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INTRODUCTION AND OBJECTIVE:Medical malpractice (MP) is an important issue in our country. There has been controversy surrounding PSA testing and prostate cancer screening, specifically the United S...

68Ga-labeled urea-based inhibitors of the prostate-specific membrane antigen (PSMA), such as 68Ga-labeled N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED)-PSMA-11, are promising small molecules for targeting prostate cancer. A new radiopharmaceutical, 68Ga-labeled tris(hydroxypyridinone) (THP)-PSMA, has a simplified design for single-step kit-based radiolabeling. It features the THP ligand, which forms complexes with 68Ga3+ rapidly at a low concentration, at room temperature, and over a wide pH range, enabling direct elution from a 68Ge/68Ga generator into a lyophilized radiopharmaceutical kit in 1 step without manipulation. The aim of this phase 1 study was to assess the safety and biodistribution of 68Ga-THP-PSMA. Methods: Cohort A comprised 8 patients who had proven prostate cancer and were scheduled to undergo prostatectomy; they had Gleason scores of 7-10 and a mean prostate-specific antigen level of 7.8 μg/L (range, 5.4-10.6 μg/L). They underwent PET/CT after the administration of 68Ga-THP-PSMA. All patients proceeded to prostatectomy (7 with pelvic nodal dissection). Dosimetry from multi-time-point PET imaging was performed with OLINDA/EXM. Cohort B comprised 6 patients who had positive 68Ga-HBED-PSMA-11 PET/CT scanning results and underwent comparative 68Ga-THP-PSMA scanning. All patients were monitored for adverse events. Results: No adverse events occurred. In cohort A, 6 of 8 patients had focal uptake in the prostate (at 2 h: average SUVmax, 5.1; range, 2.4-9.2) and correlative 3+ staining of prostatectomy specimens on PSMA immunohistochemistry. The 2 68Ga-THP-PSMA scans with negative results had only 1+/2+ staining. The mean effective dose was 2.07E-02 mSv/MBq. In cohort B, 68Ga-THP-PSMA had lower physiologic background uptake than 68Ga-HBED-PSMA-11 (in the parotid glands, the mean SUVmax for 68Ga-THP-PSMA was 3.6 [compared with 19.2 for 68Ga-HBED-PSMA-11]; the respective corresponding values in the liver were 2.7 and 6.3, and those in the spleen were 2.7 and 10.5; P < 0.001 for all). In 5 of 6 patients, there was concordance in the number of metastases identified with 68Ga-HBED-PSMA-11 and 68Ga-THP-PSMA. Thirteen of 15 nodal abnormalities were subcentimeter. In 22 malignant lesions, the tumor-to-liver contrast with 68Ga-THP-PSMA was similar to that with 68Ga-HBED-PSMA (4.7 and 5.4, respectively; P = 0.15), despite a higher SUVmax for 68Ga-HBED-PSMA than for 68Ga-THP-PSMA (30.3 and 10.7, respectively; P < 0.01). Conclusion:68Ga-THP-PSMA is safe and has a favorable biodistribution for clinical imaging. Observed focal uptake in the prostate was localized to PSMA-expressing malignant tissue on histopathology. Metastatic PSMA-avid foci were also visualized with 68Ga-THP-PSMA PET. Single-step production from a Good Manufacturing Practice cold kit may enable rapid adoption.

