Pretransplant Immunosuppression Research Articles

Failure to prolong pancreatic islet allograft survival in rats with donor-specific blood transfusions and immunosuppression.

The effects on pancreatic islet allograft survival of donor-specific blood transfusions (DST) in combination with pre- and posttransplant immunosuppression were studied. A total of 12 groups of rats (n = 105) with chemically induced diabetes underwent islet allotransplantation. Multiple DST or third-party blood transfusions (TPT) were given prior to transplantation. Pretransplant immunosuppression consisted of azathioprine and prednisolone, and low-dose cyclosporin A was used for posttransplant immunosuppression. TPT, as well as separate or combined pre- and posttransplant immunosuppression without blood transfusions, did not prolong islet allograft survival. DST resulted in either primary nonfunction of the islet allografts or a markedly decreased islet allograft survival. These findings contrast with the beneficial effect of DST on whole-organ allograft survival in rats previously described by others.

Failure to prolong pancreatic islet allograft survival in rats with donor-specific blood transfusions and immunosuppression

Abstract. The effects on pancreatic islet allograft survival of donor-specific blood transfusions (DST) in combination with pre-and posttransplant immunosuppression were studied. A total of 12 groups of rats (n= 105) with chemically induced diabetes underwent islet allotransplantation. Multiple DST or third-party blood transfusions (TPT) were given prior to transplantation. Pretransplant immunosuppression consisted of azathioprine and prednisolone, and low-dose cyclosporin A was used for posttransplant immunosuppression. TPT, as well as separate or combined pre-and posttransplant immunosuppression without blood transfusions, did not prolong islet allograft survival. DST resulted in either primary nonfunction of the islet allografts or a markedly decreased islet allograft survival. These findings contrast with the beneficial effect of DST on whole-organ allograft survival in rats previously described by others.

Development of immunity in human severe primary T cell deficiency following haploidentical bone marrow stem cell transplantation.

Recent advances in the prevention of graft-vs-host disease (GVHD) have allowed the use of haploidentical bone marrow cells for correction of lethal genetic defects of the immune system. Sequential analyses of blood lymphocyte phenotypes and functions were done before and after transplantation of haploidentical marrow stem cells into 17 infants with severe primary T cell deficiencies. The marrow was depleted of post-thymic T cells and most other mature marrow cells by soy lectin agglutination and sheep erythrocyte rosetting. The studies were performed to define the time course and extent of appearance of immune function, and to identify factors leading to resistance to engraftment. No pretransplant immunosuppression was used. T cell function was detected between 34 and 287 days after transplantation, but a sharp rise usually occurred between 84 and 115 days, and normal function was reached between 113 and 210 days. Fifteen of the patients are alive from 6 to 41 mo post-transplantation, 12 have improved or have normal T lymphocyte function, and nine have proven T cell chimerism. Increased immunoglobulins of several isotypes have been noted in 11 patients and specific antibodies in seven patients, although B cell chimerism has been detected in only one patient. B cell function required 2 to 2.5 yr for normalization. No GVHD occurred in 14 patients, and the other three had only transient mild skin rashes. Two patients died of viral infections. Failure to engraft was correlated with some pre-transplant lymphocyte responses to mitogens and allogeneic cells (three cases), but not with the presence of pre-transplant natural killer cell function (five cases) nor with the presence of purine salvage pathway enzyme deficiencies (four cases). The latter, however, was associated with poor lymphoid function in two patients. These studies indicate that the thymic microenvironment of most infants with severe combined immunodeficiency disease is capable of differentiating donor stem cells to mature and functioning T lymphocytes which can cooperate with apparently normal host B cells for antibody production.

Cadaver renal transplantation ignoring peak-reactive sera in patients with markedly decreasing pretransplant sensitization.

A review of more than 3000 cadaver donor renal allograft recipients transplanted between June 1977 and July 1982 as part of the South-Eastern Organ Procurement Foundation (SEOPF) Prospective Study was performed to identify patients who received a transplant following a significant decrease in pretransplant sensitization as measured by the percentage of panel-reactive antibody (PRA). Such patients were identified as having had a most reactive (historical peak sera) PRA level at least 40 percentage points higher than their last sample tested prior to transplant (current sera). Additional data were obtained on 157 of these patients, who also had no history of pretransplant immunosuppression and had a negative pretransplant crossmatch with current sera. Data included the dates of pretransplant sera samples, the specific techniques used for each serum sample that was crossmatched or screened for PRA, and the serological results. The population studied included 17 of 87 first-transplant recipients and 17 of 70 regrafted recipients whose pretransplant crossmatches with peak sera were positive or not done. These subgroups showed no decrease in graft or patient survival compared with cohorts (70/87 first-transplant recipients and 53/70 regrafted recipients) for whom peak sera crossmatching was performed with negative results. Additional stratification for the techniques used in crossmatching and screening, as well as the interval between peak and current PRA levels, showed no significant associations with eventual graft or patient outcome. These results suggest that crossmatch testing using peak sera may not be important in predicting eventual graft or patient outcome for patients with a marked decrease in PRA prior to transplantation and a negative crossmatch with current sera.

MARROW TRANSPLANTATION FOR RETICULAR DYSGENESIS RESULTING IN IMMUNOLOGIC RECONSTITUTION WITHOUT MYELOID RECONSTITUTION

Reticular dysgenesis is a rare syndrome characterized by combined immunodeficiency and neutropenia. We have cared for a child, whose sister died of overwhelming sepsis at 2 months of age, who was referred for neutropenia. Further work-up revealed a severe combined immunodeficiency. The patient had evidence of excessive suppressor cell activity as detected in both mixed lymphocyte cultures and an assay designed to measure in vitro immunoglobulin synthesis. He had circulating T cells that bore the maternal HLA haplotype. He was treated without pre-transplant immunosuppression by allogenic marrow transplantation from his histocompatible 5 yr old nonaffected sister. Within one week the maternal T cell haplotype was no longer detectable. Excessive suppressor cell activity was not detectable by 3 weeks. There was significant improvement in his immune function as early as one month (PHA stimulation index 2.7 → 143; serum IgG 134 mg/dl → 512 mg/dl). However the patient has remained neutropenic with a maximum neutrophil count of 0.3 × 109/1. Cytogenetic analysis revealed an xx karotype in peripheral blood and an xy karotype in marrow chromosomes. Six months post transplant he is developing normally without infection. Marrow transplantation without preparation can restore immune function but additional immunosuppression may be necessary for complete myeloid reconstitution.