Recombinant immunoblot in the serodiagnosis of Lyme borreliosis. Comparison with indirect immunofluorescence and enzyme-linked immunosorbent assay

Frequency of Lyme disease in patients with tick contact and identification of ticks from Bolu province of Turkey

BACKGROUND OBJECTIVES

Lyme disease is a multisystemic disease caused by the bacteria in the Borrelia burgdorferi sensu lato complex, which is transmitted by ticks of the Ixodes genus. Although there are seroprevalence studies and case reports of Lyme disease from various regions in Turkey, there is no widespread epidemiological research. This study aimed to determine the frequency of Lyme disease in the cases followed-up after tick contact and to examine the isolated ticks to reveal tick population from Bolu province.

METHODS

In this study, cases who applied to the emergency department due to tick contact between April and September 2020 were firstly evaluated in our infectious diseases and clinical microbiology outpatient clinic on the third day of exposure and antibodies against Lyme disease were investigated with the IFA method to exclude the patients who were previously exposed to B. burgdorferi. Thereafter, patients were requested to continue outpatient visits at the 1 st and 3 rd month control. At these controls, serum samples were taken to study B.burgdorferi antibodies with the ELISA method which were stored at - 20°C until the study day.

RESULTS

Out of 123 patients who came to first control, 69 patients continued later to at least one of the two controls (either at first or third month). Of these 69 patients, only one (1.4%) was diagnosed with Lyme borreliosis according to clinical and laboratory features. Erythema migrans did not occur in any of the cases. Serum samples were assessed by ELISA method. Asymptomatic infection was detected in 22 cases (30.5%). In addition, we could obtain 46 ticks from our cases and two genera were identified. Forty-two (91.3%) were Ixodes spp. , and two (4.3%) were Hyalomma spp.

INTERPRETATION CONCLUSION

In this study, which was carried out for the first time in the province of Bolu, it was concluded that the cases presenting with a history of tick contact were most frequently exposed to Ixodes spp ticks, and the probability of developing Lyme borreliosis was low (1,4%) during the three-month follow-up period. Further studies with more number of cases and more extended follow-up period are needed.

Isolated Intracranial Hypertension as a Presentation of Pediatric Lyme Borreliosis: A Case Report and Literature Review

BACKGROUND

It is extremely rare for Lyme borreliosis to present solely with features of increased intracranial pressure. The treatment of pediatric Lyme neuroborreliosis with oral versus intravenous antibiotics remains controversial.

METHODS

Case report and literature review.

RESULTS

A 13-year-old male presented with five days of binocular diplopia, several weeks of headache, and a history of multiple tick bites six weeks prior. His examination showed a left eye abduction deficit and bilateral optic disc edema. Magnetic resonance imaging (MRI) of the brain with contrast showed tortuosity of the optic nerves, prominence of the optic nerve sheaths, and enhancement of the left fifth and bilateral sixth cranial nerves. Lumbar puncture showed an elevated opening pressure and a lymphocytic pleocytosis. Lyme IgM and IgG antibodies were positive in the serum and cerebrospinal fluid. The patient was treated with intravenous ceftriaxone for two days empirically followed by doxycycline by mouth for 19 days. Symptoms began improving after 48 hours. The strabismus resolved after two weeks, and the papilledema improved slowly with complete resolution at six months.

CONCLUSIONS

Lyme neuroborreliosis can present as isolated intracranial hypertension in the pediatric population; it can be differentiated from idiopathic intracranial hypertension on MRI, and lumbar puncture and can be confirmed with serum antibody testing. Oral doxycycline can be considered for Lyme neuroborreliosis in children.

First Human Case of Tick-Borne Encephalitis in Non-Endemic Region in Italy: A Case Report

Tick-borne encephalitis (TBE), a human viral infectious disease caused by the tick-borne encephalitis virus (TBEV), is emerging in Italy, especially in the north-eastern area. No human cases of autochthonous TBE have been reported in Italy’s central regions (such as Emilia-Romagna, Italy). However, here we describe the first human case of TBEV infection in this region, pointing to endemic transmission of TBEV, supporting the concept of circulation of TBEV and of the presence of a possible hot spot in the Serramazzoni region in the Emilian Apennines.

Lyme Neuroborreliosis in Children

Lyme neuroborreliosis (LNB) is an infectious disease, developing after a tick bite and the dissemination of Borrelia burgdorferi sensu lato spirochetes reach the nervous system. The infection occurs in children and adults but with different clinical courses. Adults complain of radicular pain and paresis, while among the pediatric population, the most common manifestations of LNB are facial nerve palsy and/or subacute meningitis. Moreover, atypical symptoms, such as fatigue, loss of appetite, or mood changes, may also occur. The awareness of the various clinical features existence presented by children with LNB suspicion remains to be of the greatest importance to diagnose and manage the disease.

Laboratory Diagnosis of Lyme Borreliosis

Lyme borreliosis is caused by a growing list of related, yet distinct, spirochetes with complex biology and sophisticated immune evasion mechanisms. It may result in a range of clinical manifestations involving different organ systems, and can lead to persistent sequelae in a subset of cases. The pathogenesis of Lyme borreliosis is incompletely understood, and laboratory diagnosis, the focus of this review, requires considerable understanding to interpret the results correctly. Direct detection of the infectious agent is usually not possible or practical, necessitating a continued reliance on serologic testing. Still, some important advances have been made in the area of diagnostics, and there are many promising ideas for future assay development. This review summarizes the state of the art in laboratory diagnostics for Lyme borreliosis, provides guidance in test selection and interpretation, and highlights future directions.

Evolutionary Genetics of Borrelia

The genus Borrelia consists of evolutionarily and genetically diverse bacterial species that cause a variety of diseases in humans and domestic animals. These vector-borne spirochetes can be classified into two major evolutionary groups, the Lyme borreliosis clade and the relapsing fever clade, both of which have complex transmission cycles during which they interact with multiple host species and arthropod vectors. Molecular, ecological, and evolutionary studies have each provided significant contributions towards our understanding of the natural history, biology and evolutionary genetics of Borrelia species; however, integration of these studies is required to identify the evolutionary causes and consequences of the genetic variation within and among Borrelia species. For example, molecular and genetic studies have identified the adaptations that maximize fitness components throughout the Borrelia lifecycle and enhance transmission efficacy but provide limited insights into the evolutionary pressures that have produced them. Ecological studies can identify interactions between Borrelia species and the vertebrate hosts and arthropod vectors they encounter and the resulting impact on the geographic distribution and abundance of spirochetes but not the genetic or molecular basis underlying these interactions. In this review we discuss recent findings on the evolutionary genetics from both of the evolutionarily distinct clades of Borrelia species. We focus on connecting molecular interactions to the ecological processes that have driven the evolution and diversification of Borrelia species in order to understand the current distribution of genetic and molecular variation within and between Borrelia species.

Interactions Between Ticks and Lyme Disease Spirochetes

Borrelia burgdorferi sensu lato causes Lyme borreliosis in a variety of animals and humans. These atypical bacterial pathogens are maintained in a complex enzootic life cycle that primarily involves a vertebrate host and Ixodes spp. ticks. In the Northeastern United States, I. scapularis is the main vector, while wild rodents serve as the mammalian reservoir host. As B. burgdorferi is transmitted only by I. scapularis and closely related ticks, the spirochete-tick interactions are thought to be highly specific. Various borrelial and arthropod proteins that directly or indirectly contribute to the natural cycle of B. burgdorferi infection have been identified. Discrete molecular interactions between spirochetes and tick components also have been discovered, which often play critical roles in pathogen persistence and transmission by the arthropod vector. This review will focus on the past discoveries and future challenges that are relevant to our understanding of the molecular interactions between B. burgdorferi and Ixodes ticks. This information will not only impact scientific advancements in the research of tick- transmitted infections but will also contribute to the development of novel preventive measures that interfere with the B. burgdorferi life cycle.

