Some aspects of changed histopathologic appearance of acute rejection in cardiac allografts after prophylactic application of OKT3

The histopathologic findings of therapy-requiring acute rejection in the cardiac allograft observed in endomyocardial biopsy specimens taken from patients under prophylactic administration of OKT3 show certain differences in comparison with the classic description of acute rejection. These differences are characterized above all by a distinctly reduced cellularity of the infiltrates, with a relative decrease of T cells, as well as edema and retrogressive changes, up to necroses of myocytes with marked fragmentation; some patients also have increased vascular reactions. Furthermore, an earlier occurrence of and an increased frequency of changes corresponding to the so-called lymphoma-like lesions ("Quilty" effect) were observed in patients who received immunosuppressive prophylaxis with OKT3. The changed histopathologic findings of therapy-requiring acute rejection under prophylactic application of OKT3 may, to a certain extent, explain the discrepant results reported by different transplant groups with respect to the frequency of rejection episodes and the time when the first episode of therapy-requiring rejection occurs after heart transplantation.

Donor heart-related variables and early mortality after heart transplantation

Impaired donor heart function after heart transplantation results in the necessity for prolonged catecholamine and ventilatory support of the patient. Subsequently the risk of multiorgan impairment, infection, and rejection will be increased. In this retrospective analysis we tried to identify donor-related risk factors in patients who died early after transplantation. Of 174 patients undergoing heart transplantation from October 1985 through October 1988, 22 (12.6%) died early. Of the total, 39 cases were evaluated retrospectively for donor-related logistic and metabolic factors. All donors were analyzed with respect to the early mortality for age, weight, height, maximum dopamine concentration, thyroid hormone levels, and the duration from brain death until explantation and ischemia. Thirty patients were survivors (group A); nine patients died early (group B). By multiple regression analysis a significant influence (group A vs group B) of donor age, dopamine support, and ischemic time on early mortality could be demonstrated, whereas donor weight and height, hormone levels of triiodothyronine and thyroxine, and duration of brain death showed no correlation. From this limited experience we conclude that use of hearts from older donors with higher catecholamine support and longer ischemic times will result in an increased early mortality. In contrast, no influence of prolonged brain death times and metabolic factors could be demonstrated.

Hyperacute rejection in heart allografts. Case studies

Hyperacute rejection in orthotopic heart allografts is a rare event. In our material from a total collective of 524 heart-transplanted patients, we have observed two cases of hyperacute rejection, which are presented in this case report. Histopathologically, this entity is characterized above all by the following triad: pronounced edema, hemorrhages, and regressive changes up to necroses of myocytes. Besides the well-known risk factors, our report draws attention to two further factors possibly associated with an increased risk of hyperacute rejection: 1) repeated cardiac surgery prior to the transplantation, and 2) presence of identical viral genomes in recipient's and donor's heart.

Treatment of rejection after heart transplantation: what dosage of pulsed steroids is necessary?

Histologically proved rejection after heart transplantation is commonly treated with intravenous steroids, 1 gm/day for 3 days. This regimen may result in severe side effects, however, both metabolic and infectious. In a total of 663 rejection episodes, we treated 397 with conventional steroid therapy, 1000 mg per day for 3 days (group 1), 199 with 500 mg/day for 3 days (group 2), and 67 with 250 mg/day for 3 days (group 3). Response to treatment was assessed by control biopsy after 1 week and graded as ongoing, resolving, or resolved rejection. The efficacy of the three regimens showed no significant differences between the groups as determined by the results of the subsequent biopsy. Ongoing rejection, resolving rejection, and resolved rejection, respectively: group 1-3.3%, 66.5%, 30.2%; group 2-8.0%, 66.8%, 25.2%; group 3-4.5%, 73.1%, 22.4%. We conclude that comparable effects, even with a considerable reduction of pulsed steroids, may be obtained in the treatment of cardiac allograft rejection, if triple-drug immunosuppression is used for maintenance therapy. It seems likely that steroid side effects may be decreased without jeopardizing the graft.

T-cell lymphoma after heart transplantation

A 26-year-old woman who had undergone orthotopic heart transplantation because of dilative cardiomyopathy received a triple-drug immunosuppressive regimen (cyclosporine A, azathioprine, and prednisolone). During her relatively frequent episodes of acute rejection, she was treated with methylprednisolone and repeated application of ATG. A short time before the patient's death, a fine-needle aspiration of the liver revealed the cytologic diagnosis of a malignant pleomorphic medium-size cell non-Hodgkin's lymphoma of a higher grade of malignancy. Immunosuppression was reduced, and the patient died in cardiogenic shock related to a histologically confirmed episode of severe acute rejection 264 days after the transplantation. On autopsy, the malignant lymphoma previously diagnosed by fine-needle aspiration cytology was found to be present in the liver as the only extranodal localization. The immunohistologic analysis of the immunophenotype specified the lymphomatous neoplasia as a T-cell lymphoma. The particular importance of this case is that it is, to our knowledge, the third case of proven T-cell lymphoma following organ grafting documented in the literature and the first case described in a cardiac allograft recipient.

