Abstract: Immunological pathogenesis is one of the important mechanisms of endometriosis. Recently，studies show that the over-expressed high mobility group box 1 protein （HMGB1） plays some roles in the development of endometriosis by regulating inflammation，neoangiogenesis，invasiveness，migration and apoptosis of ectopic endometrium. Regulatory T cells （Treg cells） are also closely related to endometriosis. Abnormal amount and dysfunction of Treg cells in endometriosis lead to an imbalanced immunological microenvironment （including immuno-deficiency and immune-escape），promoting the implantation and growth of ectopic endometrium. Growing studies suggest that HMGB1 plays an important role in immunological pathogenesis of endometriosis by enhancing the secretion of Treg cells，reducing apoptosis of Treg cells and strengthening the immunosuppression of Treg cells.

Key words: HMGB1 protein, T-Lymphocytes, regulatory, Endometriosis