Complement-dependent cytotoxicity/CDC crossmatch testing has been an important assay in histocompatibility/tissue typing laboratories to establish graft and host compatibility. At its most basic concept, the cytotoxic crossmathc seeks to address the question: "Does a recipient have alloantibodies against an allograft that may lead to graft rejection and/or dysfunction?"
Except in syngeneic cases, donor grafts will have varying degrees of antigen mismatch compared with patient/recipient. This mismatch can result in sensitization following transplantation. Alloantibodies against the HLA antigens, the human major histocompatibility complex, are the most important alloantibodies associated with graft rejection and dysfunction.
The traditional method performed by Histocompatibility/Tissue Typing/HLA laboratories to detect donor-specific alloantibodies(DSA) is the complement dependent cytotoxicity/CDC assay. The basic CDC crossmatch is performed by isolating donor cells(usually lymphocytes from peripheral blood, spleen or lymph node) and exposing donor cells to recipient serum with the addition of exogenous complement. When DSA are present in patient serum,these antibodies can bind HLA molecules expressed by donor lymphocytes. If DSA are complement-fixing isotype(s) and are present in sufficient titer, donor lymphocytes then undergo complement-mediated damage and death.
Peña J R, et al. (2013). Complement-dependent cytotoxicity crossmatch. Transplantation Immunology: Methods and Protocols, 257-283.