Expression of filaggrin in normal and keratinized conjunctiva.

Purpose: We wanted to investigate filaggrin expression in normal conjunctiva and in conjunctiva exposed to different degrees of mechanical stress. Mechanical stress results in parakeratinization of the conjunctiva. If filaggrin is expressed in the milder forms of parakeratinization, it might be used as a sensitive marker of mechanical stress.

Methods: Immunohistochemical staining using antibodies to filaggrin was performed on paraffin sections of normal human conjunctiva, and on conjunctiva with different degrees of mechanical conjunctival stress.

Results: Filaggrin was not expressed in the normal conjunctiva, nor in conjunctiva with milder forms of mechanical stress. Intense staining of filaggrin was seen in the conjunctiva of a patient with Stevens-Johnson syndrome, and marked expression of filaggrin was found in the conjunctival epithelium of a patient with moderate dysplasia of the conjunctiva.

Conclusion: Filaggrin is not a sensitive marker of mechanical stress; it is, however, expressed in some moderate and severe forms of parakeratinization of the conjunctiva.