Evolutionary ecology of Lyme Borrelia

The bacterial genus, Borrelia, is comprised of vector-borne spirochete species that infect and are transmitted from multiple host species. Some Borrelia species cause highly-prevalent diseases in humans and domestic animals. Evolutionary, ecological, and molecular research on many Borrelia species have resulted in tremendous progress toward understanding the biology and natural history of these species. Yet, many outstanding questions, such as how Borrelia populations will be impacted by climate and land-use change, will require an interdisciplinary approach. The evolutionary ecology research framework incorporates theory and data from evolutionary, ecological, and molecular studies while overcoming common assumptions within each field that can hinder integration across these disciplines. Evolutionary ecology offers a framework to evaluate the ecological consequences of evolved traits and to predict how present-day ecological processes may result in further evolutionary change. Studies of microbes with complex transmission cycles, like Borrelia, which interact with multiple vertebrate hosts and arthropod vectors, are poised to leverage the power of the evolutionary ecology framework to identify the molecular interactions involved in ecological processes that result in evolutionary change. Using existing data, we outline how evolutionary ecology theory can delineate how interactions with other species and the physical environment create selective forces or impact migration of Borrelia populations and result in micro-evolutionary changes. We further discuss the ecological and molecular consequences of those micro-evolutionary changes. While many of the currently outstanding questions will necessitate new experimental designs and additional empirical data, many others can be addressed immediately by integrating existing molecular and ecological data within an evolutionary ecology framework.

Guidelines for diagnosis and treatment in neurology - Lyme neuroborreliosis

Lyme borreliosis is the most common tick-borne infectious disease in Europe. A neurological manifestation occurs in 3–15% of infections and can manifest as polyradiculitis, meningitis and (rarely) encephalomyelitis.

This S3 guideline is directed at physicians in private practices and clinics who treat Lyme neuroborreliosis in children and adults.

Twenty AWMF member societies, the Robert Koch Institute, the German Borreliosis Society and three patient organisations participated in its development. A systematic review and assessment of the literature was conducted by the German Cochrane Centre, Freiburg (Cochrane Germany).

The main objectives of this guideline are to define the disease and to give recommendations for the confirmation of a clinically suspected diagnosis by laboratory testing, antibiotic therapy, differential diagnostic testing and prevention.

Immunoblot reactivity at follow-up in treated patients with Lyme neuroborreliosis and healthy controls

About 5-20% of the general population in endemic areas have seroprevalence for anti-borrelial antibodies. Previous studies have shown a high rate of 25-97% of persisting anti-borrelial antibodies in patients with treated Lyme neuroborreliosis (LNB) at follow-up. These studies used immunoblots with antigens from whole-cell sonicates, which could be less specific than modern recombinant antigens. We assessed the seroprevalence of anti-borrelial antibodies in serum from patients with definite LNB and healthy controls with a line immunoblot using highly specific recombinant antigens. We retrospectively identified patients with treated definite LNB who were treated at the Medical Center-University of Freiburg. Serum from LNB patients at a mean follow-up period of 4.9 years (SD: 3.3) and serum from healthy controls were assessed for anti-borrelial antibodies with a line immunoblot with recombinant antigens. A total of 45 patients with definite LNB and 40 healthy controls were included. Ten LNB patients (22.7%) had persisting antibodies (IgG and/or IgM) in serum at follow-up. Serum samples from six healthy controls (15%) were positive for anti-borrelial antibodies (IgG and or IgM). Prevalence of positive IgM or IgG antibodies showed no statistically significant difference between LNB patients at follow-up and healthy controls (IgM p = 0.32, IgG p = 0.54). Immunoblot reactivity patterns at follow-up in LNB patients did not have statistically significant differences from healthy controls. The discrepancy regarding earlier studies reporting higher amounts of LNB patients with persisting antibodies could be due to a higher specificity of the antigens used in recombinant immunoblots compared to other immunoblots (e.g., whole-cell sonicates). The results of our study should be replicated in a larger prospective multi-center study.

Laboratory diagnosis of Lyme borreliosis: Current state of the art and future perspectives

This review is directed at physicians and laboratory personnel in private practice and clinics who treat and diagnose Lyme borreliosis (LB) in patients as part of their daily work. A major objective of this paper is to bring together background information on Borrelia (B.) burgdorferi sensu lato (s.l.) and basic clinical knowledge of LB, which is one of the most frequently reported vector-borne diseases in the Northern Hemisphere. The goal is to provide practical guidance for clinicians and for laboratory physicians, and scientists for a better understanding of current achievements and ongoing obstacles in the laboratory diagnosis of LB, an infectious disease that still remains one of the diagnostic chameleons of modern clinical medicine. Moreover, in bringing together current scientific information from guidelines, reviews, and original papers, this review provides recommendations for selecting the appropriate tests in relation to the patient's stage of disease to achieve effective, stage-related application of current direct and indirect laboratory methods for the detection of B. burgdorferi s.l. Additionally, the review aims to discuss the current state of the art concerning the diagnostic potential and limitations of the assays and test methods currently in use to optimize LB patient management and provide insight into the possible future prospects of this rapidly changing area of laboratory medicine.

To test or not to test? Laboratory support for the diagnosis of Lyme borreliosis: a position paper of ESGBOR, the ESCMID study group for Lyme borreliosis

BACKGROUND

Lyme borreliosis (LB) is a tick-borne infection caused by Borrelia burgdorferi sensu lato. The most frequent clinical manifestations are erythema migrans and Lyme neuroborreliosis. Currently, a large volume of diagnostic testing for LB is reported, whereas the incidence of clinically relevant disease manifestations is low. This indicates overuse of diagnostic testing for LB with implications for patient care and cost-effective health management.

AIM

The recommendations provided in this review are intended to support both the clinical diagnosis and initiatives for a more rational use of laboratory testing in patients with clinically suspected LB.

SOURCES

This is a narrative review combining various aspects of the clinical and laboratory diagnosis with an educational purpose. The literature search was based on existing systematic reviews, national and international guidelines and supplemented with specific citations.

IMPLICATIONS

The main recommendations according to current European case definitions for LB are as follows. Typical erythema migrans should be diagnosed clinically and does not require laboratory testing. The diagnosis of Lyme neuroborreliosis requires laboratory investigation of the spinal fluid including intrathecal antibody production, and the remaining disease manifestations require testing for serum antibodies to B. burgdorferi. Testing individuals with non-specific subjective symptoms is not recommended, because of a low positive predictive value.

Five-Antigen Fluorescent Bead-Based Assay for Diagnosis of Lyme Disease

The systematically difficult task of diagnosing Lyme disease can be simplified by sensitive and specific laboratory tests. The currently recommended two-tier test for serology is highly specific but falls short in sensitivity, especially in the early acute phase. We previously examined serially collected serum samples from Borrelia burgdorferi-infected rhesus macaques and defined a combination of antigens that could be utilized for detection of infection at all phases of disease in humans. The five B. burgdorferi antigens, consisting of OspC, OspA, DbpA, OppA2, and the C6 peptide, were combined into a fluorescent cytometric bead-based assay for the detection of B. burgdorferi antigen-specific IgG antibodies. Samples from Lyme disease patients and controls were used to determine the diagnostic value of this assay. Using this sample set, we found that our five-antigen multiplex IgG assay exhibited higher sensitivity (79.5%) than the enzyme immunoassay (EIA) (76.1%), the two-tier test (61.4%), and the C6 peptide enzyme-linked immunosorbent assay (ELISA) (77.2%) while maintaining specificity over 90%. When detection of IgM was added to the bead-based assay, the sensitivity improved to 91%, but at a cost of reduced specificity (78%). These results indicate that the rational combination of antigens in our multiplex assay may offer an improved serodiagnostic test for Lyme disease.

The diagnostic accuracy of serological tests for Lyme borreliosis in Europe: a systematic review and meta-analysis

Background

Interpretation of serological assays in Lyme borreliosis requires an understanding of the clinical indications and the limitations of the currently available tests. We therefore systematically reviewed the accuracy of serological tests for the diagnosis of Lyme borreliosis in Europe.

