Abstract
There are more opportunities to perform human leukocyte antigen (HLA) -haploidentical stem cell transplantation and cord blood transplantation, and such procedures have become quicker. Since the management of infection and graft-versus-host disease (GVHD) has recently improved, the number of HLA-mismatched transplantations has increased. The HLA-Flow method detects mismatched HLA antigens between donor and recipient using specific anti-HLA antibodies, and analyzes mixed chimerism by flow cytometry. When recipient-derived cells are detected, their cell surface markers can be analyzed. Therefore, the HLA-Flow method is very valuable in early diagnosis of engraftment failure and relapse of leukemia, and in monitoring the number of tumor cells in a rapid and convenient manner. Loss of mismatched HLA in leukemia cells can be estimated using the combination of donor-specific HLA markers and leukemia markers. Since the HLA-Flow method provides a way of detecting chimerism at a high accuracy and high sensitivity, detection of microchimerism in peripheral blood after organ transplantation has become possible. If anti-HLA IgG-isotype antibodies with high affinity can be produced instead of commercially available IgM antibodies with low affinity, the HLA-Flow method is expected to become more prevalent.
