Panel Reactive Antibody
Encyclopedia
Panel Reactive Antibody (PRA) is a blood test
that is routinely performed on patients waiting for kidney and heart transplants and measures anti-human antibodies in the blood. The PRA score is given as a percentage and can be from 0% to 99%. The PRA represents the percentage of the U.S. population that the anti-human antibody in your blood reacts with.
Patients develop anti-HLA (Human Leukocyte Antigen
) antibodies from exposure to HLA of other humans through previous transplants, blood transfusions and/or pregnancy. Patients showing high Panel Reactive Antibodies are often referred to as sensitized. Patients with high PRA (usually > 50%) are less likely to receive transplants as the risk for immediate antibody-mediated rejection of the transplanted organ is significantly increased.
Treatments to reduce PRA in sensitized transplant candidates exist including treatment with Rituximab
(a B-cell specific antibody), IVIg, protein A
immunoabsorption, plasmapheresis
etc.
Reference: Jordan and Pescovitz, Clin J Am Soc Nephrol 1: 421–432, 2006 http://cjasn.asnjournals.org/cgi/content/full/1/3/421.
Blood test
A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a needle, or via fingerprick....
that is routinely performed on patients waiting for kidney and heart transplants and measures anti-human antibodies in the blood. The PRA score is given as a percentage and can be from 0% to 99%. The PRA represents the percentage of the U.S. population that the anti-human antibody in your blood reacts with.
Patients develop anti-HLA (Human Leukocyte Antigen
Human leukocyte antigen
The human leukocyte antigen system is the name of the major histocompatibility complex in humans. The super locus contains a large number of genes related to immune system function in humans. This group of genes resides on chromosome 6, and encodes cell-surface antigen-presenting proteins and...
) antibodies from exposure to HLA of other humans through previous transplants, blood transfusions and/or pregnancy. Patients showing high Panel Reactive Antibodies are often referred to as sensitized. Patients with high PRA (usually > 50%) are less likely to receive transplants as the risk for immediate antibody-mediated rejection of the transplanted organ is significantly increased.
Treatments to reduce PRA in sensitized transplant candidates exist including treatment with Rituximab
Rituximab
Rituximab, sold under the trade names Rituxan and MabThera, is a chimeric monoclonal antibody against the protein CD20, which is primarily found on the surface of B cells...
(a B-cell specific antibody), IVIg, protein A
Protein A
Protein A is a 40-60 kDa MSCRAMM surface protein originally found in the cell wall of the bacterium Staphylococcus aureus. It is encoded by the spa gene and its regulation is controlled by DNA topology, cellular osmolarity, and a two-component system called ArlS-ArlR. It has found use in...
immunoabsorption, plasmapheresis
Plasmapheresis
Plasmapheresis is the removal, treatment, and return of blood plasma from blood circulation. It is thus an extracorporeal therapy...
etc.
Reference: Jordan and Pescovitz, Clin J Am Soc Nephrol 1: 421–432, 2006 http://cjasn.asnjournals.org/cgi/content/full/1/3/421.