Transfer of CD8+ Cells Induces Localized Hair Loss Whereas CD4+/CD25− Cells Promote Systemic Alopecia Areata and CD4+/CD25+ Cells Blockade Disease Onset in the C3H/HeJ Mouse Model

Alopecia areata (AA) is a suspected hair follicle specific autoimmune disease. The potential for cell transfer of AA using the C3H/HeJ mouse model was examined. Cells isolated from lymph nodes and spleens of AA-affected mice using magnetic bead conjugated monoclonal antibodies were subcutaneously injected into normal C3H/HeJ recipients. Within 5 wk, all CD8+ cell-injected mice exhibited localized hair loss exclusively at the site of injection that persisted until necropsy. In contrast, some CD4+ and CD4+/CD25− cell-injected mice developed extensive, systemic AA, and a combination of CD8+ and CD4+/CD25− cells injected yielded the highest frequency of systemic AA induction. CD4+/CD25+ cells were less able to transfer the disease phenotype, partially blockaded systemic AA induction by CD4+/CD25− cells, and prevented CD8+ cell-induced, injection site-localized hair loss. CD11c+ and CD19+ cells failed to promote significant phenotype changes. Increases in co-stimulatory ligands CD40 and CD80, plus increased leukocyte apoptosis resistance with reduced CD95, CD95L, and CD120b expression, were associated with successful alopecia induction. The results suggest that CD8+ cells may be the primary instigators of the hair loss phenotype. However, systemic disease expression fate is, apparently determined by CD4+/CD25− cells, while CD4+/CD25+ lymphocytes may play a predominantly regulatory role.