in HSC using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) viability assay and the potential of dexamethasone to modulate Bb-induced apoptosis in HSC by the TUNEL assay.

Results

Earlier, we reported that dexamethasone significantly reduced Bb-induced immune mediators and apoptosis in rhesus DRG cell cultures. Here, we report that dexamethasone but not meloxicam significantly reduces the levels of several cytokines and chemokines as induced by live Bb, in HSC and DRG cell cultures. Further, meloxicam does not significantly alter Bb-induced cell death in HSC, while dexamethasone protects HSC against Bb-induced cell death.

Conclusions

These data help further explain our in vivo findings of significantly reduced levels of inflammatory mediators, DRG-apoptosis, and lack of inflammatory neurodegenerative lesions in the nerve roots and DRG of Bb-infected animals that were treated with dexamethasone, but not meloxicam. Evaluating the role of the signaling mechanisms that contribute to the anti-inflammatory potential of dexamethasone in the context of LNB could serve to identify therapeutic targets for limiting radiculitis and axonal degeneration in peripheral LNB.

Gender Differences in Childhood Lyme Neuroborreliosis

BACKGROUND

Many neurological diseases show differences between genders. We studied gender differences in childhood Lyme neuroborreliosis (LNB) in an endemic area of Lyme borreliosis in Norway.

METHODS

In a population based study, all children (<14 years of age) with symptoms suspicious of LNB, including all children with acute facial nerve palsy, were evaluated for LNB by medical history, clinical examination, blood tests, and lumbar puncture. LNB was diagnosed according to international criteria.

RESULTS

142 children were diagnosed with LNB during 2001-2009. Facial nerve palsy was more common in girls (86%) than in boys (62%) (p < 0.001), but headache and/or neck stiffness as the only symptom was more common in boys (30%) than in girls (10%) (p = 0.003). The girls were younger than boys and had a shorter duration of symptoms, but boys had a higher level of pleocytosis than girls. In a multivariate analysis, both gender and having headache and neck stiffness were associated with a higher level of pleocytosis.

CONCLUSION

Girls and boys have different clinical presentations of LNB, and boys have a higher level of inflammation than girls independent of the clinical presentation.

The Putative Role of Viruses, Bacteria, and Chronic Fungal Biotoxin Exposure in the Genesis of Intractable Fatigue Accompanied by Cognitive and Physical Disability

Patients who present with severe intractable apparently idiopathic fatigue accompanied by profound physical and or cognitive disability present a significant therapeutic challenge. The effect of psychological counseling is limited, with significant but very slight improvements in psychometric measures of fatigue and disability but no improvement on scientific measures of physical impairment compared to controls. Similarly, exercise regimes either produce significant, but practically unimportant, benefit or provoke symptom exacerbation. Many such patients are afforded the exclusionary, non-specific diagnosis of chronic fatigue syndrome if rudimentary testing fails to discover the cause of their symptoms. More sophisticated investigations often reveal the presence of a range of pathogens capable of establishing life-long infections with sophisticated immune evasion strategies, including Parvoviruses, HHV6, variants of Epstein-Barr, Cytomegalovirus, Mycoplasma, and Borrelia burgdorferi. Other patients have a history of chronic fungal or other biotoxin exposure. Herein, we explain the epigenetic factors that may render such individuals susceptible to the chronic pathology induced by such agents, how such agents induce pathology, and, indeed, how such pathology can persist and even amplify even when infections have cleared or when biotoxin exposure has ceased. The presence of active, reactivated, or even latent Herpes virus could be a potential source of intractable fatigue accompanied by profound physical and or cognitive disability in some patients, and the same may be true of persistent Parvovirus B12 and mycoplasma infection. A history of chronic mold exposure is a feasible explanation for such symptoms, as is the presence of B. burgdorferi. The complex tropism, life cycles, genetic variability, and low titer of many of these pathogens makes their detection in blood a challenge. Examination of lymphoid tissue or CSF in such circumstances may be warranted.

Bacterial, Fungal, and Parasitic Infections of the Central Nervous System: Radiologic-Pathologic Correlation and Historical Perspectives

Despite remarkable progress in prevention and treatment, infectious diseases affecting the central nervous system remain an important source of morbidity and mortality, particularly in less-developed countries and in immunocompromised persons. Bacterial, fungal, and parasitic pathogens are derived from living organisms and affect the brain, spinal cord, or meninges. Infections due to these pathogens are associated with a variety of neuroimaging patterns that can be appreciated at magnetic resonance imaging in most cases. Bacterial infections, most often due to Streptococcus, Haemophilus, and Neisseria species, cause significant meningitis, whereas the less common cerebritis and subsequent abscess formation have well-documented progression, with increasingly prominent altered signal intensity and corresponding contrast enhancement. Atypical bacterial infections are characterized by the development of a granulomatous response, classically seen in tuberculosis, in which the tuberculoma is the most common parenchymal form of the disease; spirochetal and rickettsial diseases are less common. Fungal infections predominate in immunocompromised hosts and are caused by yeasts, molds, and dimorphic fungi. Cryptococcal meningitis is the most common fungal infection, whereas candidiasis is the most common nosocomial infection. Mucormycosis and aspergillosis are characterized by angioinvasiveness and are associated with high morbidity and mortality among immunocompromised patients. In terms of potential exposure in the worldwide population, parasitic infections, including neurocysticercosis, toxoplasmosis, echinococcosis, malaria, and schistosomiasis, are the greatest threat. Rare amebic infections are noteworthy for their extreme virulence and high mortality. The objective of this article is to highlight the characteristic neuroimaging manifestations of bacterial, fungal, and parasitic diseases, with emphasis on radiologic-pathologic correlation and historical perspectives.

