Aims To prospectively evaluate the changes in corneal leucocyte density with in vivo confocal microscopy (IVCM) following transplantation and to determine if leucocyte density post-transplant is an indicator of graft rejection risk.
Methods IVCM imaging of cornea pre-transplant and post-transplant at 1 week, 1, 3 and 12 months. The changes in leucocyte density associated with diagnosis, vascularisation, type of keratoplasty, topical steroid and immunosuppression treatment, allograft rejection and failure within 4 years post-transplant were analysed.
Results Sub-basal nerve plexus total central leucocyte density (SBNP-TCLD) varied with diagnosis (p<0.001), interval post-transplant (p<0.001), degree of vascularisation (p=0.001) and rejection episodes in eyes off topical steroid (p=0.01). The highest SBNP-TCLD was found in eyes with inflammation pre-transplant. Mean 12-month SBNP-TCLD in eyes which had rejection episodes was almost double that in eyes which did not (79.0 and 39.8 cells/mm2, respectively). SBNP-TCLD >63.5 cells/mm2 was associated with a higher risk of rejection within 1 year (p=0.04) and 4 years (p=0.007). Changes in leucocyte density on the donor endothelium significantly differed between penetrating keratoplasty and deep anterior lamellar keratoplasty grafts (p<0.01) and in those in which rejection episodes were observed (p<0.001).
Conclusions Leucocyte density varies with corneal diagnosis, extent of vascularisation and interval post-transplant. Topical steroid treatment is associated with reduced leucocyte density and risk of graft rejection. Higher endothelium leucocyte density correlates significantly with previous or subsequent rejection episodes. Leucocyte density measurement by IVCM may be useful in identifying transplants at risk of rejection.
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Contributors SH planned, conducted, reported the data and submitted the study. BC conducted and reported the data. CT conducted and reported the data. DFPL planned and conducted the study. SH and DFPL are responsible for the overall content in this study.
Funding Supported in part by Fight for Sight (BMRC 082), the National Institute for Health Research (NIHR) Moorfields Biomedical Research Centre and NIHR Moorfields Clinical Research Facility.
Disclaimer The sponsor or funding organisation had no role in the design or conduct of this research.
Competing interests None declared.
Patient consent Obtained.
Ethics approval South London Research Ethics Comittee.
Provenance and peer review Not commissioned; externally peer reviewed.
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