P7.82 Phylogenetic Tissue Arrays for Comparison of Alopecia Areata Between Species

J.P. Sundberg,^1,6 Jim Miller,¹ Kevin McElwee,² Thierry Olivry,³ Robert Dunstan,⁴ Thelma Lee Gross,⁵ Sarah Whitehead,⁶ David Whiting,⁷ Margaret Hogan,⁸ and Lloyd E. King⁶

¹The Jackson Laboratory, Bar Harbor, ME, USA; ²Phillip University, Marburg, Germany; ³NC State University, Raleigh, NC, USA; ⁴Texas A&M University, College Station, TX, USA; ⁵Idexx, West Sacramento, CA, USA; ⁶Vanderbilt University, Nashville, TN, USA, ⁷Baylor Hair Research and Treatment Center, Dallas, TX, USA; and ⁸BD Biosciences Pharmingen, San Diego, CA, USA

Objectives: Our goal was to collect biopsy materials from several species that develop an alopecia areata-like (AA) disease for histologic and immunohistochemical comparisons.

Methods: Paraffin blocks were obtained from confirmed diagnostic cases of alopecia areata in mice (spontaneous or graft initiated models), DEBR rats, dogs, horses, and humans. We used 49, 1.5 mm cores from donor blocks organized into a recipient block, re-melted, serially sectioned, and then stained with hematoxylin and eosin or numerous antibodies using immunohistochemistry.

Results: Each block represented a different species or experimental model. Three or more blocks were produced per species. Terminal differentiation proteins, commonly used in dermatology evaluations (K1, K5, K6, K10, K14, K15, K17, loricrin, filaggrin, involucrin, etc.) had similar patterns between species. Not all antibodies worked in all species. Changes in expression patterns corresponded to epidermal and root sheath hyperplasia secondary to trauma (skin graft).

Conclusions: Tissue arrays are a useful tool for comparing numerous biopsies simultaneously for similarities and differences. When cases representing similar diseases in other species are included, the potential value of each species as a model for specific subtypes of human alopecia areata becomes apparent.