Circulating tumor cell and cell-free RNA capture and expression analysis identify platelet-associated genes in metastatic lung cancer.

BACKGROUND: Circulating tumor cells (CTC) and plasma cell-free RNA (cfRNA) can serve as biomarkers for prognosis and treatment response in lung cancer. One barrier to the selected or routine use of CTCs and plasma cfRNA in precision oncology is the limited quantity of both, and CTCs are only seen in metastatic disease. As capture of CTCs and plasma cfRNA presents an opportunity to monitor and assess malignancies without invasive procedures, we compared two methods for CTC capture and identification, and profiled mRNA from CTCs and plasma cfRNA to identify potential tumor-associated biomarkers. METHODS: Peripheral blood was collected from ten patients with small cell lung cancer (SCLC), ten patients with non-small cell lung cancer (NSCLC) and four healthy volunteers. Two methods were used for CTC capture: the standard epithelial cell adhesion molecule (EpCam) CellSearch kit (unicapture) and EpCAM plus HER2, EGFR and MUC-1 specific combined ferrofluid capture (quadcapture). For the quadcapture, anti-cytokeratin 7 (CK7) was additionally used to assist in CTC identification. NanoString analysis was performed on plasma cfRNA and on mRNA from combined ferrofluid isolated CTCs. Expression data was analyzed using STRING and Reactome. RESULTS: Unicapture detected CTCs in 40% of NSCLC and 60% of SCLC; whereas, quadcapture/CK7 identified CTCs in 20% of NSCLC and 80% of SCLC. Bioinformatic analysis of NanoString data identified high expression of a platelet factor 4 (PF4)-related group of transcripts. CONCLUSIONS: Quadcapture ferrofluid reagent did not significantly improve CTC capture efficacy. NanoString analysis based on CTC and plasma cfRNA data highlighted an intriguing PF-4-centric network in patients with metastatic lung cancer.

Enumeration and characterization of circulating multiple myeloma cells in patients with plasma cell disorders.

We have developed an automated assay to enumerate and characterize circulating multiple myeloma cells (CMMC) from peripheral blood of patients with plasma cell disorders. CMMC show expression of genes characteristic of myeloma and fluorescence in situ hybridisation results on CMMC correlated well with bone marrow results. We enumerated CMMC from over 1000 patient samples including separate cohorts of newly diagnosed multiple myeloma and high/intermediate risk smouldering multiple myeloma (SMM) with clinical follow-up data. In newly diagnosed myeloma patient samples, CMMC counts correlated with other clinical measures of disease burden, including the percentage of bone marrow plasma cells, serum M protein, and International Staging System stage. CMMC counts decreased significantly from baseline when a remission was achieved due to treatment (P < 0·001). Patients with CMMC counts ≥100 at remission showed reduced survival relative to patients with CMMC counts <100. Patients with undetectable CMMC in remission showed further overall survival benefits. In the SMM cohort, there was a trend toward higher CMMC in patients with higher-risk myeloma precursor states. Significantly higher CMMC counts were observed between intermediate/high risk SMM patients that progressed versus those without progression (P = 0·031). CMMC allow a non-invasive means of monitoring tumour biology and may have use as a prognostic test for patients with plasma cell disorders.

Development of a method to isolate circulating tumor cells using mesenchymal-based capture.

Epithelial tumor cells can become mesenchymal cells and vice versa via phenotypic transitions, a process known as epithelial plasticity. We postulate that during the process of metastasis, circulating tumor cells (CTCs) lose their epithelial phenotype and acquire a mesenchymal phenotype that may not be sufficiently captured by existing epithelial-based CTC technologies. We report here on the development of a novel CTC capture method, based on the biology of epithelial plasticity, which isolates cells based on OB-cadherin cell surface expression. Using this mesenchymal-based assay, OB-cadherin cellular events are detectable in men with metastatic prostate cancer and are less common in healthy volunteers. This method may complement existing epithelial-based methods and may be particularly useful in patients with bone metastases.

Expression of immune checkpoints on circulating tumor cells in men with metastatic prostate cancer.

