I. Frachon et al., EMERGENCE OF INFLAMMATORY ALVEOLAR MACROPHAGES DURING REJECTION OR INFECTION AFTER LUNG TRANSPLANTATION, Transplantation, 57(11), 1994, pp. 1621-1628
Local activation of macrophages may play an important role in immune c
omplications following lung transplantation. To document such a phenom
enon, we have investigated the possible changes of alveolar macrophage
surface antigen expression after lung transplantation. Using immunocy
tofluorometry, we have analyzed the phenotype of alveolar macrophages
from 41 bronchoalveolar lavage fluids obtained from 19 lung transplant
recipients displaying various complications. The strong expression of
HLA-DR observed on almost all alveolar macrophages was similar among
groups I (no complication), II (minimal acute rejection), and III (mil
d to severe acute rejection), but was enhanced in group IV (bronchial
infection) (P<0.03). We observed no significant variation in the monoc
yte lineage CD14 antigen expression among the 4 groups, and about 83%
of alveolar macrophages expressed this marker strongly. Membrane expre
ssion of the 27E10 antigen that characterizes infiltrating macrophages
in acute inflammatory lesions was significantly higher during mild to
severe rejection episodes than in controls (P<0.02) and during bronch
ial infections (P<0.05) but not during minimal rejection. Double stain
ing experiments confirmed that 27E10-positive cells in groups III and
IV belonged to the macrophage lineage. In addition, the expression of
the 27E10 antigen on cultured alveolar macrophages was found to be inc
reased after stimulation by bacterial lipopolysaccharide or IFN-gamma.
These results indicate that a particular alveolar macrophage subpopul
ation is activated during immune events after lung transplantation. Th
is population, recognized by the 27E10 mAb, might be involved in cytok
ine production during severe acute rejection and infection episodes.