Clinical trial based on the use of a new therapeutic strategy (MSC infusion) for the treatment of patients who have developed a GVHD refractory to the usual therapeutic measures after undergoing an allogenic hematopoietic stem cell transplant.

This is a multicenter, single dose study of allogenic mesenchymal stem cell (1-2 x 10^6 MSC/Kg recipient´s bodyweight).

MSC will be infused, by a central venous catheter, to patients diagnosed with GVHD refractory to first-line or subsequent treatment.

All patients will receive the same treatment. MSC suspension will be obtained from the bone marrow aspiration of a family donor and expanded in-vitro in a specific culture medium with autologous donor´s serum and with no animal-derived products.

Inclusion Criteria:

• Patients with hematological malignancies who had been undergone an allogenic hematopoietic stem cell transplant and diagnosed with GVHD refractory to a usual treatment.
• Adequate cardiac function with no evidence of uncontrolled high blood pressure,congestive heart failure, angina pectoris, acute myocardial infarction within 6 months prior to the process.
• Adequate pulmonary function with no evidence of chronic obstructive or severe restrictive pulmonary disease.
• Patients with ages between 18 and 65 years.
• Signature of informed consent form is required to be done by patient and donor.

Exclusion Criteria:

• Patients whose hematopathology has not been controlled by the transplant or is in progress.
• Patients with bacterial, viral or fungal infection not being controlled with the adequate treatment.
• Patients with an inadequate cardiac or pulmonary function.
• Patients who, in the investigator´s point of view, are not in situation to tolerate the treatment.
• Patients who do not have the required donor (HLA-identical sibling donor and not HLA-identical sibling donor).
• Pregnant females or childbearing potential who are not on adequate contraceptive measures.
• Patients <18 or >65 years.
• Patients who do not sign the informed consent.