Human Leucocyte Antigen (HLA) molecules are expressed on all nucleated cells and are hugely polymorphic, resulting in a enormous diversity of HLA molecules in the human population. Non-self HLA molecules can be recognized as foreign and can lead to rejection in the setting of organ transplantation, and graft versus host disease in the setting of stem cell transplantation. Therefore, typing donors and recipients for their HLA molecules, as well as determining (pre-existing) immunity against foreign HLA molecules is of great importance for successful transplantation. Transplant recipients are tested when it is determined that they need a solid organ or hematopoietic stem cell transplant. Prior to transplant, potential donors are tested when they are being evaluated for compatibility with a specific donor.
- HLA typing identifies which HLA molecules individual has inherited. This can be done either by serological testing or on the DNA level. Our laboratory has several assays running for HLA typing, including Next Generation Sequencing (NGS), which provides the highest accuracy of HLA typing.
- HLA antibody screening is performed to detect antibodies to HLA antigens that may result in antibody mediated rejection of allografts. Also for HLA antibody screening several techniques are avaliable in our laboratory, of which a combined analysis is performed for clinical decision making.
Immunogenetics testing is also relevant for other diagnostics purposes, such as HLA typing of blood platelet donors to match transfusion recipients that are refractory due to existing HLA immunisation. In addition, several HLA types are associated with diseases, such as celiac disease or type 1 diabetes. The HLA types are not diagnostic for these disorders but can be useful in helping to confirm or exclude a diagnosis. Relationships have also been documented between certain alleles and sensitivities to specific drugs, such as the HIV drug Abacavir.
The Leiden HLA diagnostics laboratory holds the EFI accreditation, as well as the ISO15189 accreditation (for Medical Laboratories) issued by the National Accreditation Body (RvA for the Netherlands).