Purpose : to evaluate the efficacy of ECP in children with refractory acute GVHD This study addresses patients with persistent GVHD after steroid and/or monoclonal antibody therapy

One arm. Six sessions in two weeks. Classification in complete response (resolution of all signs of GVHD), partial response (improvement of at least one grade) or absence of response (Glucksberg criteria). Tapering depending on patient condition during weeks 2 to 10. Final evaluation at week 10. Steroid therapy tapering at the discretion of the investigator.

Inclusion Criteria:

• 0 to 30 years
• Acute GVHD refractory to steroids (disease progression after 2 days or absence of response after 4 days) and/or second line therapy (absence of response after 8 days)
• patient consent and/or parent consent

Exclusion Criteria:

• less of 10 kgs BW
• clinical or biological state precluding the apheresis
• previous GVHD therapy with anti-lymphocyte serum (excepted in the conditioning regimen)