Methods

We searched EMBASE en MEDLINE and contacted experts. Studies evaluating the diagnostic accuracy of serological assays for Lyme borreliosis in Europe were eligible. Study selection and data-extraction were done by two authors independently. We assessed study quality using the QUADAS-2 checklist. We used a hierarchical summary ROC meta-regression method for the meta-analyses. Potential sources of heterogeneity were test-type, commercial or in-house, Ig-type, antigen type and study quality. These were added as covariates to the model, to assess their effect on test accuracy.

Results

Seventy-eight studies evaluating an Enzyme-Linked ImmunoSorbent assay (ELISA) or an immunoblot assay against a reference standard of clinical criteria were included. None of the studies had low risk of bias for all QUADAS-2 domains. Sensitivity was highly heterogeneous, with summary estimates: erythema migrans 50 % (95 % CI 40 % to 61 %); neuroborreliosis 77 % (95 % CI 67 % to 85 %); acrodermatitis chronica atrophicans 97 % (95 % CI 94 % to 99 %); unspecified Lyme borreliosis 73 % (95 % CI 53 % to 87 %). Specificity was around 95 % in studies with healthy controls, but around 80 % in cross-sectional studies. Two-tiered algorithms or antibody indices did not outperform single test approaches.

Conclusions

The observed heterogeneity and risk of bias complicate the extrapolation of our results to clinical practice. The usefulness of the serological tests for Lyme disease depends on the pre-test probability and subsequent predictive values in the setting where the tests are being used. Future diagnostic accuracy studies should be prospectively planned cross-sectional studies, done in settings where the test will be used in practice.

Skin manifestations of lyme borreliosis: diagnosis and management

Lyme borreliosis is a multisystem infectious disease caused by tick-transmitted spirochetes of the Borrelia burgdorferi sensu lato complex. The three characteristic cutaneous manifestations are erythema migrans, borrelial lymphocytoma, and acrodermatitis chronica atrophicans. Erythema migrans occurs in acute Lyme borreliosis, lymphocytoma is a subacute lesion, and acrodermatitis is the typical manifestation of late Lyme borreliosis. Clinical appearances of erythema migrans and lymphocytoma (when located on the ear or breast) are characteristic, whereas acrodermatitis is often confused with vascular conditions. The diagnosis of erythema migrans is made clinically. Serologic analyses often yield false-negative results and are not required for the diagnosis. However, serologic proof of the diagnosis in lymphocytoma (approximately 90% positive) and acrodermatitis (100% positive) is mandatory. Histopathologic examination often adds substantial information in patients with skin manifestations of Lyme borreliosis and is recommended in clinically (and serologically) undecided cases of erythema migrans or lymphocytoma and is obligatory in acrodermatitis. Polymerase chain reaction for Borrelia-specific DNA (rather than culture of the spirochete) and immunohistochemical investigations (lymphocytoma) are sometimes necessary adjuncts for the diagnosis. Antibacterial treatment is necessary in all patients to eliminate the spirochete, cure current disease, and prevent late sequelae. Oral doxycycline, also effective against coinfection with Anaplasma phagocytophilum, is the mainstay of therapy of cutaneous manifestations of Lyme borreliosis. Other first-line antibacterials are amoxicillin and cefuroxime axetil. Erythema migrans is treated for 2 weeks, lymphocytoma for 3-4 weeks, and acrodermatitis for at least 4 weeks.

Evaluation of recombinant line immunoblot for detection of Lyme disease in Slovakia: comparison with two other immunoassays

In the present study the sensitivity and the specificity of three serological tests (enzyme-linked immunosorbent assay [ELISA], indirect fluorescent antibody test [IFA], and recombinant line immunoblot) were compared by examining 74 sera from patients diagnosed with Lyme disease in Eastern Slovakia. In addition, the reactivity to each of the recombinant proteins in the immunoblot was examined in order to evaluate their diagnostic value. Generally, the immunoblot (93.2%) and the ELISA (90.5%) were significantly more sensitive than the IFA (64.9%; df = 1; p < or = 0.001). Correlation between results of the ELISA, IFA, and immunoblot for IgM or IgG, when two tests were always compared, one to the other, ranged from r(s) = 0.673 to r(s) = 0.905. In the immunoblot, the highest sensitivity was observed in DbpA and VlsE proteins (76.9% and 84.6%, respectively) in IgG testing of the sera from the patient group of Lyme arthritis. VlsE proteins, together with OspC proteins, were also shown to be useful for IgM antibody detection in erythema migrans patients (up to 44.4% and 53.7% sensitivity, respectively). Our results indicate that both the ELISA and the recombinant immunoblot test were more satisfactory for seroconfirmation of Lyme disease than IFA. Moreover, the reseach confirmed diagnostic value of the in-vivo expressed proteins (VlsE and DbpA), which might have the potential to play an important role in improving whole-cell antigen-based testing.

Comparison of different Borrelia burgdorferi sensu lato strains for detection of immune response in patients with erythema migrans

The aim of the present study was to establish which combination of serological method and Borrelia strain used as an antigen would provide the most appropriate demonstration of borrelial infection in patients with eythema migrans residing in Slovenia. Four different strains were chosen as antigens: two strains of B. afzelii and two strains of B. garinii which differed in their expression of the outer proteins OspA, OspB and OspC. Each individual strain was used as antigen in immunofluorescence test (IFT), enzyme-linked immunosorbent assay (EIA) with whole borrelial cells, and EIA with ultrasonicated borrelial cells. With these 12 different tests, 100 samples were examined for the presence of specific IgM and IgG antibodies: 50 sera of blood donors and 50 sera of patients with erythema migrans. The latter were further subdivided into skin culture-positive and -negative subgroups. A commercial Western blot (WB) test was performed for 26 sera of the control group and 25 sera of patients with erythema migrans. The four different methods had distinct specificity and sensitivity. The most specific approaches were IFT (100% for IgM and 90-92% for IgG) and the WB test (100% for IgM and 73% for IgG), followed by EIA with whole borrelial cells (80-98% for IgM and 76-84% for IgG) and EIA with ultrasonicated borrelial cells (76-94% for IgM and 72-80% for IgG). The sensitivity levels of all these tests were low. The most sensitive were EIA tests with whole borrelial cells (28-36% for IgM and 32-42% for IgG) followed by EIA with ultrasonicated borrelial cells (22-32% for IgM and 24-36% for IgG), the WB test (16% for IgM and 32% for IgG) and IFT (0-2% for IgM and 14-20% for IgG). The following methods gave significant differences between patients and negative controls in detecting IgM antibodies: EIA with whole borrelial cells with both B. afzelii antigens and with antigen B. garinii that expressed OspA and OspC, EIA with ultrasonicated borrelial cells with antigen B. afzelii that expressed OspA, OspB and OspC. In detecting IgG antibodies, significant differences were observed between EIA with whole borrelial cells and with antigen B. afzelii that expressed OspA and OspB. Borreliae were isolated from the skin of 34/50 (68%) patients with erythema migrans: two strains failed to grow, while 26/32 (81%) strains were identified as B. afzelii, 5/32 (16%) as B. garinii and 1/32 (3%) as B. burgdorferi sensu stricto. No statistically significant differences in serologic test results between culture-positive and -negative patients with erythema migrans were found.

A genome-wide proteome array reveals a limited set of immunogens in natural infections of humans and white-footed mice with Borrelia burgdorferi

Humans and other animals with Lyme borreliosis produce antibodies to a number of components of the agent Borrelia burgdorferi, but a full accounting of the immunogens during natural infections has not been achieved. Employing a protein array produced in vitro from 1,292 DNA fragments representing approximately 80% of the genome, we compared the antibody reactivities of sera from patients with early or later Lyme borreliosis to the antibody reactivities of sera from controls. Overall, approximately 15% of the open reading frame (ORF) products (Orfs) of B. burgdorferi in the array detectably elicited an antibody response in humans with natural infections. Among the immunogens, 103 stood out on the basis of statistical criteria. The majority of these Orfs were also immunogenic with sera obtained from naturally infected Peromyscus leucopus mice, a major reservoir. The high-ranking set included several B. burgdorferi proteins hitherto unrecognized as immunogens, as well as several proteins that have been established as antigens. The high-ranking immunogens were more likely than nonreactive Orfs to have the following characteristics: (i) plasmid-encoded rather than chromosome-encoded proteins, (ii) a predicted lipoprotein, and (iii) a member of a paralogous family of proteins, notably the Bdr and Erp proteins. The newly discovered antigens included Orfs encoded by several ORFs of the lp36 linear plasmid, such as BBK07 and BBK19, and proteins of the flagellar apparatus, such as FliL. These results indicate that the majority of deduced proteins of B. burgdorferi do not elicit antibody responses during infection and that the limited sets of immunogens are similar for two different host species.

