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Biomedical subjects

A G Diethelm

Publications and source records attributed to A G Diethelm.

At least 73 records · Page 4Linked to original sources

Donor antigen-specific immunosuppression in cadaveric and living-related donor kidney allograft recipients.

This is a review of the University of Alabama Hospital's clinical experience with 1-haplotype-mismatched LRD renal transplants, utilizing a stored-blood DST protocol and with cadaveric renal transplants utilizing DBM transfusion. Stored-blood DST does not significantly improve LRD allograft survival either in Aza-, P-, or CsA-treated patients, although there is a trend toward better survival in Aza/DST versus Aza/no-DST recipients (78% vs 84% 12-month allograft function). Importantly, although the early acute phase graft loss was slightly diminished by DST, the late phase loss (slope of curve) was essentially identical to nontransfused patients. Thus, we cannot demonstrate a beneficial effect by the use of DST in achieving improved long-term graft survival in recipients of 1-haplotype-matched recipients. The use of cryopreserved DBM transfusions in cadaveric allograft recipients, however, has resulted in significantly improved survival compared to control patients who received the marrow donor's contralateral kidney and similar immunosuppression without marrow infusion [92% vs 73% (p = 0.01)]. DBM-transfused patients demonstrate diminished donor-specific responsiveness in MLC compared with controls. P withdrawal can be accomplished safely in the majority of marrow recipients; however, this has not been tested in the controls. Donor-nucleated cells persist in the peripheral blood of some DBM-transfused patients for at least 2 years following transplantation. Presently, the significance of persistent chimerism in these patients with respect to donor responsiveness and allograft tolerance is unclear.

Azathioprine↗

Use of cryopreserved donor bone marrow in cadaver kidney allograft recipients.

Donor-specific unresponsiveness to organ allografts remains an elusive goal in clinical transplantation, as most successful experimental protocols for the production of antigen-specific immunosuppression require lengthy recipient pretreatment. The use of an induction course of antilymphocyte serum (ALS) beginning at the time of transplantation, followed by the transfusion to the recipient of donor-specific bone marrow, has been shown in animals to induce prolonged allograft survival and is applicable for use in cadaver donor clinical transplantation. Our preliminary data in humans suggest that the transfusion of cryopreserved cadaver donor bone marrow following a short course of ALS is safe and does not induce graft-versus-host disease or allograft rejection. Twenty patients have been included in the protocol and 19 have been discharged from the hospital with functioning kidney transplants. One graft failed at 3 months. Eight patients have been withdrawn entirely from prednisone immunosuppression 3-6 months following transplantation. The contralateral kidneys from the marrow donors were transplanted into an additional 20 patients who received sequential immunosuppressive therapy without marrow transfusion. Three of these grafts have failed within 3 months due to acute rejection. Donor marrow transfusion may give rise to improved allograft and patient survival in clinical transplantation while at the same time allow for reduced requirements for nonspecific immunosuppressive agents with their undesirable side effects.

Bone Marrow Transplantation↗

Successful renal allografts in recipients with crossmatch-positive, dithioerythritol-treated negative sera. Race, transplant history, and HLA-DR1 phenotype.

Graft survival was examined in 15 renal allograft recipients from a group of 20 patients with IgM autolymphocytotoxic antibody that could be removed in a crossmatch assay using a reducing agent, dithioerythritol (DTE). The significant differences in this group of 20 patients compared with end-stage renal disease (ESRD) patients lacking autolymphocytotoxic antibodies included an increased frequency of black patients (P = 0.002), a lack of previous transplants (P = 0.003), and an increased frequency of the HLA-DR1 phenotype (P = 0.0001). Sex and the number of transfusions did not appear significant, whereas the cause of ESRD was primarily systemic lupus erythematosus. Fifteen of the 20 patients were transplanted against a positive donor crossmatch. Eleven were recipients of cadaveric kidneys, nine of which are still functioning for periods ranging from 0.5 to 40 months. Two fo the cadaveric recipients died with functional grafts. Four received living-related donor transplants, one of which was lost to acute rejection one month posttransplant, while the remaining three have survived 1.5, 9, and 21 months, respectively. Fourteen patients had immediate allograft function with no hyperacute rejection and only one case of acute tubular necrosis (ATN) was found. In summary, a negative crossmatch using DTE-treated, autologous reactive recipient sera may identify a group of patients who can be transplanted with minimal concern for hyperacute rejection or ATN. In addition to cause of ESRD, race, transplant history, and HLA-DR phenotype may further define this group of transplant candidates having IgM autolymphocytotoxic antibody. Extrapolation of these conclusions to transplant candidates lacking autolymphocytotoxic antibodies is not warranted.

