OBJECTIVETo investigate the expression of cytokeratins (CK) in the normal human gingival epithelium and to explore the difference between junctional epithelium (JE), oral epithelium (OE) and sulcular epithelium (SE).

METHODSTeeth specimens with gingival tissue were collected from 5 people. Paraffin-embedded sections were stained with monoclonal antibodies responded respectively to human CK5/6, 7, 8/18, 10/13, 16, 17, 19, 20.

RESULTSCK7 and 17 was not expressed in all strata of JE, OE and SE. CK5/6 and 20 were weekly or moderately expressed in the suprabasal, and not expressed in the basal layer of all three epithelia. CK10/13 and 16 were positive in all strata of JE and in the suprabasal layers of OE and SE. CK10/13 was moderately to strongly expressed and CK16 was weekly to moderately expressed. The staining for CK19 was intense in all strata of JE and the basal layer of OE and SE. There was a remarkable demarcation between JE and SE. The pattern of CK8/18 expression was similar to that of CK19, but was weaker. Besides the basal layer, some suprabasal layers close to the basal layer were stained.

CONCLUSIONSJE is an unique non-differentiated stratified epithelium different from OE and SE. CK19 would be a histological marker and CK10/13, 16 would be the cellular markers to differentiate JE from OE and SE.