Isolation of acute myeloid leukemia blasts from blood using a microfluidic device

Acute myeloid leukemia (AML) is the most common form of acute leukemia in adults and associated with poor prognosis. Unfortunately, most of the patients that achieve clinical complete remission after the treatment will ultimately relapse due to the persistence of minimal residual disease (MRD), that is not measurable using conventional technologies in the clinic. Microfluidics is a potential tool to improve the diagnosis by providing early detection of MRD. Herein, different designs of microfluidic devices were developed to promote lateral and vertical mixing of cells in microchannels to increase the contact area of the cells of interest with the inner surface of the device. Possible interactions between the cells and the surface were studied using fluid simulations. For the isolation of leukemic blasts, a positive selection strategy was used, targeting the cells of interest using a panel of specific biomarkers expressed in immature and aberrant blasts. Finally, once the optimisation was complete, the best conditions were used to process patient samples for downstream analysis and benchmarking, including phenotypic and genetic characterisation. The potential of these microfluidic devices to isolate and detect AML blasts may be exploited for the monitoring of AML patients at different stages of the disease.

POS0891 REUMA.pt/MYOSITIS – THE PORTUGUESE REGISTRY OF INFLAMMATORY MYOPATHIES

Background

The idiopathic inflammatory myopathies (IMM) module of the Rheumatic Diseases Portuguese Register (Reuma.pt/Myositis) is a tool used to systematically evaluate IIM patients.

Objectives

To clinically characterise the Reuma.pt/Myositis cohort.

Methods

Multicentre open cohort study, including IIM patients registered in Reuma.pt up to January 2022. Data collected included demographic, clinical, and treatment data and patient-reported outcomes. Data were presented as frequencies and median (interquartile range) for categorical and continuous variables, respectively.

Results

280 patients were included, 71.4% female, 89.4% Caucasian, with a median age at diagnosis and disease duration of 48.9 (33.6-59.3) and 5.3 (3.0-9.8) years, respectively. Patients were classified as having definite (N=57/118, 48.3%; N=35/224, 15.6%), likely (N=23/118, 19.5%; N=50/224, 22.3%), or possible (N=2/118, 1.7%; N=46/224, 20.5%) IIM by 2017 EULAR/ACR and Bohan-Peter criteria, respectively. Disease subtypes included dermatomyositis (DM, N=122/280, 43.6%), polymyositis (N=59/280, 21.1%), myositis in overlap syndromes (N=41/280, 14.6%), clinically amyopathic DM (N=17/280, 6.1%), nonspecific myositis (N=13/280, 4.6%), mixed connective tissue disease (N=12/280, 4.3%), immune-mediated necrotizing myositis (N=9/280, 3.2%), and inclusion bodies myopathy (N=7/280, 2.5%). Over the course of the disease, the most common symptoms were proximal muscle weakness (N=180/215, 83.7%), arthralgia (N=127/249, 52.9%), erythema (N=63/166, 38.0%), fatigue (N=47/127, 37.0%), Raynaud’s phenomenon (N=76/234, 32.5%), and dysphagia (N=33/121, 27.3%), and the most common clinical signs were Gottron’s sign (N=75/184, 40.8%), heliotrope rash (N=101/252, 40.1%), Gottron’s papules (N=93/237, 39.2%), and arthritis (N=38/98, 38.8%). Organ involvement included lung (N=78/230, 33.9%), oesophageal (N=40/221, 18.1%), and heart (N=11/229, 4.8%) involvements. Most patients expressed myositis-specific (MSA, N=158/242, 65.3%) and/or myositis-associated (MAA, 112/242, 46.3%) antibodies. The most frequent antibodies were anti-SSA/SSB (N=70/231, 30.3%), anti-Jo1 (N=56/236, 23.7%), and anti-Mi2 (N=31/212, 14.6%). Most patients had a myopathic pattern on electromyogram (N=101/138, 73.2%), muscle oedema in magnetic resonance (N=33/62, 53.2%), and high CK (N=154/200, 55.0%) and aldolase levels (N=74/135, 54.8%) at diagnosis, with median highest CK levels of 1308 (518-3172) and aldolase of 42 (12-121) mg/dL. Neoplasia was found in 11/127 patients (8.7%), most commonly breast (N=3/11, 27.3%), non-melanoma skin (N=2/11, 18.2%), and colorectal (N=2/11, 18.2%) cancer (Table 1). Most patients with cancer-associated myositis had DM (N=8/11, 72.7%) and expressed MSA (N=6/11) and/or MAA (N=3/11). The most used drugs over the course of disease were glucocorticoids (N=201/280, 71.8%), methotrexate (N=117/280, 41.8%), hydroxychloroquine (N=87/280, 31.1%), azathioprine (N=85/280, 30.4%), mycophenolate mofetil (N=56/280, 20.0%), intravenous immunoglobulin (N=55/280, 19.6%), and rituximab (N=45/280, 16.1%). At the last follow-up, there was a median MMT8 of 150 (142-150), modified DAS skin of 0 (0-1), global VAS of 10 (0-50) mm, and HAQ of 0.125 (0.000-1.125).

Table 1.

Autoantibodies in cancer-associated myositis

CancerIIMAutoantibodiesBreastDM (3)Mi2, SRP (+ SSA/SSB), Pm/SclSkin (non-melanoma)Clinically amyopathic DM, PMJo1, SAE1 (+SSA/SSB)ColorectalDM (2)Mi2 (2)KidneyDM-LungDM-LymphomaInclusion bodies myopathy-UnknownDM-

Conclusion

Reuma.pt/Myositis adequately captures the main features of inflammatory myopathies’ patients, depicting in this first report a heterogeneous population, with frequent muscle, joint, skin and lung involvements. Of interest, most patients reached low disease activity at the last follow-up appointment.

