The influence of removing passenger cells on the fate of skin and parathyroid allografts. Evidence for major histocompatibility complex restriction in transplantation immunity

Studies with mice on the survival of skin grafts incompatible with respect to the histocompatibiiity-Y transplantation antigen or to skin-specific antigens, as well as studies with rats on the fate of cultured parathyroid allografts, provide evidence for major histocompatibility restriction in transplantation immunity. If confirmed, these studies indicate that islet allografts devoid of passenger leukocytes might survive better in major histocompatibility complex incompatible recipients.

Transplantation of islets and bone marrow cells to animals with immune insulitis

The results of islet transplantation in an animal model of spontaneous immune insulitis were studied to see whether this disease process might damage transplanted tissue. Since the insulitis occurs only in "BB" rats (which are not genetically uniform) syngeneic grafts could not be used, therefore allograft rejection was avoided by rendering "BB" rats tolerant of WF transplantation antigens by inoculating them neonatally with WF bone marrow cells. Despite the resultant tolerant state, which permitted successful engraftment of WF skin and islets transplanted to artificially diabetic "BB" rats, tolerant "BB" rats with spontaneous diabetes accepted transplanted WF islets only briefly before they were destroyed by immune insulitis. "BB" rats were found to have abnormalities in immune response (delayed skin graft rejection and decreased alloreactivity in mixed lymphocyte response). "BB" rats that were treated neonatally with WF bone marrow. Moreover, "BB" rats inoculated with WF bone marrow neonatally were found less likely to become diabetic than untreated "BB" controls. It is suggested that the chimeric state (persistence of WF bone marrow cells) may be responsible for the improved immune response and perhaps for the decreased susceptibility to diabetes.

Evidence for major histocompatibility complex restriction in transplantation immunity

Studies on the survival of histocompatibility-Y antigen (H-Y)-incompatible and skin-specific antigen (Skn)-incompatible skin grafts in mice, as well as those concerned with the survival of cultured parathyroid allografts in rats, indicate that grafts provoke a strong immune response only if they include donor macrophages (or Langerhans cells) or if major histocompatibility complex-compatible macrophages are available to react with cells bearing the foreign antigens.

Spontaneous diabetes in rats: destruction of islets is prevented by immunological tolerance

Spontaneous diabetes occurring in "BB" rats (derived from a colony of outbred Wistar rats) is the result of destruction of pancreatic islets by infiltrating mononuclear cells (insulitis) and may be a disease very similar to human juvenile onset diabetes. Both diseases probably have an autoimmune etiology. Evidence is presented that islets transplanted to diabetic BB rats are destroyed by the original disease process. Inoculation of bone marrow from normal (nondiabetes-susceptible) rat donors into neonatal BB recipients usually prevented the development of hyperglycemia.

Immunologic problems in islet transplantation

Rapid rejection of islet allografts is due to both cellular and antibody mechanisms. Isolated islets transplanted intraportally across a major histocompatibility complex (MHC) barrier in rats are rejected in 3–5 days. However, with MHC identity, the median survival time can be as long as 30.5 days. In mice, isolated islets transplanted between H-2-compatible strains survive no more than 1 wk, only a few days more than with an H-2-incompatible cross. In addition, in certain strains of rats and mice, islet isografts from male donors are rejected by female recipients. Fetal pancreases transplanted beneath the kidney capsule (Lewis to Fisher) are rapidly rejected by 4 days, although long-established grafts of fetal pancreas are not vulnerable to rejection in contrast to adult islets. Minimizing histoincompatibility has been unsuccessful in overcoming rejection because of the universal vulnerability of transplanted islets, and attempts to minimize immunogenicity by use of fetal tissue have not prevented rejection; however, culture of donor tissue may prove helpful in reducing immunogenicity. Transplantation of islet tissue into immunologically privileged sites has not resulted in reliable reversal of diabetes. immunosuppression by pharmacologie agents such as cyclophosphamide, azathioprine, and corticosteroids was of minor effectiveness, but antilymphocytic serum was quite effective in rodents, even on xeno-grafts when the injections were continued. Immunologic tolerance produced at birth by donor lymphopoietic cells permits later engraftment of isolated donor islets or whole pancreas. However, enhancement by anti-donor antibody has not been greatly effective in protecting islets against rejection. The possibility that autoimmunity to islet tissue might interfere with the function of transplanted islets was tested in three types of possible autoimmunity: (1) repeated small doses of streptozotocin, (2) encephalomyocarditis virus, and (3) “BB” rats. In all three cases, transplanted islets were effective in reversing experimental diabetes.

