Evaluation of serum neutrophil-to-lymphocyte ratio in corneal graft rejection after low-risk penetrating keratoplasty.

Purpose: To evaluate systemic inflammatory parameters in patients with corneal graft rejection after low-risk penetrating keratoplasty.

Methods: Patients undergoing penetrating keratoplasty with indications of keratoconus, pseudophakic bullous keratopathy, and Fuchs endothelial dystrophy were analyzed retrospectively. Patients who had an endothelial rejection attack within two years post-transplant were included in the rejection group (n = 20), whereas patients with at least two years of post-transplant follow-up without graft rejection or failure were included in the control group (n = 46). All patients' clinical features and preoperative laboratory parameters were obtained from hospital records. The neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio, and platelet-to-lymphocyte ratio of the groups were calculated and compared.

Results: There was no difference between the two groups in terms of age, sex, indication, postmortem time and storage time of grafts, graft diameter, follow-up time, and common systemic diseases (p > 0.05). The NLR was found to be significantly lower in the rejection group when compared with the control group (2.04 ± 1.17, 2.66 ± 0.91, respectively, p = 0.023). There was no significant difference between the groups in terms of MLR and PLR (p = 0.243, p = 0.101, respectively).

Conclusions: Although a high NLR value, which is an indicator of systemic inflammatory condition, is associated with many ocular diseases, NLR was found to be lower in patients with a rejection episode after transplant surgery when compared with the control group. Further studies are needed to clarify the role of these hematologic parameters in graft rejection.