Posttransplantation lymphoproliferative disorders in pediatric thoracic organ recipients

OBJECTIVE

To determine the frequency, predisposing factors, clinical presentation, and outcome of posttransplantation lymphoproliferative disorders (PTLDs) in pediatric thoracic organ transplant recipients.

METHODS

Retrospective review of the medical records of all 120 children who survived longer than 1 month after thoracic organ transplantation at our center.

RESULTS

PTLD was diagnosed in 14 patients (11.7%), including 7.7% of heart and 19.5% of heart-lung/lung recipients. Presentation of PTLD was variable, ranging from asymptomatic lung nodules on chest radiograph to diffuse multiorgan failure. Treatment with a reduction of immunosuppression and antiviral therapy resulted in resolution of PTLD in eight patients. Eight patients died. PTLD contributed to death in five. No patient seropositive for Epstein-Barr virus (EBV) before transplantation had PTLD. There was a significant association between primary EBV infection after transplantation and the presence of PTLD.

CONCLUSIONS

PTLD occurs with greater frequency in pediatric thoracic organ transplant recipients than in the adult transplant population. Primary EBV infection after transplantation is the major risk factor for the development of PTLD. Patients in whom primary EBV infection develops after transplantation should be managed with a reduction in immunosuppression and with heightened surveillance for the development of PTLD.

Critical issues in pediatric lung transplantation

Forty children (aged 1 to 18 years, 27 female and 13 male) have undergone heart-lung (21), double lung (17), and single lung (2) transplant procedures at our center from 1985 through April 1994. The indications for transplantation have been diverse, primary pulmonary hypertension (10), cystic fibrosis (11), congenital heart disease (10), arteriovenous malformation (3), emphysema (1), graft-versus-host disease (1), rheumatoid lung (1), cardiomyopathy (1), desquamative interstitial pneumonitis (1), and Proteus syndrome (1). The actuarial 1-year survival was 73% (mean follow-up 2 years). One-year actuarial survival for disease groups ranged from 60% for cystic fibrosis to 90% for congenital heart disease. We have identified six issues critical to the patient and programatic survival of pediatric lung transplantation. Our experience and management strategies in these areas are reviewed. Cytomegalovirus: Cytomegalovirus disease developed in six of eight patients with cytomegalovirus mismatching (donor +/recipient-) and in seven of 32 patients who survived more than 30 days (23%). All but cytomegalovirus donor -/recipient- patients were treated with ganciclovir for 4 weeks after transplantation. Obliterative bronchiolitis: Obliterative bronchiolitis developed in seven of 32 (25%) patients who survived more than 30 days. Obliterative bronchiolitis was manifest within the first posttransplantation year as a rapid decline in small airway function. Aggressive augmentation of immunosuppression has been used with little success. Posttransplantation lymphoproliferative disease: Posttransplantation lymphoproliferative disease developed in five of 32 (15%) patients who survived more than 30 days developed. One patient died (17% mortality) despite retransplantation. In four patients the disease resolved with reduction in immunosuppression alone, and one required the addition of interferon alfa. Cystic fibrosis: We have changed our management strategies to avoid triple drug immunosuppression, perioperative blood and bronchial cultures, aggressive antimicrobial therapy, and exclusion of patients with panresistant organisms; this has resulted in elimination of infectious mortalities thus far in the pediatric cystic fibrosis group. Airways: In 21 heart-lung recipients with tracheal anastomoses we have had no airway complications. The double and single lung transplant recipients accounted for 34 bronchial and one tracheal anastomoses. Three (9%) bronchial stenoses developed. Two were treated with silicone stents and one with balloon dilation.(ABSTRACT TRUNCATED AT 400 WORDS)

Developmental regulation of re-uptake of phosphatidylcholine by type II alveolar epithelium

Type II alveolar epithelia produce, store and secrete pulmonary surfactant, a phospholipid and protein mixture which stabilizes alveoli at low lung volumes and, thereby, prevents alveolar collapse. We determined the developmental changes in the uptake, metabolism and reutilization of surfactant-related phospholipid in primary cultures of type II cells derived from fetal rat lung. Primary cultures of fetal and neonatal type II cells were incubated in media containing labelled liposomes. After the incubation phospholipids were extracted from the cells and uptake of label was analyzed. Re-uptake of radiolabelled dipalmitoyl phosphatidylcholine (DPPC) was concentration-dependent in undifferentiated fetal cells, differentiated fetal cells and neonatal cells. Re-uptake of DPPC by undifferentiated fetal cells was lower than re-uptake by both differentiated fetal and neonatal cells at 15 and 75 microM PC. Binding of DPPC to the cell surface involved a protein interaction, since trypsin was able to dissociate this trypsin-releasable fraction from internalized label. Undifferentiated fetal, differentiated fetal and neonatal cells all exhibited approx. 50% metabolic degradation of internalized phospholipid. Degraded lipids were reutilized in the synthesis of phosphatidylglycerol, but neonatal cells resynthesized twice as much phosphatidylglycerol as did undifferentiated fetal cells. These are the first studies which show that morphologically undifferentiated fetal type II cells are capable of the uptake of surfactant phospholipid as well as the degradation and reutilization of internalized phospholipid. Re-uptake, degradation and reutilization of internalized phospholipid appear to be under developmental control.