Pulmonary hemosiderosis (PH) is a pulmonary hemosiderin deposition which caused by alveolar capillary hemorrhage. PH is easy to recurrent and can lead to pulmonary fibrosis and insufficiency if the disease was poor controlled. Steroid is the most common drug that was administered in acute phase of the disease. However, considered the side-effects, steroid is not suitable for long-time maintenance. Therefore, it is necessary to explore a new therapy. Bone marrow mesenchymal stem cells (BMSC) are a kind of adult stem cells with high self-renewal and multi-directional differentiation potential in bone marrow. It has become a hot topic in immunosuppressive and tissue repair therapy in recent years. To date, homing, colonization and differentiation of BMSCs in the lung have been observed in animal models of pulmonary hypertension, radiation pneumonitis and pulmonary fibrosis. It had been reported that BMSC transplantation in acute lung injury in mice, inflammation of lung injury can significantly improve. The aim of this study is to explore the effect of BMSC on PH and its mechanism, and to explore a new way to promote the repair of IPH. It is expected to improve the status of IPH therapy in children, especially improve the prognosis of refractory PH.

Inclusion Criteria:

• Patients diagnosed with Pulmonary hemosiderosis at an age less than 18 years.

Exclusion Criteria:

• Patients who cannot finish the established causes or die during the causes.