Regulatory T-Cells in Alopecia Areata: New Evidence
Jodi Speiser, Kumaran Mudaliar, Vikas Mehta, Sheela Gorordo, Roger Heyna, Ameet Kini, Kelli Hutchens. Loyola University Medical Center, Maywood, IL
Background: Alopecia areata (AA) is believed to have an autoimmune mechanism in which the hair follicles are targeted by CD4+ and CD8+ lymphocytes. It has been proposed that the pathogenesis of AA shares similar pathogenesis with other autoimmune cutaneous diseases, such as vitiligo. Studies investigating the autoimmune mechanism of vitiligo have demonstrated that regulatory T-cells (Tregs) are a key component in cutaneous immune privilege. Almost all studies examining Tregs and AA have been performed in mouse models. Our study compares the quantity of the CD25+/FoxP3+ Tregs in AA to the quantity of regulatory T-cells in folliculitis arising in non-autoimmune non-scarring alopecias in human specimens.
Design: A retrospective review of our electronic pathology database was performed to identify all cases of AA diagnosed by scalp biopsy (January 2002 through May 2011), and reviewed to confirm the original diagnosis. Additionally, 2 cases of folliculitis arising in non-autoimmune non-scarring alopecias were included for comparison. In the 9 cases of confirmed alopecia areata and 2 cases of folliculitis, immunohistochemical double staining for CD3/FoxP3, CD8/FoxP3 and CD25/FoxP3 were evaluated. Specifically, the number of CD25+/FoxP3+ cells was determined for each case by counting the total number of CD25+/FoxP3+ cells in 3 randomly chosen areas of peri-follicular inflammation at 40X. The CD3/FoxP3 stains were used to confirm the presence of T-cells and the CD8/FoxP3 stains were used to rule out CD8+/CD25+/FoxP3+ regulatory T-cells.
Results: Of the 9 AA cases and 2 folliculitis cases examined, 100% (11/11) demonstrated some degree of CD25+/FoxP3+ expression. The mean number of CD25+/FoxP3+ cells in the AA specimens was 2.9 cells (range 2 – 4 cells) and was significantly lower [p=0.0001 (two-tailed unpaired t test)] than the mean number of cells in the folliculitis cases (8.5 cells; range 8 – 9 cells). The CD3/FoxP3 stain demonstrated that the majority of peri-follicular inflammatory cells were CD3+, all FoxP3 positive cells coexpressed CD3, and rare scattered cells were CD3-. The CD8/FoxP3 stain demonstrated no cells that simultaneously stained for CD8 and FoxP3.
Conclusions: This study demonstrated that there is a significant decrease in CD25+/FoxP3+ Tregs in AA when compared to folliculitis arising within non-autoimmune non-scarring alopecias. These findings are similar to results from studies investigating Tregs in vitiligo. However, they are in contrast to published literature on AA in mouse models. Further studies in human subjects need to be examined in order to characterize the role of CD25+FoxP3+ Tregs in AA.
Monday, March 19, 2012 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 85, Monday Morning