A Device Created to Detect Myeloma Cells in Blood Samples

Medical engineers have developed a microfluidic device that can be used as a non-invasive tool for diagnosing multiple myeloma and monitoring the disease's progression. The innovative device has allowed researchers to detect a specific type of circulating blood cells that are associated with shorter survival times. Existing methods have not always been able to identify these cells in patients' blood when present in low quantities.

About Multiple Myeloma

Multiple myeloma is one of the most common and dangerous forms of blood cancer. It is characterized by the malignant transformation of hematopoietic stem cells – precursors to leukocytes, which are also known as plasma cells. These cells are part of the immune system and are responsible for fighting infections by producing antibodies that target pathogens.

As a result, a large number of pathologically altered plasma cells accumulate in the bone marrow, hindering the formation and growth of healthy blood cells. Instead of producing "therapeutic" antibodies, these malignant cells produce abnormal proteins that cause a range of serious health problems.

This disease is called multiple myeloma because it can affect various parts of the body, including the spine, skull, pelvis, and ribs. In the early stages, symptoms may be absent, but as the disease progresses, it ultimately leads to painful sensations in the bones, kidney problems, weakness, nausea, unexplained weight loss, and recurrent infections.

Multiple myeloma is considered incurable – the progression of the disease can be halted with medication therapy, and remission often lasts for years. However, for most patients, the disease eventually returns and progresses.

According to the latest estimates from the American Cancer Society, nearly 27,000 new cases of multiple myeloma are registered each year in the United States, with more than 11,000 patients with this diagnosis dying.

The New Device Can Filter Cancer Cells

Recent studies have shown that some plasma cells that have undergone malignant transformation leave the bone marrow and enter the bloodstream. The presence of these cells, known as circulating clonal plasma cells, has previously been associated with shorter survival times among patients.

Until now, detecting this type of cell using existing tools has been problematic, especially when they are present in low concentrations. The fact is that most methods involve pre-processing the blood sample, during which a significant portion of the necessary cells is destroyed.

As recently reported in the journal Microfluidics, researchers at the American Institute of Physics have developed a device capable of detecting and filtering circulating clonal plasma cells in small blood samples. The filtering device isolates malignant plasma cells from healthy ones based on the principles of microhydrodynamics, also known as microfluidics. This modern technology allows for working with very small volumes of liquids, manipulating them, and controlling the processes occurring within them.

The team designed tiny columns in the flow channel of the device in such a way that they capture cancer cells while allowing healthy ones to pass through. To achieve this, specialists used a computational model that allowed them to compare columns of different shapes and sizes. Ultimately, they calculated the optimal parameters that allowed them to extract particles of the desired size from the liquid. It turned out that diamond-shaped columns had the lowest resistance to flow, and that by making them longer and sharper, their filtering action could be improved.

Red blood cells are the smallest of the blood plasma cells, with a diameter ranging from 6 to 8 microns. White blood cells are somewhat larger – their diameter ranges from 7 to 30 microns. Although circulating malignant plasma cells are generally larger than the others – their diameter varies from 30 to 50 microns – the smallest of them are the same size as the largest leukocytes.

However, white blood cells have the ability to change shape and can squeeze through the columns, while malignant plasma cells are more rigid, cannot change shape, and therefore get stuck in the filter.

Researchers tested the filtering device using cultured cancer cells and blood samples taken from patients with multiple myeloma. These experiments showed that the number of circulating plasma cells captured by the filter in patients with active disease was significantly higher compared to patients in remission and healthy individuals.

"This device demonstrates high potential as a non-invasive method for early detection or monitoring the progression of multiple myeloma," commented the lead author of the study, Lidan Yu.