Heidi Sillanpää

Recombinant or peptide antigens in the serology of Lyme arthritis in children

The performance of ELISAs with the recombinant antigens decorin-binding protein A (DbpA), DbpB, and BBK32 (from Borrelia afzelii, B. garinii, and B. burgdorferi sensu stricto) and VlsE peptide antigen invariable region 6 (IR(6)) were evaluated in the serodiagnosis and follow-up of children with Lyme arthritis (LA). Serum samples were obtained from 52 children with clinically typical and serologically confirmed LA. In IgG ELISAs, at diagnosis, 50 samples were positive for BBK32, 51 for DbpA, 40 for DbpB, and 51 for IR(6). In the posttreatment follow-up, the rate of decline of the antibodies to the recombinant protein antigens or to IR(6) did not appear useful in the prediction of the treatment response or the clinical course of LA. Yet, IR(6) seems to have the greatest potential to be used universally in the diagnostic serology of Lyme borreliosis (LB). Alternate to that, the use of several specific borrelial antigens, in parallel, might improve the accuracy of serology for LB.

Cerebrospinal fluid chemokine CXCL13 in the diagnosis of neuroborreliosis in children

Abstract Background: The diagnosis of Lyme neuroborreliosis (LNB) requires laboratory confirmation because neurological symptoms indicative of LNB are not specific. Recent studies have suggested that a chemokine, CXCL13, could have an important role in the diagnosis of LNB. The aim of this study was to assess CXCL13 levels in the cerebrospinal fluid (CSF) of children with LNB. Methods: CSF samples were available for 57 children with symptoms indicative of LNB. Based on the presence of anti-flagella antibodies and pleocytosis in CSF, patients were divided into 3 different groups: confirmed LNB (n = 24), possible LNB (n = 16), and non-LNB (n = 17). CXCL13 levels were determined with a commercial kit (Quantikine). Results: All 24 patients with confirmed LNB had elevated CXCL13 levels in CSF. Elevated CXCL13 was also observed in the majority of patients without anti-flagella antibodies in the CSF (possible LNB). Of the 17 non-LNB and 50 control samples, 1 was positive. Conclusions: In LNB, the production of CXCL13 in CSF seems to precede antibody production. Assessment of CSF CXCL13 may improve the diagnostics for children with possible LNB.

Antibody responses to borrelia IR6 peptide variants and the C6 peptide in Swedish patients with erythema migrans

The aim of this study was to evaluate the antibody responses to different VlsE protein IR(6) peptide variants and the synthetic C6 peptide in acute and convalescent (2-3 and 6 months) serum samples from Swedish patients with clinical erythema migrans (EM). Serum samples were prospectively collected from 148 patients with EM and compared to serum samples obtained from 200 healthy blood donors. The IgG responses to 3 IR(6) peptide variants originating from Borrelia burgdorferi (B. burgdorferi) sensu stricto, B. garinii, and B. afzelii were measured by enzyme-linked immunosorbent assays (ELISAs) and compared to a commercial C6 peptide ELISA. Seropositivity rate in the IR(6) or C6 peptide ELISAs ranged from 32% to 58% at presentation, 30-52% after 2-3 months, and 20-36% after 6 months. At presentation, positive antibodies in any of the 4 ELISAs were found in 66%. In 7/52 (13%), C6-negative EM cases, serological reaction was found to the B. burgdorferi sensu stricto-derived IR(6) peptide. In patients reporting previous LB compared to those without previous LB, significantly higher seropositivity rates were noted for all IR(6) peptides, but not for the C6 peptide. In the serology of EM in Europe, C6 ELISA does not seem to cover all cases. An ELISA using a mixture of B. burgdorferi sensu stricto IR(6) peptide and the C6 peptide could be of value in the serodiagnosis of LB in Europe. Further studies on combinations of variant IR(6) peptides and the C6 peptide in other manifestations of LB are needed to address this issue.