Disclosure of Interests

None declared

Discriminating Epithelial to Mesenchymal Transition Phenotypes in Circulating Tumor Cells Isolated from Advanced Gastrointestinal Cancer Patients

Gastrointestinal (GI) cancers constitute a group of highest morbidity worldwide, with colorectal cancer (CRC) and gastric cancer being among the most frequently diagnosed. The majority of gastrointestinal cancer patients already present metastasis by the time of diagnosis, which is widely associated with cancer-related death. Accumulating evidence suggests that epithelial-to-mesenchymal transition (EMT) in cancer promotes circulating tumor cell (CTCs) formation, which ultimately drives metastasis development. These cells have emerged as a fundamental tool for cancer diagnosis and monitoring, as they reflect tumor heterogeneity and the clonal evolution of cancer in real-time. In particular, EMT phenotypes are commonly associated with therapy resistance. Thus, capturing these CTCs is expected to reveal important clinical information. However, currently available CTC isolation approaches are suboptimal and are often targeted to capture epithelial CTCs, leading to the loss of EMT or mesenchymal CTCs. Here, we describe size-based CTCs isolation using the RUBYchip™, a label-free microfluidic device, aiming to detect EMT biomarkers in CTCs from whole blood samples of GI cancer patients. We found that, for most cases, the mesenchymal phenotype was predominant, and in fact a considerable fraction of isolated CTCs did not express epithelial markers. The RUBYchip™ can overcome the limitations of label-dependent technologies and improve the identification of CTC subpopulations that may be related to different clinical outcomes.

HER2 Expression in Circulating Tumour Cells Isolated from Metastatic Breast Cancer Patients Using a Size-Based Microfluidic Device

HER2 is a prognostic and predictive biomarker in breast cancer, normally assessed in tumour biopsy and used to guide treatment choices. Circulating tumour cells (CTCs) escape the primary tumour and enter the bloodstream, exhibiting great metastatic potential and representing a real-time snapshot of the tumour burden. Liquid biopsy offers the unique opportunity for low invasive sampling in cancer patients and holds the potential to provide valuable information for the clinical management of cancer patients. This study assesses the performance of the RUBYchip™, a microfluidic system for CTC capture based on cell size and deformability, and compares it with the only FDA-approved technology for CTC enumeration, CellSearch®. After optimising device performance, 30 whole blood samples from metastatic breast cancer patients were processed with both technologies. The expression of HER2 was assessed in isolated CTCs and compared to tissue biopsy. Results show that the RUBYchipTM was able to isolate CTCs with higher efficiency than CellSearch®, up to 10 times more, averaging all samples. An accurate evaluation of different CTC subpopulations, including HER2+ CTCs, was provided. Liquid biopsy through the use of the RUBYchipTM in the clinic can overcome the limitations of histological testing and evaluate HER2 status in patients in real-time, helping to tailor treatment during disease evolution.

Seedless Cu Electroplating on Co-W Thin Films in Low pH Electrolyte: Early Stages of Formation

The use of Ta/TaN barrier bilayer systems in electronic applications has been ubiquitous over the last decade. Alternative materials such as Co-W or Ru-W alloys have gathered interest as possible replacements due to their conjugation of favourable electrical properties and barrier layer efficiency at reduced thicknesses while enabling seedless Cu electroplating. The microstructure, morphology, and electrical properties of Cu films directly electrodeposited onto Co-W or Ru-W are important to assess, concomitant with their ability to withstand the electroplating baths/conditions. This work investigates the effects of the current application method and pH value of the electroplating solution on the electrocrystallisation behaviour of Cu deposited onto a Co-W barrier layer. The film structure, morphology, and chemical composition were studied by X-ray diffraction, scanning electron microscopy and atomic force microscopy, as well as photoelectron spectroscopy. The results show that the electrolyte solution at pH 1.8 is incapable of creating a compact Cu film over the Co-W layer in either pulsed or direct-current modes. At higher pH, a continuous film is formed. A mechanism is proposed for the nucleation and growth of Cu on Co-W, where a balance between Cu nucleation, growth, and preferential Co dissolution dictates the substrate area coverage and compactness of the electrodeposited films.

Enhanced magnetic microcytometer with 3D flow focusing for cell enumeration

We report the design and characterization of a lateral and vertical hydrodynamic focusing feature for whole cell detection on a miniaturized flow cytometer. The developed system, based on magnetic sensing, incorporates spin valve sensors on the bottom of the microfluidic channels that detect cells labeled with magnetic beads. An adaptable 3D hydrodynamic focusing system was developed that pushes labeled cells towards the bottom of the microchannel, closer to the sensors, allowing increased signal amplitude for cells labeled with magnetic beads and enhanced discrimination of labeled cells. Fluorescence microscopy indicates that the lateral and vertical hydrodynamic focusing effect was adequately implemented, consistent with simulation predictions. The sensitivity of the system to detect labeled cells was improved by at least two-fold. By estimating the coverage of magnetic beads on cells, the signal from labeled cells could be predicted using a mathematical model, which also demonstrated the sensitivity of the signal to the height of the cells relative to the sensor. The system is versatile allowing interchangeable flow rates for cells with different diameters.