Clinical relevance of minor histocompatibility antigens

Objective: The minor histocompatibility antigens (MiHA) are epitopes composed of polymorphic essential peptides evoking alloimmune responses limited to a variety of human leukocyte antigen (HLA) alleles. These peptides are allelic cellular proteins and encoded by autosomal genes or by genes of the Y chromosome. MiHAs may be immunogenic or nonimmunogenic in characteristic. They are either ubiquitously expressed in many cells and tissues or restricted to the hematopoietic system cells. Some of these MiHA can also be expressed by tumor cells. Upon hematopoietic stem cell transplantation (HSCT) for hematological malignancies responses to MiHA may develop as graft-versus-host-disease or graft rejection, but can also contribute to the eradication of the tumor cells named graft-versus.-leukemia effect. Our aim was to determine the MiHA distribution in Turkish healthy population and in patients with hematopoietic malignancies whereas some of them were genotypically identical HSCT recipient/donor pair.