Comparison of immunogenicity of fresh and stored blood. A study in rhesus monkeys

Lack of significant de novo HLA allosensitization in ventricular assist device recipients transfused with leukoreduced, ABO identical blood products

Ventricular assist devices provide support for a failing heart and often serve as a bridge to transplantation. The use of these devices has also been associated with allosensitization to HLA antigens because of transfusion of blood products. Our program established a protocol mandating the use of leukoreduced, irradiated and ABO identical products, including platelets, in patients receiving initial implantations of VADs as a bridge to transplantation. Recipients were tested for anti-HLA antibodies before VAD implantation and monthly post-implantation by cytotoxicity and solid phase assays. We observed minimal de novo anti-HLA sensitization (<10%) in this population of 55 patients, each receiving a mean of 90 blood components, using this approach. No patient developed broad sensitization (PRA>50%). In conclusion, The use of leukoreduced, irradiated, ABO identical blood products abrogates broad allosensitization in this highly transfused population.

Stored blood--an effective immunosuppressive method for transplantation of kidneys from unrelated donors. An 11-year follow-up

Thirty-seven patients were submitted to kidney transplantation after transfusion at 2-week intervals with 4-week stored blood from their potential donors. All patients and donors were typed for HLA-A-B and DR antigens. The patients were also tested for cytotoxic antibodies against donor antigens before each transfusion. The percentage of panel reactive antibodies (PRA) was determined against a selected panel of 30 cell donors before and after the transfusions. The patients were immunosuppressed with azathioprine and prednisone. Rejection crises were treated with methylprednisolone. The control group consisted of 23 patients who received grafts from an unrelated donor but who did not receive donor-specific pretransplant blood transfusion. The incidence and reversibility of rejection episodes, allograft loss caused by rejection, and patient and graft survival rates were determined for both groups. Non-parametric methods (chi-square and Fisher tests) were used for statistical analysis, with the level of significance set at P < 0.05. The incidence and reversibility of rejection crises during the first 60 post-transplant days did not differ significantly between groups. The actuarial graft and patient survival rates at five years were 56% and 77%, respectively, for the treated group and 39.8% and 57.5% for the control group. Graft loss due to rejection was significantly higher in the untreated group (P = 0.0026) which also required more intense immunosuppression (P = 0.0001). We conclude that transfusions using stored blood have the immunosuppressive effect of fresh blood transfusions without the risk of provoking a widespread formation of antibodies. In addition, this method permits a reduction of the immunosuppressive drugs during the process without impairing the adequate functioning of the renal graft.

Leucocyte and platelet-derived bioactive substances in stored blood: effect of prestorage leucocyte filtration

Adverse reactions to transfusion of allogeneic blood may depend on content of leucocytes and platelets and on storage-time of the erythrocyte suspensions. Therefore, we studied the efficacy of prestorage leucocyte reduction by filtration on total content and extracellular accumulation of histamine, eosinophil cationic protein (ECP), eosinophil protein X (EPX), myeloperoxidase (MPO), plasminogen activator inhibitor type-1 (PAI-1) and interleukin-6 (IL-6) in samples obtained from 5 units of SAGM blood, 7 units of plasma-reduced whole-blood and 6 units of whole-blood before and after filtration, respectively. In addition, we analysed supernatants from the same units after storage at +4 degrees C for 0, 21 and 35 d, respectively. The filtration was performed at room temperature within 2-4 h after donation. The substances were analysed by ELISA and RIA methods and we also analysed the donor plasma levels of the same bioactive substances. The total content of histamine, ECP, EPX, and MPO were 10-70-fold higher in all unfiltered erythrocyte products compared to donor plasma concentrations, while PAI-1 content was 15-20-fold higher only in plasma-reduced whole-blood and whole-blood. Prestorage leucocyte filtration significantly reduced the total histamine, ECP, EPX, MPO and PAI-1 content to levels similar to donor plasma levels in plasma-reduced whole-blood and whole-blood, while PAI-1 was still low in filtered SAGM blood. In addition, the levels of extracellular bioactive substances at d 0 after donation and filtration were within the range of concentrations in donor plasma, and there was no time-dependent accumulation during storage for 35 d at +4 degrees C. IL-6 was not detected in either plasma or samples obtained from the blood bags. These results suggest prestorage leucocyte filtration to deplete leucocyte contents to levels, which prevent the previously shown time-dependent accumulation of leucocyte derived bioactive substances in various erythrocyte suspensions. In addition, the PAI-1 results suggest leucocyte filters to reduce the obligatory platelet content in whole-blood products.

Lymphocytotoxic donor-specific response to fresh and stored blood. An experiment in immunosuppressed rhesus monkies (brief communication)

Transfusion of stored blood has been found to decrease the rate of antibody formation. Antigen immunogenicity and the recipient's immunoresponsiveness have a major role in the fate of the allograft. The combined effect of low immunogenicity and depressed responsiveness has been studied.

Facilitation of skin allograft survival by blood leucocyte extracts. A possible mechanism for the beneficial effects of blood transfusion in human transplantation

Fresh and frozen-stored mitochondrial, microsomal, and endoplasmic reticulum extracts of blood leucocytes act as potent alloantigens in human recipients. Similar results were obtained with freshly prepared extracts consisting of mixtures of all cytoplasmic fractions; storage of such mixtures at--20 C, followed by 1-2 hr thawing at 37 C abrogated their capacity to induce allograft sensitivity in 45 of 47 recipients. Donor-specific skin allografts and grafts from other sources exhibited significant attenuations in the tempo and intensity of rejection, ranging from first-set rejection to chronic rejection and/or to prolongations in allograft survival. In contrast with the 66.2% rejection rate of first-set skin grafts at 10 days in 71 normal subjects, only 29% of skin grafts from the leucocyte donor applied to 24 recipients of 0.1 to 9 Transplantation Antigen (T.A.) units of pooled cytoplasmic mixtures were rejected by that time. Only 17.4% similar grafts in 23 recipients of 25 to 515 T.A. units were rejected at 10 days. Seventeen skin grafts placed on recipients of 45 to 140 T.A. units of the same cytoplasmic preparation exhibited a slow rejection characterized by progressive shrinkage and eventual disappearance, with no evidence of hemorrhagic necrosis (chronic skin graft rejection). These results support the possibility that the attenuations in allograft reactivity observed in patients with end-stage renal disease after blood transfusions may be related to the leucocyte components of such transfusions. The capacity of blood transfusions to decrease reactivity to renal allografts in uremic patients maintained on hemodialysis stands in contrast with the ability of such transfusions to sensitize normal human recipients to donor-specific skin allografts. The differential effect may be related to the immunosuppressed state(s) documented in the uremic population, and/or the use of immunosuppressive drug therapy in such patients at the time of transplantation and thereafter.