SDC1 and chronic endometritis: Endometrial CD138+ plasma cells have been used as a diagnostic biomarker for endometrial inflammatory conditions, including chronic endometritis (CE),6, 7, 8 and the number of CD138+ plasma cells is correlated with the severity of endometrial inflammation in women with reproductive failure.7, 8, 9 Detecting isolated CD138+ plasma cell aggregates without other histological features of CE, such as stromal edema and increased stromal cell density, may also identify cases with potentially milder inflammation and related endometrial dysfunction.10