Improved Laboratory Diagnostics of Lyme Neuroborreliosis in Children by Detection of Antibodies to New Antigens in Cerebrospinal Fluid

Background: Laboratory diagnostics in Lyme neuroborreliosis need improvement. We hereby investigate 4 new recombinant or peptide Borrelia antigens in cerebrospinal fluid in children with neuroborreliosis to evaluate their performance as diagnostic antigens. Methods: An enzyme-linked immunosorbent assay was used to detect IgG antibodies to recombinant decorin binding protein A (DbpA), BBK32, outer surface protein C (OspC), and the invariable region 6 peptide (IR6). The recombinant antigens originated from 3 pathogenic subspecies; Borrelia afzelii, Borrelia garinii, and Borrelia burgdorferi sensu stricto. Cerebrospinal fluid and serum from children with clinical features indicative for neuroborreliosis (n = 57) were analyzed. Classification of patients was based on clinical symptoms and laboratory findings. Controls were children with other neurologic diseases (n = 20) and adult patients with no proven infection (n = 16). Results: Sensitivity for DbpA was 82%, for BBK32 70%, for OspC 58% and for IR6 70%. Specificities were 94%, 100%, 97%, and 97%, respectively. No single antigen was superior. When new antigens were combined in a panel, sensitivity was 80% and specificity 100%. The reference flagella antigen showed a sensitivity of 60% and a specificity of 100%. Over all, the B. garinii related antigens dominated. Conclusions: Recombinant DbpA and BBK32 as well as the peptide antigen IR6 perform well in laboratory diagnostics of neuroborreliosis in children. New antigens seem to improve diagnostic performance when compared with the routine flagella antigen. If different antigens are combined in a panel to cover the antigenic diversity, sensitivity improves further and a specificity of 100% can be achieve.

Pilot Study of Diagnostic Potential of the Mycobacterium tuberculosis Recombinant HBHA Protein in a Vaccinated Population in Finland

Background In recent years T cell based interferon gamma release assays (IGRA) have been developed for immunodiagnosis of M. tuberculosis infection. At present these assays do not discriminate between disease and latency. Therefore, more promising antigens and diagnostic tools are continuously being searched for tuberculosis immunodiagnostics. The heparin binding hemagglutinin (HBHA) is a surface protein of M. tuberculosis which promotes bacterial aggregation and adhesion to non-phagocytic cells. It has been previously assumed that native, methylated form of this protein would be a promising antigen to discriminate latent from active infection. Methodology and Principal Findings We performed a pilot investigation to study humoral and T-cell mediated immunological responses to recombinant HBHA produced in M. smegmatis or to synthetic peptides in patients with recent or past tuberculosis, with atypical mycobacteriosis, or in healthy vaccinated individuals. The T cell reactivities to HBHA were compared to the respective reactivities towards Purified Protein Derivative (PPD) and two surface secreted proteins, ie. Early Secretory Antigen Target-6 (ESAT-6) and Culture Filtrate Protein-10 (CFP-10). Our pilot results indicate that methylated recombinant HBHA induced a strong T cell mediated immune response and the production of IgG and IgM-class antibodies in all patient groups, most surprisingly in young Finnish vaccinees, as well. We observed a positive correlation between the reactivities to HBHA and non-specific PPD among all studied subjects. As expected, ESAT-6 and CFP-10 were the most powerful antigens to discriminate disease from immunity caused by vaccination. Conclusions On the basis of results of this exploratory investigation we raise concerns that in countries like Finland, where BCG vaccination was routinely used, HBHA utility might not be sufficient for diagnostics because of inability to explicitly discriminate tuberculosis infection from immunoreactivity caused by previous BCG vaccination.

New antigens for serologic diagnosis of neuroborreliosis in children.

Objective: To evaluate serology with novel Borrelia-specific protein or peptide antigens in the laboratory diagnosis of neuroborreliosis (NB) in children. Methods: The performance of enzyme-linked immunosorbent assays with several recombinant borrelial protein antigens and invariable region 6 synthetic peptide antigen and of a commercial enzyme-linked immunosorbent assay with the flagella antigen were evaluated in the serodiagnosis and follow-up of children with clinical suspicion of NB. Serum samples were obtained from 20 children with neurologic symptoms indicative of NB. The patients were retrospectively divided into 2 groups based on the laboratory tests at presentation indicating definite (n = 7) or probable (n = 13) NB. Results: In addition to cerebrospinal fluid (CSF) lymphocytic pleocytosis and CSF antiflagella antibodies, all 7 patients with definite NB had serum IgG antibodies to at least 2 of the 3 novel antigens at presentation. The 13 patients with probable NB had variable laboratory findings: CSF pleocytosis (n = 7), CSF antiflagella IgM antibodies (n = 4), serum antiflagella IgM and/or IgG antibodies (n = 10). Of these 13 patients, 7 had serum IgG antibodies to 2 of the 3 novel antigens at presentation. During long term follow-up, serum anti-invariable region 6 antibodies disappeared. Conclusions: The present study suggests that assessment of serum antibodies to a panel of Borrelia-specific antigens could improve the laboratory diagnosis of NB at presentation.