Aim To determine whether heterogeneity of cardiac scar, as assessed by cardiovascular magnetic resonance (CMR) texture analysis, may provide insight into better risk stratification for patients with previous myocardial infarction (MI). Materials and methods Patients with previous MI (n=76) were followed for a median of 371.5 days after late gadolinium enhancement (LGE) CMR. The primary endpoint was a composite of ventricular tachycardia, ventricular fibrillation, or unexplained syncope. Areas of LGE were identified and manually segmented on a short-axis projection. The characteristics of the scar heterogeneity were evaluated via CMR texture analysis. This is a filtration-histogram technique, where images are filtered using the Laplacian of a Gaussian filter to extract features different sizes (2–6 mm in radius) corresponding to fine, medium, and coarse texture scales followed by a quantification step using histogram analysis (skewness and kurtosis). Results Patients suffering arrhythmic events during the follow-up period demonstrated significantly higher kurtosis (coarse-scale, p=0.005) and lower skewness (fine-scale, p=0.046) compared to those suffering no arrhythmic events. Furthermore, Kaplan–Meier analysis showed significantly higher coarse kurtosis (p=0.004), and lower fine skewness (p=0.035) were able to predict increased incidence of ventricular arrhythmic events. Conclusions In this pilot study, indices of texture analysis reflecting textural heterogeneity were significantly associated with a greater incidence of arrhythmic events. Further work is required to delineate the role of texture analysis techniques in risk stratification post-MI.

Cancer cell metastasis is responsible for most cancer deaths. Non-invasive in vivo cancer cell tracking in spontaneously metastasizing tumor models still poses a challenge requiring highest sensitivity and excellent contrast. The goal of this study was to evaluate if the recently introduced PET radiotracer [18F]tetrafluoroborate ([18F]BF4−) is useful for sensitive and specific metastasis detection in an orthotopic xenograft breast cancer model expressing the human sodium iodide symporter (NIS) as a reporter. In vivo imaging was complemented by ex vivo fluorescence microscopy and γ-counting of harvested tissues. Radionuclide imaging with [18F]BF4− (PET/CT) was compared to the conventional tracer [123I]iodide (sequential SPECT/CT). We found that [18F]BF4− was superior due to better pharmacokinetics, i.e. faster tumor uptake and faster and more complete clearance from circulation. [18F]BF4−-PET was also highly specific as in all detected tissues cancer cell presence was confirmed microscopically. Undetected comparable tissues were similarly found to be free of metastasis. Metastasis detection by routine metabolic imaging with [18F]FDG-PET failed due to low standard uptake values and low contrast caused by adjacent metabolically active organs in this model. [18F]BF4−-PET combined with NIS expressing disease models is particularly useful whenever preclinical in vivo cell tracking is of interest.

Background It is important to study differential inflammatory cellular migration, particularly of eosinophils and neutrophils, in asthma and how this is influenced by environmental stimuli such as allergen exposure and the effects of anti asthma therapy. Methods We isolated blood neutrophils and eosinophils from 12 atopic asthmatic human volunteers (Group 1 — four Early Allergic Responders unchallenged (EAR); Group 2 — four Early and Late Allergic Responders (LAR) challenged; Group 3 — four EAR and LAR challenged and treated with systemic corticosteroids) using cGMP CD16 CliniMACS. Cells were isolated prior to allergen challenge where applicable, labelled with 99mTc-HMPAO and then re-infused intravenously. The kinetics of cellular influx/efflux into the lungs and other organs were imaged via scintigraphy over 4 h, starting at 5 to 6 h following allergen challenge where applicable. Results Neutrophils and eosinophils were isolated to a mean (SD) purity of 98.36% (1.09) and 96.31% (3.0), respectively. Asthmatic neutrophils were activated at baseline, mean (SD) CD11bHigh cells 46 (10.50) %. Isolation and radiolabelling significantly increased their activation to > 98%. Eosinophils were not activated at baseline, CD69+ cells 1.9 (0.6) %, increasing to 38 (3.46) % following isolation and labelling. Analysis of the kinetics of net eosinophil and neutrophil lung influx/efflux conformed to a net exponential clearance with respective mean half times of clearance 6.98 (2.18) and 14.01 (2.63) minutes for Group 1, 6.03 (0.72) and 16.04 (2.0) minutes for Group 2 and 5.63 (1.20) and 14.56 (3.36) minutes for Group 3. These did not significantly differ between the three asthma groups (p > 0.05). Conclusions Isolation and radiolabelling significantly increased activation of eosinophils (CD69) and completely activated neutrophils (CD11bHigh) in all asthma groups. Net lung neutrophil efflux was significantly slower than that of eosinophils in all asthma study groups. There was a trend for pre-treatment with systemic corticosteroids to reduce lung retention of eosinophils following allergen challenge., Highlights • Isolation and radiolabelling of eosinophils or neutrophils from asthmatics significantly activates them. • Corticosteroids alter eosinophil, but not neutrophil 99mTc-HMPAO radiolabelling efficiency. • Leukocyte activation as a result of manipulation ex vivo does not measurably alter lung sequestration. • Eosinophil migration through the lungs of asthmatic patients is slower than in healthy volunteers.

