Abstract
Purpose :
The purpose of this study is to determine the changes after treatment in the ocular surface microbiome (OSM) and ocular surface disease (OSD) parameters in patients with hematopoietic malignancies who are receiving chemotherapy and hematopoietic stem cell transplantation (HSCT). Prior studies have found that the OSM of patients with ocular Graft Versus Host Disease (oGVHD) following bone marrow transplant have an ocular surface consisting predominantly of Lactobacillus and Corynebacterium. We hope to assess the OSM changes over time in patients from pre- HSCT to post- HSCT timepoints to develop a better understanding of the disease dependent OSM changes.
Methods :
The study used a prospective longitudinal cohort design to assess the OSM at four different time points: prior to chemotherapy, following chemotherapy, prior to HSCT, and 100 days following HSCT. Baseline ocular surface testing was performed at initial visit. A conjunctival swab (COPAN ESwab) was used to sample the inferior fornix of each eye at each of the four specified time points discussed above. Sample DNA was amplified and underwent 16S rRNA sequencing to determine the OSM composition.
Results :
Of samples from patients who developed oGVHD (n=6) following HSCT, Lactobacillus and Corynebacterium had the highest relative abundance in 5/6 samples. Additionally, Lactobacillus and Streptococcus were present together in patients with oGVHD this contrasts with patients with other severe ocular surface disorders such as Stevens-Johnson Syndrome (SJS) where staphylococcus has a high relative abundance. Interestingly, oGVHD samples displayed similar diversity levels to Healthy samples as evidenced by the Shannon Index and Inverse Simpson alpha diversity scores, and similar predominance of Lactobacillus and Corynebacterium species.
Conclusions :
Different OSDs have a distinct OSM and treatment could play a role in altering the OSM. Changes to Corynebacterium at the second time point was seen in 5/29 eyes and 7/26 oGVHD eyes suggest that over the course of treatment, the OSM is likely evolving. Through further sample collection followed by analysis of microbiota species and diversity scores, we hope to study trends in microbiome changes during HSCT and how the changes could correlate to the development of oGVHD and the severity of symptoms.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.