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Sysmex Enters Clinical Flow Cytometry with a Portfolio of ASR Antibodies

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NEW YORK (360Dx) – Sysmex America recently said that it is entering the routine clinical flow cytometry market by offering a portfolio of analyte-specific reagent antibodies.

The move is a logical progression for the firm in a market that needs a third large industry player to join Becton Dickinson and Beckman Coulter, Joshua Johnson, corporate and key account executive of flow cytometry at Sysmex America, said in an interview.

The popularity of flow cytometry relates to its ability to sensitively differentiate negative cell populations from positive cell populations in some of its largest market applications, including leukemia and lymphoma immunophenotyping, T-cell monitoring in HIV patients, and CD-34 or stem cell enumeration in core-blood banking, Johnson said.

Because flow cytometers are open systems, the Sysmex ASRs can be used on any flow cytometer platform, the firm said, adding that this enables pathology laboratories to use the clone, or cell line, with the highest quality, regardless of supplier, for their laboratory-developed tests.

The move by Sysmex is a logical extension of its business because of the established and historic strength of its hematology products, Johnson said, adding clinical flow cytometry has been looked upon as hematology’s next step for some time.

While hematology tests can raise an alarm that a patient has the potential to have an infection or tumor because of an elevated white blood cell count, for example, a flow cytometer investigates why that count is higher, Johnson said.

"Out of millions of cells being evaluated by flow cytometry, one or two could be clinically relevant, and the instrument can identify those cells, so it's an extremely powerful tool that goes hand in hand with hematology," Johnson added.

Sysmex said that it is initially offering a portfolio of 79 analyte-specific reagents "geared toward core and gating markers prevalent in the flow cytometry community." These are reagents with antibodies that are most commonly seen in most panels in clinical flow cytometry laboratories, Johnson said.

Pathologists use them as a gating mechanism, starting at a high level and then "funneling down to the cell population of interest," Johnson noted. "You can, for instance, start with lymphocytes and look for T-cells and then proceed to ascertain whether they are helper or suppressor cells."

"What makes us unique with this ASR antibody line is that we also have a lot of antigen and clone combinations that are new to the US and North America that gives laboratories greater flexibility," he said, adding, "When you get into high multicolor testing for flow cytometry, some clones don't react well with others, and that can make positive results look negative."

In these circumstances, he said, there's some ambiguity and subjectivity to the review and interpretation of flow cytometry results. "A high-quality product that allows you to clearly discern positive from negative populations gives the pathologist or flow cytometry specialist the ability to see a disease or a cell population when otherwise they might not have seen it."

Sysmex noted that its portfolio's quality is enhanced by monoclonal antibodies with high mean fluorescent intensities that also help pathologists in their efforts to discern a negative from a positive population at less than optimal cell concentrations.

"Mean fluorescent intensity is not the only criteria you need for picking an antibody, but it's a really nice place to start," Johnson said, adding that it gives you the ability "to see cell populations when the cell count might not be tailored exactly to what you would normally need."

Besides Beckman Coulter, Becton Dickinson, and now Sysmex, a few other companies supply ASRs. Laboratory ASRs include polyclonal and monoclonal antibodies, ligands, specific receptor proteins, nucleic acid sequences, and similar reagents. In an era of continuing uncertainty around regulations for lab-developed tests, some labs are relying on commercially available ASRs as a means of simplifying their work and as a key enabler in responding to critical patient needs when tests are not otherwise available. 

In additional to supplying flow cytometry instruments, tools, and software, Becton Dickinson Life Sciences offers a portfolio of flow cytometry antibodies, including conjugated and purified antibodies.

The US Food and Drug Administration recently cleared Beckman Coulter's ClearLLab reagents through the de novo process, giving laboratorians access, for the first time, to approved antibody cocktails that aid in the immunophenotyping and detection of certain leukemias and lymphomas. The ClearLLab reagents, which run on Beckman Coulter's FC 500 one-laser, five-color flow cytometer, is performed on blood, bone marrow, or lymph nodes in patients with chronic and acute leukemia, lymphoma, myeloma, myelodysplastic syndrome, and myeloproliferative neoplasms.

Beckman Coulter also expects to launch other flow cytometry products in the near term, a company spokesperson recently told 360Dx.

But not all ASR antibodies are for flow cytometry applications.

Molecular diagnostic company Luminex offers a broad menu of ASRs based on its MultiCode-RTx technology for the identification and quantification of various pathogens. The firm's Aries system also runs both IVD and MultiCode ASRs simultaneously with a common Universal Assay Protocol.

In a document filed recently with the US Securities and Exchange Commission, the firm said that commercialization of its MultiCode analyte specific reagents outside of the US is among its focus areas over the next 12 months.

Meridian Bioscience last year launched a new ASR product line that includes a primer set and probes to detect the target sequence associated with clarithromycin-resistant Helicobacter pylori strains and to detect H. pylori, a gram-negative bacterium usually found in the stomach. The firm introduced the ASRs to address an unmet need; no commercially available in vitro diagnostic products were available for the identification of Clarithromycin-resistant strains.

Advances in diagnostics and treatments for cancer patients are helping drive demand for molecular diagnostics and the use of flow cytometry ASRs, Johnson said.

We are seeing "massive jumps in treatments but identification and especially early identification is still our best defense," he said. Flow cytometry is important in this context because it enables clinicians can see how patients are reacting to different therapeutic treatments.

In this context, industry guidelines now are starting to push toward molecular diagnosis and flow-based monitoring, he said, and monitoring and also diagnosis for cancer-related applications are among the most significant drivers for flow cytometry.

In a recent College of America Pathologists survey of hematologists, oncologists, and pathologists on the current practice of ordering tests for the diagnosis of acute leukemia, nearly all respondents reported performing flow cytometry analysis.