PlexCMV^TM

CMV

Cytomegalovirus (CMV) is a common virus that has infected half of all people by the age of 40 years (www.cdc.gov/cmv/index.html). 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. This reactivation can progress from virus that is only detected in the blood (viremia), to involvement of tissues and organs (disease), which can cause major illness.   

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

PlexCMV^TM is a lab developed blood test to measure the level of cellular immunity to Cytomegalovirus (CMV). Decreased anti-CMV immunity increases the risk of CMV infection.* 

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

Test Description

PlexCMV^TM measures functional cell-mediated immunity to CMV. 

• Whole blood, 3 ml from children, 5 ml from adults in sodium heparin green top tubes, is 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 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 
• are reported as frequencies of CMV-specific T-cells and their subsets along with thresholds for the level of CMV immunity. These thresholds have been established from studies of over 150 transplant recipients. These thresholds determine whether immunity to CMV is decreased or not. 
• Negative predictive value or the prediction of freedom from infection exceeds 90%.
• Immunosuppression protocols can vary with different types of patients and organ transplants. Establishing the level 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 preventive measures or treatment.

References:

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

*PlexCMV^TM is not FDA-approved