BACKGROUND: A subset of men with metastatic prostate cancer (mPC) responds to immune checkpoint inhibitors, and there is an unmet need to predict those most likely to benefit. We characterized circulating tumor cells (CTCs) for expression of immune checkpoint ligands in men with mPC as a non-invasive biomarker of immune evasion and immunotherapy benefit. METHODS: Three cohorts of patients were enrolled: 1) men with mCRPC starting abiraterone acetate/prednisone or enzalutamide (pre-ARSI), 2) men with mCRPC who were progressing on enzalutamide or abiraterone acetate/prednisone (post-ARSI), and 3) men with newly diagnosed metastatic hormone sensitive prostate cancer (mHSPC) starting androgen deprivation therapy. CTCs were captured using the CellSearch® system and stained for PD-L1, PD-L2, B7-H3, and CTLA-4 at baseline, on treatment, and disease progression. Summary statistics on mean CTCs per cohort, as well as rates of ligand positivity were used to analyze CTCs by cohort and by timepoint. RESULTS: Men in all cohorts and timepoints had prevalent CTC B7-H3 expression (> 80%). We found evidence for CTC PD-L1 expression across disease states, in which > 1 positive CTC or > 50% of CTCs were positive for PD-L1 in 40 and 30% of men with mHSPC, respectively, 60 and 20% of men with mCRPC pre-ARSI, and 70 and 30% of men with mCRPC post-ARSI. CTC PD-L2 expression was present in 20-40% of men in each disease state, while CTC CTLA-4 expression was rare, present in 20% of men with mCRPC pre-ARSI and 10% of men with mCRPC post-ARSI or with mHSPC. CTC immune checkpoint expression was heterogeneous within/between men and across disease states. CONCLUSIONS: We have identified that CTCs from men with mPC heterogeneously express immune checkpoints B7-H3, PD-L1, PD-L2, and CTLA-4, and the detection of these immune checkpoints may enable monitoring on immunotherapy.

Hip resurfacing and osteonecrosis: results from an independent hip resurfacing register.

INTRODUCTION: Single surgeon studies from specialized centers have suggested that metal-on-metal hip resurfacing in patients with osteonecrosis of hip joint provides good implant survival and function. METHOD: We tested the hypothesis that multicenter results of hip resurfacing, in terms of function and survival, are similar between patients with osteoarthritis and osteonecrosis. PATIENTS: 192 patients (202 hips) underwent metal-on-metal hip resurfacing at different centers around the world. We compared the revision risks in 95 patients (101 hips) with osteonecrosis and 97 patients (101 hips) with osteoarthritis. RESULTS: The mean age at operation was 42 and 43 years and the preoperative and postoperative Harris hip scores were 62 and 96 and 58 and 95 for osteonecrosis and osteoarthritis groups. Survival with revision for any reason as the end point at last follow-up was 97.7% for osteonecrosis and 95.0% for osteoarthritis. CONCLUSION: We conclude that hip resurfacing can be offered to patients with osteonecrosis.

Coming of Age in the Shadow of the Taliban: Education, Child Marriage, and the Future of Afghanistan From the Perspectives of Adolescents and Their Parents.

OBJECTIVE: To understand adolescent and parental attitudes toward education, child marriage, and the changes in matriculation for boys and girls over one generation. METHODS: Two-staged household sampling method was used in six provinces with low educational enrollment in Afghanistan during 2016. Final sample included 910 adolescents aged 12-15 years and 454 parents. Data analysis included k-Nearest Neighbour imputation for missing values. Response percentages were compared by two-tail proportional z-test for two-sample comparison or Chi-squared test for multiple groups comparison with adjusted p values. RESULTS: Adolescents reported highly valuing education but considered boys to be greater beneficiaries than girls. Over 90% of parents concur expecting their children to complete at least secondary education independent of the child's sex with more than a third (37.89%) indicating that marriage should be postponed until at least high school completion. Likewise, both boys and girls believe marriage of girls under age 18-years limits future educational opportunities as well as increases risks of domestic violence and loss of freedom. Whereas a generation ago four-out-of-five parents of today's adolescents were not in school, today that has reversed; and among 12-15 year olds in the provinces studied, 75% were in school at the time of the survey. CONCLUSIONS: In the most disadvantaged provinces of Afghanistan, almost all young adolescents surveyed (98.8%) were not married and the majority were in school while an equal percent of their parents had no formal education. Additionally, both parents report that education of their sons and daughters is highly valued; and, for two-fifths, they believe marriage should occur after completion of secondary school.

