ANTIFOLLICULAR CELL-MEDIATED AND HUMORAL IMMUNITY IN CANINE ALOPECIA-AREATA

A combination of cellular and humoral immunological assaults directed against follicular matrical cells is suspected to cause alopecia areat a (AA) in humans. The specific aims of this study were to determine wh ether cytotoxic T lymphocytes (CTL) were increased in the blood and sk in lesions of canine AA. Additionally, we wished to determine if circu lating antifollicular antibodies were present in the dog. Finally, we aimed to investigate whether bulbar inflammation was associated with d ecreased matrical cell proliferation and keratinocyte apoptosis. Canin e AA lesions were infiltrated by intrabulbar CTL, perifollicular helpe r T cells and dendritic cells. A higher percentage of CTL was present in canine AA peripheral blood compared with that of normal dogs. Tissu e-fixed and circulating antifollicular IgG antibodies were detected. R educed matrical proliferation and increased keratinocyte apoptosis was observed in inflamed hair bulbs. This study demonstrates the existenc e of antifollicular cell-mediated and humoral immunological responses in canine AA.