A study of Langerhans cells in lupus erythematosus, lichens [sic] planus, leprosy and mycosis fungoides in Singapore

Langerhans cells were studied on 184 cases of four major skin diseases - lupus erythematosus, lichen planus, leprosy, mycosis fungoides, and 44 skin biopsies from cadaver. In addition, T cell phenotyping and antibody tracing in tissues were performed on 20 cases of lupus erythematosus and 10 cases of uninvolved normal skin as controls. Antibody serology was also investigated on 120 leprosy cases and 16 cutaneous erythematosus cases. Electron microscopy was used to examine the lesions in lepromatous leprosy and mycosis fungoides. Langerhans cells were elevated in number per mm. epidermal length in lichen planus, leprosy, and mycosis fungoides. In lupus erythematosus, LC distribution in the epidermis was elevated in the chronic stage, while in the acute stage LC numbers were decreased. In the dermis of these four skin conditions, LC were observed especially in the dermal infiltrates. In the control skin, it was found that there was no difference in LC number per mm. epidermal length in Chinese, Malays and Indians. Sunlight showed an adverse effect on LC distribution in the epidermis of control skin. The difference between tanned skin and untanned skin was statistically significant. It was also observed that in control skin, there was a correlation between LC distribution and increasing age but such correlation was absent in the diseased skin. The findings in this study provide information on the role of LC in diseased skin in the Singapore population. Further study is required to link the distribution of LC in the skin with T cell phenotype, lymphocyte function, serology and HLA markers. This might provide a greater understanding of lupus erythematosus, lichen planus, leprosy and mycosis fungoides.