Metagenomic Profiling of the Ocular Surface Microbiome in Patients After Allogeneic Hematopoietic Stem Cell Transplantation

•Dysbiosis of the ocular surface microbiome in allogeneic hematopoietic stem cell transplantation patients was characterized by increased interindividual variation and a marked loss of diversity. •The microbiome of patients with ocular graft-versus-host disease (oGVHD) was distinct from patients without oGVHD. The α-diversity of the ocular surface microbiota as well as the presence of Gordonia bronchialis and Pseudomonas parafulva was associated with the severity of oGVHD. •The degree of symblepharon was positively associated with the presence of Serratia species. Purpose To investigate the characteristics of the ocular surface microbiome in patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and the associations between the microbial dysbiosis and chronic ocular graft-versus-host disease (oGVHD). Design Prospective cohort study. Methods Ocular surface samples from 48 healthy subjects and 76 patients after allo-HSCT, including 50 patients with chronic oGVHD and 26 patients without oGVHD, were collected. Species-level composition of the ocular surface microbiome was surveyed via metagenomic shotgun sequencing. OGVHD was diagnosed and graded according to the International Chronic Ocular GVHD Consensus Group criteria. Results The α-diversity of the microbiota was significantly decreased in patients after allo-HSCT. Nevertheless, we detected more types of viral species in the allo-HSCT group than the healthy group, especially anelloviruses. The mismatch of donor-recipient sex was only negatively associated with the α-diversity in male but not female recipients. Moreover, the microbiome of patients with oGVHD was distinct from patients without oGVHD. Gordonia bronchialis and Pseudomonas parafulva were enriched in patients with oGVHD and positively associated with International Chronic Ocular GVHD score. Conclusions This study suggests that the ocular surface microbiome after allo-HSCT is characterized by a loss of diversity. Furthermore, the microbial dysbiosis at the ocular surface is associated with the status and severity of chronic oGVHD. These results lay the groundwork for future investigations of the potential microbial mechanism for oGVHD. To investigate the characteristics of the ocular surface microbiome in patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and the associations between the microbial dysbiosis and chronic ocular graft-versus-host disease (oGVHD). Prospective cohort study. Ocular surface samples from 48 healthy subjects and 76 patients after allo-HSCT, including 50 patients with chronic oGVHD and 26 patients without oGVHD, were collected. Species-level composition of the ocular surface microbiome was surveyed via metagenomic shotgun sequencing. OGVHD was diagnosed and graded according to the International Chronic Ocular GVHD Consensus Group criteria. The α-diversity of the microbiota was significantly decreased in patients after allo-HSCT. Nevertheless, we detected more types of viral species in the allo-HSCT group than the healthy group, especially anelloviruses. The mismatch of donor-recipient sex was only negatively associated with the α-diversity in male but not female recipients. Moreover, the microbiome of patients with oGVHD was distinct from patients without oGVHD. Gordonia bronchialis and Pseudomonas parafulva were enriched in patients with oGVHD and positively associated with International Chronic Ocular GVHD score. This study suggests that the ocular surface microbiome after allo-HSCT is characterized by a loss of diversity. Furthermore, the microbial dysbiosis at the ocular surface is associated with the status and severity of chronic oGVHD. These results lay the groundwork for future investigations of the potential microbial mechanism for oGVHD.