Immunoblot analysis of the seroreactivity to recombinant Borrelia burgdorferi sensu lato antigens, including VlsE, in the long-term course of treated patients with erythema migrans

OBJECTIVE

We evaluated whether immunoblotting is capable of substantiating the posttreatment clinical assessment of patients with erythema migrans (EM), the hallmark of early Lyme borreliosis.

METHODS

In 50 patients, seroreactivity to different antigens of Borrelia burgdorferi sensu lato was analyzed by a recombinant immunoblot test (IB) in consecutive serum samples from a minimum follow-up period of 1 year. Antigens in the IgG test were decorin-binding protein A, internal fragment of p41 (p41i), outer surface protein C (OspC), p39, variable major protein-like sequence expressed (VlsE), p58 and p100; those in the IgM test were p41i, OspC and p39. Immune responses were correlated with clinical and treatment-related parameters.

RESULTS

Positive IB results were found in 50% before, in 57% directly after therapy and in 44% by the end of the follow-up for the IgG class, and in 36, 43 and 12% for the IgM class. In acute and convalescence phase sera, VlsE was most immunogenic on IgG testing (60 and 70%), and p41i (46 and 57%) and OspC (40 and 57%) for the IgM class. By the end of the follow-up, only the anti-p41i IgM response was significantly decreased to 24%.

CONCLUSIONS

No correlation was found between IB results and treatment-related parameters. Thus, immunoblotting does not add to the clinical assessment of EM patients after treatment.

Place des méthodes biologiques dans le diagnostic des manifestations de la borréliose de Lyme

Lyme borreliosis (LB) is a multisystemic infection transmitted by ticks. Its diagnosis is based on clinical and biological criteria. These criteria could be different in Europe than in the USA, because of the existence of multiples strains of borrelia in Europe. In primary stage of LB, the diagnosis is often clinical. In the secondary stage, LB diagnosis is established with an Elisa serology confirmed by a Western blot. The interpretation criteria of these laboratory tests should follow European recommendations (EUCALB). LB with neurological involvement should be confirmed by screening for intrathecal synthesis of borrelia antibodies in CSF. LB with rheumatologic expression could be confirmed by screening for borrelia in joint fluid by PCR. There is no strong marker of activity of the disease. Follow-up for LB is difficult, because antibodies may persist for years and LB does not confer immunization.

Microbiological and serological diagnosis of Lyme borreliosis

In Europe, Lyme borreliosis is caused by Borrelia burgdorferi sensu stricto, B. afzelii, B. garinii and the recently described species B. spielmanii. For the development of diagnostic tools, the heterogeneity of the causative agents must be considered. The serological diagnosis should follow the principle of a two-step procedure: a sensitive enzyme-linked immunosorbent analysis as the first step, followed by immunoblot (IgM and IgG) if reactive. The sensitivity and standardization of immunoblots have been enhanced by the use of recombinant antigens instead of whole cell lysates. Improved sensitivity has resulted from the use of recombinant proteins primarily expressed in vivo (e.g. VlsE) and the combination of homologous proteins from different strains (e.g. DbpA). At present, detection rates for serum antibodies are 20-50% in localized, 70-90% in disseminated early and nearly 100% in late disease. Detection of the borreliae by culture or PCR should be confined to specific indications. The best results are obtained from skin biopsies (50-70% with culture or PCR) and synovial tissue or fluid (50-70% with PCR). Cerebrospinal fluid is positive in only 10-30%. Methods that are not recommended for diagnostic purposes include antigen tests in body fluids, PCR of urine and lymphocyte transformation tests.

Lyme borreliosis

Lyme borreliosis is a tick-borne infectious disease caused by the spirochaetes Borrelia burgdorferi, B. garinii and B. afzelii. It comprises a wide spectrum of symptoms affecting skin, musculoskeletal system, heart, eyes, central and peripheral nervous system. The diagnosis is based on clinical findings in combination with detection of specific IgM and/or IgG antibodies. Diagnostic problems arise from patients with non-specific symptoms and positive IgG antibody detection. Adequate antibiotic therapy cures more than 90% of the patients. However, in some patients repeated therapy is necessary and a small number of patients develop chronic arthritis or other features. While there is currently no vaccine available, prevention of tick bite is the most effective prophylaxis.

A novel lymphocyte transformation test (LTT-MELISA) for Lyme borreliosis

Diagnosis of active Lyme borreliosis (LB) remains a challenge in clinically ambiguous, serologically indeterminant, and polymerase chain reaction-negative patients. Lymphocyte transformation tests (LTTs) have been applied to detect specific cellular immune reactivity, but their clinical application has been severely hampered by the poorly defined Borrelia antigens and nonstandardized LTT formats used. In this study, we describe the development and clinical relevance of a novel LTT using a validated format (MELISA) together with well-defined recombinant Borrelia-specific antigens. From an initial screening of 244 patients with suspected Borrelia infection or disease, 4 informative recombinant antigens were selected: OspC (Borrelia afzelii), p41-1 (Borrelia garinii), p41-2 (B. afzelii), and p100 (B. afzelii). Thereafter, 30 seronegative healthy controls were tested in LTT-MELISA(R) to determine specificity, 68 patients were tested in parallel to determine reproducibility, and 54 lymphocyte-reactive symptomatic patients were tested before and after antibiotic therapy to assess clinical relevance. Most (86.2%) of the 36.9% (90/244) LTT-MELISA positive patients were seropositive and showed symptoms of active LB. Specificity was 96.7% and reproducibility 92.6%. After therapy, most patients (90.7%) showed negative or markedly reduced lymphocyte reactivity correlating with clinical improvement. This novel LTT-MELISA assay appears to correlate with active LB and may have diagnostic relevance in confirming LB in clinically and serologically ambiguous cases.

Borreliacidal OspC antibodies specific for a highly conserved epitope are immunodominant in human lyme disease and do not occur in mice or hamsters

Humans produce highly specific borreliacidal antibodies against outer surface protein C (OspC) shortly after infection with Borrelia burgdorferi sensu stricto. We previously demonstrated the epitope recognized by immunoglobulin M (IgM) and IgG OspC borreliacidal antibodies was located within the 50 amino acids nearest the carboxy (C) terminus. In this study, we show the immunodominant epitope is located in the highly conserved region within the seven C-terminal amino acids. Six early Lyme disease sera that contained borreliacidal activity and IgM and/or IgG OspC antibodies were chosen randomly and adsorbed with truncated OspC containing the 16 or 7 amino acids nearest the C terminus. Adsorptions with each truncated protein abrogated the borreliacidal activity completely. In addition, only small concentrations of OspC antibodies remained detectable by enzyme-linked immunosorbent assay and Western blotting. Moreover, borreliacidal OspC antibodies were not induced in laboratory mice or hamsters despite heavy infections with B. burgdorferi spirochetes. These findings confirm that borreliacidal antibodies comprise the majority of the IgM and IgG OspC antibody response in human Lyme disease and that the epitope is located in the highly conserved C terminus. In addition, rodent animal models appear to be inappropriate subjects for assessing the effectiveness of the epitope for serodiagnosis or as a human Lyme disease vaccine.

Comparison of a Two- or Three-Week Regimen and a Review of Treatment of Erythema Migrans with Phenoxymethylpenicillin

BACKGROUND

A longer duration treatment is preferred in erythema migrans (EM) to prevent late complaints.