DC vaccines have been used to induce tumour-specific cytotoxic T cells . However, this approach to cancer immunotherapy has had limited success. To be successful, injected DCs need to migrate to the LNs where they can stimulate effector T cells . We and others have previously demonstrated by MRI that tumour antigen-pulsed-DCs labelled ex vivo with superparamagnetic iron oxide nanoparticles migrated to the draining LNs and are capable of activating antigen-specific T cells . The results from our study demonstrated that ex vivo superparamagnetic iron oxide nanoparticles-labelled and OVA-pulsed DCs prime cytotoxic CD8(+) T-cell responses to protect against a B16-OVA tumour challenge. In the clinic, a possible noninvasive surrogate marker for efficacy of DC vaccination is to image the specific migration and accumulation of T cells following DC vaccination.

Complement activation is a recognised mediator of myocardial ischaemia-reperfusion-injury (IRI) and cardiomyocytes are a known source of complement proteins including the central component C3, whose activation products can mediate tissue inflammation, cell death and profibrotic signalling. We investigated the potential to detect and quantify the stable covalently bound product C3d by external body imaging, as a marker of complement activation in heart muscle in a murine model of myocardial IRI. We used single-photon-emission-computed-tomography (SPECT) in conjunction with

Summary Cell-based therapies using natural or genetically modified regulatory T cells (Tregs) have shown significant promise as immune-based therapies. One of the main difficulties facing the further advancement of these therapies is that the fate and localization of adoptively transferred Tregs is largely unknown. The ability to dissect the migratory pathway of these cells in a non-invasive manner is of vital importance for the further development of in-vivo cell-based immunotherapies, as this technology allows the fate of the therapeutically administered cell to be imaged in real time. In this review we will provide an overview of the current clinical imaging techniques used to track T cells and Tregs in vivo, including magnetic resonance imaging (MRI) and positron emission tomography (PET)/single photon emission computed tomography (SPECT). In addition, we will discuss how the finding of these studies can be used, in the context of transplantation, to define the most appropriate Treg subset required for cellular therapy.

Background Macrophages represent a critical cell type in host defense, development and homeostasis. The ability to image non-invasively pro-inflammatory macrophage infiltrate into a transplanted organ may provide an additional tool for the monitoring of the immune response of the recipient against the donor graft. We therefore decided to image in vivo sialoadhesin (Sn, Siglec 1 or CD169) using anti-Sn mAb (SER-4) directly radiolabelled with 99mTc pertechnetate. Methods We used a heterotopic heart transplantation model where allogeneic or syngeneic heart grafts were transplanted into the abdomen of recipients. In vivo nanosingle-photon emission computed tomography (SPECT/CT) imaging was performed 7 days post transplantation followed by biodistribution and histology. Results In wild-type mice, the majority of 99mTc-SER-4 monoclonal antibody cleared from the blood with a half-life of 167 min and was located predominantly on Sn+ tissues in the spleen, liver and bone marrow. The biodistribution in the transplantation experiments confirmed data derived from the non-invasive SPECT/CT images, with significantly higher levels of 99mTc-SER-4 observed in allogeneic grafts (9.4 (±2.7) %ID/g) compared to syngeneic grafts (4.3 (±10.3) %ID/g) (p = 0.0022) or in mice which received allogeneic grafts injected with 99mTc-IgG isotype control (5.9 (±0.6) %ID/g) (p = 0.0185). The transplanted heart to blood ratio was also significantly higher in recipients with allogeneic grafts receiving 99mTc-SER-4 as compared to recipients with syngeneic grafts (p = 0.000004) or recipients with allogeneic grafts receiving 99mTc-IgG isotype (p = 0.000002). Conclusions Here, we demonstrate that imaging of Sn+ macrophages in inflammation may provide an important additional and non-invasive tool for the monitoring of the pathophysiology of cellular immunity in a transplant model. Electronic supplementary material The online version of this article (doi:10.1186/s13550-015-0146-7) contains supplementary material, which is available to authorized users.

