Tumour
necrosis factor alpha (
TNFalpha), a proapoptotic
cytokine, is known to be present in peritoneal fluid from women with
endometriosis. An emerging view is that soluble
TNF receptors (sTNFR) can modulate the effects of
TNFalpha by acting as
TNFalpha antagonists. To assess the relevance of sTNFRs in the pathophysiology of
endometriosis, concentrations of sTNFR I, sTNFR II and
TNFalpha in peritoneal fluid from women with
endometriosis (n = 53) and without
endometriosis (n = 40) were measured. Concentrations of both sTNFR I and sTNFR II in peritoneal fluid from women with
endometriosis were significantly higher than in peritoneal fluid from women without
endometriosis, both in the follicular and the luteal phases.
TNFalpha concentrations did not differ in patients with and without
endometriosis in both phases. When stratified by the stage of the disease, women with both stages I/II and stages III/IV exhibited significantly higher concentrations of sTNFR I and sTNFR II in peritoneal fluid, compared with women without
endometriosis, whereas no appreciable difference in the concentrations was detected between stages I/II and stages III/IV. A significant correlation was found between the concentrations of sTNFR I and sTNFR II; while the correlations between
TNFalpha and sTNFR I or sTNFR II, were either not significant or were very weak. Furthermore,
mRNA for the membrane-associated
TNF receptor type 1 and
TNF receptor type 2, both of which convey the effects of
TNFalpha, were shown to be expressed in endometriotic tissues as well as eutopic endometrium. Together, these findings suggest a possible involvement of sTNFRs in the pathophysiology of
endometriosis.