OBJECTIVES

To determine whether 20 (20d-pt) or 14 days (14d-pt) of phenoxymethylpenicillin (PenV) have similar efficacy in treating EM and preventing further sequelae.

PATIENTS AND METHODS

In a prospective double-centre study, 102 patients with EM were treated with PenV 1.5 million IU thrice daily for either 20 or 14 days and followed up for 12 months.

RESULTS

The primary cure rate after treatment with PenV was 91.5% (79.6-97.6) for 20d-pt vs. 91.7% (77.5-98.2) for 14d-pt; p > 0.99). In 7 patients (4/20d-pt and 3/14d-pt), persistent or newly arising symptoms required retreatment. After 1 year, all patients were cured. The immune response showed no statistical difference between the treatment groups in the follow-up period.

CONCLUSION

A 2-week treatment regimen of PenV seems to be as effective as a 3-week course with no statistical differences for clinical and serological findings after treatment.

Mini Erythema Migrans – A Sign of Early Lyme Borreliosis

BACKGROUND

An erythema migrans (EM) remaining smaller than 5 cm in diameter, called mini EM by us, has not been addressed in detail.

OBJECTIVE

To study the significance of the mini EM as a sign of Lyme borreliosis.

METHODS

Patients with suspected mini EM were retrospectively selected out of 257 consecutive patients with EM. The diagnosis of mini EM rested on the cultivation of Borrelia burgdorferi. Species and subtype analysis of culture isolates was performed using outer surface protein A (OspA) polymerase chain reaction followed by restriction fragment length polymorphism and sequencing of the OspA gene.

RESULTS

There was one patient with definite (0.4%) and another patient with a questionable mini EM. Borrelia garinii OspA type 6 was identified in the patient with the definite and B. burgdorferi sensu lato in the patient with the questionable mini EM.

CONCLUSION

The mini EM represents an important and apparently uncommon sign of early Lyme borreliosis.

Improvement of Lyme borreliosis serodiagnosis by a newly developed recombinant immunoglobulin G (IgG) and IgM line immunoblot assay and addition of VlsE and DbpA homologues

We developed and evaluated a recombinant Borrelia line immunoblot assay based on 18 homologues of seven different antigens, i.e., p100, p58, p41i, BmpA, VlsE, OspC, and DbpA. Each recombinant antigen can be detected separately and is distinct even from homologues with identical molecular weights. This blot was compared to the recently described recombinant Borrelia Western immunoblot assay (U. Schulte-Spechtel, G. Lehnert, G. Liegl, V. Fingerle, C. Heimerl, B. J. Johnson, and B. Wilske, J. Clin. Microbiol. 41:1299-1303, 2003). To verify sensitivity and specificity, both blots were evaluated for reactivity with Borrelia-specific immunoglobulin G (IgG) and IgM antibodies with 85 sera from patients with different manifestations of Lyme borreliosis and 110 controls. According to European interpretation criteria for Borrelia Western blots, which define a serum as positive when it recognizes at least two bands, sensitivity increased significantly from 70.6% (Western blot) to 84.7% (line blot) for IgG (P = 0.042) and from 40.0% (Western blot) to 73.8% (line blot) for IgM (P < 0.005). The increased sensitivity for IgG detection is due to the new line blot technique, whereas the improvement in detection of IgM is mainly achieved through incorporation of the additional antigens. Notably, the recombinant VlsE of Borrelia garinii strain PBi displayed the highest sensitivity of all antigens tested for IgG detection and is also one of the most useful antigens for IgM. Due to its excellent sensitivity and specificity combined with ease of evaluation, this line immunoblot assay offers a useful improvement in serodiagnosis of Lyme borreliosis.

Epidemiology and diagnosis of Lyme borreliosis

The multisystem disease Lyme borreliosis is the most frequent tick-transmitted disease in the northern hemisphere. In Europe Lyme borreliosis is most frequent in Central Europe and Scandinavia (up to 155 cases per 100,000 individuals) and is caused by the species, B. burgdorferi sensu stricto, B. afzelii and B. garinii. The recently detected genospecies A14S may also play a role in skin manifestations. Microbiological diagnosis in European patients must consider the heterogeneity of borreliae for development of diagnostic tools. According to guidelines of the USA and Germany, serological diagnosis should follow the principle of a two-step procedure (enzyme-linked immunosorbent assay (ELISA) as first step, if reactive; followed by immunoblot). The sensitivity and standardization of immunoblots has been considerably enhanced by use of recombinant antigens (p100, p58, p41i, VlsE, OspC, DbpA) including those expressed primarily in vivo (VlsE and DbpA) instead of whole cell lysates. VlsE is the most sensitive antigen for IgG antibody detection, OspC for IgM antibody detection. At present, detection rates for serum antibodies are 20%-50% in stage I, 70%-90% in stage II, and nearly 100% in stage III Lyme disease. Detection of the etiological agent by culture or polymerase chain reaction (PCR) should be confined to specific indications and specialized laboratories. Recommended specimens are skin biopsy specimens, cerebrospinal fluid (CSF) and synovial fluid. The best results are obtained from skin biopsies with culture or PCR (50%-70%) and synovial tissue or fluid (50%-70% with PCR). CSF yields positive results in only 10%-30% of patients except when the duration of symptoms is shorter than 2 weeks (50% sensitivity). Methods which are not recommended or adequately documented for diagnosis are antigen tests on body fluids, PCR of urine, and lymphocyte transformation tests.

Guidelines for the diagnosis of tick-borne bacterial diseases in Europe

Ticks are obligate haematophagous acarines that parasitise every class of vertebrate (including man) and have a worldwide distribution. An increasing awareness of tick-borne diseases among clinicians and scientific researchers has led to the recent description of a number of emerging tick-borne bacterial diseases. Since the identification of Borrelia burgdorferi as the agent of Lyme disease in 1982, 11 tick-borne human bacterial pathogens have been described in Europe. Aetiological diagnosis of tick-transmitted diseases is often difficult and relies on specialised laboratories using very specific tools. Interpretation of laboratory data is very important in order to establish the diagnosis. These guidelines aim to help clinicians and microbiologists in diagnosing infection transmitted by tick bites and to provide the scientific and medical community with a better understanding of these infectious diseases.

Diagnosis of lyme borreliosis in europe

In Europe, Lyme borreliosis is caused by at least three species, B. burgdorferi sensu stricto, B. afzelii and B. garinii. Thus microbiological diagnosis in European patients must consider the heterogeneity of Lyme disease borreliae for development of diagnostic tools such as PCR primers and diagnostic antigens. According to guidelines of the German Society of Hygiene and Microbiology, the serological diagnosis should follow the principle of a two-step procedure. A sensitive ELISA differentiating IgM and IgG is recommended as the first step. In case the ELISA is reactive, it is followed by immunoblots (IgM and IgG) as the second step. The reactive diagnostic bands should be clearly identified, which is easy if recombinant antigens are used. The sensitivity and standardization of immunoblots has been considerably enhanced by use of recombinant antigens instead of whole cell lysates. Improved sensitivity resulted from use of recombinant proteins that are expressed primarily in vivo (e.g., VlsE) and combination of homologous proteins from different strains of borrelia (e.g., DbpA). It also appears promising to use recombinant proteins (DbpA, VlsE, others) or synthetic peptides (the conserved C6 peptide derived from VlsE) as ELISA antigens. At present, detection rates for serum antibodies are 20-50% in stage I, 70-90% in stage II, and nearly 100% in stage III Lyme disease. The main goals for the future are to improve specificity in general and sensitivity for diagnosis of early manifestations (stage I and II). Detection of the etiological agent by culture or PCR should be confined to specific indications and specialised laboratories. Recommended specimens are skin biopsy specimens, CSF and synovial fluid. The best results are obtained from skin biopsies with culture or PCR (50-70%) and synovial tissue or fluid (50-70% with PCR). CSF yields positive results in only 10-30% of patients. Methods that are not recommended for diagnostic purposes are antigen tests in body fluids, PCR of urine, and lymphocyte transformation tests.

