Inclusion Criteria:

1. Informed consent.

2. Patients are required to meet the following inclusion criteria:

Any patient that has undergone allogeneic stem cell transplantation with steroid
refractory grades II-IV acute GvHD either occurring post transplant, or induced by donor
lymphocyte infusions (DLI) or T-cell add back, or chronic steroid refractory GVHD in acute
phase. Patients may be receiving local best treatment for steroid refractory GVHD. A
positive biopsy for GvHD is not required if clinical signs and symptoms are characteristic
for GvHD and other etiologies are excluded. See 6.4 for acute GvHD grading.

1. Steroids have been given, for instance methylprednisolone 2 mg/kg/day, for at least
72h in case of progressive acute GvHD, 5 days in case of stable acute GVHD (grade II
to IV) or chronic GvHD in active phase, according to the local policy.

2. Despite this treatment, the patient has unresponsive GvHD after 5 days, or
progressive acute GvHD after 72 hours. If single organ acute GvHD grade II from gut
or liver, either progression from single organ or addition of one or two more organs.
As an example, if the patient has grade II acute GvHD of the skin, GvHD is more
intense and more widespread, or GvHD also includes liver and/or gut.

3. Patients with steroid refractory GvHD fulfilling the requirements mentioned in a) -
b) may be treated with second line therapy according to the clinical guidelines at
each center prior to enrolment in this study.

4. Patients under treatment with best available local treatment for steroid resistant
GVHD will not interrupt the ongoing treatment unless clinically required for safety
reasons.

Exclusion Criteria:

1. Inability to obtain informed consent.

2. Patients with documented uncontrolled EBV, CMV or fungal infection.

3. Patients in poor clinical conditions with life expectancy of less than 30 days.