Regulatory T-cells in alopecia areata.

BACKGROUND

Alopecia areata (AA) is believed to have an autoimmune mechanism in which the hair follicles are targeted by CD4+ and CD8+ lymphocytes. Studies investigating the autoimmune mechanism of other cutaneous diseases, including vitiligo, showed that T is a component of cutaneous immune privilege. Our study uses immunohistochemical staining in formalin-fixed, paraffin-embedded tissue to examine the percentage of CD4 FoxP3 , CD25 FoxP3 , and CD8 FoxP3 T in AA in human specimens.

METHODS

Immunohistochemical double staining for CD4 FoxP3 , CD25 FoxP3 , and CD8 FoxP3 was performed on 12 AA cases and 12 other autoimmune and non-autoimmune cutaneous diseases. The frequency of CD4 FoxP3 , CD25 FoxP3 , and CD8  FoxP3 T was counted and expressed as a percentage of total CD4 , CD25 , and CD8 lymphocytes, respectively, in order to account for intersample inflammatory response variability.

RESULTS

There was a significant reduction in the mean frequency of CD4  FoxP3 and CD25  FoxP3 in AA when compared to other autoimmune and non-autoimmune cutaneous diseases.

CONCLUSION

T is significantly lower in AA when compared to other cutaneous diseases. Additionally, this immunohistochemical-staining protocol may be useful to evaluate T in formalin-fixed, paraffin-embedded specimens for other cutaneous diseases. Studies examining T in AA and other cutaneous diseases may have implications for future interventions.