Enzyme-linked immunosorbent assay, immunofluorescent assay, and recombinant immunoblotting in the serodiagnosis of early Lyme borreliosis

Serum samples from Bulgarian patients with physician-diagnosed erythema migrans (EM) (n=105) were examined using Borrelia burgdorferi ELISA (Boehring, Germany) after previous absorption with Treponema phagedenis. For IgM antibody detection sera were additionally pretreated with anti-IgG serum (RF absorbent). Serum samples of 93% of persons from healthy control group were IgM negative and all were IgG negative. Out of 105 patients with EM, 49% were IgM positive and 14 % were borderline. IgG ELISA showed positive results for 17% and borderline for 6% of the patients. Positive and borderline serum samples were examined further by immunofluorescent assay (IFA) and immunoblot test with recombinant B. burgdorferi proteins from strain PKo (B. afzelii) - p100, flagellin, OspA and OspC, and internal flagellin fragments from strains PKo and PBi (B. garinii) [B.Wilske, V.Fingerle, P. Herzer et al. 1993. Med. Microbiol. Immunol. 182:255]. IFA detected IgM antibodies against B. burgdorferi in 47 % of the positive and in none of the borderline by IgM ELISA serum samples as well as IgG antibodies in 83% of the positive and in 50% of the borderline by IgG ELISA samples. Presence of specific antibodies was confirmed by immunoblot in 71 % of the IgM ELISA postive and in 67 % of the IgG ELISA positive sera. In addition, anti-B. burgdorferi antibodies were detected in 60 % of the borderline by IgM ELISA serum samples. IgM serum reactivity was directed mainly against OspC antigen and flagellin and IgG antibodies were directed mainly against flagellin and p100. These findings clearly showed advantages of the ELISA test based on previous pretreatment of sera and capable to detect specific antibodies in more than half of patients with early Lyme borreliosis despite the well-known delayed immune response. IFA was less sensitive than ELISA in detection of anti-B. burgdorferi antibodies. An additional examination of ELISA borderline sera by immunoblot revealed more positive results. Serum reactivity to a single OspC antigen seems to be a sufficient criterion for positive IgM immunoblot.

Outer surface lipoproteins ofBorrelia burgdorferi vary in their ability to induce experimental joint injury

OBJECTIVE

To examine the ability of bacterial lipoproteins from the spirochete Borrelia burgdorferi to cause in vivo tissue injury (arthritis).

METHODS

Outer surface proteins (OSPs) from B burgdorferi were used in a rat model of antigen-induced allergic arthritis. Intraarticular challenge with recombinant OspA, OspB, and OspC in nonlipidated (peptide) and lipidated forms was performed in the left knee joint; the contralateral joint received buffer as control. Inflammation was monitored by technetium scintigraphy and histology.

RESULTS

Nonlipidated (peptide) OspA, OspB, and OspC did not induce arthritis; the only exception was polymerized OspA, which was tested in preimmunized rats. Lipidated OspA from 2 different strains and lipidated OspC induced severe arthritis, whereas lipidated OspB failed to induce injury. A synthetic analog of the OSP lipid modification, lipopeptide Pam(3)Cys-Ser-Lys(4)-OH, either alone or coupled to bovine serum albumin, also failed to induce injury. Injury did not develop in control groups that were given the appropriate buffers or lipopolysaccharide. This showed that lipidated borrelial OSPs can be potent arthritogens but vary greatly with respect to their injury-inducing potential. The possession of a lipid modification is essential but is not sufficient to render an OSP arthritogenic.

CONCLUSION

This is the first study to demonstrate that individual lipoproteins from B burgdorferi can induce experimental joint injury in vivo. These results may help elucidate the pathogenesis of Lyme arthritis and, above all, underline the importance of bacterial lipoproteins as major virulence factors.

Acylated cholesteryl galactoside as a novel immunogenic motif in Borrelia burgdorferi sensu stricto

Borrelia burgdorferi sensu lato is the causing agent of Lyme disease, an infectious disease frequently occurring in the United States, Europe, and Northern Asia. Currently, diagnosis of and vaccination strategies against this pathogen are exclusively based on proteinaceous structures. Here we report on a novel class of immunogenic glycolipids purified from B. burgdorferi sensu stricto B31. Employing a butanol/water extraction procedure with subsequent Bligh/Dyer extraction of the organic phase, thin layer chromatography analysis revealed the presence of three distinct glycolipids, which were chemically analyzed employing combined gas-liquid chromatography/mass spectroscopy, matrix-assisted laser desorption/ionization mass spectrometry, and NMR. We identified acylated cholesteryl galactoside (ACG) next to cholesteryl galactoside and alpha-monogalactosyl-diacylglycerol. After extensive purification, the glycolipids investigated failed to cause proinflammatory responses in human cells transfected with human toll-like receptor (TLR)-2 or -4. However, we observed a marked recognition of ACG by sera derived from patients suffering from Lyme disease. These data indicate that newly described ACG is involved in developing host immunity during Lyme disease and thus may be useful for diagnosis and vaccination.

Genetic diversity of the outer surface protein C gene of southern Borrelia isolates and its possible epidemiological, clinical, and pathogenetic implications

The ospC genes of 20 southern Borrelia strains were sequenced. The strains consisted of B. burgdorferi sensu stricto, B. andersonii, B. bissettii, one undescribed genospecies, MI-8, and one probably new Borrelia species, TXW-1. A high degree of similarity exists between B. burgdorferi sensu stricto and B. bissettii and between B. bissettii and B. andersonii. Lateral transfers of the ospC gene probably occurred between B. burgdorferi sensu stricto and B. bissettii and between B. bissettii and B. andersonii. Internal gene recombination appears to occur among them. The highest degree of genetic diversity among them was observed in the two variable domains (V1 and V2), semivariable domain (SV), and the species-specific epitopes (between amino acids 28 and 31). Differences in ospC sequences among southern strains reflect diversity at the strain and genospecies levels. MI-8, which was recognized as an undescribed genospecies in our previous reports, remains distinguishable in our current analysis of ospC genes and is distinct from B. burgdorferi sensu stricto. Interestingly, another undescribed southern isolate, TXW-1, was not amplified under various PCR conditions. Compared to European B. burgdorferi sensu stricto strains, American B. burgdorferi sensu stricto strains show greater genetic heterogeneity. Southern B. burgdorferi sensu stricto, B. andersonii, and B. bissettii isolates were intermixed with each other in the phylogenetic trees. In the derived trees in our work, at least one southeastern strain of B. burgdorferi, MI-2, most closely aligns with a so-called invasive cluster that possesses many proven human-invasive strains. Transmission experiments show that MI-2 and the strains in this group of southern spirochetes are able to infect mice and hamsters and that the typical vector of Lyme disease, Ixodes scapularis, can acquire the spirochetes from infected mammals. Currently, strain MI-2 appears to be the only southern isolate among the 20 we analyzed that clusters with an OspC invasive group and thus might be invasive for humans.

Laboratory testing for suspected Lyme disease

Laboratory testing for B. burgdorferi infection is intended to substantiate a physician's clinical judgment of whether a patient has Lyme disease or not. Cultivation of B. burgdorferi from a patient's skin or blood is the gold standard for demonstration of active infection, but it is expensive and lacks clinical sensitivity. Detection of spirochetal DNA in clinical samples by PCR has better sensitivity, but PCR for B. burgdorferi has not yet been standardized for more routine diagnostic testing. Detection of antibodies to B. burgdorferi is the most practical and common approach for laboratory work-up of a case of suspected Lyme disease. Serologic assays fall short of 100% sensitivity and specificity, however, and examination of a single specimen in time does not discriminate between previous and ongoing infection. Because of a background false positivity even among healthy populations of nonendemic regions, serologic testing is recommended only when there is at least a one in five chance, in the physician's estimation, that the patient has active Lyme disease. The pretest likelihood of the disease is determined by the physician in the context of epidemiologic and clinical facts of the case. This estimate can serve to reassure patients who are at low risk of B. burgdorferi infection but are seeking a Lyme test for complaints of a more nonspecific nature. Although new subunit serologic assays based on recombinant proteins are becoming available commercially, the longstanding two-test approach, in which a positive or indeterminate result with a standardized, sensitive ELISA test is followed by verification with a more specific Western blot assay, still provides the physician with a reasonably accurate and reliable assessment of the presence of antibodies to B. burgdorferi. More recent challenges for serologic testing are seropositivity in the population as the result of immunization with the Lyme disease vaccine and the emergence of new Borrelia species that cause Lyme disease-like illnesses.

