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Distribution of Langerhans cells in human hair follicle
1Department of Dermatology, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, USA.
Insights
Langerhans cells (LCs) concentrate in the upper hair follicle, specifically the infundibulum and sebaceous gland areas. This distribution suggests LCs may play a role in inflammatory skin conditions affecting the hair follicle.
Area of Science:
- Dermatology
- Immunohistochemistry
- Skin Biology
Background:
- Langerhans cells (LCs) are key immune cells in the epidermis.
- Their precise distribution within the human hair follicle is not fully understood.
- Understanding LC localization is crucial for inflammatory skin disease research.
Purpose of the Study:
- To map and quantify the distribution of Langerhans cells (LCs) within the normal human follicular epithelium.
- To correlate LC distribution with patterns of follicular inflammation in specific skin diseases.
Main Methods:
- Immunohistochemical staining using CD1a antibody on serial horizontal sections of human skin biopsies.
- Quantitative analysis of Langerhans cell counts in different follicular compartments.
Main Results:
- LCs were highly concentrated in the infundibular epithelium and follicular bulge (mean 16.16 cells).
- LCs extended into the germinative sebaceous epithelium (mean 8.84 cells).
- Rare LCs were found below the sebaceous gland entry, and none in the bulbar epithelium.
Conclusions:
- The infundibulocentric distribution of LCs in normal skin mirrors inflammatory patterns in conditions like lupus erythematosus and lichen planopilaris.
- Follicular LCs may be involved in initiating or being targeted by T cell-mediated inflammatory processes in the hair follicle.
Abstract:
Using immunohistochemical techniques, we mapped and quantified the distribution of Langerhans cells (LCs) within the follicular epithelium of normal human skin in serial horizontal sections. Ten skin biopsies from disparate, disease-free sites from individuals of various skin types were stained with antibody to CD1a. LCs concentrated in the infundibular epithelium (x=16.16 cells), including the follicular bulge, and extended into the germinative sebaceous epithelium (x=8.84). In contrast, rare LCs (x=1.06) were observed in the follicular epithelium below the entry of sebaceous glands into the follicle. LCs were absent in bulbar epithelium. This infundibulocentric distribution of LCs corresponds to the pattern of follicular inflammation in the scarring folliculitides of lupus erythematosus and lichen planopilaris, as well as allogeneic graft versus host reaction and infundibulofolliculitis of atopy. Follicular LCs may act as the trigger and/or target for these T cell-mediated inflammatory processes.