Impact of HLA-G in the outcome of vitiligo in Tunisian patients

The human leukocyte antigen (HLA) system in the skin coordinates the pigmentation and immune response and could be implicated in the pathogenesis of vitiligo. Human leukocyte antigen HLA-G is a nonclassic, major histocompatibility complex class I molecule expressed in the extravillous cytotrophoblast at the feto-maternal interface. It is known to protect the fetus from maternal cellular immunity. Analogically, it could be implicated in the pathogenesis of autoimmune diseases such as vitiligo. To compare the expression of HLA-G between vitiligo patients and healthy controls. In the present study, 22 vitiligo patients and 24 healthy controls were investigated to look for a possible correlation between HLA-G expression and this pathology. Expression of HLA-G in cutaneous biopsy specimens was investigated by immunohistochemical analysis. HLA-G was detected in the biopsy specimens of 3 (13%) out of 22 patients. This number was significantly higher in healthy controls 18 (75%) out of 24 as compared to vitiligo patients (P < 0.001). There is significant negative correlation between HLA-G expression and vitiligo. In our mind, upregulation of HLA-G expression in lesional skin could be local (superficial expression) or systemic (soluble HLA-G isoforms) compensation to restore normal pigmentation in lesions.