Comprehensive endometrial immunoglobulin subclass analysis in infertile women suffering from repeated implantation failure with or without chronic endometritis.

PROBLEM: Chronic endometritis (CE) is a local inflammatory condition with unusual plasmacyte infiltration in the endometrial stromal area. CE is frequently found in infertile women with repeated implantation failure (RIF). In this study, we comprehensively investigated the endometrial immunoglobulin (Ig) subclass expression in infertile women suffering from RIF with versus without CE.

METHOD OF STUDY: Endometrial biopsy specimens obtained from 28 infertile women with RIF and CE (the RIF-CE group), 23 infertile women with RIF but without CE (the RIF-non-CE group), and 22 proven fertile women undergoing hysterectomy for benign endometrial pathology (the control group) were immunostained for Ig subclass expression.

RESULTS: The density of IgM+, IgA1+, IgA2+, IgG1+, and IgG2+ stromal cells were significantly higher in the RIF-CE group than that in the RIF-non-CE and control group. The density of IgG2+ stromal cells was significantly higher than that of any other Ig subclass-positive cells (P<0.045) in the RIF-CE group. In serial section staining, the immunoreactivity for CD138 and Ig subclasses in the endometrial stroma was detectable in adjacent cells of some specimens in the RIF-CE group.

CONCLUSIONS: The endometrium of infertile women with RIF-CE was characterized by increase in IgM, IgA, and IgG expression and predominance of IgG2 over other Ig subclasses.