HLA presents the major genetic barrier to stem cell transplantation. However evidence that other genetic systems are involved includes GvHD and some degree of rejection even when transplanting with HLA identical siblings. A non HLA system which is thought to contribute to this is the minor histocompatibility antigen (mHA) system. Minor histocompatibility antigens comprise of peptides derived from proteins in which some degree of polymorphism exists such there may be differences between the patient and donor repertoires. These peptides can be presented to the immune system by both HLA class I and II antigens.
The best characterised minor antigens are the Y chromosome derived HY peptide and the autosomal HA1 to HA5 peptides. Minor histocompatibility antigens such as HA1 and HA2 have restricted tissue distribution and are present normally only on haematopoietic cells. Others such as HY are more ubiquitously distributed, expressed for instance on gut epithelium. HA1 and HA2 are expressed on leukaemic cells and some tumour cells, making them potential targets for cellular therapy. Minor HLA antigens are restricted by certain HLA types such as HLA-A2 for instance.
- You get all the content of this website in one easy to read pdf format
- You get a list of over 300 references in H&I
- You have access to all the articles even when offline
- You can print at your leisure
- You get pull out tables summarising disease associations
- Finally you will be making a valuable contribution to the upkeep of this site.