Background Following myocardial infarction (MI), patients are at risk of sudden cardiac death (SCD) due to ventricular arrhythmia, which can be prevented with an implantable cardioverter-defibrillator (ICD). Recommendations for ICD implantation is currently based on left ventricular ejection fraction (LVEF), however less than a quarter of patients who receive ICDs based on LVEF have appropriate therapy. Heterogeneity of scar has been implicated in the development of re-entrant arrhythmias and SCD. Texture analysis (TA) is a method of quantifying heterogeneity of tissues in imaging, usually using statistical-based methods to evaluate distribution of grey-level pixels. This study aimed to determine whether TA could be used to quantify heterogeneity of scar as a method of accurately risk stratifying patients. Methods This was a retrospective blinded analysis of late-gadolinium enhanced cardiac magnetic resonance (LGE-CMR) images. Twenty post-MI patients who received ICDs were followed up for up to 686 days after implantation. Ten of these patients went on to have events and were categorised as high risk, while the remaining ten had no events on follow up and were categorised as low risk. TA was performed on regions of interest delineating

The NanoPET/CT represents the latest generation of commercial preclinical PET/CT systems. This article presents a performance evaluation of the PET component of the system according to the National Electrical Manufacturers Association (NEMA) NU-4 2008 standard. Methods: The NanoPET/CT consists of 12 lutetium yttrium orthosilicate:cerium modular detectors forming 1 ring, with 9.5-cm axial coverage and a 16-cm animal port. Each detector crystal is 1.12 × 1.12 × 13 mm, and 1 module contains 81 × 39 of these crystals. An optical light guide transmits the scintillation light to the flat-panel multianode position-sensitive photomultiplier tubes. Analog-to-digital converter cards and a field-programmable gate array–based data-collecting card provide the readout. Spatial resolution, sensitivity, counting rate capabilities, and image quality were evaluated in accordance with the NEMA NU-4 standard. Energy and temporal resolution measurements and a mouse imaging study were performed in addition to the standard. Results: Energy resolution was 19% at 511 keV. The spatial resolution, measured as full width at half maximum on single-slice rebinning/filtered backprojection–reconstructed images, approached 1 mm on the axis and remained below 2.5 mm in the central 5-cm transaxial region both in the axial center and at one-quarter field of view. The maximum absolute sensitivity for a point source at the center of the field of view was 7.7%. The maximum noise equivalent counting rates were 430 kcps at 36 MBq and 130 kcps at 27 MBq for the mouse- and rat-sized phantoms, respectively. The uniformity and recovery coefficients were measured with the image-quality phantom, giving good-quality images. In a mouse study with an 18F-labeled thyroid-specific tracer, the 2 lobes of the thyroid were clearly distinguishable, despite the small size of this organ. The flexible readout system allowed experiments to be performed in an efficient manner, and the system remained stable throughout. Conclusion: The large number of detector crystals, arranged with a fine pitch, results in excellent spatial resolution, which is the best reported for currently available commercial systems. The absolute sensitivity is high over the field of view. Combined with the excellent image quality, these features make the NanoPET/CT a powerful tool for preclinical research.

