Monitoring the immune responses to vaccination and pertussis: bordetella pertussis and beyond

In this thesis, the monitoring of the immune system in balance and during active responses (by flow cytometry) plays a central role. In chapter 2.1 and 2.2, we investigated the optimal sample logistics for high-dimensional flow cytometry in clinical trials. In chapter 3.1-3.4, we monitored the longitidinal kinetics of circulating immune cells in humans after vaccination or bacterial challenge against Bordetella pertussis. Lastly, in chapter 4, we investigated the immune system in humans carrying a genetic variant of PLCG2 'p.P522R', which is associated with increased longevity and reduced chance of developing dementia.LUMC / Geneeskund

Divergence Measure Between Chaotic Attractors

We propose a measure of divergence of probability distributions for quantifying the dissimilarity of two chaotic attractors. This measure is defined in terms of a generalized entropy. We illustrate our procedure by considering the effect of additive noise in the well known H\'enon attractor. Comparison of two H\'enon attractors for slighly different parameter values, has shown that the divergence has complex scaling structure. Finally, we show how our approach allows to detect non-stationary events in a time series.Comment: 9 pages, 6 figure

B-cell immunophenotyping to predict vaccination outcome in the immunocompromised: a systematic review

Vaccination is the most effective measure to prevent infections in the general population. Its efficiency strongly depends on the function and composition of the immune system. If the immune system lacks critical components, patients will not be fully protected despite a completed vaccination schedule. Antigen-specific serum immunoglobulin levels are broadly used correlates of protection. These are the products of terminally differentiated B cells - plasma cells. Here we reviewed the literature on how aberrancies in B-cell composition and function influence immune responses to vaccinations. In a search through five major literature databases, 6,537 unique articles published from 2000 and onwards were identified. 75 articles were included along three major research lines: extremities of life, immunodeficiency and immunosuppression. Details of the protocol can be found in the International Prospective Register of Systematic Reviews [PROSPERO (registration number CRD42021226683)]. The majority of articles investigated immune responses in adults, in which vaccinations against pneumococci and influenza were strongly represented. Lack of baseline information was the most common reason of exclusion. Irrespective of study group, three parameters measured at baseline seemed to have a predictive value in assessing vaccine efficacy: (1) distribution of B-cell subsets (mostly a reduction in memory B cells), (2) presence of exhausted/activated B cells, or B cells with an aberrant phenotype, and (3) pre-existing immunological memory. In this review we showed how pre-immunization (baseline) knowledge of circulating B cells can be used to predict vaccination efficacy. We hope that this overview will contribute to optimizing vaccination strategies, especially in immunocompromised patients.Immunogenetics and cellular immunology of bacterial infectious disease

Longitudinal dynamics of human B-cell response at the single-cell level in response to Tdap vaccination

To mount an adequate immune response against pathogens, stepwise mutation and selection processes are crucial functions of the adaptive immune system. To better characterize a successful vaccination response, we performed longitudinal (days 0, 5, 7, 10, and 14 after Boostrix vaccination) analysis of the single-cell transcriptome as well as the B-cell receptor (BCR) repertoire (scBCR-rep) in plasma cells of an immunized donor and compared it with baseline B-cell characteristics as well as flow cytometry findings. Based on the flow cytometry knowledge and literature findings, we discriminated individual B-cell subsets in the transcriptomics data and traced over-time maturation of plasmablasts/plasma cells (PB/PCs) and identified the pathways associated with the plasma cell maturation. We observed that the repertoire in PB/PCs differed from the baseline B-cell repertoire e.g., regarding expansion of unique clones in post-vaccination visits, high usage of IGHG1 in expanded clones, increased class-switching events post-vaccination represented by clonotypes spanning multiple IGHC classes and positive selection of CDR3 sequences over time. Importantly, the Variable gene family-based clustering of BCRs represented a similar measure as the gene-based clustering, but certainly improved the clustering of BCRs, as BCRs from duplicated Variable gene families could be clustered together. Finally, we developed a query tool to dissect the immune response to the components of the Boostrix vaccine. Using this tool, we could identify the BCRs related to anti-tetanus and anti-pertussis toxoid BCRs. Collectively, we developed a bioinformatic workflow which allows description of the key features of an ongoing (longitudinal) immune response, such as activation of PB/PCs, Ig class switching, somatic hypermutation, and clonal expansion, all of which are hallmarks of antigen exposure, followed by mutation & selection processes.Molecular Epidemiolog

Highly sensitive flow cytometry allows monitoring of changes in circulating immune cells in blood after Tdap booster vaccination

Antigen-specific serum immunoglobulin (Ag-specific Ig) levels are broadly used as correlates of protection. However, in several disease and vaccination models these fail to predict immunity. In these models, in-depth knowledge of cellular processes associated with protective versus poor responses may bring added value. We applied high-throughput multicolor flow cytometry to track over-time changes in circulating immune cells in 10 individuals following pertussis booster vaccination (Tdap, Boostrix(R), GlaxoSmithKline). Next, we applied correlation network analysis to extensively investigate how changes in individual cell populations correlate with each other and with Ag-specific Ig levels. We further determined the most informative cell subsets and analysis time points for future studies. Expansion and maturation of total IgG1 plasma cells, which peaked at day 7 post-vaccination, was the most prominent cellular change. Although these cells preceded the increase in Ag-specific serum Ig levels, they did not correlate with the increase of Ig levels. In contrast, strong correlation was observed between Ag-specific IgGs and maximum expansion of total IgG1 and IgA1 memory B cells at days 7 to 28. Changes in circulating T cells were limited, implying the need for a more sensitive approach. Early changes in innate immune cells, i.e. expansion of neutrophils, and expansion and maturation of monocytes up to day 5, most likely reflected their responses to local damage and adjuvant. Here we show that simultaneous monitoring of multiple circulating immune subsets in blood by flow cytometry is feasible. B cells seem to be the best candidates for vaccine monitoring.Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological disease