Correlation between circulating endothelial cell counts and plasma thrombomodulin levels as markers for endothelial damage.

Increased numbers of circulating endothelial cells (CEC) in peripheral blood have been observed in diseases with vascular involvement, and are considered a promising surrogate marker for vascular damage. It was the objective of this study to evaluate the correlation between putative soluble markers of endothelial injury, activation, and endothelial proliferation, and absolute numbers of CEC. CEC were evaluated in 125 healthy donors and 40 patients with metastatic carcinoma by automated CD146 driven immunomagnetic isolation. Plasma concentrations of E-selectin, endoglin, and thrombomodulin were assessed by ELISA in plasma obtained from 40 healthy donors and 40 patients. CEC numbers in blood were positively correlated with plasma thrombomodulin levels, but not with levels of E-selectin and endoglin. Multivariate analysis demonstrated a significant increase in CEC numbers with age. The levels of plasma biomarkers were not influenced by age. Higher levels of thrombomodulin and E-selectin were observed in males when compared to females. In conclusion, CEC numbers correlate positively with plasma levels of thrombomodulin.

Carcinosarcoma of Tongue with Predominant Osteosarcomatous Component.

Carcinosarcoma is exceedingly rare in the oral cavity and shows presence of both carcinomatous and sarcomatous components. We report a case of carcinosarcoma of tongue in a 51-year-old male with predominant osteosarcomatous and squamous cell carcinoma components. There was no evidence of regional or systemic metastatic disease. This case represents the first reported example of this unusual neoplasm with a predominant osteosarcomatous component, arising in the tongue.

Multifocal Septic Arthritis Secondary to Infective Endocarditis: A Rare Case Report.

INTRODUCTION: Infective endocarditis (IE) is a rare cause of septic arthritis. We report a patient who presented with multifocal septic arthritis as a result of IE, which is an extremely rare condition. CASE REPORT: This 69-year-old gentleman presented to the emergency department (ED) with a 3-day history of acute right knee pain. Initial investigations demonstrated chondrocalcinosis on knee radiographs, acute renal failure with rhabdomyolysis and a CRP of 520. After treatment with intravenous fluid rehydration and analgesia, the knee aspiration grew a Group B Streptococcus, and the patient underwent arthroscopic washout. 48 h after admission the patient developed left wrist and right elbow pain. Further aspirations revealed Group B Streptococcus and the patient underwent further washouts. A multidisciplinary approach was used. Due to ongoing sepsis, an echocardiogram was performed identifying IE. The patient eventually died due to ongoing sepsis and duodenal ulceration. CONCLUSION: This case highlights the importance of considering a systemic cause such as IE for patients presenting with features of multifocal septic arthritis and ensuring all patients undergo a full medical examination as part of the clerking process. Furthermore, it emphasizes the need to adopt a multi-disciplinary approach when presented with complex patients so that the best medical care can be given to prevent morbidity and mortality.

Circulating tumor cells as a predictive biomarker in patients with small cell lung cancer undergoing chemotherapy.