Antibodies to recombinant decorin-binding proteins A and B in the cerebrospinal fluid of patients with Lyme neuroborreliosis

Cerebrospinal fluid (CSF) and serum samples from 34 patients with proven neuroborreliosis (NB) and 22 patients with suspected neuroborreliosis (SNB) from Finland were analysed for antibodies to decorin-binding proteins A (DbpA) and B (DbpB). Antibodies to recombinant protein antigens originating from Borrelia burgdorferi sensu stricto, B. afzelii, or B. garinii species were studied by enzyme-linked immunosorbent assay (ELISA). Of the 34 patients with NB, 100% of the CSF and 88% of the serum samples had IgG antibodies to 1 to 3 variants of DbpA and 79% of the CSF and 70% of the serum samples were positive for 1 to 3 DbpB variants. Antibodies to DbpB seemed to be associated with lymphocytic pleocytosis in the CSF and short duration of the disease, whereas antibodies to DbpA in the CSF were observed irrespective of the duration of the disease and lymphocytic pleocytosis. Among the variant antigens, CSF reactivity was mainly with the DbpB from B. garinii, whereas positivity with the DbpA from B. afzelii or B. garinii predominated. The results suggest that CSF antibodies to DbpB might be useful as a marker of active infection whereas antibodies to DbpA seem to persist a long time after acute phases of NB.

Performance of a multiplexed serological microarray for the detection of antibodies against central nervous system pathogens

n Abstractn n Central nervous system (CNS) infections have multiple potential causative agents for which simultaneous pathogen screening can provide a useful tool. This study evaluated a multiplexed microarray for the simultaneous detection of antibodies against CNS pathogens. The performance of selected microarray antigens for the detection of IgG antibodies against herpes simplex virus 1 and 2 (HSV-1 and HSV-2), varicella-zoster virus (VZV), adenovirus, Mycoplasma pneumoniae and Borrelia burgdorferi sensu lato, was evaluated using serum sample panels tested with reference assays used in a routine diagnostic laboratory. The microarray sensitivity for HSV-1, HSV-2, VZV, adenovirus and M. pneumonia ranged from 77% to 100%, and the specificity ranged from 74% to 97%. Very variable sensitivities and specificities were found for borrelial antigens of three different VlsE protein IR(6) peptide variants (IR6p1, IR6p2, IR6p4) and three recombinant decorin binding proteins A (DbpA; DbpAIa, DbpA91, DbpAG40). For single antigens, good specificity was shown for antigens of IR6p4 and DbpAIa (96%), while DbpA91, IR6p1 and IR6p2 were moderately specific (88–92%). The analytical sensitivity of the microarray was dependent on the borrelial IgG concentration of the specimen. The overall performance and technical features of the platform showed that the platform supports both recombinant proteins, whole viruses and peptides as antigens. This study showed diagnostic potential for all six CNS pathogens, including Borrelia burgdorferi sensu lato, using glutaraldehyde based microarray, and further highlighted the importance of careful antigen selection and the requirement for the use of multiple borrelial antigens in order to increase specificity without a major lack of sensitivity.n n

Antibodies to decorin-binding protein B (DbpB) in the diagnosis of Lyme neuroborreliosis in children

BACKGROUNDnLaboratory support is needed to confirm the clinical diagnosis of Lyme neuroborreliosis (LNB). Antibodies to Borrelia-specific proteins have been used to improve serological diagnostics. The aims of this study were to assess the occurrence of antibodies to decorin-binding protein B (DbpB) in serum and cerebrospinal fluid (CSF) in children with LNB and to evaluate the performance of DbpB variants in the diagnosis of LNB in children.nnnMETHODSnSerum and CSF sample pairs were available from 57 children evaluated for LNB. Based on the presence of anti-flagella antibodies and pleocytosis in the CSF, patients were divided into three different groups: confirmed LNB (n=24), possible LNB (n=16), and non LNB (n=17). Recombinant DbpBs from three Borrelia burgdorferi sensu lato species - Borrelia burgdorferi sensu stricto, Borrelia garinii, and Borrelia afzelii - were used in an ELISA to detect IgG antibodies.nnnRESULTSnThe sensitivity of variant recombinant DbpBs in serum and CSF samples varied between 0% and 46% and between 0% and 42%, respectively. In CSF, the most sensitive antigen was the DbpB variant from B. garinii.nnnCONCLUSIONSnSerum or CSF antibodies to DbpB do not appear to be beneficial in the laboratory diagnosis of LNB in children.