Inflammation in the pathogenesis of lyme neuroborreliosis

Lyme neuroborreliosis, caused by the spirochete Borrelia burgdorferi, affects both peripheral and central nervous systems. We assessed a causal role for inflammation in Lyme neuroborreliosis pathogenesis by evaluating the induced inflammatory changes in the central nervous system, spinal nerves, and dorsal root ganglia (DRG) of rhesus macaques that were inoculated intrathecally with live B. burgdorferi and either treated with dexamethasone or meloxicam (anti-inflammatory drugs) or left untreated. ELISA of cerebrospinal fluid showed significantly elevated levels of IL-6, IL-8, chemokine ligand 2, and CXCL13 and pleocytosis in all infected animals, except dexamethasone-treated animals. Cerebrospinal fluid and central nervous system tissues of infected animals were culture positive for B. burgdorferi regardless of treatment. B. burgdorferi antigen was detected in the DRG and dorsal roots by immunofluorescence staining and confocal microscopy. Histopathology revealed leptomeningitis, vasculitis, and focal inflammation in the central nervous system; necrotizing focal myelitis in the cervical spinal cord; radiculitis; neuritis and demyelination in the spinal roots; and inflammation with neurodegeneration in the DRG that was concomitant with significant neuronal and satellite glial cell apoptosis. These changes were absent in the dexamethasone-treated animals. Electromyography revealed persistent abnormalities in F-wave chronodispersion in nerve roots of a few infected animals; which were absent in dexamethasone-treated animals. These results suggest that inflammation has a causal role in the pathogenesis of acute Lyme neuroborreliosis.

CD4+ T cells promote antibody production but not sustained affinity maturation during Borrelia burgdorferi infection

CD4 T cells are crucial for enhancing B cell-mediated immunity, supporting the induction of high-affinity, class-switched antibody responses, long-lived plasma cells, and memory B cells. Previous studies showed that the immune response to Borrelia burgdorferi appears to lack robust T-dependent B cell responses, as neither long-lived plasma cells nor memory B cells form for months after infection, and nonswitched IgM antibodies are produced continuously during this chronic disease. These data prompted us to evaluate the induction and functionality of B. burgdorferi infection-induced CD4 T(FH) cells. We report that CD4 T cells were effectively primed and T(FH) cells induced after B. burgdorferi infection. These CD4 T cells contributed to the control of B. burgdorferi burden and supported the induction of B. burgdorferi-specific IgG responses. However, while affinity maturation of antibodies against a prototypic T-dependent B. burgdorferi protein, Arthritis-related protein (Arp), were initiated, these increases were reversed later, coinciding with the previously observed involution of germinal centers. The cessation of affinity maturation was not due to the appearance of inhibitory or exhausted CD4 T cells or a strong induction of regulatory T cells. In vitro T-B cocultures demonstrated that T cells isolated from B. burgdorferi-infected but not B. burgdorferi-immunized mice supported the rapid differentiation of B cells into antibody-secreting plasma cells rather than continued proliferation, mirroring the induction of rapid short-lived instead of long-lived T-dependent antibody responses in vivo. The data further suggest that B. burgdorferi infection drives the humoral response away from protective, high-affinity, and long-lived antibody responses and toward the rapid induction of strongly induced, short-lived antibodies of limited efficacy.

Deciphering the interface between a CD40 receptor and borrelial ligand OspA

Neuroborreliosis is serious sequelae of Lyme borreliosis. Neuroinvasion is largely relied on successful translocation of Borrelia across the blood-brain barrier. Adherence of Borrelia to brain microvascular endothelial cell (BMEC) seems to be critical for translocation. Here we unfold the interface between OspA and CD40 molecules, major ligand and receptor, that are involved in adhesion of Borrelia to BMECs. We found that a region between Asn127 and Asp205 of OspA forms the CD40-receptor binding site. This region encompasses human umbilical vein endothelial cell (HUVEC) binding domain and contains a potential ligand-binding pocket lined by three amino acid residues: Arg139, Glu160 and Lys189. Disruption of this pocket (by truncation of the HUVEC binding domain) caused complete abrogation of its ability to bind CD40. To identify the amino acid residues within the HUVEC binding domain involved in the CD40 binding, site-directed mutagenesis and binding assays were performed. Results showed that Asp149, Phe165, Ala172, Val186 and Leu192 might form interface with CD40 molecule. Other side of the interface was also identified with the help of a ligand-binding assay with OspA and truncated CD40 fragments. Results exposed that cysteine rich domain 2 (CRD2) of CD40 might be the site for OspA binding. Precise knowledge of the molecular basis of the ligand-receptor interactions is essential in order to understand mechanisms of pathogenesis and could help in the development of novel therapeutics and vaccines.

