The Journal of Thoracic and Cardiovascular Surgery, Vol 106, 449-457, Copyright © 1993 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Aspects of lung transplantation that contribute to increased severity of pneumonia. An experimental study
R Aeba, JE Stout, NA Francalancia, RJ Keenan, AJ Duncan, SA Yousem, GJ Burckart, VL Yu and BP Griffith
Department of Surgery, University of Pittsburgh, PA 15213.
In lung or heart-lung transplant recipients, complications as a result of
pulmonary infections continue to be the most frequent causes of morbidity
and mortality. This study was undertaken to identify the contributions of
(1) thoracotomy, (2) interruption of lymphatic vessels and bronchial
arteries, (3) transplant procedure, (4) drug-induced immunosuppression, and
(5) graft allogenicity to the increased risk of pneumonia in lung
transplantation. Lewis rats were inoculated with 10(5) colony-forming units
of Legionella pneumophila serogroup 1 by direct instillation into the
trachea after one of the following: a general anesthetic with no operation;
a left thoracotomy; a left thoracotomy with pulmonary hilar stripping; an
isogeneic orthotopic left lung transplant with or without
immunosuppression; or an allogeneic transplant with immunosuppression with
Brown-Norway rats as donors. Immunosuppression was induced with an
intramuscular injection of cyclosporine (25 mg/kg of body weight) from the
inoculation day to day 3. All rats were killed on day 6, and severity of
infection was determined by quantitative culture of Legionella organisms in
the lungs and spleen, titer of Legionella urinary antigen, differential
cell count in bronchoalveolar lavage fluid, body weight loss, and gross
inspection of the lung. Significant increases in lung Legionella
concentration occurred as a result of the addition of pulmonary hilar
stripping (from 10(5.13 +/- 0.34) in the thoracotomy group to 10(5.66 +/-
0.25) in the thoracotomy with hilar stripping group, p = 0.013) and the
addition of immunosuppression (from 10(5.47 +/- 0.47) in the isogeneic
transplant group to 10(6.94 +/- 0.52) in the isogeneic transplant with
immunosuppression group, p = 0.00016). Thoracotomy, transplant procedures,
and allogenicity itself resulted in no significant increases. The results
for all other indicators paralleled those for lung culture. We conclude
that the combination of drug- induced immunosuppression with lung
denervation and interruption of lymphatic vessels and bronchial arteries
results in the early development and increased severity of pneumonia in
lung transplantation.
