"Smoldering" Rejection of Keratolimbal Allograft.

Purpose: The purpose of this study was to report a case of "smoldering" keratolimbal allograft (KLAL) rejection in a patient with subtherapeutic levels of systemic immunosuppression in temporal association with BNT162b2 messenger RNA vaccination for severe acute respiratory syndrome coronavirus 2.

Methods: This was a case report.

Observations: A 72-year-old man presented with circumferential perilimbal engorgement, stagnation, and tortuosity of vessels with mild chemosis in his right eye KLAL segments 1 month after receiving the BNT162b2 messenger RNA vaccine while his tacrolimus trough blood levels were subtherapeutic measuring <2 ng/mL. He had undergone KLAL 6.5 years before for total limbal stem cell deficiency from a chemical injury and had been stable without any history of rejection. The donor was blood type O, and the patient had no systemic comorbidities. The patient was treated with hourly difluprednate 0.05% and increasing of his oral tacrolimus dose to 2 mg twice a day with improvement of rejection signs.

Conclusions: There may be a temporal association between KLAL rejection after immunization against severe acute respiratory syndrome coronavirus 2 in patients with subtherapeutic levels of systemic immunosuppression. Patients should be on alert for any ocular signs or symptoms postimmunization and present for treatment immediately.