Techniques of immunosuppression after cardiac transplantation

Quilty effect has the features of lymphoid neogenesis and shares CXCL13-CXCR5 pathway with recurrent acute cardiac rejections

Quilty effect (QE) is a frequent, yet enigmatic feature of cardiac allograft, since it is apparently devoid of clinical significance, though its association with acute (A) rejection (R) is strongly suspected. It was observed in 126/379 biopsies from 22 patients during the first posttransplant year. Most grade (G)2R biopsies displayed a concomitant QE. The following features typical of QE were identified: (a) focal angiogenesis and lymphangiogenesis associated with bFGF, VEGF-C and VEGF-A expression, (b) marked infiltrate of CD4(+)T and CD20(+)B followed by CD8(+)T lymphocytes arranged around PNAd(+)HEV-like vessels. Most QE appear as distinct B-T-cell-specific areas with lymphoid follicles sometimes endowed with germinal center-like structures containing VCAM-1(+)CD21(+)FDC and CD68(+)macrophages, which frequently expressed CXCL13. These cells were also found in mantle-like zones, where small lymphocytes expressed CXCR5, otherwise in the whole area of not clustered lymphoid aggregates. CXCL13 was also expressed, in association with CD20(+)B lymphocyte recruitment, in G2R biopsies obtained from patients with recurrent AR. QE has features of a tertiary lymphoid tissue suggesting an attempt, by the heart allograft, to mount a local response to a persistent alloantigen stimulation resulting in aberrant CXCL13 production, as also occurs in recurrent AR. CXCL13-CXCR5 emerge as a common molecular pathway for QE and recurrent episodes of AR.

Endomyocardial infiltration by B and NK cells foreshadows the recurrence of cardiac allograft rejection

Heart allograft outcome is unpredictable and acute rejection episodes still occur despite the improvement of immunosuppressive regimens. We therefore investigated whether the immunopathological profile of endomyocardial biopsies might underlie the variations in the clinical course of a graft. Biopsies from transplanted patients were analysed by histology, immunohistochemistry (associated with digital image analysis), confocal and electron microscopy to determine the type and the functional state of leukocytes infiltrating the myocardium, together with their ultrastructural features and those of the graft itself. In comparison with biopsies with grade 0R or grade 1R rejection, those from patients with grade 2R rejection displayed significant infiltration of macrophages, T lymphocytes, and CD83+ and DC-SIGN+ dendritic cells. Fifty-seven per cent were invaded by CD20+B lymphocytes, most of which expressed CD69 activation marker and cooperated in interleukin-12 production, and by CD69+CD94+NK cells expressing interferon-gamma. Ultrastructural signs of myocyte degeneration and microvessel rupture by NK cells were frequent. These patients developed recurrent episodes of acute allograft rejection. Endomyocardial B and NK infiltrates are involved in the dynamics of allograft rejection and are associated with a high risk of its recurrence. Immunopathological assessment of endomyocardial biopsies may thus serve to forecast the probable outcome of a heart allograft.

Heart transplantation--an update

Cardiologists caring for heart transplant recipients must be familiar with the pharmacology, drug interactions, and drug toxicity of those agents used extensively in clinical practice (cyclosporine, prednisone, azathioprine, polyclonal and monoclonal anti-T-cell agents) and the newer treatments [methotrexate, FK-506, rapamycin, mycophenolate mofetil (RS61443), deoxyspergualin, anti-CD4 monoclonal antibodies, total lymphoid irradiation, and photophoresis]. Another important aspect of medical follow-up is the detection, differential diagnosis, and treatment of allograft dysfunction. Hemodynamic abnormalities that occur as a result of rejection or a direct drug effect must be differentiated from physiologic changes. Cardiac allograft vasculopathy is the primary impediment to the long-term survival of heart transplant recipients. Immunopathogenesis, prevention, early detection, and treatment of allograft vasculopathy should be the major focus of heart transplantation research.

Adult Cardiac Transplantation

Patients with severe drug-refractory heart failure experience one of two modes of death. Either they collapse from an arrhythmia and are deemed to have had sudden death, or they die of progressive congestive heart failure. In either instance, their poor functional status during life limits their ability to perform usual daily activities. Currently, the only proven long-term benefit to these patients is heart transplantation. The technique that led to the first human-to-human heart transplantation nearly 30 years ago has changed very little; however, refinements in post operative care have kept research in this field at the fore for many years. Immediate postoperative hemodynamic stabilization by experienced clinicians may improve a patient's chances of survival after heart transplantation. Improved immunosuppressive agents have decreased life-threatening rejection episodes. Better knowledge of the infectious diseases that attack these immunosuppressed patients has also contributed to the nearly 85% one-year survival of heart transplantation recipients. The longest surviving heart transplantation recipient remains alive and well after more than 22 years. The development of transplant-related coronary artery disease may be the only transplantation-associated factor that keeps recipients from living for many decades. Transplantation coronary artery disease leads the list of late causes of mortality. Unlike native coronary artery disease, there exists ongoing difficulty in both diagnosis and treatment of this dreaded complication. We cover current standards and future possibilities in adult heart transplantation. We look at history, demographics, indications, management, and outcome in these patients, as well as future goals.

Cardiac transplantation: a review for critical care nurses

Advances in immunology, immunosuppressive therapy, and preservation techniques have contributed to making cardiac transplantation an accepted therapy for end-stage heart disease. One-year survival rates now exceed 90% at some transplant centers. However, serious complications, such as infection, rejection, coronary artery disease, and malignancies, continue to plague long-term survival rates in this patient population. Balancing the immune system between infection and rejection requires the special expertise of experienced cardiologists and immunologists. An improved understanding of the immune system promises to increase long-term survival rates of cardiac transplant recipients. Critical care nurses require special assessment skills to meet the demanding challenges of cardiac transplant recipients in the immediate postoperative period. The impact of cardiac denervation, immunosuppression, and the risk for acute rejection add a different perspective for nursing interventions in the critical care environment. With mortality rates remaining at 8 to 10% for the first month following cardiac transplantation, the skill of critical care nurses is crucial to decreasing morbidity and increasing survival during the acute perioperative period.

Management of patients after cardiac transplantation

During the past decade, the morbidity and mortality associated with cardiac transplantation have decreased dramatically. The current survival for patients who undergo orthotopic cardiac transplantation is 80 to 90% at 1 year and 70 to 80% at 5 years; these results are attributed chiefly to improved immunosuppression and the consequent decrease in infectious illnesses and rejection. Because surgical mortality and technique have not changed appreciably during the past 20 years, improved survival can be ascribed to advances in the medical management of recipients of cardiac transplants. Medical problems frequently encountered in such patients include allograft rejection, allograft vasculopathy, hypertension, renal dysfunction, hyperlipidemia, hyperglycemia, malignant disorders, general surgical disease, and osteopenic bone disease. Hence, the expertise needed for management of patients who undergo cardiac transplantation is not confined to a particular specialty--optimal care necessitates the integrated efforts of a team, including transplant physicians and personnel to provide broad subspecialty and laboratory support. Meticulous management with proactive intervention and minimal effective immunosuppression will prevent or ameliorate many problems and contribute to increased survivorship and improved quality of life. For additional substantive improvement in long-term survival and quality of life for recipients of cardiac allografts, multicenter, prospective, and placebo-controlled clinical investigations will be necessary.