Objective: To study the possibility of a correlation between polymorphism of human leukocyte antigen (HLA)-I antigen and occurrence of endometriosis (Em).
Methods: Polymorphism of HLA-I A and B locations were detected by mini-lymphocytotoxin test in 40 surgically proven Em patients and 50 normal controls. The frequency of different antigens on both A and B sites were compared between the 2 groups.
Results: No significant difference of the antigen frequency at HLA-I A site was shown between Em and control groups. However, at HLA-I B site, frequency of B46 antigen in Em group was significantly higher [33% Vs 16%, P < 0.05, relative risk (RR) 2.5278] and frequency of B48 antigen in Em group was significantly lower (3% Vs 16% P < 0.05, RR 0.1346) as compared with those of the controls.
Conclusions: The occurrence of Em may be associated with the presence of HLA-I B46 antigen. On the contrary, the HLA-I B48 antigen might play a protective role against Em.