BACKGROUND: There are no biomarkers for assessment of disease burden or activity of therapy in SCLC. PATIENTS AND METHODS: We conducted a prospective study enumerating serial CTCs in patients with newly diagnosed limited disease (LD) and extensive stage (ED) SCLC. CTCs demonstrating DNA damage and apoptosis based on γH2AX and M30 staining were also assessed. We correlated CTC number with disease stage, survival outcomes and tumor burden by RECIST. RESULTS: Between 03/2011-10/2013, 50 evaluable patients were enrolled (20 LD). Baseline CTC number was higher for ED (median CTC 71 vs. 1.5 for LD; p 0.0004). Patients with <5 CTC had longer PFS but not OS (11 vs. 6.7 months, p 0.0259 and 15.5 vs. 12.9 months, p 0.4357). A higher cutoff (CTC<50 or CTC≥50) was significantly correlated with both OS (20.2 vs. 11.8 months, p 0.0116) and PFS (10 vs. 4.8 months, p 0.0002). Patients with <5 CTC on day 1 of cycle 2 had longer PFS (10 vs. 3.17 months, p<0.001) and OS (18 vs. 9 months, p 0.0001). Patients with an increase in γ2HAX-positive CTCs after chemotherapy had longer OS compared to patients without an increase (25.3 vs. 9 months, p 0.15). CONCLUSIONS: This study demonstrates that CTCs at baseline and Cycle 2 of chemotherapy correlate with disease stage and survival in patients with SCLC, suggesting that CTCs may be used as a surrogate biomarker for clinical response. Confirmatory prospective clinical trials are needed before we can incorporate routine evaluation of CTCs into clinical practice.

A Whole Blood Molecular Signature for Acute Myocardial Infarction.

Chest pain is a leading reason patients seek medical evaluation. While assays to detect myocyte death are used to diagnose a heart attack (acute myocardial infarction, AMI), there is no biomarker to indicate an impending cardiac event. Transcriptional patterns present in circulating endothelial cells (CEC) may provide a window into the plaque rupture process and identify a proximal biomarker for AMI. Thus, we aimed to identify a transcriptomic signature of AMI present in whole blood, but derived from CECs. Candidate genes indicative of AMI were nominated from microarray of enriched CEC samples, and then verified for detectability and predictive potential via qPCR in whole blood. This signature was validated in an independent cohort. Our findings suggest that a whole blood CEC-derived molecular signature identifies patients with AMI and sets the framework to potentially identify the earlier stages of an impending cardiac event when used in concert with clinical history and other diagnostics where conventional biomarkers indicative of myonecrosis remain undetected.

Development of a Novel c-MET-Based CTC Detection Platform.

UNLABELLED: Amplification of the MET oncogene is associated with poor prognosis, metastatic dissemination, and drug resistance in many malignancies. We developed a method to capture and characterize circulating tumor cells (CTC) expressing c-MET using a ferromagnetic antibody. Immunofluorescence was used to characterize cells for c-MET, DAPI, and pan-CK, excluding CD45(+) leukocytes. The assay was validated using appropriate cell line controls spiked into peripheral blood collected from healthy volunteers (HV). In addition, peripheral blood was analyzed from patients with metastatic gastric, pancreatic, colorectal, bladder, renal, or prostate cancers. CTCs captured by c-MET were enumerated, and DNA FISH for MET amplification was performed. The approach was highly sensitive (80%) for MET-amplified cells, sensitive (40%-80%) for c-MET-overexpressed cells, and specific (100%) for both c-MET-negative cells and in 20 HVs. Of 52 patients with metastatic carcinomas tested, c-MET CTCs were captured in replicate samples from 3 patients [gastric, colorectal, and renal cell carcinoma (RCC)] with 6% prevalence. CTC FISH demonstrated that MET amplification in both gastric and colorectal cancer patients and trisomy 7 with gain of MET gene copies in the RCC patient. The c-MET CTC assay is a rapid, noninvasive, sensitive, and specific method for detecting MET-amplified tumor cells. CTCs with MET amplification can be detected in patients with gastric, colorectal, and renal cancers. IMPLICATIONS: This study developed a novel c-MET CTC assay for detecting c-MET CTCs in patients with MET amplification and warrants further investigation to determine its clinical applicability. Mol Cancer Res; 14(6); 539-47. ©2016 AACR.

Expression of epithelial cell adhesion molecule in carcinoma cells present in blood and primary and metastatic tumors.

