328. Mechanismen der langzeitakzeptanz allogener rattenlebertransplantate: makrophagenaustausch und suppressorzellaktivierung

Summary After orthotopic rat liver transplantation in the fully allogeneic BN (RT-1n) to LEW (RT-11) combination, the phenomenon of spontaneous tolerance of donor antigen occurs. We demonstrate two different immune mechanisms that may account for this process. Using adoptive transfer assays we show the presence of donor-specific T-suppressor lymphocytes in the spleens of long-term surviving liver graft, recipients. These cells prolong - adoptively transferred into irradiated syngeneic hosts — the survival of donor-specific (BN) but not third-party (DA) renal allografts (I00 days vs 1I days in control groups). Secondly, we demonstrate the replacement of Kupffer cells in the graft by recipient macrophages using polymorphic monoclonal antibodies in an immunoperoxidase technique. This may contribute to graft adaptation and thus to long-term graft acceptance.     

Prolongation of small bowel allograft survival with a sequential therapy consisting of a synthetic MHC class II peptide and temporarily low-dose cyclosporine A

It has been extensively documented the role of the indirect pathway of allorecognition in allograft rejection. However, recent data demonstrate that the manipulation of this pathway could be also sufficient to promote prolongation of allograft survival. In the present study we evaluated the effect of preoperative immunization with the WF-specific MHC class II peptides RT1.D2 and RT1.B2 in combination with low-dose CsA from days 0 to 7 (5 mg/kg/day) and from days 8 to 30 (1 mg/kg/day) after WF small bowel transplantation. Seven days before and on the day of transplantation, LEW recipients were immunized with the two WF MHC class II peptides RT1.B2 and RT1.D2. The CsA monotherapy induced an allograft survival of 49.3 +/- 6.1 days. MHC class II peptide immunization had a limited effect on allograft survival for RT1.D2 (47.1 +/- 3.8 days) and induced prolongation of allograft survival for RT1.B2 (73.6 +/- 34.6 days). This effect seems to be based on the absence or silence of RT1.B2-reactive T cells and rejection seems to be correlated with the presence of RT1.B2-specific T cells in the late phase. Therefore, the combination of RT1.B2 with low-dose CsA shifts the immunological response and protects small bowel allograft rejection.     

Chemical Characterization of Macrophage Cytotoxicity Factor,Macrophage Migration Inhibitory Factor,T-Helper Cell-Replacing Factor and Colony-Stimulating Factor from Culture Supernatants of Concanavalin A-Stimulated Murine Spleen Cells

Supernatants from Concanavalin A-stimulated murine spleen cells were subjected to hydrophobic interaction chromatography on phenyl-Sepharose. Macrophage cytotoxicity factor (MCF), macrophage migration inhibitory factor (MIF), T-helper cell-replacing factor (TRF) and colony-stimulating factor (CSF) were bound at high ionic strength and were released stepwise at low ionic strength. CSF thus could be separated from MCF, MIF and TRF and the bulk of other proteins. Chromatography of pools containing MCF, MIF and TRF on Sephadex did not lead to a separation of the three activities which were all found in a molecular weight range of 25.000-55.000. Isoelectric focusing of these pools in pH range from 4 to 9 gave two peaks for MCF at pH 8.2 and 7.2, whereas MIF activity focused from pH 4.5 to 5.5. TRF activity was found in a single sharp peak at pH 5.3. The results demonstrate that the four biological activities can be distinguished on a chemical basis and are accessible for purification and chemical characterization.     

Hemolytic anemia and hexokinase deficiency associated with malformations

Summary Hexokinase deficiency in the red cells caused a hemolytic anemia in a 28 y. old woman who revealed multiple malformations and a latent diabetes mellitus.Supported by Deutsche Forschungsgemeinschaft (Grant Go 236/2).     

Myocardial-infarction after adjuvant chemotherapy for resected stage-ii nonseminomatous testicular cancer

Although acute toxicity of cisplatin-based chemotherapy of germ cell tumors is considerable, major vascular complications have been reported infrequently. This report describes the case of a 36-year-old man developing myocardial infarction after the first cycle of adjuvant cisplatin-based chemotherapy for resected stage II testicular cancer. A close temporal association between the administration of chemotherapy and the vascular event suggests a cause and effect relationship. A drug-induced endothelial cell damage may be an important pathogenetic factor. Although reports on vascular accidents following treatment of testicular cancer raise concern with regard to the safety of chemotherapy, at present the very low incidence of such complications should not enter into therapeutic decisions.     

