Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare severe cutaneous adverse reactions (SCARs) to drugs.

To date, no curative drug has demonstrated with a good level of evidence its ability to promote SJS and TEN healing and could contribute to earlier reepithelialisation. Mesenchymal stroma cells (MSCs) therapy represents a new therapeutic approach. eg, in patients with cardiovascular diseases, neurological diseases, renal transplantation, lung diseases as acute respiratory distress syndrome.

Recently, MSCs have been proposed in both burn wound healing with a significantly decrease of the unhealed burn area and in cutaneous radiation.

Moreover, MSCs have immunomodulation properties potentially effective in refractory acute and chronic graft versus host disease (GVHD) by improving thymic function and induction of Tregs. Indeed, MSCs are able to migrate to inflamed tissues after stimulation by pro-inflammatory cytokines and to modulate the local inflammatory reactions. MSCs have also demonstrated their ability to promote tissue remodelling, angiogenesis and immunomodulation through either differentiation or secretion of several growth factors such as VEGF, basic FGF and various cytokines.

Therefore, combining their immunomodulation effect and secretion of soluble factors involved in wound repair, MSCs might be valuable as a cell therapy strategy for promoting cutaneous healing in SJS-TEN syndrome and subsequently decrease the morbi-mortality.

Inclusion Criteria:

• Patients ≥ 18 and ≤ 75 years-old
• Admission ≤ 10 days after the index date (date of the first symptoms of the disease)
• Patient with confirmed SJS-TEN diagnosis hospitalized in the department of Dermatology or intensive care medicine
• At least 10 % of detachable-detached body surface area at any time during the first 10 days after the index date (date of the first symptoms of the disease)
• Who, after the nature of the study has been explained to them or a support person (if applicable), and prior to any protocol specific procedures being performed, have given written consent according to local regulatory requirements
• Affiliated to a social security scheme

Exclusion Criteria:

• Pregnant or breastfeeding women
• History of malignant disease within the past ten years and or presence of metastasis
• Positive serology for HIV
• Active infection for hepatitis B or C
• Detection of Coronavirus SARS CoV-2 RNA on admission (positive RT-PCR), if performed in the usual care
• Decompensated cardiac failure
• Uncontrolled epilepsia
• Previous history of allogenic bone marrow transplantation
• Participation in other interventional drug research Patient deprived of liberty by a judicial or administrative decision or under the protection of justice
• Any psychological, familial, sociological or geographical condition potentially hampering compliance with the research protocol and follow-up schedule
• Patient under tutorship or curatorship
• Patient under psychiatric care according to art. L1121-6 CSP