The epithelial cell adhesion molecule (EpCAM) is involved in homophilic cell-cell adhesion in normal epithelia and is frequently overexpressed in primary and metastatic adenocarcinomas. It has been postulated that during detachment and dissemination of tumor cells, EpCAM may be down-regulated. Circulating tumor cells (CTC) may demonstrate this phenomenon as they have successfully escaped their local microenvironment and entered the circulation. EpCAM expression of CTC was compared to tumor cells in paraffin-embedded tissue arrays containing various benign diseases and carcinomas. EpCAM expression on CTC was determined by flow cytometry (FCM) and by immunohistochemistry (IHC) in paraffin-embedded tissue. To permit comparison of FCM results to those derived by IHC, EpCAM was quantified on cancer cell lines by FCM and then paraffin-embedded cell-blocks of these lines were used as staining guides for IHC analysis of tissue arrays. By IHC, 97% (384/397) of solid tissues analyzed had detectable EpCAM, with 72% of tissues showing antigen expression levels of > or =400,000 EpCAM molecules per cell. FCM analysis of CTC from 100 metastatic carcinoma patients with > or =2 CTC/90 microl blood showed EpCAM expression ranging from 9,900 to 246,000 (mean 49,700) antigens per cell. EpCAM expression was approximately 10-fold lower on CTC as compared to primary and metastatic tissues, suggesting that EpCAM expression is transient and dependent upon the local micro-environment. This supports the hypothesis that this adhesion molecule is down-regulated on carcinoma cells in the circulation.

Tumor cells circulate in the peripheral blood of all major carcinomas but not in healthy subjects or patients with nonmalignant diseases.

PURPOSE: The purpose of this study was to determine the accuracy, precision, and linearity of the CellSearch system and evaluate the number of circulating tumor cells (CTCs) per 7.5 mL of blood in healthy subjects, patients with nonmalignant diseases, and patients with a variety of metastatic carcinomas. EXPERIMENTAL DESIGN: The CellSearch system was used to enumerate CTCs in 7.5 mL of blood. Blood samples spiked with cells from tumor cell lines were used to establish analytical accuracy, reproducibility, and linearity. Prevalence of CTCs was determined in blood from 199 patients with nonmalignant diseases, 964 patients with metastatic carcinomas, and 145 healthy donors. RESULTS: Enumeration of spiked tumor cells was linear over the range of 5 to 1,142 cells, with an average recovery of >/=85% at each spike level. Only 1 of the 344 (0.3%) healthy and nonmalignant disease subjects had >/=2 CTCs per 7.5 mL of blood. In 2,183 blood samples from 964 metastatic carcinoma patients, CTCs ranged from 0 to 23,618 CTCs per 7.5 mL (mean, 60 +/- 693 CTCs per 7.5 mL), and 36% (781 of 2,183) of the specimens had >/=2 CTCs. Detection of >/=2 CTCs occurred at the following rates: 57% (107 of 188) of prostate cancers, 37% (489 of 1,316) of breast cancers, 37% (20 of 53) of ovarian cancers, 30% (99 of 333) of colorectal cancers, 20% (34 of 168) of lung cancers, and 26% (32 of 125) of other cancers. CONCLUSIONS: The CellSearch system can be standardized across multiple laboratories and may be used to determine the clinical utility of CTCs. CTCs are extremely rare in healthy subjects and patients with nonmalignant diseases but present in various metastatic carcinomas with a wide range of frequencies.

Cytogenetic evidence that circulating epithelial cells in patients with carcinoma are malignant.