The partial-volume effect (PVE) can compromise the quantitative accuracy of preclinical positron emission tomogprahy (PET) images. We investigated this effect by simulating a NEMA NU4 mouse Image Quality Phantom (including calculation of a spatially variant position-dependent point spread function (PSF) ) as well as measuring it. Three different types of deconvolution-based partial- volume corrections were applied: the Lucy-Richardson (LR), Van Cittert (VC) and Wiener (WNR) algorithms. For simulation and phantom measurement, partial-volume correction was applied. Based on optimal parameters the same methods were used to correct data of a mouse study acquired with the NanoPET/CT™ preclinical scanner (Mediso Ltd. Budapest, Hungary and and Bioscan Inc., Washington DC, USA). The algorithms used successfully improve the values of recovery coefficients to varying extents both in simulation and measurement. The preliminary mouse study shows improvement in quantification. Full validation is subject to further investigation.

The normal function of lymphatic vessels is to facilitate the trafficking of antigen presenting cells to draining lymph nodes where they evoke an immune response. Donor lymphatic vessels are not connected to that of recipients' during organ transplantation. The pathophysiology of this disruption has received little attention. Murine heterotopic cardiac transplantation has been used extensively in transplantation research. Following vascularized organ transplantation, the main site of allosensitization is thought to be in the spleen of the recipient as a result of migration of donor passenger leukocytes via blood. Here, using Single Photon Emission Computed Tomography/Computerized Tomography (SPECT/CT) lymphoscintigraphy, we studied the pattern of lymphatic flow from mouse heterotopic abdominal cardiac grafts and identified mediastinal lymph nodes as the draining nodes for the donor graft. Staining with HY tetramer after transplantation of HY mismatched heart grafts and ELISPOT following allogeneic grafts to detect donor specific T cells revealed them as important sites for allosensitization. Our data indicates that mediastinal lymph nodes play a crucial role in the alloimmune response in this model, and should be used for ex vivo and adoptive transfer studies after transplantation in addition to the spleen.

A double blind, randomized, controlled Phase 2 clinical trial was conducted to assess the safety, immunogenicity, and biologic impact of the vaccine candidate Apical Membrane Antigen 1- Combination 1 (AMA1-C1), adjuvanted with Alhydrogel®. Participants were healthy children 2-3 years old living in or near the village of Bancoumana, Mali. A total of 300 children received either the study vaccine or the comparator. No impact of vaccination was seen on the primary endpoint, the frequency of parasitemia measured as episodes >3000 per μL per day at risk. There was a negative impact of vaccination on the hemoglobin level during clinical malaria, and mean incidence of hemoglobin

Background Apical Membrane Antigen 1 (AMA1) of Plasmodium falciparum merozoites is a leading blood-stage malaria vaccine candidate. Protection of Aotus monkeys after vaccination with AMA1 correlates with antibody responses. Study Design/Results A randomized, controlled, double-blind phase 1 clinical trial was conducted in 54 healthy Malian adults living in an area of intense seasonal malaria transmission to assess the safety and immunogenicity of the AMA1-C1 malaria vaccine. AMA1-C1 contains an equal mixture of yeast-expressed recombinant proteins based on sequences from the FVO and 3D7 clones of P. falciparum, adsorbed on Alhydrogel. The control vaccine was the hepatitis B vaccine (Recombivax). Participants were enrolled into 1 of 3 dose cohorts (n = 18 per cohort) and randomized 2:1 to receive either AMA1-C1 or Recombivax. Participants in the first, second, and third cohorts randomized to receive AMA1-C1 were vaccinated with 5, 20 and 80 µg of AMA1-C1, respectively. Vaccinations were administered on days 0, 28, and 360, and participants were followed until 6 months after the final vaccination. AMA1-C1 was well tolerated; no vaccine-related severe or serious adverse events were observed. AMA1 antibody responses to the 80 µg dose increased rapidly from baseline levels by days 14 and 28 after the first vaccination and continued to increase after the second vaccination. After a peak 14 days following the second vaccination, antibody levels decreased to baseline levels one year later at the time of the third vaccination that induced little or no increase in antibody levels. Conclusions Although the AMA1-C1 vaccine candidate was well-tolerated and induced antibody responses to both vaccine and non-vaccine alleles, the antibody response after a third dose given at one year was lower than the response to the initial vaccinations. Additionally, post-vaccination increases in anti-AMA1 antibody levels were not associated with significant changes in in vitro growth inhibition of P. falciparum. Trial Registration ClinicalTrials.gov NCT00343005

