Immunogenetic selection of donors for haematopoietic stem cell transplantation: an approach

Histocompatibility between the patient and his donor is a prerequisite for the success of transplantation of haematopoietic stem cells (HSCT). Histocompatibility testing is clinically performed by HLA typing. HLA typing can be highly informative if performed in families. In this case, comparatively little typing effort often allows to predict the identity of whole HLA haplotypes. HLA typing becomes more demanding, however, if unrelated individuals have to be considered as donors. Given the huge diversity of HLA molecules the answer to the question, whether patient and donor possess 'matched' HLA types requires considerable typing effort. Interaction between the HLA typing laboratory and the clinician is highly needed. It has to be agreed upon what loci are considered relevant and what degree of resolution is necessary. Furthermore, a strategy has to be developed, which ensures that a maximum of potential donors are tested in a reasonable time frame avoiding at the same time a work-overload of the laboratory and an excessive uneconomical typing effort. At present, experience with HSCT with unrelated donors is limited. So there is no consent on the 'correct' way of choosing unrelated donors. Each transplantation centre will have its own characteristic needs, resources, manpower and skills; therefore, the ways vary between centres. I want to present the approach in Vienna.