Improved standardization of flow cytometry diagnostic screening of primary immunodeficiency by software-based automated gating

BackgroundMultiparameter flow cytometry (FC) is essential in the diagnostic work-up and classification of primary immunodeficiency (PIDs). The EuroFlow PID Orientation tube (PIDOT) allows identification of all main lymphocyte subpopulations in blood. To standardize data analysis, tools for Automated Gating and Identification (AG&I) of the informative cell populations, were developed by EuroFlow. Here, we evaluated the contribution of these innovative AG&I tools to the standardization of FC in the diagnostic work-up of PID, by comparing AG&I against expert-based (EuroFlow-standardized) Manual Gating (MG) strategy, and its impact on the reproducibility and clinical interpretation of results.MethodsFC data files from 44 patients (13 CVID, 12 PID, 19 non-PID) and 26 healthy donor (HD) blood samples stained with PIDOT were analyzed in parallel by MG and AG&I, using Infinicyt (TM) software (Cytognos). For comparison, percentage differences in absolute cell counts/mu L were calculated for each lymphocyte subpopulation. Data files showing differences >20% were checked for their potential clinical relevance, based on age-matched percentile (p5-p95) reference ranges. In parallel, intra- and inter-observer reproducibility of MG vs AG&I were evaluated in a subset of 12 samples.ResultsThe AG&I approach was able to identify the vast majority of lymphoid events (>99%), associated with a significantly higher intra- and inter-observer reproducibility compared to MG. For most HD (83%) and patient (68%) samples, a high degree of agreement (<20% numerical differences in absolute cell counts/mu L) was obtained between MG and the AG&I module. This translated into a minimal impact (<5% of observations) on the final clinical interpretation. In all except three samples, extended expert revision of the AG&I approach revealed no error. In the three remaining samples aberrant maturation and/or abnormal marker expression profiles were seen leading in all three cases to numerical alarms by AG&I.ConclusionAltogether, our results indicate that replacement of MG by the AG&I module would be associated with a greater reproducibility and robustness of results in the diagnostic work-up of patients suspected of PID. However, expert revision of the results of AG&I of PIDOT data still remains necessary in samples with numerical alterations and aberrant B- and T-cell maturation and/or marker expression profiles.Stemcel biology/Regenerative medicine (incl. bloodtransfusion

Aortoiliac steno-occlusion in young women: A single center experience and review of the literature

Peripheral obliterating arterial disease characterized by aortoiliac steno-occlusion occurring in relatively young women of small stature, is frequently reported in the literature under the name small aorta syndrome. Although it remains unclear whether small aorta syndrome represents a separate entity, the small size of the distal aorta increases risk for aortoiliac occlusive disease. Patients usually present with lower extremity claudication and typical risk factors. This paper shows an analysis of the literature focusing on the pathogenesis, clinical features, risk factors and treatment, as well as a single center experience with this disorder

Carotid stent mobility with regard to head movements: In vitro analysis

Given that considerable motion of the carotid artery is present during head movements, we hypothesized that a flexible stent with low torsion might be favorable to avoid stress imparted to the stent and carotid artery. Therefore, we evaluated the flexibility of different expanded carotid stents before and after deployment in a carotid artery in vitro. Subsequently, we evaluated torsion of the bare expanded stents. Five stents (Wallstent [Boston Scientific Corp., Natick, MA], Acculink [Guidant Corp., Indianapolis, IN], Precise [Cordis Corp., Johnson & Johnson Company, Warren, NJ], Carotid SE [Medtronic AVE, Santa Rosa, CA], and Protégé [EV3, Plymouth, MN]) were tested. Flexibility was determined using a three-point bend test recording the bending load (BL) in grams required to flex the stent 25°. Increased BL implies decreased flexibility. Torsion was measured by recording the rotation load (RL) in grams required to rotate the stents 30° along its axis. Increased RL implies increased torsion. In the bare expanded state, the median BL was 6 g (range 1-22 g). The BL increased to 38 g (range 20-41 g) after deployment in a carotid artery, with the Carotid SE (21 g) and Wallstent (36 g) showing significantly lower BL (p < .0001 and p = .0016, respectively). Overall, the RL was 11 g (range 1-76 g). Significantly higher RL was required to rotate the Wallstent (73 g) and Precise (20 g) stents (p < .0001). The flexibility of the currently used stents decreases after deployment in a carotid artery irrespective of its flexibility in the bare state. Two stents showed increased torsion compared with the other stents. Limitations in both flexibility and torsion might influence the long-term performance of carotid angioplasty stenting

Modular branched endograft system for aortic aneurysm repair: Evaluation in a human cadaver circulation model

A circulation model was created in 6 nonaneurysmal human cadavers to evaluate the deliverability, deployment, and acute performance of a modular branched endograft system for treatment of aortic aneurysms containing essential branch vessels. Two fenestrations were created in an appropriately sized aortic main endograft. Under fluoroscopic guidance, the main endograft was advanced to the target site and the fenestrations were aligned with the ostia of the renal arteries. Branch grafts were placed through the fenestrations into the renal arteries. The outcome was evaluated by post implant angiography and autopsy. Eleven branch grafts were deployed at the target site. All targeted renal arteries showed good patency. At autopsy, all main endografts were adequately deployed, and 10 of 11 branch grafts were locked in place. In this model, deliverability and deployment of the modular branch graft system is feasible in a reliable, predictable, and timely fashion