Changes in distribution pattern of CD8 lymphocytes in the scalp in alopecia areata during treatment with diphencyprone

For many years, the role of T lymphocytes was hypothesized as being a major factor responsible for hair loss in alopecia areata (a.a.). While numerous lymphocytic populations were found around hair bulbs, changes in their distribution patterns in the skin during the course and recovery of the disease remain unknown. In the present study, distribution of CD8 lymphocytes in biopsies obtained from a.a. patients was measured before and during treatment using diphencyprone (DCP). Results show about a 600% increase in the number of CD8 lymphocytes under the epithelium and about a 250% increase around hair bulbs and other epidermal appendages during the study. These results were more significant in a group, which had good clinical response to the treatment. No change in the quantity of CD8 lymphocytes was observed around the blood vessels. Since CD8 lymphocytes are considered to be directly involved in the hair destruction process in a.a., their increased number around hair bulbs followed by hair regrowth may suggest that during DCP treatment they regain normal reactivity to hair antigens.