It is of note that our patient population was not selected on the basis of respiratory symptomatology. Clinical evaluation on the day of follow-up pulmonary function testing did not reveal significant signs or symptoms of respiratory disease in this population. Our data indicate that CGVHD is associated with the development of progressive airflow obstruction which often is asymptomatic. None of the patients in the present study developed symptomatic or rapidly progressive bronchiolitis obliterans. Obstructive ventilatory defects following marrow transplantation may be more prevalent than previously suspected, since CGVHD ultimately occurs in approximately 30 percent of patients posttransplantation. It also may be possible to detect early manifestations of CGVHD by serial lung function testing. Click Here
The origin of progressive air flow obstruction following bone marrow transplantation remains obscure. Similar long-term pulmonary complications have been described following combined heart-lung transplantation. In these patient populations, the developmerit of obliterative bronchiolitis has been thought to be a manifestation of isolated lung rejection and/or viral infection. The fact that obliterative bronchiolitis has not been described as a complication of renal, hepatic and other organ transplantation requiring similarly intense immunosuppression suggests that obliterative bronchiolitis may be a unique manifestation of lung graft rejection or CGVHD within the lung. Support for this concept comes from the fact that class 2 MHC antigens are known to be expressed on human vascular endothelium and immune inflammation (immune interferon and activated T cells) appears to increase the level of expression. Similar induction of class 2 MHC antigen expression has been shown for various tissue epithelial cells, including lung epithelial cells, at sites of cellular inflammation. Bronchial epithelium may be a cellular target for CGVHD within the lung. Since loss of epithelial integrity after inflammatory damage has been implicated in the development of bronchial hyperresponsiveness, it would be of interest to test asymptomatic marrow recipients with evidence of airway obstruction for potential reversibility.
Category: Bone Marrow Transplantation
Tags: bone marrow transplantation, obstructive airway, Pulmonary function