Abstract
Purpose :
Commensal microflora co-evolves with their hosts on the ocular surface. Host microflora contains a number of components capable of activating immunological cascades and exert pathologic effects. The status of commensal microflora relates to several diseases such as infections and autoimmune diseases. However, the exact pathogenic role of microflora in cGVHD-related dry eye is still unclear. HSCT recipients are subjected to high risk factors such as receiving irradiation, immune suppressive medication, and steroid therapy.
Based on these findings, we envisage that ocular surface microflora is disturbed and plays a role in the pathogenic process of cGVHD-related dry eye. This study aims to elucidate the status of microflora on the ocular surface in patients with cGVHD-inducing dry eye and to discover the changes in the composition of ocular surface microflora.
Methods :
The prospective study was performed at dry eye outpatient clinic at Keio University hospital between Aug 4 and Dec 4 2015. We harvested conjunctival microorganism with a cotton swab and obtained samples from the following 3 groups, 27 eyes/19 GVHD cases (10 males, 9 females, median: 59.0 years old), 13 eyes/9 non-GVHD cases (5 males, 4 females, median: 52.0 years old), and 10 eyes/5 health controls (1 male, 4 females, median: 54.0 years old). After collecting the samples, traditional culture-based methods were performed to examine the microflora on the ocular surface.
Results :
Ocular surface microflora in cGVHD patients was more complex in diversity compared with that in non-GVHD patients and controls. Staphylococcus Epidermidis, Corynebacterium species, Propionibacterium Acnes, Staphylococcus Aureus, Haemophilus Influenza, Enterobactor Cloacae, Alpha-haemo Streptococcus, Aerobic gram-positive coccus, and other Staphylococcus species were observed in the patients with dry eye triggerd by cGVHD, whereas only a few gram-positive cocci were detected in the non-GVHD patients and controls.
Conclusions :
We found that ocular surface microflora in cGVHD patients is more diverse than that in non-GVHD patients and controls. These results suggest the diversity of microflora is involved in the pathogenic process of cGVHD-related dry eye. Further examination using state-of-the-art methods will be needed to gain greater insights into the diversity of microflora on the cGVHD-affected ocular surface.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.