PURPOSE: Numerous studies of circulating epithelial cells (CECs)have been described in cancer patients, and genetic abnormalities have been well documented. However, with one exception in colorectal cancer, there has been no report of matching the genetic abnormalities in the CECs with the primary tumor. The purpose of this investigation was to determine (a) whether CECs in patients including those with early tumors are aneusomic and (b) whether their aneusomic patterns match those from the primary tumor, indicating common clonality. EXPERIMENTAL DESIGN: Thirty-one cancer patients had CECs identified by immunofluorescence staining using a monoclonal anti-cytokeratin antibody. Their CECs were analyzed by enumerator DNA probes for chromosomes 1, 3, 4, 7, 8, 11, or 17 by dual or tricolor fluorescence in situ hybridization. Touch preparations of the primary tumor tissue were available from 17 of 31 patients and hybridized with the same set of probes used to genotype the CECs. RESULTS: The number of CECs from each patient ranged from 1-92 cells/cytospin. CECs showed abnormal copy numbers for at least one of the probes in 25 of 31 patients. Touch preparations from the primary tumors of 13 patients with aneusomic CECs were available. The pattern of aneusomy matched a clone in the primary tumor in 10 patients. CONCLUSIONS: We conclude that the vast majority of CECs in breast, kidney, prostate, and colon cancer patients are aneusomic and derived from the primary tumor.

Use of circulating tumor cell technology (CELLSEARCH) for the diagnosis of malignant pleural effusions.

RATIONALE: Cytological analysis of pleural effusions (PEs) has a sensitivity of approximately 60%. We hypothesized that the CELLSEARCH technology (Janssen Research and Development, Huntingdon Valley, PA) currently used to detect circulating tumor cells could be adapted for the identification of tumor cells in PEs. METHODS: This was a single-center, prospective, observational study. Pleural fluid from subjects with undiagnosed PEs were analyzed by CELLSEARCH technology, which uses an epithelial cell adhesion molecule antibody-based capture system/cytokeratin antibodies to identify tumor cells. Subjects were prospectively monitored by periodic chart review to determine the etiology of the PE. MEASUREMENTS AND MAIN RESULTS: One hundred thirty-two subjects were analyzed. A malignant etiology was established in 81 subjects. The median number of "positive" pleural epithelial cells (PECs) detected per milliliter of pleural fluid was 6 in the benign group. The number of PECs was 52 in the malignant nonepithelial group (NS) and 526 in the malignant epithelial group (P < 0.001). Unlike blood, there was a baseline number of "positive" cells in benign pleural fluids; however, any cutoff greater than 852 positive cells/ml had 100% specificity. The area under the receiver operating characteristic curve was 0.86. Nine percent of our cancer cases had high numbers of PECs (>280/ml) but a negative or nondefinitive cancer diagnosis by cytology. CONCLUSIONS: The pleural CELLSEARCH assay may serve as a valuable addition to traditional cytology and provide useful information regarding the diagnosis of malignant effusions. Major advantages include that it is well standardized, relatively inexpensive, has a rapid turnaround, and is easily available. Our data support the conduct of additional studies of this approach to assist in the diagnosis of malignant PEs.

Characterization of circulating endothelial cells in acute myocardial infarction.

Acute myocardial infarction (MI), which involves the rupture of existing atheromatous plaque, remains highly unpredictable despite recent advances in the diagnosis and treatment of coronary artery disease. Accordingly, a clinical measurement that can predict an impending MI is desperately needed. Here, we characterize circulating endothelial cells (CECs) using an automated and clinically feasible CEC three-channel fluorescence microscopy assay in 50 consecutive patients with ST-segment elevation MI and 44 consecutive healthy controls. CEC counts were significantly elevated in MI cases versus controls, with median numbers of 19 and 4 cells/ml, respectively (P = 1.1 × 10(-10)). A receiver-operating characteristic (ROC) curve analysis demonstrated an area under the ROC curve of 0.95, suggesting near-dichotomization of MI cases versus controls. We observed no correlation between CECs and typical markers of myocardial necrosis (ρ = 0.02, creatine kinase-myocardial band; ρ = -0.03, troponin). Morphological analysis of the microscopy images of CECs revealed a 2.5-fold increase (P < 0.0001) in cellular area and a twofold increase (P < 0.0001) in nuclear area of MI CECs versus healthy controls, age-matched CECs, as well as CECs obtained from patients with preexisting peripheral vascular disease. The distribution of CEC images that contained from 2 to 10 nuclei demonstrates that MI patients were the only subject group to contain more than 3 nuclei per image, indicating that multicellular and multinuclear clusters are specific for acute MI. These data indicate that CEC counts may serve as a promising clinical measure for the prediction of atherosclerotic plaque rupture events.