Cerebrospinal fluid CXCL13 is a prognostic marker for aseptic meningitis

In exceptional cases, patients with aseptic meningitis eventually develop aseptic meningoencephalitis. To find a candidate marker for the development of aseptic meningoencephalitis in adult patients diagnosed with aseptic meningitis, we compared 12 different cytokines/chemokines in cerebrospinal fluid (CSF) from 5 patients with aseptic meningoencephalitis, 8 patients with aseptic meningitis, and 8 patients with control disease. Only the CXCL13 concentration was significantly elevated in the CSF of the group with aseptic meningoencephalitis compared with the group with aseptic meningitis. Thus, CSF CXCL13 may be a useful marker for predicting the prognosis of aseptic meningitis.

Cerebrospinal fluid T-regulatory cells recognize Borrelia burgdorferi NAPA in chronic Lyme borreliosis

The NapA protein of B. burgdorferi is essential for the persistence of spirochetes in ticks. One of the most intriguing aspects of NapA is its potential to interfere with the host immune system. Here, we investigated the role of the acquired immune responses induced by NapA in the cerebrospinal fluids (CSF) of patients with chronic Lyme borreliosis. We evaluated the cytokine profile induced in microglia cells and CSF T cells following NapA stimulation. We report here that NapA induced a regulatory T (Treg) response in the CSF of patients with chronic Lyme borreliosis and it is able to expand this suppressive response by promoting the production of TGF-beta and IL-10 by microglia cells. Collectively, these data strongly support a central role of NapA in promoting both Treg response and immune suppression in the CSF of patients with chronic Lyme borreliosis and suggest that NapA and the Treg pathway may represent novel therapeutic targets for the prevention and treatment of the disease.

Nervous system Lyme disease

Lyme disease, the multisystem infectious disease caused by the tick-borne spirochete Borrelia burgdorferi involves the nervous system in 10-15% of affected individuals. Manifestations include lymphocytic meningitis, cranial neuritis, radiculoneuritis, and mononeuropathy multiplex. Encephalopathy, identical to that seen in many systemic inflammatory diseases, can occur during active systemic infection. It is not specific to Lyme disease and only rarely is evidence of nervous system infection. Diagnosis of systemic disease is based on demonstration of specific antibodies in peripheral blood by means of two-tier testing with an ELISA and Western blot. Central nervous system infection often results in specific antibody production in the CSF, demonstrable by comparing spinal fluid to blood serologies. Treatment is straightforward and curative in most instances. Many patients can be treated effectively with oral antibiotics such as doxycycline; in severe CNS infection parenteral treatment with ceftriaxone or other similar agents is highly effective. Treatment should usually be for 2 to at most 4 weeks. Longer treatment adds no therapeutic benefit but does add substantial risk.

Diagnosis of multiple sclerosis

This chapter will serve as a guide for the diagnosis of multiple sclerosis (MS). Primary aims include a review of both the common and atypical clinical manifestations of MS, a detailed discussion of the alternative diagnoses which can mimic MS, as well as a review of the current established diagnostic criteria and a history of their development. It will also review the distinct disease courses and MS variants. The goal of the chapter is to facilitate the diagnostic process for clinicians so that they may expedite early diagnosis and treatment in an effort to alter disease outcomes and ultimately improve patients' quality of life.

Lyme disease: case report of persistent Lyme disease from Pulaski County, Virginia

A 50-year-old woman from Pulaski, Virginia, presented to a local clinic with headaches, fever, generalized joint pain, excessive thirst and fluid intake, and a progressing rash on her back. On physical examination, she had a large circular red rash on her back with a bull’s-eye appearance, 16 × 18 cm in diameter. Serologic tests confirmed a diagnosis of Lyme disease. The patient could recall a walk through the woods 3 weeks prior, although she never noticed a tick on her body. Following a prolonged course of antibiotics, this case report presents a patient with ongoing symptoms consistent with post-treatment Lyme disease.

A pattern approach to focal white matter hyperintensities on magnetic resonance imaging

Evaluation of focal white matter hyperintensities on magnetic resonance imaging in any age group is always challenging because the cause of these hyperintensities varies extensively. Understanding the clinical presentation, pathophysiology, and associated imaging findings can allow the radiologist to limit the differential diagnosis. A specific imaging approach including age, pattern of distribution, signal characteristics on various sequences, enhancement pattern, and other ancillary findings helps to identify a correct cause for these hyperintensities. This article provides a pattern approach to differentiate various common and a few uncommon diseases presenting as focal white matter hyperintensities.

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.