Studies on the Control of Hyperacute Rejection in Hyperimmunized Rat: Combination of Donor Specific Blood Transfusion (DST) and Immunosuppressive Drugs

In order to decrease preformed cytotoxic antibodies, which are the main cause of hyper-acute rejection, donor specific blood transfusion (hereafter designated as DST) was performed. Immunosuppressants were administered at the same time to examine whether the combined treatment with DST can inhibit rapid reproduction of antibodies in the serum of a sensitized recipient.
Hyper immunized Fischer rat recipients were used as experimental models. Blood of ACI rat was transfused to the recipients as DST. Beta-methosone and Anti-lymphocyte serum (hereafter designated as ALS) were given as immuno suppressive drugs combined with DST.
The heart of ACI rat was transplanted to the hyperimmunized Fischer recipent treated as described above. The cardiac graft survival time was observed and the change in cytotoxic antibody titer of the recipient was determined with the elapse of time.
Performed cytotoxic antibodies formed by hyperimmunization were adsorbed or diminished, by DST, and the heart graft survivied for about 54 hr in the group treated with DST, while it was hyperacutely rejected after about 0.4 hr in controls.
However, DST was effective only when it was performed once. Transfusion after that acted as a booster, inducing reproduction of anti T-cell warm cytotoxic antibody (CA-TW). Therefore repeated transfusion was thought to be contraindication.
Beta-methasone or ALS were administered after adsorption of antibodies by DST in order to prevent antibodies from being rapidly formed again in the serum of a sensitized recipient. The suppressive effect was greatest in the group treated with combination of DST and ALS, and the heart graft survivied for 94 hr. In this group, the pattern of rejection was not hyperacute rejection but acute to accerelated one. It wa revealed that hyperacute rejection can be depressed to some extent.