Organ donation and transplantation allows for the transfer of a healthy organ from one person to another person who is at the end stage of organ failure. When a person has a life-threatening injury or disease that affects their organ or tissue, transplant can give them a second chance at living a normal life. The transplanted organ can be gotten from a living or deceased donor.
In living donors, a person consents to spare a portion of their healthy organ, such as one kidney or a portion of the liver, while taking measures to protect the health of the remaining organ. Deceased donors are people who consent to donating their organ or tissue in the event of death. Sometimes, the relatives of the deceased may consent on their behalf, after death, to donate their organs.
Typical organs and tissues that may be donated include the kidneys, liver, heart, lungs, pancreas, intestines, skin, bone, and cornea. The most common organ transplants are kidney and liver transplants. A living donor can donate a portion of their liver or one of their kidneys. The heart can only be donated in the event of brain death.
Organ Transplant Testing
Before a transplant can occur, the healthcare provider must test and certify that the donor is in general good health and the organ to be donated is healthy. They must also certify that the donor is a right match for the recipient. This involves testing that the blood and tissue type of the donor and recipient match to reduce the risk of a rejection. One of the ways to verify donor-recipient match is through HLA typing.
HLA Typing with QTYPE HLA Typing in Real Time
Human Leukocyte Antigen (HLA) fights foreign substances in a person’s body. That is, the human leukocyte antigen (HLA) checks to see whether a cell belongs to a person’s body or not. When it determines that the cell or organ does not originally belong in that body, it fights to kill it off. Medical personnels understand that HLA matching is essential to the success of a transplant and survival of the organ in the body of the new owner.
HLA typing is a genetic test and the time it takes to determine an accurate genotype of sufficient resolution is critically important. CareDx’s QTYPE is currently the fastest real-time PCR product for HLA typing, allowing for the identification of alleles from HLA-A, B, C, DRB1, DRB3, DRB4, DRB5, DQA1, DQB1, DPA1 and DPB1 loci, at low-to-intermediate resolution in less than one hour.
How QTYPE Works
Principle QTYPE utilizes TaqMan™ probe-based quantitative PCR (qPCR) reactions. Each well of the QTYPE qPCR plate contains pre-aliquoted dried primer pairs, designed to specifically bind a subset of HLA alleles, and a reporter probe designed to bind to a sequence specific location between the primers. The reaction mixes consist of minimally one HLA assay and one internal control assay. Depending on the level of multiplexing, there may be more than one HLA assay per well.
QTYPE test is validated to use with qPCR instruments like the Roche LightCycler 480. The Olerup QTYPE is a CE/IVD medical device with a simple workflow: DNA is mixed with Mater Mix and water, then dispensed into QTYPE plate. The plate is sealed, centrifuged for 2 minutes and loaded into the qPCR instrument. The run takes approximately 45 minutes. The results are then imported to SCORE 6 and the analysis takes approximately 5 minutes.
QTYPE Results
The use of sequence-specific fluorescent probes allows for multiplexing, i.e. the detection of multiple targets in a single well, extending the number of reactions in one PCR run to over 700 using the QTYPE kit.
Internal control reaction performed in each well is used to confirm that reaction mixture and sample DNA were added to the well and to correct for slight differences in amount of DNA across the whole plate. A no template control reaction detects any contamination from genomic DNA or amplicon. Every allele is detected by at least two different reactions, providing functional redundancy.
References:
Beata K., Diogo S., Ben P., Anna H., David C. S. (2019). QTYPE®, the Fastest Method for HLA Genotyping by Real-Time PCR. CareDx International AB, Stockholm, Sweden.
Beata K., Nathalie I., Connie Xu, Dan Dou, Supaneda N. K., Christopher N. N., Ben P., Anna H., David C. S. (2021). Genetic risk factors in solid organ transplantation: beyond classical human leukocyte antigen. CareDx AB, Stockholm, Sweden; CareDx Pty Ltd, Fremantle, Australia.
Organ Donation and Transplantation (https://my.clevelandclinic.org/health/treatments/11750-organ-donation-and-transplantation) Accessed 13/08/2024.