Hla typing and matching multiple pre and posttransplant factors including patient, disease stage, and transplantrelated aspects can impact transplant outcomes. Hml is used by the national marrow donor program nmdp. Hlamatchmaker is a useful tool to determine epletbased mismatch acceptability for sensitized patients considered for transplantation or in need of compatible platelet transfusions. National tissue typing laboratory new zealand blood service. During tissue typing, an individuals human leukocyte antigens hla are identified. Testing details for hla typing for platelet support. Additional studies, including screening for hla antibodies and other platelet serology assays may be useful. Transplant donors hla typing is performed on family members when they have volunteered to see if they are a match for a relative who needs a kidney, liver, lung, bone marrow, or other type of transplant. This is the procedure to collect some of your stem cells. Platelet donation 301 platelets and hla typing stanford. Representative data generated from an hlaa02112402 sample.
While ngs has altered the hla typing landscape, it has also raised new issues. While the majority of patients can receive platelets with any hla type, it is. While the majority of patients can receive platelets with any hla type, it is possible for a patients body to create antibodies against certain ones, which. Ajh educational material test of the month determination. Use of hla hpa selected platelets transfusion guidelines. Hla typing was performed by molecular ssossp method and antibody identification was achieved using luminex single antigen assay following an initial screening test. A fhir human leukocyte antigen hla interface for platelet. Services available at hla laboratories may vary, so. Hla antibody screening of recipients hla antibody testing is performed on the recipient to determine if there are any antibodies present that would target the donated organ or tissue. The human leukocyte antigen hla gene cluster plays a crucial role in adaptive immunity and is thus relevant in many biomedical applications. They are looking at about 10 different genetic markers, typically. Platelet antigens and antibody detection blackwell.
The human leukocyte antigen hla system, originally discovered as the result of a transfusion reaction, is now known to play a crucial role in many areas of clinical medicine. Highresolution, dnabased hla typing methods can distinguish amino acid polymorphisms at the allele level. As a result, clinical teams will more readily identify patients in need of hla matched platelets, and our institution will be able to better utilize platelet. Hla sequencingbased typing systems product bulletin hla typing product bulletin figure 1.
Hlamatchmaker is a software algorithm that predicts hla compatibility by identifying immunogenic epitopes represented by amino acid triplets in antibody. Undetected hla incompatibility has been suspected as a cause of refractoriness to hla matched platelet transfusions. The hla gene complex resides on a 3 mbp stretch within chromosome 6p21. Specimen must have the patients first and last name, a date of draw and a unique identifier written on the tube. The main function of the hla molecules is to present antigenic peptides to the immune system and in this way regulate the induction of immune responses. While the majority of patients can receive platelets with any hla type, it is possible for a patients body to create antibodies against certain ones, which means they could have a negative reaction to or get no benefit from a platelet. Your immune system uses these markers to recognize which cells belong in your body and which do not. Management of patients refractory to platelet transfusion. As only a small selection of donors are suitable search for suitably matched donors a. Ngs approaches for hla typing are supported by software for automated assignment of hla alleles. However, patients can sometimes produce antibodies to the hla molecules expressed on platelets, which reduce the effectiveness of platelet transfusion.
Platelet transfusions for unresponsive patientsdisease associations b27ankylosing spondylitis dq6 sleep disorders. Hla and hpaalloimmunization rate in the setting of. Many patients who develop platelet transfusion refractoriness ptr require. In subsequent blood transfusions, alloantibodies against donor hpa may cause immunological reactions in the recipients blood, resulting in the lysis of the transfused platelets and. Pdf hlamatchmakerdriven analysis of response to hla matched. Note the even base incorporation at the four heterozygote positions, the low background noise, and baseline resolution of the peaks. In 1977, the laboratory began hla testing for bone marrow transplant recipients and for recipients of kidney transplants. It is also being used to assess the degree of hla mismatch permissibility eplet load to reduce allosensitization and improve transplant outcome in nonsensitized. If your hla type matches the patients, you will have a health screening to make sure youre healthy enough to donate stem cells. Transplantation services australian red cross lifeblood. Hla class i antibodies, thus limiting their use to gpspeci. As an outpatient, requires two hla selected platelet unitsweek to maintain an adequate platelet count. Patients were tested for the presence of hla and hpa antibodies at the canadian blood services platelet immunology laboratory. The trusight hla v2 sequencing panel provides clinical researchers with a broadcoverage, ultrahighresolution human leukocyte antigen hla typing solution for simple, rapid assessment of the hla region in a single assay.
