Distribution patterns of the OKM 5 antigen in normal and diseased human epidermis

The distribution of OKM 5-positive dendritic cells in the epidermis was investigated in 75 cases of inflammatory dermatoses and in 14 cases of normal human skin by immunohistochemical and morphometric methods. Furthermore 6 cases of normal human skin, 14 cases of nevocellular nevi, 26 cases of malignant melanoma, 7 cases of contact dermatitis and 6 cases of mycosis fungoides have been examined with special emphasis on the expression of OKM 5 antigen on keratinocytes. OKM 5-positive dendritic cells were present in normal human epidermis at a density of 46 +/- 3.4 cells/mm2 section area. However, there was a significant increase in cutaneous drug eruptions (166 +/- 17.2 cells/mm2; U-test: p less than or equal to 0.05). Concerning OKM 5-positive keratinocytes, a mean percentage of 10.2% +/- 5.0% OKM 5-positive keratinocytes was found in nevocellular nevi, compared to 0.5% +/- 0.5% in the adjacent skin. The corresponding values for malignant melanomas were 52.5% +/- 3.4% (lesional epidermis) and 7.1% +/- 2.2% (adjacent epidermis). There were significant differences of both lesional and adjacent epidermis between nevi and melanomas (U-test: p less than or equal to 0.05). Our cases of contact dermatitis revealed a mean percentage of 19.3% +/- 6.7% OKM 5-positive keratinocytes, whereas in mycosis fungoides the corresponding value represents 42.7% +/- 6.2%. The differences between the percentage of OKM 5-positive keratinocytes in normal epidermis and contact dermatitis as well as mycosis fungoides were significant (U-test).(ABSTRACT TRUNCATED AT 250 WORDS)