High prevalence of autoimmune diseases in women with endometriosis: a case-control study

The immune system seems to be involved in the pathogenesis of endometriosis. Peritoneal chronic inflammation is present and natural killer cells and macrophages abnormalities have been reported in women with the disease. Moreover, a higher production of serum autoantibodies has been found, which could be related to various factors; some still need to be clarified. The correlation between endometriosis and autoimmune diseases is still unclear with few and conflicting available data. The aim of this study was to evaluate the prevalence of autoimmune diseases, as conditions with a possible common pathogenetic factor, in women affected by endometriosis, in order to address future research on its pathogenesis. This retrospective case-control study includes one hundred and forty-eight women with endometriosis and 150 controls. All women were aged between 18 and 45. Informed consent was obtained from all participants of the study. Considered autoimmune diseases include systemic lupus erythematosus (SLE), celiac disease (CD), inflammatory bowel disease (IBD), and autoimmune thyroiditis. Statistical comparison of patients and control group was performed by means of chi-square test or Fisher's exact test as appropriate. Statistical comparison of parametric variable (age) among the groups was performed by t-test for unpaired data. Age was expressed as mean. A value of .05 or less was considered as significant. In the case group, five patients were affected by IBD, while the disease was not observed in the control group (p = .07). SLE was found in eight patients in the case group, while only one was found in the control group (p = .01). Fifteen women in the case group were affected by CD, while the disease was present only in one woman in the control group (p<.0001). A significant correlation was also found between endometriosis and autoimmune thyroiditis: 80 patients with endometriosis had thyroid diseases versus 14 patients in the control group (p<.0001). Our study reports an association between endometriosis and autoimmune disorders, showing a higher prevalence of autoimmune diseases in women affected by endometriosis. These results support a possible autoimmune pathogenesis of endometriosis.