The use of magnetic beads coated with soluble HLA class I or class II proteins in antibody screening and for specificity determinations of donor-reactive antibodies.

An adequate method that will permit rapid specificity determination of donor reactive antibodies is urgently needed. Such a method could also be used for monitoring the presence of HLA antibodies in panel scanning. We here describe a method using magnetic beads coated with soluble HLA antigens that can be directly added to patient serum for efficient absorption of HLA antibodies. The entire procedure takes 45 min, and can therefore be easily adopted for use in acute crossmatching situations. Furthermore since no live cells are required for identification of alloantibodies in the screening for HLA specific panel-reactive antibodies, it can be used as an ideal complement for screening of panel-reactive antibodies. Binding of antibodies to the antigen-coated beads is easily visualized using flow cytometry. A new method for quick purification of soluble MA antigens from a pool of lymphocytes or thrombocytes is also presented.