Researchers have recently identified bacterial proliferation on the skin as a factor associated with the development of acute skin graft-versus-host disease (GVHD) in the first few months following allogeneic hematopoietic stem cell transplantation (HSCT).
The results were published in Leukemia by Nadine Bayer, MSc, a doctoral student at the Medical University in Vienna (MedUni Vienna), and colleagues.
The single-center, observational study examined the skin and stool of 50 patients with a hematologic malignancy before conditioning and for up to one year after they had undergone allogeneic HSCT at the Department of Bone Marrow Transplantation at MedUni Vienna and Vienna General Hospital. Additional samples were collected from healthy, age-matched volunteers (n=15).
Analyzing the skin microbiome of patients who developed acute skin GVHD in the first few weeks or months after receiving the stem cells from the donor, the researchers found a decrease in bacterial abundance. Specifically, alpha diversity, a measure of microbial diversity within a single sample, was lower after cutaneous acute GVHD onset and was predictive of disease severity.
“The reduction in proliferation was particularly pronounced in severe cases of GVHD—even before symptoms appeared,” said senior author Georg Stary, PhD, of the Department of Dermatology at MedUni Vienna.
However, the scientists also found that patients with acute skin GVHD had an overabundance on the skin of Staphylococcus spp at days 100 and 365, measured by both molecular (16S amplicon sequencing and fluorescence in situ hybridization) and culture-based approaches. The colonization with staphylococci observed in the skin of acute GVHD patients was also accompanied by high infiltration of CD45+ leukocytes even before disease development.
“Our data suggest that changes in recolonization dynamics after HSCT and overgrowth of Staphylococcus spp in skin [acute] GVHD lesions may augment antigen-presentation in [mononuclear phagocytes] and increased activation of T cells, which are well known hallmarks of GVHD pathogenesis,” the authors concluded.
The identification of the skin microbiome in GVHD may assist in improving treatment, the researchers said.
“Follow-up studies will now show whether the change in the skin microbiome may contribute to the development of GVHD and whether new therapeutic approaches can be identified from the knowledge gained,” said Dr. Stary.
Bayer N, Hausman B, Pandey RV, et al. Disturbances in microbial skin recolonization and cutaneous immune response following allogeneic stem cell transfer. Leukemia. 2022. doi:10.1038/s41375-022-01712-z