Recombinant assay for serodiagnosis of Lyme disease regardless of OspA vaccination status

All current seroassays using cultured Borrelia burgdorferi as their antigen source have been rendered obsolete by the recombinant OspA Lyme disease vaccine. OspA is the major outer surface protein expressed in cultured B. burgdorferi, and any seroassay that uses whole organisms as its antigen source cannot differentiate between subjects who received the vaccine and those who were naturally infected. We developed a new sensitive and specific enzyme-linked immunosorbent assay (ELISA) utilizing recombinant chimeric borrelia proteins devoid of OspA (rNon-OspA) that can be used to detect antibodies to diagnostically important B. burgdorferi antigens in both OspA-vaccinated and nonvaccinated individuals. We tested sera from patients with Lyme disease and with conditions associated with false-positive serologies, OspA-vaccinated individuals, and healthy high-risk workers from an area of endemicity and normal sera from individuals from areas of nonendemicity. The rNon-OspA test was compared with two commercially available whole-cell immunoassays. The rNon-OspA assay is as sensitive and specific as the whole-cell assay (P > 0.05) for detection of anti-B. burgdorferi antibodies. However, the rNon-OspA assay can differentiate between populations comprised of naturally infected and OspA-vaccinated individuals (P < 0.05). Our data demonstrate that this new sensitive rNon-OspA ELISA can be used for the laboratory detection of B. burgdorferi antibodies regardless of vaccination status and could replace existing serologic assays for Lyme disease.

Coiling phagocytosis of Borrelia burgdorferi by primary human macrophages is controlled by CDC42Hs and Rac1 and involves recruitment of Wiskott-Aldrich syndrome protein and Arp2/3 complex

Lyme borreliosis is a multisystemic disorder primarily affecting the skin, nervous system, and joints. It is caused by the spirochete Borrelia burgdorferi sensu lato and is transmitted via ticks of the Ixodidae family. Persistence of borreliae within macrophages has been implicated in the often chronic history of borreliosis. The uptake of B. burgdorferi by professional phagocytes occurs predominantly by coiling phagocytosis, a host cell-driven process in which single pseudopods wrap around and engulf the spirochetes. In the present study, we investigated the molecular machinery and the signal transduction pathways controlling the formation of these unique uptake structures. We found that the phagocytosis of borreliae by primary human macrophages is accompanied by the formation of f-actin-rich structures, which in their morphological organization correspond well to the earlier described coiling pseudopods. Further experiments revealed that Wiskott-Aldrich Syndrome protein and Arp2/3 complex, major regulators of actin polymerization, are also recruited to these sites of actin accumulation. In addition, inhibition of an upstream regulator of Wiskott-Aldrich Syndrome protein, the Rho-family GTPase CDC42Hs, greatly inhibited the occurrence of borrelia-induced phagocytic uptake structures. Inhibition of Rac1, another Rho family GTPase, had a less-pronounced inhibitory effect, while blocking of Rho activity showed no discernible influence. These results suggest that basic mechanisms of actin polymerization that control other types of phagocytosis are also functional in the formation of the morphologically unique uptake structures in coiling phagocytosis. Our findings should enhance the understanding of the infection process of B. burgdorferi and contribute to devising new strategies for countering Lyme disease.

A European multicenter study of immunoblotting in serodiagnosis of lyme borreliosis

A European multicenter study of immunoblotting for the serodiagnosis of Lyme borreliosis showed considerable variation in results obtained from tests with a panel of 227 serum samples. Six laboratories used different immunoblot methods, and a wide range of bands was detected in all the assays. Multivariable logistic regression analysis of data from individual laboratories was used to determine the most discriminatory bands for reliable detection of antibodies to Borrelia burgdorferi sensu lato. These bands were used to construct individual interpretation rules for the immunoblots used in the six laboratories. Further analysis identified a subset of eight bands, which were important in all the laboratories, although with variations in significance. Possible European rules, all closely related, were formulated from these bands, although there was no single rule that gave high levels of sensitivity and specificity for all the laboratories. This is a reflection of the wide range of methodologies used, especially the use of different species and strains of B. burgdorferi sensu lato. The panel of European rules provides a framework for immunoblot interpretation which may be adapted in relation to the characteristics of Lyme borreliosis in local areas.

Western immunoblot analysis for distinguishing vaccination and infection status with Borrelia burgdorferi (Lyme disease) in dogs

Serodiagnosis of Lyme borreliosis in dogs is complicated by the use of commercially available Lyme disease vaccines that may cross-react with certain diagnostic assays. Western immunoblotting may be used to distinguish between dogs naturally exposed and those vaccinated against Borrelia burgdorferi. Because current vaccines are not 100% efficacious and dogs may be vaccinated after natural exposure, certain dogs may show serum antibody responses against both natural and vaccine exposure (dual status). In this study, samples from 17 nonexposed, 17 B. burgdorferi-bacterin vaccinated, 13 naturally exposed, and 8 dual-status dogs were tested by western immunoblot to determine if dual-status dogs could be reliably differentiated from naturally infected or vaccinated dogs. Reaction to outer surface protein A antigen of B. burgdorferi (31 kD) was a consistent marker for vaccination, appearing in all samples from vaccinate and dual-status dogs and in no samples from single-status naturally exposed dogs. Antibodies to 4 bands, at 80, 39, 29, and 28 kD, were present in all naturally infected and dual-status dogs. No samples from vaccinated or nonexposed dogs were reactive to all 4 of these bands simultaneously. Thus, vaccine and natural exposure produce differing antibody responses, whereas dual-status dogs produced the full antibody response of both types of exposure.

Peptide-based OspC enzyme-linked immunosorbent assay for serodiagnosis of Lyme borreliosis

Sera from 210 patients with Lyme borreliosis (LB) were studied by an enzyme-linked immunosorbent assay (ELISA) based on a synthetic peptide (pepC10) comprising the C-terminal 10-amino-acid residues of OspC of Borrelia burgdorferi. We found that 36.3 and 45.0% of the serum samples from patients with erythema migrans (EM) and neuroborreliosis (NB), respectively, displayed immunoglobulin M (IgM) anti-pepC10 reactivities, while these samples rarely (</=8%) displayed IgG antibody reactivities. Sera from patients with acrodermatitis chronica atrophicans did not contain anti-pepC10 antibodies. The diagnostic performance of this newly developed peptide ELISA was compared with those of an ELISA based on the full-length recombinant OspC protein (rOspC) and a commercially available ELISA based on the B. burgdorferi flagellum (Fla). The sensitivity of the IgM pepC10 ELISA was slightly lower (P < 0.04) than that of the rOspC ELISA for EM patients (36.3 versus 43.8%), while there was no difference for NB patients (45.0 versus 48.0%). However, the optical density values obtained by the pepC10 ELISA were generally higher than those obtained by the rOspC ELISA, leading to a significantly better quantitative discrimination between seropositive patients with NB and controls (P < 0.008). The specificity of the pepC10 ELISA was similar to those of the rOspC ELISA and the Fla ELISA for relevant controls including patients with syphilis and mononucleosis. Although the overall diagnostic sensitivity of the Fla ELISA was superior, 8.8 and 12.0% of the EM and NB patients, respectively, were antibody positive only by the pepC10 ELISA. Thus, use of a diagnostic test for LB based on the detection of IgM antibodies to pepC10 and Fla has increased sensitivity for the diagnosis of early LB.