Successful islet transplantation in spontaneous diabetes

Optimism for islet transplantation is based on reversal of diabetes artificially induced in animals by pancreatectomy or beta cell toxins. In naturally occurring diabetes, implanted islets might be destroyed by the etiologic agent of the original disease; e.g., virus infection, genetic factors, or autoimmunity. Genetically determined diabetes in obese mice, in fact, is resistant to islet transplantation. Since these mice are hyperinsulinemic and not similar to human juvenile onset diabetes (JOD), more appropriate models were sought, "BB" rats spontaneously develop a syndrome remarkably similar to human JOD. We have studied 279 BB rats. In 31 rats the sudden onset of severe hyperglycemia was observed. Sinc BB rats proved to be AgB2 on serological typing, WF (AgB2) donors were selected. Six hundred Wistar-Furth isolated islets were transplanted intraportally in 10 BB diabetic rats immunosuppressed with antilymphocyte serum. All 10 recipients became normoglycemic, remaining so for 1 to 6 monts. An additional animal model studied was virus-induced diabetes in mice, since viral etiology of human diabetes seems likely. DBA mice receiving encephalomyocarditis virus became severely and persistently diabetic. Eight received syngeneic fetal pancreas to the renal subcapsule and became normoglycemic. Removal of the graft 30 days later demonstrated viable islets histologically and resulted in recurrent diabetes. That virally induced murine diabetes and one spontaneous syndrome in rats which is similar to human JOD responded to beta cell implantation argues that this treatment will be effective in man.

Results of 100 consecutive femoropopliteal vein grafts for limb salvage

One hundred consecutive patients with femoropopliteal autogenous vein grafts for limb salvage were reviewed five years later. In this group 40% died and 30% of the limbs had been lost at the end of five years. Limb survival correlated best with adequacy of distal run-off, but not with the presence or absence of diabetes. Forty-seven per cent of the grafts were still patent among surviving patients, and when combined with the limbs that were viable despite failure of the original graft, 70% of the limbs were salvaged among the survivors at five years. Temporary graft patency was effective in preserving ischemic tissue by facilitating healing of ulcers or limited amputations. Femoral-popliteal bypass grafting in the presence of advanced ischemia is capable of improving the quality of life for many of these patients.

Disseminated mycobacterium kansasii infection presenting as cellulitis in a recipient of a renal homograft

A recipient of a renal homograft developed disseminated infection caused by Mycobacterium kansaii. He initially presented with cellulitis and abscesses in one foot, and was thought to have a pyogenic bacterial infection. The daily administration of prednisone and azathioprine appears to have prevented the typical cell-mediated granulomatous reaction to mycobacterial infection and to have contributed to the patient's atypical inflammatory response. A switch to alternate-day prednisone combined with antimycobacterial medication resulted in rapid healing without rejection of the homograft.

Renal transplantation at the University of Pennsylvania Medical Center: an update of results in the cyclosporine era

This chapter presents a summary of living-related, living-unrelated, and cadaver renal transplantation performed at the University of Pennsylvania Medical Center between January 1984 and October 1992. Over the past 9 years, 895 patients (557 males, 338 females, mean age 42 yrs) received 942 renal transplants; 599 patients received kidneys from cadaver donors (n = 627) and 296 patients received kidneys (n = 315) from living donors of all types. During this period, 151 patients were retransplanted, sometimes more than once (159 total retransplants, 124 secondary grafts, and 35 third or more transplants). An analysis of patient ant graft survival rates (calculated by actuarial methods) for different categories of transplant recipients was performed. Black recipients, as a racial subcategory, had the poorest graft outcome, especially when followed over the long term. Graft survival rates for Black recipients who were retransplanted with cadaver grafts were even worse and were noted to be similar to the diabetic population that received cadaver retransplants (66% vs 62% at 1 yr and 32% vs 25% at 5 yrs). Diabetic recipients of living-donor transplants had excellent graft survival results, similar to nondiabetic, living-donor recipients (patient survival rates 98% and 92% vs 97% and 92% at 1 and 5 yrs; graft survival rates 92% and 82% vs 92% and 82% at 1 and 5 yrs). HLA-identical recipients of first cadaver grafts demonstrated the best outcome in the entire cadaver series (graft survival rates 91% and 83% at 1 and 5 yrs, respectively). HLA-identical recipients of second or more cadaver grafts had poorer results than expected (50% graft survival at 1 yr) despite a 100% patient survival rate. HLA-identical recipients of living-related grafts had the best graft survival rates (96% at 1 yr and 94% at 5 yrs) and superior graft survival rates for retransplanted grafts as well (100% at 1 and 5 yrs). We conclude that in the last decade, patient and graft survival rates for cadaveric and living-donor renal transplants have improved dramatically relative to the results obtained in the pre-CsA era. Long-term graft survival in Black recipients remains lower than in other races, suggesting the need to analyze other factors to explain poorer graft survival in this recipient population. Results in diabetic recipients continue to be excellent at our center, encouraging the continuation of our aggressive approach to try to transplant diabetics as early as possible, particularly when a living donor is available.