Feasibility and Safety of Low-Dose Mesenchymal Stem Cell Infusion in Lung Transplant Recipients

Background We have previously shown bone marrow-derived mesenchymal stem cells (MSCs) may shift immune responses toward anti-inflammatory pathways and stabilize the course of obstructive chronic lung allograft syndrome (o-CLAD) after lung transplantation. In this study, we measured the response of lower dose infusions. Methods We infused low-dose MSCs intravenously in 13 patients who had developed moderate-to-severe o-CLAD. Three had previously received an infusion of MSCs from a different donor and were re-dosed at 1 x 10(6) MSC/kg, while 5 received a first dose at 1 x 10(6) MSC/kg and five received an even lower dose at 0.5 x 10(6) MSC/kg. We recorded pulmonary function tests before and after infusion, and patients were followed clinically for 12 months. Results Infusions were well tolerated, and no significant adverse events were recorded in the first 30 days. There was significant decline (mean +/- SD) in forced vital capacity (FVC) (3.49 +/- 1.03 vs 3.18 +/- 0.94 L, P = .03) and forced expiratory volume in 1 second (FEV1) (2.28 +/- 0.86 vs 1.77 +/- 0.49 L, P = .04) over the year preceding infusion. FVC (3.18 +/- 0.94 vs 3.46 +/- 0.99 L, P = .53) and FEV1 was not significantly changed (1.77 +/- 0.49 vs 1.88 +/- 0.75, P = .72) when comparing values immediately prior to infusion to those obtained 1 year after infusion, indicating a possible stabilizing effect on lung function decline due to o-CLAD. Conclusion Intravenous infusions of bone marrow-derived MSCs are well tolerated in lung transplant recipients with moderate-to-severe CLAD. Low-dose MSCs appear to slow progression of CLAD in some patients.