The dominant epitope of Borrelia garinii outer surface protein C recognized by sera from patients with neuroborreliosis has a surface-exposed conserved structural motif

Epitope mapping of outer surface protein C (OspC) by using sera from patients with neuroborreliosis led to the identification of one single major immunodominant epitope within the C-terminal 10 amino acid residues. Peptide binding studies and alanine replacement scanning of the C-terminal decapeptide, PVVAESPKKP, revealed a critical role for the PKKP sequence and its terminal carboxyl group for the binding of immunoglobulin M (IgM) antibodies from patients with Lyme borreliosis. Electron microscopy of antibody-labeled spirochetes indicated that the C-terminal region is exposed on the surface of the spirochete. Based on homology to proteins of known function, this region most probably adopts a polyproline II-like helix, which is found in surface-exposed structures involved in protein-protein interactions. This structural motif is highly conserved in Borrelia species causing Lyme borreliosis and subjected to purifying selection. We suggest that the abundance of the C-terminal region of OspC on the surface of B. burgdorferi allows a multimeric high-avidity interaction between the spirochete and surface Igs on B cells. The resulting cross-linking of surface Igs on B cells may induce a T-cell-independent B-cell activation without IgM-to-IgG switching, thus explaining the lack of IgG antibodies to OspC in neuroborreliosis.

A one-step solid phase immunoassay for simultaneous detection of serum IgG and IgM antibodies to Borrelia burgdorferi

A one-step immunoassay for simultaneous detection of serum IgG and IgM antibodies to Borrelia burgdorferi has been developed. The assay is based on C1q, which binds to immune complexes containing IgG and/or IgM antibodies. Micro-beads pre-coated with antibodies to human C1q are mixed with human serum samples and fluorochrome-labelled B. burgdorferi flagellum antigen. In the presence of serum IgG and/or IgM antibodies to B. burgdorferi, fluorochrome-labelled antigen/antibody complexes are formed. These are then bound by serum C1q and are subsequently captured on the anti-C1q-coated beads. The sample is analysed on a flow cytometer and the presence of fluorescent beads is, thus, indicative of a positive test result. In the present study the sensitivity and specificity of the assay are compared to those of the indirect IDEIA B. burgdorferi IgG and the mu-chain capture IDEIA B. burgdorferi IgM ELISAs for separate determination of IgG and IgM. Detection using a flow cytometer can be performed without separation of the beads from the reaction mixture, which means that in practice, the method is carried out as a one-step assay and it is, thus, very suitable for automation. Other advantages of this kind of assay includes an antibody/antigen reaction which occurs in solution and the potential of using the method for the detection of antibodies against several antigens from the same or different infectious agents (multi-parameter screening).

Lyme borreliosis

Lyme borreliosis (Lyme disease) is often said to be associated with "protean" manifestations, a reference to the ancient god Proteus, who could assume many forms and thus elude his pursuers. This legendary quality has clouded our understanding of Lyme borreliosis by giving Borrelia burgdorferi infection a mythical aura of its own. This review shows that this illness, while incompletely understood, is far more palpable than Proteus and is (in most cases) much more readily subdued. The clinical presentations of Lyme borreliosis do differ in North America and Eurasia, possibly due to the differing pathogenicity of distinct genospecies of Borrelia burgdorferi. The most common manifestation, however, in both continents is erythema migrans. Diagnosis should rest on a careful history and objective clinical findings, supported by appropriately chosen laboratory tests. Reports of coinfection with other tick-borne diseases should prompt a fresh look at Lyme borreliosis. Assertions about "protean manifestations" of B burgdorferi infection should be reappraised. Advances in laboratory techniques are welcome but culture remains the gold standard for the diagnosis--and no laboratory test result should substitute for careful clinical observation and critical analysis.

Diagnostic value of proteins of three Borrelia species (Borrelia burgdorferi sensu lato) and implications for development and use of recombinant antigens for serodiagnosis of Lyme borreliosis in Europe

More and more assays for the serodiagnosis of Lyme borreliosis (LB) are based on recombinant antigens. However, so far, there is no consensus as to which are the most specific and sensitive proteins and how they should be used in combination to obtain tests with the best discrimination abilities. The present study was preceded by a detailed analysis of Western blots (WB) using whole-cell lysates of Borrelia burgdorferi sensu stricto strain PKa2, B. afzelii PKo, and B. garinii PBi (U. Hauser, G. Lehnert, R. Lobentanzer, and B. Wilske, J. Clin. Microbiol. 35:1433-1444, 1997). For the present work, the data bank from that study, containing information about the reactivities of 330 sera (from patients at different stages of LB [n = 189]; control group, n = 141), was reused. The specificities and sensitivities of various combinations of proteins from different strains were calculated for different interpretation criteria. For immunoglobulin G (IgG) WB, the recommended combination of antigens available to date as recombinant proteins included p83/100 of PKa2, p83/100 of PKo, p39 of PKo, p39 of PBi, and OspC of PBi (interpretation criterion, at least one reactive band required for a positive WB; specificity, 96.5%; sensitivity, 56.1%). The further addition of p58 of PKo, p17 of PKo, or p14 of PKo was most favorable in terms of both a considerable gain of sensitivity and little loss of specificity. IgG Western blotting with a whole-cell lysate of strain PKo might be improved by the addition of OspC of PBi. For IgG WB, the best combination, out of all bands, was p83/100, p58, p39, p30, and p21 of all three strains and OspC of PBi, p17b of PBi, p56 of PKa2, p43 of PKo, p17 of PKo, and p14 of PKo (interpretation criterion, at least two reactive bands required for a positive WB; specificity, 97.2%; sensitivity, 61.4%). An interpretation criterion of at least two reactive bands is more reliable than one of only one reactive band. For IgM WB, the best combination was OspC of PKo, OspC of PBi, p39 of all three strains, p17 of PKo, and strong reactions with p41 of all three strains (interpretation criterion, at least one reactive band required; specificity, 97.9%; sensitivity, 47.0%).

Enzyme-linked immunosorbent assay using recombinant OspC and the internal 14-kDa flagellin fragment for serodiagnosis of early Lyme disease

The outer surface protein C (OspC) and the internal 14-kDa flagellin fragment of strain GeHo of Borrelia burgdorferi sensu stricto were expressed as recombinant proteins in Escherichia coli and were purified for use in an immunoglobulin M (IgM) enzyme-linked immunosorbent assay (OspC-14-kDa antigen ELISA). No hint at disturbing protein-protein interferences, which might influence the availability of immunoreactive epitopes, was found when the recombinant antigens were combined in the ELISA. The recombinant OspC-14-kDa antigen ELISA was compared to a commercial IgM ELISA that used a detergent cell extract from Borrelia afzelii PKo as the antigen. According to the manufacturer's information, the cell extract contains, in addition to other antigens, the following diagnostically relevant antigens: the 100-kDa (synonyms, 93- and 83-kDa antigens), 41-kDa, OspA, OspC, and 17-kDa antigens. The specificity was adjusted to 95% on the basis of data for 154 healthy controls. On testing of 104 serum samples from patients with erythema migrans (EM), the sensitivity of the recombinant ELISA (46%) for IgM antibodies was similar to that of the commercial ELISA (45%). However, when 42 serum samples from patients with polyclonal B-cell stimulation due to an Epstein-Barr virus infection were tested, false-positive reactions were significantly less frequent in the recombinant ELISA (10%) than in the whole-cell-extract ELISA (23%). OspC displays sequence heterogeneity of up to 40% according to the genomospecies. However, when the reactions of serum specimens from controls and EM patients with OspC from representative strains of B. burgdorferi sensu stricto (strain GeHo) and B. afzelii (strain PKo) were compared in an ELISA, almost no differences in specificity and sensitivity were seen. This demonstrates that the sera predominantly recognize the common epitopes of OspC tested in this study. In conclusion, we suggest that the OspC-14-kDa antigens ELISA is a suitable test for the detection of an IgM response in early Lyme disease.