Tolerance of rat liver allografts induced by short-term selective immunosuppression combining monoclonal antibodies directed against CD25 and CD54 with subtherapeutic cyclosporine

BACKGROUND: Our purpose was to develop and evaluate protocols for selective immunosuppression after liver transplantation using the monoclonal antibodies (mAbs) NDS-61, directed against the interleukin-2 receptor (CD25), and 1A29, directed against the intercellular adhesion molecule-1 (CD54), in combination with subtherapeutic cyclosporine (CsA). METHODS: Orthotopic rat liver transplantation (ORLT) was performed in a DA-to-LEW strain combination. Immunosuppression was administered from day 0 to +13. Functional parameters such as survival time, body weight, and serum bilirubin levels were measured and the liver grafts were evaluated histologically. RESULTS: A stepwise tapering of CsA from 3 to 0.25 mg/kg/day reduced the long-term survival rate. All animals died at a CsA dosage of 0.25 mg/kg/day, which was therefore defined as subtherapeutic. Monotherapy with the anti-CD25 mAb was performed at dosages of 600 and 1800 microg/kg/day. The lower mAb dosage resulted in a long-term survival rate of 12% and was defined as subtherapeutic. The combination therapy of CsA (0.25 mg/kg/day) and anti-CD25 mAb (600 microg/kg/day) produced a synergistic effect and led to a long-term survival rate of 84%. This survival rate was significantly higher than those after either CsA (P<0.005) or anti-CD25 mAb (P<0.001) monotherapy. Both dosages (10 and 30 microg/kg/day) of anti-CD54 mAb monotherapy as well as anti-CD54 mAb combined with a subtherapeutic dosage of CsA were ineffective in preventing acute allograft rejection. The addition of anti-CD54 mAb (30 microg/kg/day) to combined CsA plus anti-CD25 mAb therapy (triple therapy), however, increased the long-term survival rate to 100%. In the triple therapy group there was no rejection process in the liver allografts at any time, and donor-specific tolerance could be shown by donor-specific and third-party heterotopic heart transplantation. CONCLUSIONS: The synergistic action of subtherapeutic CsA plus anti-CD25 mAb NDS-60 could be demonstrated, whereas anti-CD54 mAb only had a positive effect in a triple therapy group. Triple therapy prevented both acute and chronic rejection and induced donor-specific tolerance.     

Endovascular therapy in combination with conventional vascular surgery for the treatment of peripheral arterial obliterative disease

INTRODUCTION: In a prospective trial we analysed the results and the management of complications following a combined endovascular and vascular surgical therapy of peripheral occlusive arterial disease (POAD). PATIENTS AND METHODS: From November 1998 until January 2001 a total number of 61 patients with 64 extremities were included in this study. By preoperative angiography 19 patients had stenoses at three levels, 42 patients suffered from stenoses at two levels. The iliac axis was recanalized by intraluminal angioplasty (ITA) plus stent placement under general anesthesia. Simultaneously an infrainguinal bypass reconstruction and a local thrombendarterectomy (TEA) rsp. were performed. Intra- and postoperative complications and the patency rates as assessed by colour doppler ultrasound and angiography were analysed. RESULTS: The rate of conversion from endovascular to conventional surgery was 12.5 %. In 56 cases the endovascular therapy of the iliac axis was successful. In 28 patients a distal bypass was implanted, in 25 patients a local TEA was performed. Intraoperatively 6 dissections (10.7 %) were noted, dislocation of stents were seen in 4 patients (7.1 %), perforations occurred in 2 patients (3.6 %). Both perforations and 5/6 dissections were detected intraoperatively and were treated by endovascular means without complications. The early postoperative patency rate was 98.2 %, the secondary patency rate was 100 % and the cumulative patency rate after two years was 98.2 %. DISCUSSION: ITA and stent placement in the iliac axis can be established quickly and safely by the vascular surgeon. Intraoperative complications can be managed by endovascular means in most cases. Stent dislocation is avoidable in most cases. The complication rate after such combined endovascular therapy and conventional vascular surgery is determined by the surgical but not the endovascular part. Excellent early results and low complication rates lead to the conclusion that endovascular therapy in combination with conventional vascular surgery seems to be a reasonable supplement to the therapeutic options for the treatment of POAD.