[Unilateral lung transplantation]

For patients with terminal pulmonary fibrosis unilateral lung transplantation offers a new therapeutic option. At the Hannover Medical School 5 patients have been successfully treated by single lung transplantation. In 3 patients a left, and in 2 patients a right lung transplant was performed. One patient required intraoperative support by cardiopulmonary bypass. Bronchial omentopexy was used in all instances. Currently all patients are alive. A marked improvement of pulmonary function parameters was seen in all cases. The patients are all able to lead a normal life.

Distant organ procurement in clinical lung- and heart-lung transplantation. Cooling by extracorporeal circulation or hypothermic flush

The scarcity of suitable donors for single lung and heart-lung transplantation calls for methods of medium-term pulmonary preservation to allow for distant organ procurement. At our institution, the first five grafts (four heart-lung, one single lung) were cooled by means of a transportable extracorporeal circulation unit, while the last eight grafts (four heart-lung, four single lung) were flush-perfused with modified cold Euro-Collins solution. The technique of extracorporated circulation included aortic and right atrial cannulation and cooling to 12 degrees-14 degrees C (rectal temperature) using a bubble oxygenator. Bypass times ranged between 41 and 52 min. Following excision, the organs were transported in ice-cold donor blood for ischemic times from 171 to 310 min. For cold flush preservation, simultaneous coronary (cold St. Thomas's solution) and pulmonary artery perfusion (Euro-Collins solution, 50 ml/kg over 4 min) were initiated simultaneously. The organs were transported in cold Euro-Collins solution for ischemic times of 175 to 270 min. In heart-lung transplantations the first postoperative arterial PO2 upon arrival at the intensive care unit was 120 +/- 38 Torr in the extracorporeal circulation and 140 +/- 38 Torr in the Euro-Collins solution group. Six of eight patients were extubated within 48 h after cardiopulmonary grafting. We conclude that pulmonary function following heart-lung or single lung preservation with simple hypothermic flush is as good or better than that following extracorporeal circulation. Since distant organ retrieval is much more convenient without the latter, preservation using Euro-Collins solution is preferred.

Oxygen free radical scavengers to prevent pulmonary reperfusion injury after heart-lung transplantation

Oxygen free radical scavengers, such as superoxide dismutase (SOD) and catalase (CAT), have been shown to reduce effectively myocardial reperfusion injury. No such data have been reported for cold global pulmonary ischemia, which is required in heart-lung transplantation. Heterotopic heart-left lung allotransplantation was performed in 18 dogs after single-flush perfusion of the lungs with Euro-Collins solution (60 ml/kg), cardioplegic arrest, and 6 hours of cold global ischemia. Six dogs served as controls. In six other dogs prostacyclin (PGI2) was administered both into the pulmonary artery (20 ng/kg/min) and to the Euro-Collins solution (15 mg/L) before explantation (group A). Grafts in six other dogs were preserved with Euro-Collins solution plus SOD (40,000 U/L) and CAT (100,000 U/L)(group B). In addition, SOD (1 mg/kg) and CAT (1.5 mg/kg) were given intravenously during the first 20 minutes of reperfusion. There was no significant difference in cardiac output, right and left atrial pressures, nor pulmonary arteriolar resistance among the groups. In contrast, left atrial oxygen pressure (PO2) values were best in group B. At all times, PO2 values in animals in groups A and B exceeded those in control animals. Compared with control animals with Euro-Collins solution preservation alone, animals with both PGI2 and SOD/CAT preservation had significantly improved pulmonary function after heart-lung transplantation. Better oxygenation in the SOD/CAT group (group B) suggests an important impact of oxygen free radicals during reperfusion.

Left ventricular function, tricuspid incompetence, and incidence of coronary artery disease late after orthotopic heart transplantation

Functional results and data concerning the incidence and severity of graft atherosclerosis (GASC) and tricuspid incompetence (TI) in the intermediate term after orthotopic heart transplantation (HTX) are still striking. We examined 92 patients 1, 2, and 3 years after HTX by right and left heart catheterization in order to evaluate pump function, the status of the coronary arteries and the extend of TI, using a double indicator thermodilation technique. Mean left ventricular volumes and ejection fraction were normal 1 and 2 years post-transplant. The incidence of GASC was 8/87 (9.2%) at 1, and 11/92 (12%) at 2 years. It was more frequent (16%) in patients with preexisting coronary artery disease (IHD) than in patients with underlying dilative cardiomyopathy (DCM) (11%). At the end of the 1st postoperative year, 62% of patients were free of TI, whereas only 38% had normal valve function 2 years posttransplant. In 9/14 (64%) of patients, consecutively assessed at 1 and 2 years, TI had increased between both investigations. Preoperative haemodynamics, the number of endomyocardial biopsies and rejection episodes as well as preoperative cardiac size did not correlate with TI. Left ventricular volumes and ejection fraction are normal in the intermediate term after HTX. The incidence of GASC was less than 10% at 1 year and did not significantly increase thereafter. TI is a frequent and yet unexplained finding after HTX showing a considerable tendency to increase with time, but with little or not haemodynamic consequence.

