Epitope-Specific Evolution of Human B Cell Responses to Borrelia burgdorferi VlsE Protein from Early to Late Stages of Lyme Disease.

Most immunogenic proteins of Borrelia burgdorferi, the causative agent of Lyme disease, are known or expected to contain multiple B cell epitopes. However, the kinetics of the development of human B cell responses toward the various epitopes of individual proteins during the course of Lyme disease has not been examined. Using the highly immunogenic VlsE as a model Ag, we investigated the evolution of humoral immune responses toward its immunodominant sequences in 90 patients with a range of early to late manifestations of Lyme disease. The results demonstrate the existence of asynchronous, independently developing, Ab responses against the two major immunogenic regions of the VlsE molecule in the human host. Despite their strong immunogenicity, the target epitopes were inaccessible to Abs on intact spirochetes, suggesting a lack of direct immunoprotective effect. These observations document the association of immune reactivity toward specific VlsE sequences with different phases of Lyme disease, demonstrating the potential use of detailed epitope mapping of Ags for staging of the infection, and offer insights regarding the pathogen's possible immune evasion mechanisms.

Operating Room Traffic Increases Aerosolized Particles and Compromises the Air Quality: A Simulated Study.

BACKGROUND: Strategies to prevent bacterial fallout and reduce particle count in the operating room (OR) are key components of preventing periprosthetic joint infection. Although OR traffic control is an important factor, a quantitative study has not been performed to investigate the influence of personnel and door opening on OR air quality. This simulated study aimed to examine the influence of these 2 factors on particle density in OR with and without the laminar air flow (LAF). METHODS: Both experiments took place within an empty OR of an arthroplasty unit equipped with an LAF system. First, the number of particles in the air was counted using a particle counting apparatus while 9 persons entered the room, one every 15 minutes. Second, the door was opened and closed starting with zero door openings per minute and increasing to 4 in 15-minute increments. Both experiments were performed once with the LAF turned on and once without. RESULTS: The number of personnel in the OR and the number of door openings per minute correlate with the density of particles. Both relationships were significantly reduced by turning the LAF on (correlation coefficients <0.4). With the LAF being turned on, the particle density per person decreased from 211.19 to 18.19 particles/ft3 (P < .001) and the particle density per rate of door openings declined from 117.80 to 1.90 particles/ft3 (P = .017). CONCLUSION: This study confirms that personnel and door opening are a major source of particles in the OR air. Controlling traffic is critical for reduction of particles and is likely to be a key preventative strategy in reducing periprosthetic joint infection. LAF is protective against the negative influence of number of people and door openings.

Novel molecular signatures in mononuclear cell populations from patients with systemic lupus erythematosus.

To gain novel insights into the immunopathogenesis of systemic lupus erythematosus we have analyzed gene expression data from isolated CD4+ T cells, CD8+ T cells, CD19+ B cells, and CD56+ NK-cell enriched peripheral blood cell fractions from patients and healthy donors. As predicted, type I interferon-inducible gene transcripts are overexpressed in all populations. Transcripts preferentially expressed in SLE CD4+ and CD8+ T cells include those associated with Tregulatory and Th17 effector cell programs, respectively, but in each case additional transcripts predicted to limit differentiation of those effector cells are detected. Evidence for involvement of the Wnt/ß-catenin pathway was observed in both B and T cell fractions, and novel transcripts were identified in each cell population. These data point to disrupted T effector cell differentiation and the Wnt/ß-catenin pathway as contributors to immune dysfunction in SLE while further supporting a central role for the type I interferon pathway in lupus.

Enhanced rho-associated protein kinase activation in patients with systemic lupus erythematosus.

OBJECTIVE: Rho-associated protein kinases (ROCKs) have been implicated in the pathogenesis of cardiovascular and renal disorders. We recently showed that ROCKs could regulate the differentiation of murine Th17 cells and the production of interleukin-17 (IL-17) and IL-21, two cytokines associated with systemic lupus erythematosus (SLE). The goal of this study was to assess ROCK activation in human Th17 cells and to evaluate ROCK activity in SLE patients. METHODS: An enzyme-linked immunosorbent assay (ELISA)-based ROCK activity assay was used to evaluate ROCK activity in human cord blood CD4+ T cells differentiated under Th0 or Th17 conditions. We then performed a cross-sectional analysis of 28 SLE patients and 25 healthy matched controls. ROCK activity in peripheral blood mononuclear cell (PBMC) lysates was determined by ELISA. Cytokine and chemokine profiles were analyzed by ELISA. RESULTS: Human cord blood CD4+ T cells differentiated under Th17 conditions expressed higher levels of ROCK activity than did CD4+ T cells stimulated under Th0 conditions. Production of IL-17 and IL-21 was inhibited by the addition of a ROCK inhibitor. SLE PBMCs expressed significantly higher levels of ROCK activity than did healthy control PBMCs (1.25 versus 0.56; P = 0.0015). Sixteen SLE patients (57%) expressed high levels of ROCK (optical density at 450 nm >1). Disease duration, lymphocyte count, and azathioprine use were shown to be significant independent predictors of ROCK activity in multivariable analyses. CONCLUSION: Consistent with previous results in the murine system, increased ROCK activation was associated with Th17 cell differentiation. Moreover, enhanced ROCK activity was observed in a subgroup of SLE patients. These data support the concept that the ROCK pathway could represent an important therapeutic target for SLE.

Increased IFNα activity and differential antibody response in patients with a history of Lyme disease and persistent cognitive deficits.

Following antibiotic treatment for Lyme disease, some patients report persistent or relapsing symptoms of pain, fatigue, and/or cognitive deficits. Factors other than active infection, including immune abnormalities, have been suggested, but few clues regarding mechanism have emerged. Furthermore, the effect of antibiotic treatment on immune response in affected individuals remains unknown. In this study, a longitudinal analysis of specific immune markers of interest was carried out in patients with a history of Lyme disease and persistent objective memory impairment, prior to and following treatment with either ceftriaxone or placebo. IFNα activity was measured by detection of serum-induced changes in specific target genes, using a functional cell-based assay and quantitative real-time PCR. Level and pattern of antibody reactivity to brain antigens and to Borrelia burgdorferi proteins were analyzed by ELISA and immunoblotting. Sera from the patient cohort induced significantly higher expression of IFIT1 and IFI44 target genes than those from healthy controls, indicating increased IFNα activity. Antibody reactivity to specific brain and borrelial proteins was significantly elevated in affected patients. IFNα activity and antibody profile did not change significantly in response to ceftriaxone. The heightened antibody response implies enhanced immune stimulation, possibly due to prolonged exposure to the organism prior to the initial diagnosis and antibiotic treatment of Lyme disease. The increase in IFNα activity is suggestive of a mechanism contributing to the ongoing neuropsychiatric symptoms.