The Skin Microbiome in Graft Versus Host Disease

Pre-moistened skin swabs will be collected before the patient starts the conditioning regimens (before conditioning; start of HSCT = day 0, on the day of the transplantation an the repeated in week 4, 12, 24, 36 and 52 after allo-HSCT. The first swab serves as baseline reference (ideally taken at the earliest one week after a systemic antibiotic treatment). Swabs will be taken from the neck, back, right hip, buccal oral cavity and the genital mucosae. In patients who develop acute or chronic skin-GVHD additional swabs will be taken from affected skin at the time of diagnosis and then again according to the schedule of the non-lesioned skin swabs.

During the first visit, a single skin punch biopsy will be taken to state the skin condition and microbiome before allo-HSCT. Further biopsies will only be taken in case of acute or chronic cutaneous GVHD. A 4-6 mm punch biopsy will be taken from the affected skin area and a second one from a nearby unaffected part of the skin. Before the biopsy, skin disinfection will be performed to avoid contamination with surface bacteria.

an additional tube of blood (2.7ml) and an additional tube of serum (6ml) will be taken and frozen during visits 1, 2, 3 and 7 in the course of blood collection, in order to be able to carry out any later laboratory tests that may prove to be useful depending on the course of the study.