Cryofiltration for removal of anti-blood group antibody in ABO-incompatible kidney transplantation

ABO-incompatible kidney transplantations have been performed in recent years in an effort to overcome the limited number of cadaveric kidney donors. In such cases, a double filtration plasmapheresis is usually required to decrease both IgG and IgM anti-blood antibodies to at least 8x or less. However, incomplete elimination of antibodies often causes renal allografts to be high risk. In this study, we tried cryofiltration (CRYO) in an ABO-incompatible renal transplant patient. The donor was a 56-year-old father with A blood-type. CRYO was introduced three times before transplantation to a 29-year-old man with B blood-type in order to reduce anti-A antibodies. Initial IgM and IgG titers were 128x and negative, respectively. The CRYO system consisted of a plasma separator (Plasmaflo OP-05, Asahi medial Co., 0.3 mu m), a cooling chamber and a plasma filter (Cascadeflo AC-1740, Asahi medial Co., 0.02 mu m). The separated heparinized plasma was cooled down to 1.7 degrees C and filtered as cryogel through the second filter. Eight to nine liters of plasma were immunoadsorbed in one run. Tacrolimus, azathioprine, methlprednisolone and anti-lymphocyte globulin were used as an initial immunosuppression. IgM anti-A antibodies were remarkably reduced to 2x after the final CRYO. Serum C3 and ACH50 were lowered until nearly trace level. Although hypoproteinemia was observed after CRYO, it recovered within a day by supplying with cryopreserved plasma. Postoperative clinical coures was satisfactory with a decreased in serum creatinine level to 1.4 mg/dl on 2 days after transplantation and no evidence of rejection, in spite of prompt recovery of IgM anti-A antibodies to 128x observed 8 days later. In the current case, we used CRYO as a new approach for immuno-adsorpton, showing that the IgM anti-A antibodies were dramatically reduced. Neither hyperacute rejection nor accelerated rejection was observed by the depletion of antibodies and complements. In conclusion, CRYO for the removal of the anti blood antibodies in kidney grafted patients with major ABO-incompatibility is useful.