Background Chimeric antigen receptors (CARs) are fusion molecules that re-direct T-cell specificity against a selected cell surface target. Recent successes in the treatment of haematological malignancies using CD19-specific CAR T cells has moved this approach into the clinical mainstream. On target, off tumour toxicity, inadequate homing, and limited survival of CAR T cells are important challenges to the adaptation of this promising technology to treat solid tumours. We aimed to address these limitations while developing a clinically applicable T-cell immunotherapy for the commonest male malignancy, prostate cancer. Targeting has been directed against prostate-specific membrane antigen (PSMA), a cell-surface glycoprotein that is overexpressed by more than 80% of cases, with highest levels in castration-resistant disease Methods A tripartite cassette of genes named PIN4 was developed to re-direct human T cells against prostate cancer. PIN4 mediates the stoichiometric co-expression of: P28ζ, a CAR specific for PSMA; the human sodium iodide symporter (hNIS), which allows real-time PET/SPECT imaging of T cells; and 4αβ, a chimeric cytokine receptor that permits ex-vivo expansion and enrichment of PIN4 -positive T cells using interleukin (IL) 4. To promote the survival and trafficking of PIN4 T cells to the tumour, methods for targeting IL4 to tumour-associated stroma are being developed. To test these immunotherapeutic strategies in vivo, we developed a metastatic model of prostate cancer using PSMA–firefly luciferase-engineered PC3-LN3 (PLP) cells, inoculated subcutaneously in immune compromised SCID/beige mice. Tumour metastases in this model were imaged with bioluminescence imaging. SPECT was used for serial imaging of T cells, after administration of technetium-99m pertechnetate ( 99m TcO4). Findings Ex-vivo expansion accompanied by selective enrichment of PIN4 + T cells occurred consistently in response to IL4, whereas comparable enrichment was not seen in response to the non-selective signal provided by IL2. IL4-expanded PIN4 + T cells retained type 1 polarity and showed potent P28ζ-dependent anti-tumour activity against a panel of PSMA-positive prostate cancer cell lines. Function of hNIS in PIN4 + T cells was first confirmed in vitro by 99m TcO4 uptake studies. Then, we infused PIN4 + or control T cells in mice with metastatic PSMA+ PLP prostate cancer. We showed that PIN4 + T cells could be repeatedly imaged by SPECT, after the administration of 99m TcO4. Evidence of proliferation of PIN4 + T cells at sites of metastatic PLP deposits was observed. Interpretation We have a highly effective strategy for prostate cancer therapy with PIN4 , which overcomes the challenges of ex-vivo expansion and T-cell survival. The goal of this work is to further improve the therapeutic window for PIN4 therapy, with a clear view to clinical translation. Funding The Prostate Cancer Charity, Academy of Medical Sciences, King's Health Partners Biomedical Research Centre.

The well-known perfusion tracer CuPTSM, labelled with 62Cu or 64Cu, is believed to be trapped in cells non-selectively by a bioreductive mechanism. It is proposed that by modifying the ligand to increase its electron donor strength (for example by adding alkyl functionality or replacing sulphur ligands with oxygen ligands), the copper complexes will become less easily reduced and tracers with selectivity for hypoxic tissues could thus be developed. The aim of this work was to prepare 64Cu-labelled complexes of two series of ligands, based on the bis(thiosemicarbazone) (13 ligands) and bis(salicylaldimine) (3 ligands) skeletons, and to evaluate the hypoxia dependence of their uptake in cells. The complexes were incubated with Chinese hamster ovary cells under normoxic and hypoxic conditions, and the cells isolated by centrifugation to determine radioactivity uptake at various time points up to 90 min. Several members of both series demonstrated significant (P

