TGF-beta2, tenascin, and integrin beta1 expression in superior limbic keratoconjunctivitis.

PURPOSE: To determine the pathophysiological etiology of superior limbic keratoconjunctivitis (SLK), we compared the superior limbic conjunctivae of SLK patients and normal controls.

METHODS: Frozen sections of conjunctival specimens from five SLK patients and two controls were examined by immunohistochemical methods. Transforming growth factor (TGF)-beta2, integrin beta1, and tenascin (TN) were chosen for analysis because their expression is known to be affected by mechanical stress or injury. The staining pattern was observed by confocal laser scanning microscopy.

RESULTS: Prominent positive TGF-beta2 staining on the surface region and heterogeneous staining in the suprabasal region were observed in the SLK specimens. TN expression was markedly up-regulated in the subepithelial stroma. In addition, suprabasal expression of integrin beta1 was observed.

CONCLUSIONS: Up-regulation of TGF-beta2 and TN suggested that an increased amount of mechanical stress existed in the conjunctivae of the SLK patients. In addition, deposition of TN and suprabasal expression of integrin beta1 suggested that chronic minor injury contributed to the pathogenesis of SLK.