Non-invasive heart transplant rejection testing
clinical significance
Rejection is an important cause of death in recipients after heart transplantation. Rejection after transplantation is divided into hyperacute, acute and chronic rejection according to the time of occurrence. Acute rejection is related to cellular immunity. Chronic rejection is related to humoral immunity, leading to perivascular inflammation and gradual decline in donor heart function. Early detection of rejection can assist early clinical intervention and is of great significance to the long-term survival of transplanted hearts.
Endomyocardial biopsy (EMB) is the gold standard for diagnosing heart transplant rejection, but it is limited by its invasiveness and is difficult to widely carry out.
In recent years, non-invasive examination methods have attracted attention, such as Doppler ultrasound and intramyocardial electrogram, but they are highly subjective and have limited diagnostic value. Biological indicators have extremely high levels of monitoring and diagnosis, such as donor-derived cell-free DNA (dd-cfDNA). During acute rejection, dd-cfDNA in the recipient's blood will increase by 1% to 5%.
Detection principle
Cell free DNA (cfDNA) refers to DNA fragments free from cell apoptosis or necrosis and free outside cells. The plasma of heart transplant patients contains cfDNA derived from apoptosis of donor heart cells. A large amount of research and experimental data show that cfDNA is a new biomarker that indicates the health status of transplanted organs and has the advantages of non-invasive, sensitive and real-time.
The AlloDx heart transplant non-invasive rejection test uses second-generation gene sequencing technology to capture and detect cell-free gene sequences derived from donor tissues in the patient's peripheral blood, and uses the independently developed bioinformatics algorithm model HDSS (High Dimension SNP Seq) to evaluate the rate of apoptosis or necrosis of donor tissue cells, thereby non-invasively detecting the patient's transplant organ rejection reaction.