Abstract:

Objective To analyze the distribution and density of Langerhans cells and dermal CD68 positive histiocytes in lesions of secondary keloid. Methods Tissue specimens were resected from the lesions of 30 patients with secondary keloid and normal skin of 14 human controls. Immunohistochemistry was performed to observe the expressions of CD68 and CD1a in these specimens. A micrometer was used to count the number of positively stained cells per unit area. The Student's t test was conducted for data analysis by using the SPSS software. Results The density of CD1a+ Langerhans cells was （61 ± 49） cells/mm2 in the epidermis of secondary keloid lesions, （258 ± 61） cells/mm2 in the control epidermis, and （40 ± 65） cells/mm2 in the dermis of keloid lesions. CD68+ cells were absent in the epidermis of keloid lesions. Significant differences were observed in the density of CD1a+ Langerhans cells between the lesional and normal control epidermis （t = 9.88, P < 0.001） and in the percentage of CD68+ cells in nucleated cells between the superficial dermis of lesions and control skin （62% ± 12% vs. 70% ± 14%, t = 2.66, P < 0.05）. The density of dermal CD68+ histiocytes was similar between the lesions and control skin （（287 ± 73） cells/mm2 vs. （290 ± 22） cells/mm2, t = 0.02, P > 0.05）. Conclusions In keloid lesions, Langerhans cells decrease in the epidermis but increase in the dermis, CD68+ histiocytes are absent in the epidermis, and reduced in the dermis with a declined percentage in nucleated cells.

Key words: macrophages