Multiple Myeloma 1 Transcription Factor Is Superior to CD138 as a Marker of Plasma Cells in Endometrium

Abstract

Chronic endometritis is characterized by plasma cell (PC) infiltration of endometrial stroma. Identification of PCs can be challenging by routine hematoxylin and eosin (H&E) stain due to the low numbers of PCs or to their being obscured by other cells in the stroma. CD138 is widely used as an ancillary immunohistochemistry stain to identify PCs; however, it has a high background reaction. In this study, multiple myeloma 1 (MUM1) transcription factor is introduced as an alternative PC marker in endometrial tissues. In this study, 311 endometrial biopsies, submitted to rule out chronic endometritis, were selected. They were divided into Group I (n = 87) and Group II (n = 224). Both had MUM1 and H&E while Group I also had accompanying CD138 stains. In both groups combined, MUM1 detected plasma cells in 48% of the cases, while CD138 and H&E identified the cells in 23% and 15% of the biopsies, respectively. In addition to having a clean background, MUM1 is a more sensitive stain than CD138 for detection of PCs in endometrium.

MUM-1 immunohistochemistry has high accuracy and reliability in the diagnosis of chronic endometritis: a multi-centre comparative study with CD-138 immunostaining

“…These important results deserve consideration concerning the peculiar characteristics of the techniques under comparison. As previously mentioned, CD-138 antigen is constitutively expressed not only by plasma cells, but also by the epithelial cells of the endometrial glandular surface [18,22]. Therefore, epithelial cells can appear as marked elements in the endometrial staining with anti-CD-138 monoclonal antibodies, generating a focal or diffuse background reaction.…”

“…Identification of plasma cells by conventional tissue staining alone is difficult. Plasmacytes typically have a large cell body, high nuclei/cytoplasm ratio, basophilic cytoplasm and nuclei with heterochromatin rearrangement referred to as "spoke-wheel" or "clock-face" pattern [18]. These morphological features of plasmacytes are not always evident under microscopic examination, as plasma cells often exhibit an appearance similar to stromal fibroblasts and mononuclear leukocytes that reside in the human endometrium [15].…”

“…Although CD-138 immunostaining is validated for CE diagnosis, it should be used with caution. Other than plasmacytes, also endometrial epithelial cells constitutively express CD-138 on their plasma membrane, potentially leading to a false-positive diagnosis of CE [18,22]. Consequently, new insights on the staining techniques for plasma cells are warranted.…”

The role of endometrial B cells in normal endometrium and benign female reproductive pathologies: a systematic review

“…CE has been linked with adverse reproductive outcomes including RIF and RPL ( Huang et al , 2020 ). Our search retrieved one paper that focused on endometritis (acute and chronic) ( Disep et al , 2004 ) and seven papers focused solely on CE ( Toth et al , 2007 ; Kitaya and Yasuo, 2010a ; Kitaya et al , 2014 ; Liu et al , 2018 ; Parks et al , 2018 ; Cicinelli et al , 2019 ; Song et al , 2019 ). In the included papers, there was no agreed definition or test for the diagnosis of CE, and both hysteroscopic examination and histopathological assessment have been used.…”

“…In histopathological assessment, CE was confirmed by the presence of plasma cells, identified by markers, such as CD138 and multiple myeloma oncogene 1 (MUM1), or morphological assessment after standard histological staining with hematoxylin phloxine saffron stain (HPS) or hematoxylin and eosin (H&E) ( Table IV ). Using different diagnostic methods to identify B cells, plasma cells or Igs, the reported prevalence of CE varied in the same cohort ( Toth et al , 2007 ; Liu et al , 2018 ; Parks et al , 2018 ; Cicinelli et al , 2019 ; Song et al , 2019 ; Zargar et al , 2020 ).…”