[Indications and results of orthotopic heart transplantation in coronary heart disease]

In parallel to increasing numbers of orthotopic heart transplantations performed during recent years, the proportion of patients with preexisting ischemic cardiomyopathy (ICM) enlarged. The present study examined peri- and postoperative risk factors and the prognosis of patients with coronary artery disease after orthotopic heart transplantation in comparison to a group with dilatated cardiomyopathy (DCM). This comparison revealed a higher risk of severe rejection episodes in patients with coronary artery disease, whereas infections were not more frequent. Graft atherosclerosis was found in a higher incidence in patients with preexisting ICM than in the DCM group. The overall incidence of graft atherosclerosis was less than 10% at one and at two years after orthotopic heart transplantation. Postoperative renal function was more impaired in the group of ICM patients, although blood levels of cyclosporine A were lower in this group. In the ICM group one and two year survival rates were 75% and 74%, respectively. Although survival rates are lower in this patient group, if compared to DCM patients (84% and 83%), orthotopic heart transplantation seems to be acceptable therapeutic alternative for endstage coronary artery disease.

Regulation of enzymes of lysine biosynthesis in Corynebacterium glutamicum

The regulation of the six enzymes responsible for the conversion of aspartate to lysine, together with homoserine dehydrogenase, was studied in Corynebacterium glutamicum. In addition to aspartate kinase activity, the synthesis of diaminopimelate decarboxylase was also found to be regulated. The specific activity of this enzyme was reduced to one-third in extracts of cells grown in the presence of lysine. Aspartate-semialdehyde dehydrogenase, dihydrodipicolinate synthase, dihydrodipicolinate reductase, and diaminopimelate dehydrogenase were neither influenced in their specific activity, nor inhibited, by any of the aspartate family of amino acids. Homoserine dehydrogenase was repressed by methionine (to 15% of its original activity) and inhibited by threonine (4% remaining activity). Inclusion of leucine in the growth medium resulted in a twofold increase of homoserine dehydrogenase specific activity. The flow of aspartate semialdehyde to either lysine or homoserine was influenced by the activity of homoserine dehydrogenase or dihydrodipicolinate synthase. Thus, the twofold increase in homoserine dehydrogenase activity resulted in a decrease in lysine formation accompanied by the formation of isoleucine. In contrast, repression of homoserine dehydrogenase resulted in increased lysine formation. A similar increase of the flow of aspartate semialdehyde to lysine was found in strains with increased dihydrodipicolinate synthase activity, constructed by introducing the dapA gene of Escherichia coli (coding for the synthase) into C. glutamicum.

Cytoimmunologic monitoring in early and late acute cardiac rejection

The absolute concentration of circulating lymphoblasts and prelymphoblasts has been shown repeatedly to closely correlate with acute cardiac rejection in heart transplant recipients. Little information, however, is available with respect to the reliability of this measurement in the late postoperative course. Fifty-two heart transplant recipient operated on from October 1985 through September 1986 were studied with cytoimmunologic monitoring for lymphocyte activation in peripheral blood. Immunosuppressive therapy consisted of azathioprine, cyclosporine, and steroids. Endomyocardial biopsies were obtained at regular intervals. Cytoimmunologic monitoring was performed daily during hospitalization and together with endomyocardial biopsy at outpatient visits. A total of 768 endomyocardial biopsies and 1077 mononuclear concentrates for study of lymphocyte activation were obtained. Concentration of activated cells showed a significant increase during acute rejection. Cytoimmunologic monitoring had an overall sensitivity of 76% and a specificity of 79%. Within 90 days after transplantation cytoimmunologic monitoring showed a sensitivity of 84%, which decreased to 71% beyond 3 months. We therefore conclude that cytoimmunologic monitoring, a noninvasive adjunct for diagnosis of acute allograft rejection, cannot replace routine endomyocardial biopsy, particularly in view of a significant loss in sensitivity in the late postoperative course.

[Hyperimmunoglobulin treatment in CMV infections following heart transplantation]

Clinically manifest cytomegalovirus (CMV) infections, with and without pulmonary involvement, occurred in two patients after heart transplantation. The diagnosis was confirmed immunologically. After administration of CMV hyperimmunoglobulin and prophylactic antibiotics and a reduction of immunosuppressives, rapid clinical improvement ensued so that both patients were discharged from hospital after seven and ten days, respectively.

Pneumocystis carinii pneumonia following heart transplantation

Pneumocystis carinii pneumonia represents a rare complication that is associated with a high mortality following heart transplantation. The cases of two heart transplant recipients who developed Pneumocystis pneumonia within the first 3 postoperative months are reported. Both patients had severe clinical symptoms of the disease; the diagnosis was confirmed by bronchoalveolar lavage, and the patients were treated with a combination of trimethoprim and sulfamethoxazole. Both patients recovered and are well at the time of this report.