The most common cause of immunological refractoriness to random donor platelet transfusion is the presence of hlaspecific antibodies in the patient receiving platelet transfusion. The laboratory has also joined international proficiency test programs to ensure consistent typing accuracy. Human leukocyte antigen hla typing is used to match patients and donors for bone marrow or cord blood transplants. Hla testing is performed and test results are kept on file to compare with results from those people who need a donor match. This means, the same data can be accessed from several workplaces. By defining a fhir interface to an internal tissue typing hla database, we were able to facilitate a platelet visualization tool and calculated panel reactive antibody cpra web service. Hlapra and hla typing most common target of antibodies in immunemediated platelet refractoriness hlapra tested for via flow cytometry using beads coated with purified hla antigens quantifies sensitization and gives ab specificity patients hla type determined by sequencing. The assignment of triplets to hla antigens based solely on lowresolution molecular typing is a limitation of our study. Platelet genotyping is critical in screening atrisk fetuses for the presence of the hpa corresponding to the maternal antibody.
Hlaselected platelets for platelet refractory patients. Human platelet antigen hpa are glycoproteins expressed on the. With hpa1 ab ready gene you have the possibility of typing pregnant women specifically. The lifecodes hla typing kits rapid utilize sso methodology to identify hla alleles present in a locusspecific pcramplified sample. Hla matching requires typing the patient for hla class i antigens. Hla selected platelets hla class i typing 1x 6ml edta anticoagulated sample hla a, b,c type hla class i type using pcrssp or luminex sso technology antigen level of typing hla antibody identification 1x 6ml clotted serum sample luminex technology to identify antibody specificity. Hla typing of patients and donors selection and issue of hla compatible platelets documentation of posttransfusion increments. While nextgeneration sequencing data are often available for a patient, deducing the hla genotype is difficult because of substantial sequence similarity within the cluster and exceptionally high variability of the loci. Platelets express a lot of hla antigens so a platelet transfusion causes exposure to foreign hla.
The traditional management of alloimmunemediated platelet refractoriness is by hla typing of donors and recipients. Hla laboratories also provide dna based typing for genetic polymorphisms of cytokine genes, minor histocompatibility antigens and natural killer cell immunoglobulinlike receptor kir genes, and for posthct engraftment monitoring using short tandem repeat str markers. Hla typinghla antibody detectiondonorrecipient placementcrossmatchingimmune monitoring posttransplant. Hla typing bioinformatics tools wes analysis omicx. Request pdf hlaselected platelets for platelet refractory patients with hla antibodies. Hla testing identifies the major hla antigens that are present on the surface of an individuals cells and the antibodies to hla antigens as well as the genes that are. It is expected that in the near future the availability of lowcost genotyping platforms will vastly expand the availability of hlatyped platelet donors. Determination of an unrelated donor pool size for human leukocyte. The software indicates the alleles present in each sample.
These cellsurface proteins are responsible for the regulation of the immune system in humans. The transplantation and immunogenetics service also provides hla typing for the australian bone marrow donor registry. A significant fraction of hla matched transfusions do not produce. Human platelet antigens hpa are glycoproteins expressed on platelet membranes. Hla typing is not as easy as blood type, and gets into dna testing, so a blood bank would not be able to readily tell you your hla type, and naming your type is not quite as simple as a letter and plus or minus sign. Tbg molecular typing laboratory provides a suite of hlatyping service certified by ashi american society of histocompatibility and immunology with the highest quality assurance. Fluogene is a unique method for molecular hla, rbc and hpa typing combining all advantages. This is done to see if your stem cells are a good match for the recipient the patient. One 10cc acd blood tube yellow top, solution a or b labeling requirements. Hla selected platelets hla class i typing 1x 6ml edta anticoagulated sample hlaa, b,c type hla class i type using pcrssp or luminex sso technology. Application of hlahpa testing to patients and donors 16. Hlamatchmakerdriven analysis of responses to hlatyped platelet.
