A 47-year-old man with a history of multiple corneal allografts for recurrent herpes simplex keratitis developed a subtotal nonhealing corneal epithelial defect. The patient was treated with hourly drops of autologous serum. A ringlike infiltrate was subsequently observed, followed by reepithelialization of the graft. The patient later suffered allograft rejection of the cornea and recurrence of the epithelial defect, and a repeated penetrating keratoplasty was performed. Examination of the excised button demonstrated a total epithelial defect, changes compatible with allograft rejection, and, in addition, eosinophilic granular deposits within the superficial corneal stroma that corresponded to the "immune ring" observed clinically. Immunoperoxidase staining was positive for IgG, IgM, IgA, and kappa and lambda light chains. These pathologic changes lend credence to the hypothesis that the precorneal tear film may be a source of immunoglobulin that becomes deposited within the stroma.