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.