Introduction To date, our knowledge of in vivo migration of neutrophils and eosinophils in homeostasis and disease states is based on granulocytes. Here we present a pilot study using purified human eosinophils or neutrophils and demonstrate their differential in vivo kinetics in asthmatic and healthy volunteers. Methods: On two separate occasions 100 ml of blood was obtained from eight human volunteers (4 mild stable asthmatics and 4 non asthmatic, healthy volunteers) Granulocytes were separated using gradient Ficoll-Paque PLUS 1.084 centrifugation. Superparamagnetic particles coupled to a monoclonal antibody against CD16, a surface marker present in neutrophils, were incubated with the granulocytes (containing eosinophils and neutrophils). CliniMACS system (Miltenyi biotec, Bergisch-Gladbach, Germany; and Becton-Dickinson, Oxford, UK) was used to obtain highly purified (>93% pure) human blood eosinophils or neutrophils (>; 97%). Purified cells were labelled with Tc-99m HMPAO (Ceretec, GE Healthcare) under aseptic cGMP conditions and 75–100 MBq of labelled cells were administered intravenously. Dynamic lung images were acquired for the first 30 minutes. Further static scans of 5 minutes each were acquired at 1; 2 and 4 hours. Results: We were able to obtain highly purified neutrophils (positive selection) or eosinophils (negative selection). Kinetics of eosinophils in lung, liver and spleen differed significantly from kinetics of neutrophils. Initial dynamic lung images revealed a significant difference in the time activity curves for eosinophils and neutrophils. Migration of eosinophils from the lungs followed a monexponential clearance (t1/2) of 4.16 min. While neutrophil had significantly different clearance half-lives of 13.72 min (p=0.0019). There were significant differences in eosinophil and neutrophil migration and distribution in the liver and spleen (p Conclusions For the first time it has been possible to identify distinct patterns of neutrophil and eosinophil migration through lung, liver and spleen in both healthy volunteers and stable asthmatics. This technique provides the opportunity for rapid throughput screening of novel therapeutic agents designed to alter leukocyte migration in disease conditions, or to further phenotype disease such as asthma.

Background Apical Membrane Antigen-1 (AMA1) is one of the leading blood stage malaria vaccine candidates. AMA1-C1/Alhydrogel® consists of an equal mixture of recombinant AMA1 from FVO and 3D7 clones of P. falciparum, adsorbed onto Alhydrogel®. A Phase 1 study in semi-immune adults in Mali showed that the vaccine was safe and immunogenic, with higher antibody responses in those who received the 80 µg dose. The aim of this study was to assess the safety and immunogenicity of this vaccine in young children in a malaria endemic area. Design This was a Phase 1 dose escalating study in 36 healthy children aged 2–3 years started in March 2006 in Donéguébougou, Mali. Eighteen children in the first cohort were randomized 2∶1 to receive either 20 µg AMA1-C1/Alhydrogel® or Haemophilus influenzae type b Hiberix® vaccine. Two weeks later 18 children in the second cohort were randomized 2∶1 to receive either 80 µg AMA1-C1/Alhydrogel® or Haemophilus influenzae type b Hiberix® vaccine. Vaccinations were administered on Days 0 and 28 and participants were examined on Days 1, 2, 3, 7, and 14 after vaccination and then about every two months. Results to Day 154 are reported in this manuscript. Results Of 36 volunteers enrolled, 33 received both vaccinations. There were 9 adverse events related to the vaccination in subjects who received AMA1-C1 vaccine and 7 in those who received Hiberix®. All were mild to moderate. No vaccine-related serious or grade 3 adverse events were observed. There was no increase in adverse events with increasing dose of vaccine or number of immunizations. In subjects who received the test vaccine, antibodies to AMA1 increased on Day 14 and peaked at Day 42, with changes from baseline significantly different from subjects who received control vaccine. Conclusion AMA-C1 vaccine is well tolerated and immunogenic in children in this endemic area although the antibody response was short lived. Trial Registration Clinicaltrials.gov NCT00341250