Defective phagocytosis and clearance of Pseudomonas aeruginosa in the lung following bone marrow transplantation.
Bone marrow transplantation (BMT) is an important therapeutic option for a variety of malignant and nonmalignant disorders. Unfortunately, BMT recipients are at increased risk of infection, and in particular, pulmonary complications occur frequently. Although the risk of infection is greatest during the neutropenic period immediately following transplant, patients are still vulnerable to pulmonary infections even after neutrophil engraftment. We evaluated the risk of infection in this postengraftment period by using a well-established mouse BMT model. Seven days after syngeneic BMT, B6D2F(1) mice are no longer neutropenic, and by 3 wk, they demonstrate complete reconstitution of the peripheral blood. However, these mice remain more susceptible throughout 8 wk to infection after intratracheal administration of Pseudomonas aeruginosa; increased mortality in the P. aeruginosa-infected BMT mice correlates with increased bacterial burden in the lungs as well as increased systemic dissemination. This heightened susceptibility to infection was not secondary to a defect in inflammatory cell recruitment to the lung. The inability to clear P. aeruginosa in the lung correlated with reduced phagocytosis of the bacteria by alveolar macrophages (AMs), but not neutrophils, decreased production of TNF-alpha by AMs, and decreased levels of TNF-alpha and IFN-gamma in the bronchoalveolar lavage fluid following infection. Expression of the beta(2) integrins CD11a and CD11c was reduced on AMs from BMT mice compared with wild-type mice. Thus, despite restoration of peripheral blood count, phagocytic defects in the AMs of BMT mice persist and may contribute to the increased risk of infection seen in the postengraftment period.
Ojielo
Charles I
CI
Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor, MI 48109-0642, USA.
Cooke
Kenneth
K
Mancuso
Pete
P
Standiford
Theodore J
TJ
Olkiewicz
Krystyna M
KM
Clouthier
Shawn
S
Corrion
Leigh
L
Ballinger
Megan N
MN
Toews
Galen B
GB
Paine
Robert
R
Moore
Bethany B
BB
D000818:Animals; D016026:Bone Marrow Transplantation / Q000009:adverse effects / Q000276:immunology*; D018821:CD18 Antigens / Q000032:analysis / Q000096:biosynthesis; D002454:Cell Differentiation / Q000276:immunology; D002465:Cell Movement; D004306:Dose-Response Relationship, Immunologic; D006410:Hematopoiesis / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis / Q000172:deficiency; D016753:Interleukin-10 / Q000096:biosynthesis / Q000172:deficiency; D008168:Lung / Q000276:immunology* / Q000382:microbiology* / Q000473:pathology; D016676:Macrophages, Alveolar / Q000276:immunology / Q000378:metabolism / Q000637:transplantation; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D009504:Neutrophils / Q000276:immunology; D010587:Phagocytosis / Q000276:immunology*; D011183:Postoperative Complications / Q000276:immunology / Q000382:microbiology / Q000401:mortality / Q000473:pathology; D011552:Pseudomonas Infections / Q000097:blood / Q000276:immunology* / Q000382:microbiology* / Q000401:mortality; D011550:Pseudomonas aeruginosa / Q000254:growth & development* / Q000276:immunology*; D018805:Sepsis / Q000097:blood / Q000276:immunology / Q000382:microbiology / Q000401:mortality; D015996:Survival Rate; D014185:Transplantation, Isogeneic; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000172:deficiency
D018821:CD18 Antigens; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D007371:Interferon-gamma