Pulmonary Complications after T-Cell Depleted Allogeneic Stem Cell Transplantation: Low Incidence and Strong Association with Acute GVHD.

Lung injury limits the success of hematopoietic stem cell transplantation (HSCT). The overall incidence varies from 30–50% and noninfectious causes occur in one third to one half of these. We reviewed pulmonary complications in 369 patients who received either allo-BMT or allo-PBSCT at our institution between 1993 and 2003. Control subjects were selected from the same database and matched on sex, underlying diagnosis, age, type of transplantation and cytomegalovirus-serostatus. For all patients the conditioning myeloablative regimen consisted of cyclophosphamide (60 mg/kg/day for 2 days) followed by total body irradiation (total lung dose 850 cGy). The graft was partially T-cell depleted (1–2 x 10⁵ T cells/kg).

Sixty-one patients (16.5%) developed pulmonary complications, which were diagnosed at a median of 22 weeks after transplantation (range 2–263). Twenty-one patients (5.7%) developed infectious pneumonia. Non-infectious complications were further subclassified as BO (3.5%), BOOP (0.5%), DAH (0.8%), IPS (5.4%) or mixed etiology (0.5%). Acute GVHD ≥ grade II was significantly more common in patients with pulmonary complications than in the controls (36/61 versus 24/61 patients, P=0.02). There was no significant difference in the incidence of chronic GVHD (in 26/48 pulmonary patients versus 20/55 controls, P=0.1). Median survival was 41 weeks (range 4–583) for the pulmonary patients and 173 weeks (range 8–582) for the control subjects. These data illustrate that the incidence of pulmonary complications is low after T-cell depleted HSCT and demonstrate a clear association with acute GVHD. Improvement of the poor outcome of pulmonary complications is of utmost importance. Current studies at our institution are focused at the detection of early markers so that possible pre-emptive-like therapy can be initiated before symptomatic lung damage arises.