Cytomegalovirus (CMV) is a common virus. Half of the population will have been infected by this virus by the age of 40. Most infections do not cause symptoms. CMV persists after the initial infection and can reactivate in individuals whose immune systems are compromised by immunosuppressive drugs, viral infections, or genetic changes. A CMV infection can manifest as a virus that is detected in the bloodstream, a condition known as viremia. In more severe cases, it can invade tissues and organs, which can cause major illness.
CMV infection is accompanied by loss of cell-based immunity to the virus. In transplant patients, this infection leads physicians to lower immunosuppression and start antiviral drugs. This can lead to rejection of the transplanted organ in some patients or side effects of antiviral drugs in others. CMV can also recur after completion of antiviral drug therapy, either because cell-based immunity has not recovered or because the virus has become resistant. Knowing whether cell-based immunity to CMV is intact or decreased can further indicate when to start or stop antiviral drugs or modify immunosuppression.
PlexCMVTM measures the level of cellular immunity to Cytomegalovirus (CMV) to help formulate personalized antiviral therapy or immunosuppressive treatment.
PlexCMVTM is a lab-developed blood test that measures the level of cellular immunity to Cytomegalovirus (CMV). Decreased cellular immunity increases the risk of CMV infection. Knowledge about cellular immunity to CMV and therefore the risk of CMV infection can be combined with available clinical data to plan additional treatment for your patient.
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Assay Category |
Lab-developed test, antigen-specific T-cell function. |
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Intended Use |
To measure cell-mediated immunity to the Cytomegalovirus (CMV). |
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Methodology |
Stimulation of peripheral blood leukocytes with CMV-pp65 antigen, flow cytometry. |
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Test Report |
Available within 6 hours of receiving a blood sample. |
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Test Readout |
Frequency (%) of CMV-specific T-cells that express CD154, an inflammatory marker. |
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Reference Range |
In healthy adults, the mean +/- SD frequency of CMV-specific T-cells was 3.9 +/- 1.9% with a range of 0.4 to 8.4%. |
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Test Interpretation |
CMV-specific T-cell frequency of 1.7% or greater is seen in 93% of patients who are free of CMV viremia. |
Purpose
Knowledge about immunity to CMV and therefore the risk of CMV infection can be combined with available clinical data to plan additional treatment for your patient.
Rationale
Reactivation of CMV is accompanied by loss of cell-based immunity to the virus. In transplant patients, reactivation leads physicians to lower immunosuppression and start antiviral drugs. This can lead to rejection in some patients or side effects of antiviral drugs in others. CMV can also recur after completion of antiviral drug therapy and can progress to CMV disease. Knowing whether cell-based immunity to CMV is intact or decreased can further guide when to start or stop antiviral drugs or modify immunosuppression.
Intended Use
To measure the level of cell-mediated immunity to CMV.
Procedure
PlexCMVTM measures functional cell-mediated immunity to CMV.
- A whole blood sample, 3 mL from children and 5 mL from adults, in sodium heparin (green top) tubes. Samples are to be shipped at ambient temperature overnight to Plexision’s reference laboratory.
- CMV-specific T-cells and their subsets, which express the inflammatory marker, CD154, are measured after stimulation with CMV pp65 antigen.
- Simultaneously, recipient T-cell stimulation with mitogen measures general T-cell responsiveness.
- Results are reported within 6 hours after blood samples reach the laboratory.
- Results are reported as frequencies of CMV-specific T-cells.
- For reference, the frequency of CMV-specific T-cells which is associated with freedom from CMV infection is also provided. This threshold frequency has been established from studies in over 140 transplant recipients. The frequency is used to assess whether the patient is protected against CMV infection or not.
Performance
- CMV-specific T-cell frequency of 1.7% or greater was seen in 93% of transplant recipients without CMV infection. Thus, the negative predictive value of this test is 93%.