Tissue typing is the matching of a patient, who requires a solid organ or bone marrow transplant, with potential donors ensuring they are compatible. Alternatively, platelet crossmatching may be performed to screen for platelets that. Application of hlahpa testing to patients and donors. These typing methods, particularly ssp, have permitted rapid hla typing that does not rely on viable cells, significant numbers of lymphocytes, or adequate antigen expression on different cell types. Hlamatchmakerdriven analysis of responses to hlatyped. In addition, platelet genotyping may play a role in popu. The baby has inherited its hla type from each parent. Hlamatchmaker is a software algorithm that predicts hla compatibility by identifying.
Repeated platelet transfusion often induces alloimmunization to hlaantigens resulting in a state of refractoriness of the thrombocytopenic patient. Platelet hla testing services canadian blood services. Such patients can be successfully treated with platelet concentrates from an hla compatible sibling donor 1. Thus, testing can be performed using small samples of blood or other tissue that would be inadequate for serologic typing, and provides a highly.
Hla typing is also performed on unrelated individuals who wish to become a bone marrow donor through the donation registry. Human leukocyte antigen hla typing and matching be the. Fluogene is a unique method for molecular hla, rbc and hpa typing combining all advantages of the ssppcr with the speed of endpoint fluorescence detection. Based in epsom, auckland the national tissue typing laboratory is responsible for tissue typing tests in support of new zealands bone marrow and solid organ transplant programs. Many potential donors are needed to sustain human leukocyte antigen matched platelet transfusion programs because of the different types of antigens and the. Hla are proteins or markers found on most cells in your body. The human leukocyte antigen hla system or complex is a group of related proteins that are encoded by major histocompatibility complex mhc gene complex in human.
The degree of human leukocyte antigen hla matching between the transplant recipient and the hematopoietic cell graft has a significant impact the outcomes of related and unrelated. Hlamatching in platelet refractoriness background platelet refractoriness. Sequence data are analysed and interpreted by software dedicated to hla typing. Hml is used by the national marrow donor program nmdp, a usbased registry of over seven million volunteer donors, for reporting genotyping results 16.
Canadian blood services national platelet immunology reference laboratory npirl is an accredited laboratory that provides hla and hpa antigen typing. Request for testing immunogeneticshla and platelet. The hla typing software also has a multiuser option. If you are currently part of our platelet program, you may one day. Human platelet antigens hpa are glycoproteins expressed on the membrane. Interpretation of hla typing results for entry into unet.
Hla genes are highly polymorphic, which means that they have. This sequence is from positions 288308 at the 3l of exon 2. If hla from the donor is recognized by the recipients immune system as different from the recipients own hla, an immune response. Undetected hla incompatibility has been suspected as a cause of refractoriness to hlamatched platelet transfusions. Human leukocyte antigen testing red cross blood services. These hpas can stimulate the production of alloantibodies after transfusion. Colindale for hospitals in the south sheffield for hospitals in the north. Human leucocyte antigen hla compatible platelet searching and matching is performed in sydney ntis and melbourne vtis for patients nationally, as well as diagnostic investigations for specialised transfusion reactions. At stanford blood center sbc, platelet donations are tested for each donors specific hla type. Hla molecules are presented on the surface of cells and facilitate interactions between immune cells such as dendritic cells and t cells that lead to adaptive immune responses.
Hla genotyping is important to identify the best donorrecipient. Until genotyping of all new donors becomes standard practice, it is wise to genotype donors who are expected to increase the genetic diversity of. The hla genes that individuals inherit are responsible for the hla antigens present on their cells. The blood centers immunogeneticshla laboratory was established in 1975 to provide hla typing for platelet transfusion recipients. Human leukocyte antigens hla are specialized proteins present on the surface of all cells in the body except red blood cells.