Autoantibodies to markers of oxidative stress are elevated in women with endometriosis

OBJECTIVE: To measure autoantibodies that recognize oxidatively modified proteins in the sera of women with surgically proven endometriosis. DESIGN: Prospective study. SETTING: Tertiary care academic medical center. PATIENT(S): Women undergoing surgery for endometriosis or tubal ligation. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Serum and peritoneal fluid autoantibody titers to malondialdehyde-modified low-density lipoprotein, oxidized low-density lipoprotein, and lipid peroxide-modified rabbit serum albumin determined by ELISA. Correlation of autoantibody titers with revised American Fertility Society staging classification, symptoms, and morphologic type of endometriosis. RESULT(S): Mean (+/-SEM) serum autoantibody titers (in optical density units) to the three antigens were as follows: [1] lipid peroxide-modified rabbit serum albumin, 0.49 +/- 0.12 units in the patients with endometriosis and 0.2 +/- 0.02 units in the controls; [2] oxidized low-density lipoprotein, 0.22 +/- 0.005 units in the patients with endometriosis and 0.18 +/- 0.006 units in the controls; and [3] malondialdehyde-modified low-density lipoprotein, 0.21 +/- 0.005 units in the patients with endometriosis and 0.16 +/- 0.003 units in the controls. There was no correlation between autoantibody titers and revised American Fertility Society stage, symptoms, or morphologic type of endometriosis. Peritoneal fluid did not contain autoantibodies to any of the three antigens. CONCLUSION(S): Autoantibodies to markers of oxidative stress were significantly increased in women with endometriosis. These findings strongly support our data demonstrating that women with endometriosis have enhanced oxidative stress.