Endothelial cells in peripheral blood of healthy subjects and patients with metastatic carcinomas.

BACKGROUND: A lack of standardized assays and consensus of cell definition has lead to a wide variation in the reported range of circulating endothelial cells (CECs). METHODS: An automated rare cell analysis system was used to enumerate nucleated, CD146+/CD105+/CD45- CECs in 4 mL of blood. RESULTS: Recoveries of spiked HUVECs were linear over a range of 0-1,241 cells (R2>or=0.99) with recoveries of >or=70% at each spike level. Correlation coefficient values for interoperator variability and duplicate sample variation were (R2=0.99 and 0.90), respectively. Correlation of CEC counts between tubes 1-2 and 2-3 drawn from the same subject in sequence differed (R2=0.48 and 0.63, respectively). The normal CEC reference range established in 249 healthy donors was 1-20 CECs/mL blood. CEC counts were significantly higher in the 206 metastatic carcinoma patients (P<0.0001). CONCLUSION: CECs can be accurately and reproducibly enumerated in blood and are elevated in metastatic carcinomas compared with healthy donors. Phlebotomy procedures can affect endothelial cell counts.

Magnetic field design for selecting and aligning immunomagnetic labeled cells.

BACKGROUND: Recently we introduced the CellTracks cell analysis system, in which samples are prepared based on a combination of immunomagnetic selection, separation, and alignment of cells along ferromagnetic lines. Here we describe the underlying magnetic principles and considerations made in the magnetic field design to achieve the best possible cell selection and alignment of magnetically labeled cells. Materials and Methods Computer simulations, in combination with experimental data, were used to optimize the design of the magnets and Ni lines to obtain the optimal magnetic configuration. RESULTS: A homogeneous cell distribution on the upper surface of the sample chamber was obtained with a magnet where the pole faces were tilted towards each other. The spatial distribution of magnetically aligned objects in between the Ni lines was dependent on the ratio of the diameter of the aligned object and the line spacing, which was tested with magnetically and fluorescently labeled 6 microm polystyrene beads. The best result was obtained when the line spacing was equal to or smaller than the diameter of the aligned object. CONCLUSIONS: The magnetic gradient of the designed permanent magnet extracts magnetically labeled cells from any cell suspension to a desired plane, providing a homogeneous cell distribution. In addition, it magnetizes ferro-magnetic Ni lines in this plane whose additional local gradient adds to the gradient of the permanent magnet. The resultant gradient aligns the magnetically labeled cells first brought to this plane. This combination makes it possible, in a single step, to extract and align cells on a surface from any cell suspension.

Cell analysis system based on compact disk technology.

BACKGROUND: A cell analysis system was developed to enumerate and differentiate magnetically aligned cells selected from whole blood. The cellular information extracted is similar to the readout of musical information from a compact disk (CD). Here we describe the optical design and data processing of the system. The performance of the system is demonstrated using fluorescent-labeled cells and beads. Materials and Methods System performance was demonstrated with 6-microm polystyrene beads labeled with magnetic nanoparticles and allophycocyanin (APC) and immunomagnetically aligned leukocytes, fluorescently labeled with Oxazine750 and CD4-APC, CD8-Cy5.5, and CD14-APC/Cy7 in whole blood. RESULTS: The sensitivity of the system was demonstrated using APC-labeled beads. With this system, beads containing 333 APC molecules could easily be resolved from the background. This level of sensitivity was not achievable with a commercial flow cytometer. A maximum of 20,000 immunomagnetically labeled cells could be aligned and analyzed in between 0.6 m of Ni lines, distributed over a surface area of 18 mm(2) and extracted from a blood volume that depended on the height of the chamber. The utility of the system was demonstrated by performing a three-color CD4-CD8-CD14 assay. CONCLUSIONS: We built a cell analysis system based on immunomagnetic cell selection and alignment and analysis of fluorescent signals employing CD-technology that is as good or better than current commercial analyzers. The cell analysis can be performed in whole blood or any other type of cell suspension without extensive sample preparation.