Comparison of conditioning regimens for alveolar macrophage reconstitution and innate immune function post bone marrow transplant

The authors compared efficiency of alveolar macrophage (AM) reconstitution from donor bone marrow Post transplant following 4 chemotherapy conditioning regimens and 2 total body irradiation (TBI) regimens. TBI regimens are more effective in inducing AM reconstitution from donor marrow. However mire conditioned with 13 Gy split-dose TBI or a dual-chemotherapy regimen (25 mg/kg busu fan x 4 days plus cyclophosphamide 100 mg/kg x 2 days) both demonstrate significant AM repopulation from donor marrow. Additionally, both protocols resulted in impaired pulmonary host defense associated with overproduction of prostaglandin E-2 and I-2 by AMs and impaired AM phagocylosis post bone marrow transplant.