Absorption↗

Hypertension in cyclosporine-treated renal transplant recipients is sodium dependent.

PURPOSE: Physicians increasingly prescribe cyclosporine as an immunosuppressive agent for both organ-transplant and non-organ-transplant recipients. Investigators have reported a high incidence of drug-induced hypertension even when clinical nephrotoxicity was not present. We wanted to determine the reason. PATIENTS AND METHODS: A comparison was made of hypertension in 15 cyclosporine-treated transplant recipients with that in a similar group of 15 azathioprine-treated transplant recipients. RESULTS: Hypertension in the cyclosporine group responded differently from that seen in the azathioprine group and from previously described forms of post-transplantation hypertension. Hypertensive cyclosporine-treated patients show a sodium acquisitive renal state that responds to sodium restriction. Unlike rat models, which suggest cyclosporine-induced stimulation of the renin-angiotensin system, or previous forms of post-transplant hypertension in humans, plasma renin levels were not elevated and blood pressure did not respond to a test dose of captopril. CONCLUSION: Hypertension in cyclosporine-treated patients is an iatrogenic form of hypertension that may be associated with an early, subtle, renal defect in sodium excretion, a genesis of hypertension that is consistent with Guyton's view of essential hypertension.

Adult↗

A comparison of OKT3 monoclonal antibody and corticosteroids in the treatment of acute renal allograft rejection.

The monoclonal antibody OKT3 (Ortho Pharmaceutical, Raritan, NJ) was utilized in two separate protocols for treatment of acute renal allograft rejection in patients receiving cyclosporine, azathioprine, and prednisone for maintenance immunosuppression. In Group I, 54 patients received steroids for primary treatment of acute rejection with OKT3 used for resistant rejections and second rejection episodes. In Group II, 34 patients received OKT3 as primary treatment of acute rejection while steroids were used for rescue and second rejection episodes. OKT3 successfully reversed 82% of initial acute rejection episodes in Group II as compared with a 63% reversal with steroids in Group I. Rescue treatment was required in only 15% of Group II patients compared with 33% of Group I patients. Overall patient survival was 96% and 94%, respectively, for steroid primary and OKT3 primary treatments. Allograft survival at 3 months was identical, 74% in both groups. Based on allograft survival data, OKT3 is equally effective either as primary treatment for allograft rejection, or for rescue therapy if initial corticosteroid treatment fails.

Acute Disease↗

Important risk factors of allograft survival in cadaveric renal transplantation. A study of 426 patients.

Multiple risk factors contribute to the allograft survival of patients who have cadaveric renal transplantation. A retrospective review of 19 such factors in 426 patients identified race, DR match, B + DR match, number of transplants, and preservation time to have a significant influence. The parametric analysis confirmed the effect to be primarily in the early phase, i.e., first 6 months. All patients received cyclosporine with other methods of immunosuppression resulting in an overall 1-year graft survival rate of 66%. The overall 1-year graft survival rate in the white race was 73% and in the black race was 57% (p = 0.002). Allograft survival and DR match showed white recipients with a 1 DR match to have 75% survival at 1 year compared with 57% in the black patient (p = 0.009). If HLA B + DR match was considered, the white recipient allograft survival increased to 76%, 84%, and 88% for 1, 2, and 3 match kidneys by parametric analysis. Patients receiving first grafts had better graft survival (68%) than those undergoing retransplantation (58%) (p = 0.05). Organ preservation less than 12 hours influenced allograft survival with a 78% 1-year survival rate compared with 63% for kidneys with 12-18 hours of preservation. Despite the benefits of B + DR typing, short preservation time, and first transplants to the white recipient, the allograft survival in the black recipient remained uninfluenced by these parameters.

Adolescent↗