- In recipients who did not have IgG antibodies to the CMV virus, the incidence of CMV infection was 5% of 1.7% CMV-specific T-cells were present, and 62% of CMV-specific T-cells were less than 1.7% (p=0.004).
- The data was generated by testing 145 samples, of which 19 were known positive and the remainder were known negative.
Benefits
- Recipient-donor combinations where one or both show no antibody to the CMV virus are administered preventive antiviral medications because they are at high risk to develop CMV infection. These medications can suppress blood cell counts which predisposes to other infections.
- Establishing the level of anti-CMV immunity at baseline and during periods of high dose immunosuppression permits the level of anti-CMV immunity to be assessed in each patient. This can help formulate personalized antiviral therapy or immunosuppressive treatment.
Sample & Shipping
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Sample Type |
A whole blood sample is collected in a sodium heparin (green-top) tube. |
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Volume |
3 mL in children and 5 mL in adults. |
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Transport Conditions |
Ship priority overnight, at room temperature. The sample must get to Plexision within 30 hours of the phlebotomy. |
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Specimen Stability |
30 hours at room temperature from the time of the phlebotomy. |
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Sample Discard Criteria |
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How to order
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Test Brochure | View and download the product brochure here. |
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Ordering Tests |
Please complete this form, print, and fax it to 412-224-2776. |
PlexCMVTM is a blood test that helps your healthcare provider determine your level of protection from CMV infection after transplantation.
Transplant recipients of any age and individuals that have low general immunity and are at risk for CMV infection can benefit from the PlexCMVTM test.
The PlexCMVTM test must be ordered by your healthcare provider. The test requires half to one teaspoon of a blood sample. This sample is then shipped overnight to Plexision’s laboratory for analysis. Results are sent to your healthcare provider within 6 hours of your sample arriving at the laboratory. Your healthcare provider will help you understand what these results.
Results are ready within 6 hours after the laboratory receives the blood sample.
The PlexCMVTM test determines whether the recipient has protective levels of cell-mediated immunity for CMV infection. This immunity is measured in a type of white blood cell called the T-lymphocyte. Protective levels of immunity to CMV are associated with a decreased risk of CMV infection. Decreased anti-CMV immunity increases the risk of CMV infection. When combined with other clinical information and laboratory tests, the results of PlexCMVTM can help your healthcare provider decide whether to start, stop, or continue antiviral treatment.
The results are reported as the frequency of CMV-specific T-cells. CMV-specific T-cell frequencies of 1.7 or greater are associated with freedom from CMV infection in 93% of transplant recipients.
Determining when to start, stop, or continue antiviral drugs for CMV infection is essential in order to enhance benefits and reduce side effects. Knowledge about the level of cell-based immunity to CMV can be combined with other clinical data by your healthcare provider to make such clinical decisions.
The PlexCMVTM test must be ordered by your healthcare provider. The test requisition form is provided here. The completed form can be faxed to 412-224-2776. If there are any questions, please contact (855) PLE.XISION (753.9474) or 412-224-2504.
Plexision will bill your healthcare facility or your insurance plan as indicated on the requisition form. Plexision’s patient assistance plans will assist with the cost of PlexCMVTM if there is no insurance coverage.
1. US Patent 9606109
2. Ashokkumar C, Green M, Soltys K, Michaels M, Mazariegos G, Reyes-Mugica M, Higgs BW, Spishock B, Zaccagnini M, Sethi P, Rzempoluch A, Kepler A, Kachmar P, Remaley L, Winnier J, Jones K, Moir K, Fazzolare T, Jenkins K, Hartle T, Falik R, Ningappa M, Bond G, Khanna A, Ganoza A, Sun Q, Sindhi R. CD154-expressing CMV-specific T cells associate with freedom from DNAemia and may be protective in seronegative recipients after liver or intestine transplantation. Pediatr Transplant. 2019 Oct 27:e13601. doi: 10.1111/petr.13601. [Epub ahead of print] PMID: 31657119
*PlexCMVTM is not FDA-approved